WorldWideScience

Sample records for neutron interrogation laboratory

  1. Survey of Neutron Generators for Active Interrogation

    Energy Technology Data Exchange (ETDEWEB)

    Moss, Calvin Elroy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Myers, William L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sundby, Gary M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chichester, David L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Johnson, James P. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-05-02

    Some of these commercially available generators meet all of the requirements in Table 1, but there are other concerns. Most generators containing SF6 will be required to have the SF6 gas removed for shipping because of DOT regulations. However, Thermo Fisher has a DOT exemption. The P211 and B211 from Thermo Fisher meet the requirements listed in Table 1, but they are old designs and are no longer offered for sale. Also, they require 15 minutes or more of warmup before neutron output is available, and they lack a modern digital control. The nGen-300C from Starfire Industries is interesting because it is a portable system, but it uses the DD reaction for 2.5 MeV neutrons, which are not as penetrating as the 14 MeV neutrons from the DT reaction. The MP 320 from Thermo Fisher is another portable system, but the minimum pulse rate is 250 Hz, which is too fast for measurement of delayed neutrons and re-interrogation by delayed neutrons between pulses. The Genie 16 from Sodern (from France) probably meets the requirements, but the required power is probably too high for battery operation. The generators from Russia and China may be difficult to purchase, and service may not be available. The power required by some of these generators is low enough that batteries can be used. The portable units, nGen-300C and the MP320, could easily be operated with batteries. Other generators with low power requirements, as specified in the above vendors list, could possibly be operated with reason size batteries. The batteries do not need to be internal to the generator, but can be in a separate package. The availability of high capacity lithium batteries with sophisticated safety circuits makes battery operation more possible now than when lead acid batteries were used. The best path forward probably requires working with vendors of the existing systems. If Starfire Industries could be persuaded to put tritium in their nGen-300C generator, possibly in collaboration with a national

  2. Improved Fission Neutron Data Base for Active Interrogation of Actinides

    Energy Technology Data Exchange (ETDEWEB)

    Pozzi, Sara; Czirr, J. Bart; Haight, Robert; Kovash, Michael; Tsvetkov, Pavel

    2013-11-06

    This project will develop an innovative neutron detection system for active interrogation measurements. Many active interrogation methods to detect fissionable material are based on the detection of neutrons from fission induced by fast neutrons or high-energy gamma rays. The energy spectrum of the fission neutrons provides data to identify the fissionable isotopes and materials such as shielding between the fissionable material and the detector. The proposed path for the project is as follows. First, the team will develop new neutron detection systems and algorithms by Monte Carlo simulations and bench-top experiments. Next, They will characterize and calibrate detection systems both with monoenergetic and white neutron sources. Finally, high-fidelity measurements of neutron emission from fissions induced by fast neutrons will be performed. Several existing fission chambers containing U-235, Pu-239, U-238, or Th-232 will be used to measure the neutron-induced fission neutron emission spectra. The challenge for making confident measurements is the detection of neutrons in the energy ranges of 0.01 – 1 MeV and above 8 MeV, regions where the basic data on the neutron energy spectrum emitted from fission is least well known. In addition, improvements in the specificity of neutron detectors are required throughout the complete energy range: they must be able to clearly distinguish neutrons from other radiations, in particular gamma rays and cosmic rays. The team believes that all of these challenges can be addressed successfully with emerging technologies under development by this collaboration. In particular, the collaboration will address the area of fission neutron emission spectra for isotopes of interest in the advanced fuel cycle initiative (AFCI).

  3. Design and characterisation of a pulsed neutron interrogation facility

    International Nuclear Information System (INIS)

    Favalli, A.; Pedersen, B.

    2007-01-01

    The Joint Research Centre recently obtained a license to operate a new experimental device intended for research in the field of nuclear safeguards. The research projects currently being planned for the new device includes mass determination of fissile materials in matrices and detection of contraband non-nuclear materials. The device incorporates a commercial pulsed neutron generator and a large graphite mantle surrounding the sample cavity. In this configuration, a relatively high thermal neutron flux with a long lifetime is achieved inside the sample cavity. By pulsing the neutron generator, a sample may be interrogated by a pure thermal neutron flux during repeated time periods. The paper reports on the design of the new device and the pulsed fast and thermal neutron source. The thermal neutron flux caused by the neutron generator and the graphite structure has been characterised by foil activation, fission chamber and 3 He proportional counter measurements. (authors)

  4. Active Interrogation of Sensitive Nuclear Material Using Laser Driven Neutron Beams

    Energy Technology Data Exchange (ETDEWEB)

    Favalli, Andrea [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Roth, Markus [Technische Universitaet, Darmstadt (Germany)

    2015-05-01

    An investigation of the viability of a laser-driven neutron source for active interrogation is reported. The need is for a fast, movable, operationally safe neutron source which is energy tunable and has high-intensity, directional neutron production. Reasons for the choice of neutrons and lasers are set forth. Results from the interrogation of an enriched U sample are shown.

  5. Background and Source Term Identification in Active Neutron Interrogation Methods

    Science.gov (United States)

    2011-03-24

    background source terms during active neutron interrogation. Oxide Percent SiO2 60.6 Al2O3 15.9 CaO 6.4 MgO 4.7 Na2O 3.1 Fe 6.7 K2O 1.8 TiO2 0.7... P2O5 0.1 Table 5. Chemical Properties of Continental Crust Provides the average amount of each element present in the earth’s crust for

  6. Using Electronic Neutron Generators in Active Interrogation to Detect Shielded Fissionable Material

    Science.gov (United States)

    Chichester, David L.; Seabury, Edward H.

    2009-04-01

    Experiments have been performed at Idaho National Laboratory to study methodology and instrumentation for performing neutron active interrogation die-away analyses for the purpose of detecting shielded fissionable material. Here we report initial work using a portable DT electronic neutron generator with a 3He neutron detector to detect shielded fissionable material including enriched uranium and reactor grade plutonium. Measurements have been taken of bare material as well as of material hidden within a large plywood cube. Results from this work have demonstrated the efficacy of the die-away neutron measurement technique for quickly detecting the presence of special nuclear material hidden within plywood shields by analyzing the time dependent neutron signals in-between neutron generator pulses. Using a DT electronic neutron generator operating at 300 Hz with a yield of approximately 0.36 times 108 neutrons per second, 2.2 kg of enriched uranium hidden within a 61 cm times 61 cm times 71 cm volume of plywood was positively detected with a measurement signal 2-sigma above the passive background within 1 second. Similarly, for a 500 second measurement period a lower detection limit approaching the gram level could be expected with the same simple set-up.

  7. Neutron interrogation of actinides with a 17 MeV electron accelerator and first results from photon and neutron interrogation non-simultaneous measurements combination

    Energy Technology Data Exchange (ETDEWEB)

    Sari, A., E-mail: adrien.sari@cea.fr [CEA, LIST, Laboratoire Capteurs et Architectures Electroniques, 91191 Gif-sur-Yvette Cedex (France); Carrel, F.; Lainé, F. [CEA, LIST, Laboratoire Capteurs et Architectures Electroniques, 91191 Gif-sur-Yvette Cedex (France); Lyoussi, A. [CEA, DEN, 13108 Saint-Paul-Lez-Durance Cedex (France)

    2013-10-01

    In this article, we demonstrate the feasibility of neutron interrogation using the conversion target of a 17 MeV linear electron accelerator as a neutron generator. Signals from prompt neutrons, delayed neutrons, and delayed gamma-rays, emitted by both uranium and plutonium samples were analyzed. First results from photon and neutron interrogation non-simultaneous measurements combination are also reported in this paper. Feasibility of this technique is shown in the frame of the measurement of uranium enrichment. The latter was carried out by combining detection of prompt neutrons from thermal fission and delayed neutrons from photofission, and by combining delayed gamma-rays from thermal fission and delayed gamma-rays from photofission.

  8. Neutron stars as cosmic neutron matter laboratories

    International Nuclear Information System (INIS)

    Pines, D.

    1986-01-01

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

  9. The SVM Method for Fissile Mass Estimation through Passive Neutron Interrogation: Advances and Developments

    International Nuclear Information System (INIS)

    Dubi, C.; Shvili, Israel I.

    2014-01-01

    Fissile mass estimation through passive neutron interrogation is now one of the main techniques for NDT of fissile mass estimation, due to the relative transparency of neutron radiation to structural materials- making it extremely effective in poorly characterized or dirty samples . Passive neutron interrogation relies on the fact that the number of neutrons emitted (per time unit) due to spontaneous fissions from the sample is proportional to the mass of the detected sample. However, since the measurement is effected by additional neutron sources- mainly (D±n) reactions and induced fission chain in the tested sample, a naive estimation, assuming a linear correspondence between the mass of the detected sample and the average number of detections, is bound to give an over estimation of the mass. Since most passive interrogation facilities are based on 3He detectors, the origin of the neutron cannot be determined by analyzing the energy spectrum (as all neutrons arrive at the detector in more or less the same energy), and a mathematical 'filter' is used to evaluate the noise to source ratio in the detection signal. The basic idea behind the mathematical filter is to utilize the fact that the different neutron sources have different statistical attributes- in particular, both the source event rate and the distribution of the number of neutrons released in each event differs between the different sources. There for, by studying the higher moments of the neutron population, new information about the source to noise ration may be obtained

  10. Low level transuranic wastes assay by photon interrogation and neutron counting: application to the concrete packages

    International Nuclear Information System (INIS)

    Lyoussi, A.

    1994-03-01

    A comprehensive programme is currently in progress at several laboratories for the development of sensitive, practical and non destructive assay techniques for the quantification of low-level transuranics (TRU) in bulk solid wastes. The present document presents an active detection method for radioactive wastes embedded in high-density matrices, mainly concrete packages. The high density of the packages, as well as their high water content (up to 25%), means only high-energy neutrons or gamma particles have a high enough range to activate the enclosed actinides. Our aims were to evaluate the feasibility of dosing transuranians by induced photofission, and to optimize an experimental system with a view to improving detection limits. The system uses a pulsed electron beam from a linear accelerator (LINAC) to produce high-energy photon bursts from a metallic converter. The photons induce fissions in TRU. When a fission is induced in trace amounts of TRU contaminants in waste material, it provides ''signatures'' from fission products that can be used to assay the material before disposal. We give here the results from counting photofission-induced delayed neutrons from 239 Pu, 235 U and 238 U in three sample matrices: glass, polyethylene and concrete. We counted delayed neutrons emitted after each pulse of the LINAC using the ''Sequential PHoton Interrogation and Neutron Counting Signatures'' (SPHINCS) technique. The electron linear accelerator operates at 15 MeV, 140 mA and 2.5 μs wide pulse at a 50 Hz rate. Finally, use of an electron linear accelerator as a particle source, experimental and electronics details, measurements results and their interpretation and future experimental works are discussed. (author). 53 refs., 101 figs., 21 tabs

  11. Irradiation Effects for the Pulsed Fast Neutron Analysis (PFNA) Cargo Interrogation System

    Energy Technology Data Exchange (ETDEWEB)

    Slater, C.O.

    2001-02-02

    At the request of Safety and Ecology Corporation of Tennessee, radiation effects of the proposed Pulsed Fast Neutron Analysis (PFNA) Cargo Interrogation System have been examined. First, fissile cargo were examined to determine if a significant neutron signal would be observable during interrogation. Results indicated that ample multiplication would be seen for near critical bare targets. The water-reflected sphere showed relatively little multiplication. By implication, a fissile target shielded by hydrogenous cargo might not be detectable by neutron interrogation, particularly if reliance is placed on the neutron signal. The cargo may be detectable if use can be made of the ample increase in the photon signal. Second, dose rates were calculated at various locations within and just outside the facility building. These results showed that some dose rates may be higher than the target dose rate of 0.05 mrem/h. However, with limited exposure time, the total dose may be well below the allowed total dose. Lastly, estimates were made of the activation of structures and typical cargo. Most cargo will not be exposed long enough to be activated to levels of concern. On the other hand, portions of the structure may experience buildup of some radionuclides to levels of concern.

  12. Evaluation of the neutron self-interrogation approach for assay of plutonium in high materials

    International Nuclear Information System (INIS)

    Russo, P.A.; Menlove, H.O.; Fife, K.W.; West, M.H.

    1987-01-01

    The pyrochemical scrap recovery processes, designed to extract impurities from plutonium metal and compounds, generate a variety of plutonium-laden residues consisting of high (α,n) matrices of varying chemical composition, and often containing grams to tens of grams of americium. For such materials, multiplication corrections based on real neutron coincidence count rate, R, and total neutron count rate, T, measurements cannot be applied because of the large, unknown, and variable (α,n) component in the total neutron emission rate. A study of the prototype self-interrogation assay method is in progress at the Los Alamos plutonium facility. In the self-interrogation approach, the assay signature R(IF)/T is a function of effective fissile plutonium content, where R(IF) is the induced fission component of the measured reals rate, and T is the measured, (α,n)-dominated totals rate. The present study includes a calibration effort using standards consisting of mixtures of PuO 2 and PuF 4 in a salt-strip matrix. The neutron measurements of the standards and the process materials have been performed at the Los Alamos Plutonium Facility. The precision and accuracy of the self-interrogation method applied to pyrochemical residues is examined in this study

  13. Development of the QA/QC Procedures for a Neutron Interrogation System

    Energy Technology Data Exchange (ETDEWEB)

    Obhodas, Jasmina; Sudac, Davorin; Valkovic, Vladivoj [Ruder Boskovic Institute, 10000 Zagreb (Croatia)

    2015-07-01

    In order to perform QA/QC procedures for a system dedicated to the neutron interrogation of objects for the presence of threat materials one needs to perform measurements of reference materials (RM) having the same (or similar) atomic ratios as real materials. It is well known that explosives, drugs, and various other benign materials, contain chemical elements such as hydrogen, oxygen, carbon and nitrogen in distinctly different quantities. For example, a high carbon-to-oxygen ratio (C/O) is characteristic of drugs. Explosives can be differentiated by measurement of both C/O and nitrogen-to-oxygen (N/O) ratios. The C/N ratio of the chemical warfare agents, coupled with the measurement of elements such as fluorine and phosphorus, clearly differentiate them from the conventional explosives. Correlations between theoretical values and experimental results obtained in laboratory conditions for C/O and N/C ratios of simulants of hexogen (RDX), TNT, DLM2, TATP, cocaine, heroin, yperite, tetranitromethane, peroxide methylethyl-ketone, nitromethane and ethyleneglycol dinitrate are presented. (authors)

  14. Design of a novel instrument for active neutron interrogation of artillery shells.

    Directory of Open Access Journals (Sweden)

    Camille Bélanger-Champagne

    Full Text Available The most common explosives can be uniquely identified by measuring the elemental H/N ratio with a precision better than 10%. Monte Carlo simulations were used to design two variants of a new prompt gamma neutron activation instrument that can achieve this precision. The instrument features an intense pulsed neutron generator with precise timing. Measuring the hydrogen peak from the target explosive is especially challenging because the instrument itself contains hydrogen, which is needed for neutron moderation and shielding. By iterative design optimization, the fraction of the hydrogen peak counts coming from the explosive under interrogation increased from [Formula: see text]% to [Formula: see text]% (statistical only for the benchmark design. In the optimized design variants, the hydrogen signal from a high-explosive shell can be measured to a statistics-only precision better than 1% in less than 30 minutes for an average neutron production yield of 109 n/s.

  15. Direct fissile assay of highly enriched UF6 using random self-interrogation and neutron coincidence response

    International Nuclear Information System (INIS)

    Stewart, J.E.; Menlove, H.O.

    1983-01-01

    A new nondestructive method for direct assay of 235 U mass contained in Model 5A uranium hexafluoride (UF 6 ) product storage cylinders has been successfully tested in the laboratory and under field conditions. The technique employs passive neutron self-interrogation and uses the ratio of coincidences-to-totals counts as a measure of bulk fissile mass. The accuracy of the method is 6.8% (1 sigma) based on field measurements of 44 Model 5A cylinders, 11 of which were either only partially filled or contained reactor return material. The cylinders contained UF 6 with enrichments from 5.96% to 97.6%. Count times were 3 to 6 min depending on 235 U mass. Samples ranged from below 1 kg to over 16 kg of 235 U. Because the method relies primarily on fast neutron self-interrogation, complete sampling of the UF 6 takes place. This feature alleviates inhomogeneity problems and offers increased assurance of the presence of stated amounts of bulk fissile material as compared with current verification methods

  16. Determination of Fissile Material by Neutron Transport Interrogation: Computer simulations of the neutron transport

    International Nuclear Information System (INIS)

    Bruggeman, M.; Mandoki, R.; Van Iseghem, P.

    1994-09-01

    Monte Carlo simulations are used to investigate the performance and possible optimization of simple passive and active neutron assay systems for the determination of fissile material in waste packages. The active system uses external alpha-neutron or gamma-neutron sources -with mean neutron energies below 1 MeV- which continuously irradiates the waste sample. The discrimination between these source neutrons and the neutrons from induced fission in the detection process is based on the different transport properties of these neutrons. The detection limits obtained with the active system is of the order of 1 g 235 U in 1000 s measuring time

  17. Expected count rate for the Self- Interrogation Neutron Resonance Densitometry measurements of spent nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Rossa, Riccardo [SCK.CEN, Belgian Nuclear Research Centre, Boeretang, 200 - B2400 Mol (Belgium); Universite libre de Bruxelles, Ecole polytechnique de Bruxelles - Service de Metrologie Nucleaire, CP 165/84, Avenue F.D. Roosevelt, 50 - B1050 Brussels (Belgium); Borella, Alessandro; Van der Meer, Klaas [SCK.CEN, Belgian Nuclear Research Centre, Boeretang, 200 - B2400 Mol (Belgium); Labeau, Pierre-Etienne; Pauly, Nicolas [Universite libre de Bruxelles, Ecole polytechnique de Bruxelles - Service de Metrologie Nucleaire, CP 165/84, Avenue F.D. Roosevelt, 50 - B1050 Brussels (Belgium)

    2015-07-01

    The Self-Interrogation Neutron Resonance Densitometry (SINRD) is a passive neutron technique that aims at a direct quantification of {sup 239}Pu in the fuel assemblies by measuring the attenuation of the neutron flux in the energy region close to the 0.3 eV resonance of {sup 239}Pu. The {sup 239}Pu mass is estimated by calculating the SINRD signature, that is the ratio between the neutron flux integrated over the fast energy region and around the 0.3 eV resonance region. The SINRD measurement approach considered in this study consists in introducing a small neutron detector in the central guide tube of a PWR 17x17 fuel assembly. In order to measure the neutron flux in the energy regions defined in the SINRD signature, different detector types are used. The response of a bare {sup 238}U fission chamber is considered for the determination of the fast neutron flux, while other thermal-epithermal detectors wrapped in neutron absorbers are envisaged to measure the neutron flux around the resonance region. This paper provides an estimation of the count rate that can be achieved with the detector types proposed for the SINRD measurement. In the first section a set of detectors are evaluated in terms of count rate and sensitivity to the {sup 239}Pu content, in order to identify the optimal measurement configuration for each detector type. Then a study is performed to increase the count rate by increasing the detector size. The study shows that the highest count rate is achieved by using either {sup 3}He or {sup 10}B proportional counters because of the high neutron efficiency of these detectors. However, the calculations indicate that the biggest contribution to the measurement uncertainty is due to the measurement of the fast neutron flux. Finally, similar sensitivity to the {sup 239}Pu content is obtained by using the different detector types for the measurement of the neutron flux close to the resonance region. Therefore, the count rate associated to each detector type

  18. Field Prototype of the ENEA Neutron Active Interrogation Device for the Detection of Dirty Bombs

    Directory of Open Access Journals (Sweden)

    Nadia Cherubini

    2016-10-01

    Full Text Available The Italian National Agency for New Technologies, Energy, and Sustainable Economic Development (ENEA Neutron Active Interrogation (NAI device is a tool designed to improve CBRNE defense. It is designed to uncover radioactive and nuclear threats including those in the form of Improvised Explosive Devices (IEDs, the so-called “dirty bombs”. The NAI device, at its current development stage, allows to detect 6 g of 235U hidden in a package. It is easily transportable, light in weight, and with a real-time response. Its working principle is based on two stages: (1 an “active” stage in which neutrons are emitted by a neutron generator to interact with the item under inspection, and (2 a “passive” stage in which secondary neutrons are detected originating a signal that, once processed, allows recognition of the offence. In particular, a clear indication of the potential threat is obtained by a dedicated software based on the Differential Die-Away Time Analysis method.

  19. Low level transuranic wastes assay by photon interrogation and neutron counting: application to the concrete packages

    International Nuclear Information System (INIS)

    Lyoussi, A.

    1994-02-01

    The present document presents an active detection method for radioactive wastes embedded in high-density matrices, mainly concrete packages. The high density of the packages, as well as their high water content (up to 25%), means only high-energy neutrons or gamma particles have a high enough range to activate the enclosed actinides. Our aims were to evaluate the feasibility of dosing transuranians by induced photofission, and to optimize an experimental system with a view to improving detection limits. The system uses a pulsed electron beam from a linear accelerator (LINAC) to produce high-energy photon bursts from a metallic converter. The photons induce fissions in TRU. When a fission is induced in trace amounts of TRU contaminants in waste material, it provides 'signatures' from fission products that can be used to assay the material before disposal. We give here the results from counting photofission-induced delayed neutrons from 239 Pu, 235 U and 238 U in three sample matrices: glass, polyethylene and concrete. We counted delayed neutrons emitted after each pulse of the LINAC using the 'Sequential PHoton Interrogation and Neutron Counting Signatures' (SPHINCS) technique which had been developed in this thesis work. The experimental process described below (SPHINCS) is one of the first to use a LINAC assay method combined with sequential detection using delayed neutrons. The SPHINCS process enhances the available counts by a factor about 20 compared with the counting of delayed neutrons only after the irradiation period. The electron linear accelerator operates at 15 MeV, 140 mA, and 2.5 μs wide pulse at a 50 Hz rate. Finally, use of an electron linear accelerator as a particle source, experimental and electronics details, measurements results and their interpretation and the future experimental works are discussed. (author)

  20. Neutron interrogation to identify chemical elements with an ion-tube neutron source (INS)

    International Nuclear Information System (INIS)

    Alvarez, R.A.; Dougan, A.D.; Rowland, M.R.; Wang, T.F.

    1995-01-01

    A non-destructive analysis technique using a portable, electric ion-tube neutron source (INS) and gamma ray detector has been used to identify the key constituent elements in a number of sealed munitions, and from the elemental makeup, infer the types of agent within each. The high energy (14 MeV) and pulsed character of the neutron flux from an INS provide a method of measuring, quantitatively, the oxygen, carbon, and fluorine content of materials in closed containers, as well as the other constituents that can be measured with low-energy neutron probes. The broad range of elements that can be quantitatively measured with INS-based instruments provides a capability of verifying common munition fills; it provides the greatest specificity of any portable neutron-based technique for determining the full matrix of chemical elements in completely unrestricted sample scenarios. The specific capability of quantifying the carbon and oxygen content of materials should led to a fast screening technique which, can discriminate very quickly between high-explosive and chemical agent-filled containers. (author) 12 refs.; 5 figs.; 3 tabs

  1. 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.

  2. Simulated Performance of the Integrated Passive Neutron Albedo Reactivity and Self-Interrogation Neutron Resonance Densitometry Detector Designed for Spent Fuel Measurement at the Fugen Reactor in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Ulrich, Timothy J. II [Los Alamos National Laboratory; Lafleur, Adrienne M. [Los Alamos National Laboratory; Menlove, Howard O. [Los Alamos National Laboratory; Swinhoe, Martyn T. [Los Alamos National Laboratory; Tobin, Stephen J. [Los Alamos National Laboratory; Seya, Michio [Los Alamos National Laboratory; Bolind, Alan M. [Los Alamos National Laboratory

    2012-07-16

    An integrated nondestructive assay instrument, which combined the Passive Neutron Albedo Reactivity (PNAR) and the Self-Interrogation Neutron Resonance Densitometry (SINRD) techniques, is the research focus for a collaborative effort between Los Alamos National Laboratory (LANL) and the Japanese Atomic Energy Agency as part of the Next Generation Safeguard Initiative. We will quantify the anticipated performance of this experimental system in two physical environments: (1) At LANL we will measure fresh Low Enriched Uranium (LEU) assemblies for which the average enrichment can be varied from 0.2% to 3.2% and for which Gd laced rods will be included. (2) At Fugen we will measure spent Mixed Oxide (MOX-B) and LEU spent fuel assemblies from the heavy water moderated Fugen reactor. The MOX-B assemblies will vary in burnup from {approx}3 GWd/tHM to {approx}20 GWd/tHM while the LEU assemblies ({approx}1.9% initial enrichment) will vary from {approx}2 GWd/tHM to {approx}7 GWd/tHM. The estimated count rates will be calculated using MCNPX. These preliminary results will help the finalization of the hardware design and also serve a guide for the experiment. The hardware of the detector is expected to be fabricated in 2012 with measurements expected to take place in 2012 and 2013. This work is supported by the Next Generation Safeguards Initiative, Office of Nuclear Safeguards and Security, National Nuclear Security Administration.

  3. Enhancing the performance of a tensioned metastable fluid detector based active interrogation system for the detection of SNM in <1 m3 containers using a D-D neutron interrogation source in moderated/reflected geometries

    Science.gov (United States)

    Grimes, T. F.; Hagen, A. R.; Archambault, B. C.; Taleyarkhan, R. P.

    2018-03-01

    This paper describes the development of a SNM detection system for interrogating 1m3 cargos via the combination of a D-D neutron interrogation source (with and without reflectors) and tensioned metastable fluid detectors (TMFDs). TMFDs have been previously shown (Taleyarkhan et al., 2008; Grimes et al., 2015; Grimes and Taleyarkhan, 2016; Archambault et al., 2017; Hagen et al., 2016) to be capable of using Threshold Energy Neutron Analysis (TENA) techniques to reject the ∼2.45 MeV D-D interrogating neutrons while still remaining sensitive to >2.45 MeV neutrons resulting from fission in the target (HEU) material. In order to enhance the performance, a paraffin reflector was included around the accelerator head. This reflector was used to direct neutrons into the package to increase the fission signal, lower the energy of the interrogating neutrons to increase the fission cross-section with HEU, and, also to direct interrogating neutrons away from the detectors in order to enhance the required discrimination between interrogating and fission neutrons. Experiments performed with a 239 Pu-Be neutron source and MnO2 indicated that impressive performance gains could be made by placing a parabolic paraffin moderator between the interrogation source and an air-filled cargo container with HEU placed at the center. However, experiments with other cargo fillers (as specified in the well-known ANSI N42.41-2007 report), and with HEU placed in locations other than the center of the package indicated that other reflector geometries might be superior due to over-"focusing" and the increased solid angle effects due to the accommodation of the moderator geometry. The best performance for the worst case of source location and box fill was obtained by placing the reflector only behind the D-D neutron source rather than in front of it. Finally, it was shown that there could be significant gains in the ability to detect concealed SNM by operating the system in multiple geometric

  4. Neutron radiography at the Risoe National Laboratory

    International Nuclear Information System (INIS)

    Domanus, J.C.; Gade-Nielsen, P.; Knudsen, P.; Olsen, J.

    1981-11-01

    In this report six papers are collected which will be presented at the First World Conference on Neutron Radiography in San Diego, U.S.A., 7 - 10 December 1981. They are preceded by a short description of the activities of Risoe National Laboratory in the field of post-irradiation examination of nuclear fuel. One of the nondestructive methods used for this examination is neutron radiography. In the six conference papers different aspects of neutron radiography performed at Risoe are presented. (author)

  5. Silicon Carbide and Diamond Neutron Detectors for Active Interrogation Security Applications

    Science.gov (United States)

    Hodgson, Michael

    A thorough investigation has been carried out in order to determine the suitability of diamond and silicon carbide for active interrogation applications. This included electrical and radiological characterisation of single crystal diamond (D-SC) and polycrystalline diamond (D-PC) detectors; epitaxial silicon carbide (SiC-EP) and semi-insulating silicon carbide (SiC-SI); all compared against the performance of a commercial silicon PIN photodiode (Si-PIN) from Hamamatsu. This work aided in determining whether the detectors were suitable for radiation detection purposes, as well as obtaining the operational criteria for use. Characterisation work was also conducted on semi-insulating silicon carbide detectors from three different suppliers, as well as on detectors fabricated via different techniques. This work demonstrated the robustness of the material, as the charge collection properties were unaffected by contact fabrication technique. Changes in current-voltage characteristics were observed for different contact fabrication methods, but were generally still low (≈nA) over the ranges tested (+/-500V). Following this work the performance of selected detectors was measured against criteria for the AWE active interrogation project. Radiation dose dependent performance deterioration was observed in the SiC-SI and D-PC detectors, with decreased charge collection efficiency (-45+/-4%) and intrinsic efficiency (-40% at -400V) observed respectively. It is not clear as to whether these effects are a result of bulk material damage or contact/surface/mount damage, but an increase in the current-voltage relationship was also observed on these detectors, as well as the Si-PIN (SiC-SI≈+25% and D-PC≈+20% at -400V; Si- PIN≈+300% at -25V). Instability of the peak position and/or counting rate with irradiation time was observed in D-SC, D-PC and all the semi-insulating SiC (polarisation effect). For D-SC this was primarily with alpha particles and stability would be

  6. Neutron interrogator assay system for the Idaho Chemical Processing Plant waste canisters and spent fuel: preliminary description and operating procedures manual

    International Nuclear Information System (INIS)

    Menlove, H.O.; Eccleston, G.; Close, D.A.; Speir, L.G.

    1978-05-01

    A neutron interrogation assay system is being designed for the measurement of waste canisters and spent fuel packages at the new Idaho Chemical Processing Plant to be operated by Allied Chemical Corp. The assay samples consist of both waste canisters from the fluorinel dissolution process and spent fuel assemblies. The assay system is a 252 Cf ''Shuffler'' that employs a cyclic sequence of fast-neutron interrogation with a 252 Cf source followed by delayed-neutron counting to determine the 235 U content

  7. Preliminary evaluation of a Neutron Calibration Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Alvarenga, Talysson S.; Neves, Lucio P.; Perini, Ana P.; Sanches, Matias P.; Mitake, Malvina B.; Caldas, Linda V.E., E-mail: talvarenga@ipen.br, E-mail: lpneves@ipen.br, E-mail: aperini@ipen.br, E-mail: msanches@ipen.br, E-mail: mbmitake@ipen.br, E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Federico, Claudio A., E-mail: claudiofederico@ieav.cta.br [Instituto de Estudos Avancados (IEAv/DCTA), Sao Jose dos Campos, SP (Brazil). Dept. de Ciencia e Tecnologia Aeroespacial

    2013-07-01

    In the past few years, Brazil and several other countries in Latin America have experimented a great demand for the calibration of neutron detectors, mainly due to the increase in oil prospection and extraction. The only laboratory for calibration of neutron detectors in Brazil is localized at the Institute for Radioprotection and Dosimetry (IRD/CNEN), Rio de Janeiro, which is part of the IAEA SSDL network. This laboratory is the national standard laboratory in Brazil. With the increase in the demand for the calibration of neutron detectors, there is a need for another calibration services. In this context, the Calibration Laboratory of IPEN/CNEN, Sao Paulo, which already offers calibration services of radiation detectors with standard X, gamma, beta and alpha beams, has recently projected a new calibration laboratory for neutron detectors. In this work, the ambient equivalent dose rate (H⁎(10)) was evaluated in several positions inside and around this laboratory, using Monte Carlo simulation (MCNP5 code), in order to verify the adequateness of the shielding. The obtained results showed that the shielding is effective, and that this is a low-cost methodology to improve the safety of the workers and evaluate the total staff workload. (author)

  8. Neutron Standards Laboratory of the CIEMAT

    International Nuclear Information System (INIS)

    Guzman G, K. A.; Mendez V, R.; Vega C, H. R.

    2014-08-01

    By means of a calculation series with Monte Carlo methods and the code MCNPX was characterized the neutrons field produced by the existent calibration sources in the Neutron Standards Laboratory of the Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT). The laboratory has two neutron calibration sources one of 241 AmBe and other 252 Cf that are stored in a water pool. A detailed three-dimensional model of the room was built with the base of stainless steel remarking in the selector to the sources that situates them to 4 m of the floor to be irradiated on the irradiation table and the storage pool. Each one of the sources was defined on the model in its double steel encapsulated. The spectra were calculated with different cases with the purpose of to calculate the contribution of each element that impacts to the neutrons transport. The spectra of the calibration sources were calculated to different distances regarding the source from 0, 15, 35, 50 to 300 cm on the base and in a same way the values of the ambient dose equivalent using the approaches of the ICRP-74. The results show clearly that the great contribution in the modification of the spectrum is attributed to the walls, and floor of the Neutron Standards Laboratory installations. (Author)

  9. Neutronics issues for a laboratory microfusion facility

    International Nuclear Information System (INIS)

    Tobin, M.T.

    1987-01-01

    Discussion concerning goals or design of the Laboratory Microfusion Facility (LMF) should include an understanding of the neutronics issues involved. We consider such aspects as first wall shielding requirements, safety standards as they will apply to such an Inertial Confinement Fusion (ICF) facility, and the interior chamber environment. The selection of materials for the first wall, neutron moderator and absorber, and gamma ray shielding is discussed. We conclude that water or carbon are the choices for bulk neutron moderation and boron placed just in front of the first wall the choice for neutron absorber. Selection of the in-chamber materials and diagnostic design will greatly affect the relative hazards after a shot. Lead is the high-Z material of choice and plastic expendables for the diagnostics. Although a poor gamma ray attenuator, carbon is the choice for this function since it also compensates for the direct neutron shine effects and does not itself activate. Electronics may need to be hardened to the prompt gamma and neutron dose

  10. Neutronics analysis of the Laboratory Microfusion Facility

    International Nuclear Information System (INIS)

    Tobin, M.T.; Singh, M.S.; Meier, W.R.

    1988-01-01

    The radiological safety hazards of the experimental area (EA) for the proposed Inertial Confinement Fusion (ICF) Laboratory Microfusion Facility (LMF) have been examined. The EA includes those structures required to establish the proper pre-shot environment, point the beams, contain the pellet yield, and measure many different facets of the experiments. The radiation dose rates from neutron activation of representative target chamber materials, the laser beam tubes and the argon gas they contain, the air surrounding the chamber, and the concrete walls of the experimental area are given. Combining these results with the allowable dose rates for workers, we show how radiological considerations affect access to the inside of the target chamber and to the diagnostic platform area located outside the chamber. Waste disposal and tritium containment issues are summarized. Other neutronics issues, such as radiation damage to the final optics and neutron heating of materials placed close to the target, are also addressed. 16 refs., 2 figs., 1 tab

  11. Anisotropy of neutron sources of Neutron Metrology Laboratory, IRD, Brazil

    International Nuclear Information System (INIS)

    Silva, A.C.F.; Silva, F.S.; Leite, S.P.; Creazolla, P.G; Patrão, K.C.S.; Fonseca, E.S. da; Fernandes, S.S.; Pereira, W.W.

    2017-01-01

    The anisotropy measurements have as main objective to define the emission of the radiation by different angles of an encapsulated neutron source. The measurements were performed using a Long Accuracy Counter (PLC) Detector in the Low Dispersion Room of the LNMRI / IRD with different neutron sources. Each measurement was made using a support for the source, emulated through an arduino system to rotate it. The carrier is marked with a variation of 5 °, ranging from 0 ° to 360 °, for the work in question only half, 0 ° to 180 ° is used for a total of nineteen steps. In this paper three sources of 241 AmBe (α, n) 5.92 GBq (16 Ci) were used, neutron sources having the following dimensions: 105 mm in height and 31 mm in diameter. The PLC was positioned at a distance of 2 meters from the neutron source and has a radius of 15 cm for the detection area. The anisotropy factor of the 241 AmBe source was 17%. The results in this work will focus mainly on the area of radioprotection and studies that will improve the process of routine measurements in laboratories and instrument calibrations. (author)

  12. Application of active neutronic interrogation method to the line analysis in reprocessing plant

    International Nuclear Information System (INIS)

    Passard, C.

    1993-01-01

    In a reprocessing plant of irradiated spent fuels, the knowledge in real time (line analysis) of uranium and plutonium quantities present in solutions is an extremely important parameter to control the proceeding and for the apparatus safety. The active neutronic analysis give a nondestructive non intrusive and quick measure to know the concentrations. This method consists in inducing fissions in nuclides with a neutron source and then to detect the particles which come from

  13. Neutron interrogation systems using pyroelectric crystals and methods of preparation thereof

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Vincent; Meyer, Glenn A.; Falabella, Steven; Guethlein, Gary; Rusnak, Brian; Sampayan, Stephen; Spadaccini, Christopher M.; Wang, Li-Fang; Harris, John; Morse, Jeff

    2017-08-01

    According to one embodiment, an apparatus includes a pyroelectric crystal, a deuterated or tritiated target, an ion source, and a common support coupled to the pyroelectric crystal, the deuterated or tritiated target, and the ion source. In another embodiment, a method includes producing a voltage of negative polarity on a surface of a deuterated or tritiated target in response to a temperature change of a pyroelectric crystal, pulsing a deuterium ion source to produce a deuterium ion beam, accelerating the deuterium ion beam to the deuterated or tritiated target to produce a neutron beam, and directing the ion beam onto the deuterated or tritiated target to make neutrons using a voltage of the pyroelectric crystal and/or an HGI surrounding the pyroelectric crystal. The directionality of the neutron beam is controlled by changing the accelerating voltage of the system. Other apparatuses and methods are presented as well.

  14. Design of a Cold Neutron Laboratory Building

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Sang Ik; Kim, Y. K.; Jung, H. S.; Park, Y. C.; Kim, H. G.; Lee, B. C.; Ahn, S. H.; Han, Y. S.; Kim, H. R

    2006-04-15

    This report is summarized of the design results of a Cold Neutron Laboratory Building (CNLB) and its whole technical documents submitted to the regulatory body. This report is composed of the CNLB's safety analysis report in the final version and the question and answer documents carried out for its screening to get an approval. The objective of this report is to keep the design results about following terms. Also, it is intended to record serially the technical work conducted for its screening and to find out easily the whole process of the CNLB project. Civil and Architectural Design for CNLB, Seismic and Structure Analysis for CNLB, Shielding Design of the Neutron Guide and the Experimental Equipment and Design of the Compressed Air, Cooling Water, Ventilation, Fire Protection, Electricity System, and etc on.

  15. Dielectric RheoSANS - Simultaneous Interrogation of Impedance, Rheology and Small Angle Neutron Scattering of Complex Fluids.

    Science.gov (United States)

    Richards, Jeffrey J; Gagnon, Cedric V L; Krzywon, Jeffery R; Wagner, Norman J; Butler, Paul D

    2017-04-10

    A procedure for the operation of a new dielectric RheoSANS instrument capable of simultaneous interrogation of the electrical, mechanical and microstructural properties of complex fluids is presented. The instrument consists of a Couette geometry contained within a modified forced convection oven mounted on a commercial rheometer. This instrument is available for use on the small angle neutron scattering (SANS) beamlines at the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR). The Couette geometry is machined to be transparent to neutrons and provides for measurement of the electrical properties and microstructural properties of a sample confined between titanium cylinders while the sample undergoes arbitrary deformation. Synchronization of these measurements is enabled through the use of a customizable program that monitors and controls the execution of predetermined experimental protocols. Described here is a protocol to perform a flow sweep experiment where the shear rate is logarithmically stepped from a maximum value to a minimum value holding at each step for a specified period of time while frequency dependent dielectric measurements are made. Representative results are shown from a sample consisting of a gel composed of carbon black aggregates dispersed in propylene carbonate. As the gel undergoes steady shear, the carbon black network is mechanically deformed, which causes an initial decrease in conductivity associated with the breaking of bonds comprising the carbon black network. However, at higher shear rates, the conductivity recovers associated with the onset of shear thickening. Overall, these results demonstrate the utility of the simultaneous measurement of the rheo-electro-microstructural properties of these suspensions using the dielectric RheoSANS geometry.

  16. Classifying threats with a 14-MeV neutron interrogation system.

    Science.gov (United States)

    Strellis, Dan; Gozani, Tsahi

    2005-01-01

    SeaPODDS (Sea Portable Drug Detection System) is a non-intrusive tool for detecting concealed threats in hidden compartments of maritime vessels. This system consists of an electronic neutron generator, a gamma-ray detector, a data acquisition computer, and a laptop computer user-interface. Although initially developed to detect narcotics, recent algorithm developments have shown that the system is capable of correctly classifying a threat into one of four distinct categories: narcotic, explosive, chemical weapon, or radiological dispersion device (RDD). Detection of narcotics, explosives, and chemical weapons is based on gamma-ray signatures unique to the chemical elements. Elements are identified by their characteristic prompt gamma-rays induced by fast and thermal neutrons. Detection of RDD is accomplished by detecting gamma-rays emitted by common radioisotopes and nuclear reactor fission products. The algorithm phenomenology for classifying threats into the proper categories is presented here.

  17. 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

  18. Anisotropy of neutrons sources of the Neutron Metrology Laboratory

    International Nuclear Information System (INIS)

    Silva, A.C.F.; Silva, F.S.; Creazolla, P.G.; Patrão, K.C.S.; Fonseca, E.S. da; Pereira, W.W.

    2017-01-01

    The anisotropy measurements have as main objective to define the emission of the radiation by different angles of an encapsulated neutron source. Measurements were performed using a Precision Long Counter (PLC) detector in the Laboratório de Baixo Espalhamento of the LNMRI / IRD. In this study were used an 241 AmBe (α,n) 5.92 GBq and a 238 PuBe (α,n) 1.85 TBq. The anisotropy factor was 8.65% to 241 AmBe and 4.36% to 238 PuBe, due to variations in the source encapsulation. The results in this work will focus mainly on the area of radiation protection and studies that will improve the process of routine measurements in laboratories and instrument calibrations. (author)

  19. Cadmium Subtraction Method for the Active Albedo Neutron Interrogation of Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Worrall, Louise G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Croft, Stephen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-02-01

    This report describes work performed under the Next Generation Safeguards Initiative (NGSI) Cadmium Subtraction Project. The project objective was to explore the difference between the traditional cadmium (Cd) ratio signature and a proposed alternative Cd subtraction (or Cd difference) approach. The thinking behind the project was that a Cd subtraction method would provide a more direct measure of multiplication than the existing Cd ratio method. At the same time, it would be relatively insensitive to changes in neutron detection efficiency when properly calibrated. This is the first published experimental comparison and evaluation of the Cd ratio and Cd subtraction methods.

  20. Discrimination of chemical and high-explosive munitions by neutron interrogation for arms control treaty verification

    International Nuclear Information System (INIS)

    Caffrey, A.J.; Cole, J.D.; Gehrke, R.J.; Greenwood, R.C.; Krebs, K.M.

    1993-01-01

    For treaty verification purposes, due to the hazards of direct sampling of chemical and explosive munitions, non-destructive evaluation methods have important safety advantages. The authors assay method employs neutrons from a californium-252 radioisotopic source to induce capture and inelastic reactions in a munition under test, and the resulting gamma radiation is measured with an high-purity germanium gamma-ray detector. For field verification, a portable, battery-operated assay system has been developed that performs automatic spectrum analysis and agent identification in near-real time. In tests with actual chemical and high explosives munitions, the assay method reliably identifies nerve agents GB and VX, blister agents HD and L, white phosphorous, and high explosives

  1. Low energy neutron background in deep underground laboratories

    Energy Technology Data Exchange (ETDEWEB)

    Best, Andreas, E-mail: andreas.best@lngs.infn.it [INFN, Laboratori Nazionali del Gran Sasso (LNGS), 67100 Assergi (Italy); Department of Physics and The Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Görres, Joachim [Department of Physics and The Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Junker, Matthias [INFN, Laboratori Nazionali del Gran Sasso (LNGS), 67100 Assergi (Italy); Kratz, Karl-Ludwig [Department for Biogeochemistry, Max-Planck-Institute for Chemistry, 55020 Mainz (Germany); Laubenstein, Matthias [INFN, Laboratori Nazionali del Gran Sasso (LNGS), 67100 Assergi (Italy); Long, Alexander [Department of Physics and The Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Nisi, Stefano [INFN, Laboratori Nazionali del Gran Sasso (LNGS), 67100 Assergi (Italy); Smith, Karl; Wiescher, Michael [Department of Physics and The Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States)

    2016-03-11

    The natural neutron background influences the maximum achievable sensitivity in most deep underground nuclear, astroparticle and double-beta decay physics experiments. Reliable neutron flux numbers are an important ingredient in the design of the shielding of new large-scale experiments as well as in the analysis of experimental data. Using a portable setup of {sup 3}He counters we measured the thermal neutron flux at the Kimballton Underground Research Facility, the Soudan Underground Laboratory, on the 4100 ft and the 4850 ft levels of the Sanford Underground Research Facility, at the Waste Isolation Pilot Plant and at the Gran Sasso National Laboratory. Absolute neutron fluxes at these laboratories are presented.

  2. Control of radioactive wastes and coupling of neutron/gamma measurements: use of radiative capture for the correction of matrix effects that penalize the fissile mass measurement by active neutron interrogation; Controle des dechets radioactifs et couplage de mesures neutron/gamma: exploitation de la capture radiative pour corriger les effets de matrice penalisant la mesure de la masse fissile par interrogation neutronique active

    Energy Technology Data Exchange (ETDEWEB)

    Loche, F

    2006-10-15

    In the framework of radioactive waste drums control, difficulties arise in the nondestructive measurement of fissile mass ({sup 235}U, {sup 239}Pu..) by Active Neutron Interrogation (ANI), when dealing with matrices containing materials (Cl, H...) influencing the neutron flux. The idea is to use the neutron capture reaction (n,{gamma}) to determine the matrix composition to adjust the ANI calibration coefficient value. This study, dealing with 118 litres, homogeneous drums of density less than 0,4 and composed of chlorinated and/or hydrogenated materials, leads to build abacus linking the {gamma} ray peak areas to the ANI calibration coefficient. Validation assays of these abacus show a very good agreement between the corrected and true fissile masses for hydrogenated matrices (max. relative standard deviation: 23 %) and quite good for chlorinated and hydrogenated matrices (58 %). The developed correction method improves the measured values. It may be extended to 0,45 density, heterogeneous drums. (author)

  3. High-sensitive detection by direct interrogation of 14 MeV Acc neutrons, (1). Uranium-contained metal matrix in a waste dram

    International Nuclear Information System (INIS)

    Haruyama, Mitsuo; Takase, Misao; Tobita, Hiroshi; Mori, Takamasa

    2004-01-01

    Previously, authors reported that the 14 MeV-neutron direct interrogation method has made possible measure for the discrimination of clearance levels of concrete solidification uranium waste. In this paper, applicability of the method to metal waste matrix is discussed based on the results of simulation experiments by the continuation energy Monte Carlo calculation code (MVP). The problem is that self-neutron moderation effect in a waste cannot be expected when a waste matrix is metal. To solve this, a moderator is adopted so as to surround a metal waste drum and to slow down suitably a 14 MeV neutrons. The simulation calculation showed that this effect is satisfactorily large. The detection limit of radioactivity concentration to 4.5% enriched uranium has been found to be 0.0973 Bq/g in the metal waste model of 215.59 kg gross weight, in which 61 pipes are stuffed into its drum. Moreover, the position-dependent sensitivity difference in a metal waste drum can be settled as small as to ±13.5%. In conclusion, it can be said that 14 MeV-neutron direct interrogation method can be applied to the waste of a metal system: the detection sensitivity is high enough and the position-dependent sensitivity difference is small admittedly. Hence the method can be applied also to discrimination measurement of the clearance level of metal uranium waste. (author)

  4. 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.

  5. Neutrons from rock radioactivity in the new Canfranc underground laboratory

    International Nuclear Information System (INIS)

    Amare, J; Bauluz, B; Beltran, B; Carmona, J M; Cebrian, S; GarcIa, E; Gomez, H; Irastorza, I G; Luzon, G; MartInez, M; Morales, J; Solorzano, A Ortiz de; Pobes, C; Jpuimedon; RodrIguez, A; Ruz, J; Sarsa, M L; Torres, L; Villar, J A

    2006-01-01

    Measurements of radioactivity and composition of rock from the main hall of the new Canfranc underground laboratory are reported. Estimates of neutron production by spontaneous fission and (α, n) reactions are given

  6. Neutrons from rock radioactivity in the new Canfranc underground laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Amare, J [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain); Bauluz, B [Departamento de Ciencias de la Tierra, Universidad de Zaragoza (Spain); Beltran, B [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain); Carmona, J M [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain); Cebrian, S [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain); GarcIa, E [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain); Gomez, H [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain); Irastorza, I G [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain); Luzon, G [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain); MartInez, M [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain); Morales, J [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain); Solorzano, A Ortiz de [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain); Pobes, C [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain); Jpuimedon; RodrIguez, A [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain); Ruz, J [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain); Sarsa, M L [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain); Torres, L [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain); Villar, J A [Laboratorio de Fisica Nuclear, Universidad de Zaragoza (Spain)

    2006-05-15

    Measurements of radioactivity and composition of rock from the main hall of the new Canfranc underground laboratory are reported. Estimates of neutron production by spontaneous fission and ({alpha}, n) reactions are given.

  7. Neutron background measurements in the underground laboratory of Modane

    International Nuclear Information System (INIS)

    Chazal, V.; Chambon, B.; De Jesus, M.; Drain, D.; Pastor, C.; Vagneron, L.; Brissot, R.; Cavaignac, J.F.; Stutz, A.; Giraud-Heraud, Y.

    1997-07-01

    Measurements of the background neutron environment, at a depth of 1780 m (4800 mWe) in the Underground Laboratory of Modane (L.S.M) are reported. Using a 6 Li liquid scintillator, the energy spectrum of the fast neutron flux has been determined. Monte-Carlo calculations of the (α,n) and spontaneous fission processes in the surrounding rock has been performed and compared to the experimental result. In addition, using two 3 He neutron counters, the thermal neutron flux has been measured. (author)

  8. Impact of the Cryogen Free Revolution on Neutron Scattering Laboratories

    Science.gov (United States)

    Kirichek, Oleg

    A global shortage of helium gas can seriously jeopardise the scientific programmes of neutron scattering laboratories due to the use of cryogenic sample environment in the majority of the neutron scattering experiments. Recently developed cryogen-free technology allows a significant reduction or even a complete elimination of liquid helium consumption. Here we review the impact of the cryogen-free revolution on cryogenic equipment used at large neutron facilities, such as cryostats, dilution refrigerators, superconducting magnets and other cryogenic systems. Particular attention is given to the newly developed superconducting magnets for neutron diffraction and spectroscopy experiments. Use of the cryogen-free approach, as well as cutting-edge superconducting magnet technology and advanced neutron optics allows researcher to achieve extraordinary performance in their experiments, opening up new opportunities in neutron scattering research.

  9. Simultaneous photon and neutron interrogation using an electron accelerator in order to quantify actinides in encapsulated radioactive wastes; Double interrogation simultanee neutrons et photons utilisant un accelerateur d'electrons pour la caracterisation separee des actinides dans les dechets radioactifs enrobes

    Energy Technology Data Exchange (ETDEWEB)

    Jallu, F

    1999-09-24

    Measuring out alpha emitters, such as ({sup 234,235,236,238}U {sup 238,239,240,242,}2{sup 44P}u, {sup 237}Np {sup 241,243}Am...), in solid radioactive waste, allows us to quantify the alpha activity in a drum and then to classify it. The SIMPHONIE (SIMultaneous PHOton and Neutron Interrogation Experiment) method, developed in this Ph.D. work, combines both the Active Neutron Interrogation and the Induced Photofission Interrogation techniques simultaneously. Its purpose is to quantify in only one measurement, fissile ({sup 235}U, {sup 239,241}Pu...) and fertile ({sup 236,238}U, {sup 238,240}Pu...) elements separately. In the first chapter of this Ph.D. report, we present the principle of the Radioactive Waste Management in France. The second chapter deals with the physical properties of neutron fission and of photofission. These two nuclear reactions are the basis of the SIMPHONIE method. Moreover, one of our purposes was to develop the ELEPHANT (ELEctron PHoton And Neutron Transport) code in view to simulate the electron, photon and neutron transport, including the ({gamma}, n), ({gamma}, 2n) and ({gamma}, f) photonuclear reactions that are not taken into account in the MCNP4 (Monte Carlo N-Particle) code. The simulation codes developed and used in this work are detailed in the third chapter. Finally, the fourth chapter gives the experimental results of SIMPHONIE obtained by using the DGA/ETCA electron linear accelerators located at Arcueil, France. Fissile ({sup 235}U, {sup 239}Pu) and fertile ({sup 238}U) samples were studied. Furthermore, comparisons between experimental results and calculated data of photoneutron production in tungsten, copper, praseodymium and beryllium by using an electron LINear Accelerator (LINAC) are given. This allows us to evaluate the validity degree of the ELEPHANT code, and finally the feasibility of the SIMPHONIE method. (author)

  10. Study and development of a method allowing the identification of actinides inside nuclear waste packages, by active neutron or photon interrogation and delayed gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Carrel, F.

    2007-10-01

    An accurate estimation of the alpha-activity of a nuclear waste package is necessary to select the best mode of storage. The main purpose of this work is to develop a non-destructive active method, based on the fission process and allowing the identification of actinides ( 235 U, 238 U, 239 Pu). These three elements are the main alpha emitters contained inside a package. Our technique is based on the detection of delayed gammas emitted by fission products. These latter are created by irradiation with the help of a neutron or photon beam. Performances of this method have been investigated after an Active Photon or Neutron Interrogation (INA or IPA). Three main objectives were fixed in the framework of this thesis. First, we measured many yields of photofission products to compensate the lack of data in the literature. Then, we studied experimental performances of this method to identify a given actinide ( 239 Pu in fission, 235 U in photofission) present in an irradiated mixture. Finally, we assessed the application of this technique on different mock-up packages for both types of interrogation (118 l mock-up package containing EVA in fission, 220 l mock-up package with a wall of concrete in photofission). (author)

  11. A new method to measure the U-235 content in fresh LWR fuel assemblies via fast-neutron passive self-interrogation

    Science.gov (United States)

    Menlove, Howard; Belian, Anthony; Geist, William; Rael, Carlos

    2018-01-01

    The purpose of this paper is to provide a solution to a decades old safeguards problem in the verification of the fissile concentration in fresh light water reactor (LWR) fuel assemblies. The problem is that the burnable poison (e.g. Gd2O3) addition to the fuel rods decreases the active neutron assay for the fuel assemblies. This paper presents a new innovative method for the verification of the 235U linear mass density in fresh LEU fuel assemblies that is insensitive to the burnable poison content. The technique makes use of the 238U atoms in the fuel rods to self-interrogate the 235U mass. The innovation for the new approach is that the 238U spontaneous fission (SF) neutrons from the rods induces fission reactions (IF) in the 235U that are time correlated with the SF source neutrons. Thus, the coincidence gate counting rate benefits from both the nu-bar of the 238U SF (2.07) and the 235U IF (2.44) for a fraction of the IF reactions. Whereas, the 238U SF background has no time-correlation boost. The higher the detection efficiency, the higher the correlated boost because background neutron counts from the SF are being converted to signal doubles. This time-correlation in the IF signal increases signal/background ratio that provides a good precision for the net signal from the 235U mass. The hard neutron energy spectrum makes the technique insensitive to the burnable poison loading where a Cd or Gd liner on the detector walls is used to prevent thermal-neutron reflection back into the fuel assembly from the detector. We have named the system the fast-neutron passive collar (FNPC).

  12. Neutron capture therapy at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Fairchild, R.G.; Slatkin, D.N.; Gabel, D.

    1986-01-01

    Application of the 10 B(n,α) 7 Li reaction to cancer radiotherapy (Neutron Capture therapy, or NCT) has intrigued investigators since shortly after the discovery of the neutron. This paper summarizes data describing recently developed boronated compounds designed to serve as vehicles for boron transport to tumor. Whole-body (mouse) Neutron Capture Radiograms (NCR) of some of the most promising compounds are presented; these graphically demonstrate selective uptake in tumor, at times varying from hours to days post administration. Comparison is made to the ubiquitous distribution of inorganic boron compounds used in the first clinical trials of NCT. Since some compounds are now available that allow physiological targeting of boron to tumor at concentrations adequate for therapy, the NCR technique can be used to evaluate important questions concerning the microdistribution of boron within the tumor. The implication of these compounds to NCT is evaluated in terms of Therapeutic Gain (TG). The optimization of NCT by using band-pass filtered neutron beams is described, again in terms of TG, and irradiation times with these less intense beams are estimated. 35 references, 12 figures, 4 tables

  13. In vivo neutron activation facility at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Ma, R.; Yasumura, Seiichi; Dilmanian, F.A.

    1997-11-01

    Seven important body elements, C, N, Ca, P, K, Na, and Cl, can be measured with great precision and accuracy in the in vivo neutron activation facilities at Brookhaven National Laboratory. The facilities include the delayed-gamma neutron activation, the prompt-gamma neutron activation, and the inelastic neutron scattering systems. In conjunction with measurements of total body water by the tritiated-water dilution method several body compartments can be defined from the contents of these elements, also with high precision. In particular, body fat mass is derived from total body carbon together with total body calcium and nitrogen; body protein mass is derived from total body nitrogen; extracellular fluid volume is derived from total body sodium and chlorine; lean body mass and body cell mass are derived from total body potassium; and, skeletal mass is derived from total body calcium. Thus, we suggest that neutron activation analysis may be valuable for calibrating some of the instruments routinely used in clinical studies of body composition. The instruments that would benefit from absolute calibration against neutron activation analysis are bioelectric impedance analysis, infrared interactance, transmission ultrasound, and dual energy x-ray/photon absorptiometry.

  14. Systems report on the analysis of spent, highly enriched U-235 reactor fuel by delayed neutron interrogation

    International Nuclear Information System (INIS)

    Piper, T.C.; Kirkham, R.J.

    1990-05-01

    Design aspects are briefly given of a neutron source shuffler used to measure fissile material content of spent, highly enriched reactor fuel. The mode of operation used, results of analyzing 176 fuel packages and recommended system improvements are discussed. Four measurements were made on each of the fuel packages with the mean of the 176 standard deviations being 2.03 percent of value. The maximum individual standard deviation was 9.27 percent. Appendixes concerning imprecisions introduced by counting statistics and crane speed irregularities are given. Use of an improved neutron source shuffler, an improved fuel package motion system and modernized computer system should permit system performance to be limited mainly by counting statistics, to about 1.5 percent of measured value. A stronger source could then be installed to further enhance system operation. 16 figs., 3 tabs

  15. Upgrade of detectors of neutron instruments at Neutron Physics Laboratory in Řež

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko, E.I., E-mail: litvin@nf.jinr.ru [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 14980 Dubna (Russian Federation); Ryukhtin, V. [Nuclear Physics Institute of the CAS v.v.i., Řež 130, 250 68 Řež (Czech Republic); Bogdzel, A.A.; Churakov, A.V. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 14980 Dubna (Russian Federation); Farkas, G. [Charles University in Prague, Department of Physics of Material, Ke Karlovu 5, CZ-12116 Prague (Czech Republic); Hervoches, Ch.; Lukas, P. [Nuclear Physics Institute of the CAS v.v.i., Řež 130, 250 68 Řež (Czech Republic); Pilch, J. [Nuclear Physics Institute of the CAS v.v.i., Řež 130, 250 68 Řež (Czech Republic); Institute of Physics, Czech Academy of Sciences, Na Slovance 1992/2, 1822 Prague (Czech Republic); Saroun, J.; Strunz, P. [Nuclear Physics Institute of the CAS v.v.i., Řež 130, 250 68 Řež (Czech Republic); Zhuravlev, V.V. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 14980 Dubna (Russian Federation)

    2017-01-01

    Three neutron instruments at the Neutron Physics Laboratory (NPL) in Řež near Prague — small-angle scattering (SANS) MAUD, strain scanner SPN-100 and strain diffractometer TKSN-400 — have been modernized recently with new 2D position-sensitive detectors (PSDs) from JINR, Dubna. Here we report on the progress made in relation to the possibilities of the diffractometers due to the improved performance of the detectors. The first part of the paper is dedicated to a detailed description of the hardware and software of the PSDs, as well as its integration with the in-house experimental control software. Then practical examples of neutron scattering experiments for each of the upgraded facilities are presented.

  16. Practical aspects of operating a neutron activation analysis laboratory

    International Nuclear Information System (INIS)

    1990-07-01

    This book is intended to advise in everyday practical problems related to operating a neutron activation analysis (NAA) laboratory. It gives answers to questions like ''what to use NAA for'', ''how to find relevant research problems'', ''how to find users for the technique'', ''how to estimate the cost of the analysis and how to finance the work'', ''how to organize the work in a rational way'' and ''how to perform the quality control''. It gives advice in choosing staff, equipment, and consumables and how to design facilities and procedures according to need and available resources. Potential applications of economic or environmental importance, reactor facilities, counting and measuring equipment of the lab, cooperation with other analytical groups and competitiveness of NAA are discussed by experienced analysts. The compiled 8 tables of data useful for neutron activation analysts are a valuable asset for research labs as well as industrial quality control units. Refs, figs and tabs

  17. Structural Analysis and Seismic Design for Cold Neutron Laboratory Building

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Sangik; Kim, Y. K.; Kim, H. R

    2007-05-15

    This report describes all the major results of the dynamic structural analysis and seismic design for the Cold Neutron Laboratory Building which is classified in seismic class II. The results are summarized of the ground response spectrum as seismic input loads, mechanical properties of subsoil, the buoyancy stability due to ground water, the maximum displacement of the main frame under the seismic load and the member design. This report will be used as a basic design report to maintenance its structural integrity in future.

  18. Structural Analysis and Seismic Design for Cold Neutron Laboratory Building

    International Nuclear Information System (INIS)

    Wu, Sangik; Kim, Y. K.; Kim, H. R.

    2007-05-01

    This report describes all the major results of the dynamic structural analysis and seismic design for the Cold Neutron Laboratory Building which is classified in seismic class II. The results are summarized of the ground response spectrum as seismic input loads, mechanical properties of subsoil, the buoyancy stability due to ground water, the maximum displacement of the main frame under the seismic load and the member design. This report will be used as a basic design report to maintenance its structural integrity in future

  19. Quality Assurance and Control in Laboratory using Neutron Activation Analysis

    International Nuclear Information System (INIS)

    Chung, Y. S.; Moon, J. H.; Sun, G. M.; Kim, S. H.; Baek, S. Y.; Lim, J. M.; Kim, H. R.

    2007-01-01

    In accordance with the increment of international trade associated with the worldwide globalization, the importance of quality assurance and control for the commodity produced from one's own country has been stressed. ISO (International Organization for Standards) defines quality control as 'the operational techniques and activities that are used to fulfill the requirements for quality'. Since 1996, the HANARO research reactor in the Korea Atomic Energy Research Institute has been operated thereafter initial critical operation on April 1995. Neutron activation analysis system and applied techniques which is one of a nuclear analytical technologies using reactor neutrons has been developed for user's supporting and the establishment of the quality system for a measurement and analysis, testing and inspection was implemented successfully. On the basis of the qualified NAA system, the test and measurement of more than 1500 samples which is requested from 30 organizations including industrial companies, universities and institutes carried out in NAA laboratory annually. Moreover, as the goal of mutual recognition agreement (MRA) which can be removed a technical barrier in international trade, the objectivity and the confidence of analytical quality in NAA laboratory became established through the installation of international accreditation system by implementing analytical quality system in accordance with international standards in 2001. The aim of the report was to summarize the technical management of introduction, methods and the results for a quality control and assurance which should be performed in NAA technique using the HANARO research reactor. The report will help building up effective quality control strategy in the future

  20. A virtual laboratory for neutron and synchrotron strain scanning

    International Nuclear Information System (INIS)

    James, J.A.; Santisteban, J.R.; Edwards, L.; Daymond, M.R.

    2004-01-01

    The new generation of dedicated Engineering Strain Scanners at neutron and synchrotron facilities offer considerable improvements in both counting time and spatial resolution. In order to make full use of these advances in instrumentation, the routine tasks associated with setting up measurement runs and analysing the data need to be made as efficient as possible. Such tasks include the planning of the experiment, the alignment and positioning of the specimen, the least-squares refinement of diffraction spectra, the definition of strain in the sample coordinate system, and its visualization within a 3D model of the specimen. With this aim in mind, we have written a software providing support for most of these operations. The approach is based on a virtual lab consisting of 3D models of the sample and laboratory equipment. The system has been developed for ENGIN-X, the new engineering strain scanner recently commissioned at ISIS, but it is flexible enough to be ported to other neutron or synchrotron strain scanners. The software has been designed with visiting industrial and academic researchers in mind, users who need to be able to control the instrument after only a short period of training

  1. Binary neutron star mergers: a review of Einstein's richest laboratory.

    Science.gov (United States)

    Baiotti, Luca; Rezzolla, Luciano

    2017-09-01

    In a single process, the merger of binary neutron star systems combines extreme gravity, the copious emission of gravitational waves, complex microphysics and electromagnetic processes, which can lead to astrophysical signatures observable at the largest redshifts. We review here the recent progress in understanding what could be considered Einstein's richest laboratory, highlighting in particular the numerous significant advances of the last decade. Although special attention is paid to the status of models, techniques and results for fully general-relativistic dynamical simulations, a review is also offered on the initial data and advanced simulations with approximate treatments of gravity. Finally, we review the considerable amount of work carried out on the post-merger phase, including black-hole formation, torus accretion onto the merged compact object, the connection with gamma-ray burst engines, ejected material, and its nucleosynthesis.

  2. Quality Assurance and Control in Laboratory using Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Y. S.; Moon, J. H.; Sun, G. M.; Kim, S. H.; Baek, S. Y.; Lim, J. M.; Kim, H. R

    2007-01-15

    In accordance with the increment of international trade associated with the worldwide globalization, the importance of quality assurance and control for the commodity produced from one's own country has been stressed. ISO (International Organization for Standards) defines quality control as 'the operational techniques and activities that are used to fulfill the requirements for quality'. Since 1996, the HANARO research reactor in the Korea Atomic Energy Research Institute has been operated thereafter initial critical operation on April 1995. Neutron activation analysis system and applied techniques which is one of a nuclear analytical technologies using reactor neutrons has been developed for user's supporting and the establishment of the quality system for a measurement and analysis, testing and inspection was implemented successfully. On the basis of the qualified NAA system, the test and measurement of more than 1500 samples which is requested from 30 organizations including industrial companies, universities and institutes carried out in NAA laboratory annually. Moreover, as the goal of mutual recognition agreement (MRA) which can be removed a technical barrier in international trade, the objectivity and the confidence of analytical quality in NAA laboratory became established through the installation of international accreditation system by implementing analytical quality system in accordance with international standards in 2001. The aim of the report was to summarize the technical management of introduction, methods and the results for a quality control and assurance which should be performed in NAA technique using the HANARO research reactor. The report will help building up effective quality control strategy in the future.

  3. A High Intensity Multi-Purpose D-D Neutron Generator for Nuclear Engineering Laboratories

    International Nuclear Information System (INIS)

    Ka-Ngo Leung; Jasmina L. Vujic; Edward C. Morse; Per F. Peterson

    2005-01-01

    This NEER project involves the design, construction and testing of a low-cost high intensity D-D neutron generator for teaching nuclear engineering students in a laboratory environment without radioisotopes or a nuclear reactor. The neutron generator was designed, fabricated and tested at Lawrence Berkeley National Laboratory (LBNL)

  4. Neutron generator production mission in a national laboratory.

    Energy Technology Data Exchange (ETDEWEB)

    Pope, Larry E.

    2007-08-01

    In the late 1980's the Department of Energy (DOE) faced a future budget shortfall. By the spring of 1991, the DOE had decided to manage this problem by closing three production plants and moving production capabilities to other existing DOE sites. As part of these closings, the mission assignment for fabrication of War Reserve (WR) neutron generators (NGs) was transferred from the Pinellas Plant (PP) in Florida to Sandia National Laboratories, New Mexico (SNL/NM). The DOE directive called for the last WR NG to be fabricated at the PP before the end of September 1994 and the first WR NG to be in bonded stores at SNL/NM by October 1999. Sandia National Laboratories successfully managed three significant changes to project scope and schedule and completed their portion of the Reconfiguration Project on time and within budget. The PP was closed in October 1995. War Reserve NGs produced at SNL/NM were in bonded stores by October 1999. The costs of the move were recovered in just less than five years of NG production at SNL/NM, and the annual savings today (in 1995 dollars) is $47 million.

  5. Study and development of a method allowing the identification of actinides inside nuclear waste packages, by active neutron or photon interrogation and delayed gamma-ray spectrometry; Etude et developpement d'une technique de dosage des actinides dans les colis de dechets radioactifs par interrogation photonique ou neutronique active et spectrometrie des gamma retardes

    Energy Technology Data Exchange (ETDEWEB)

    Carrel, F

    2007-10-15

    An accurate estimation of the alpha-activity of a nuclear waste package is necessary to select the best mode of storage. The main purpose of this work is to develop a non-destructive active method, based on the fission process and allowing the identification of actinides ({sup 235}U, {sup 238}U, {sup 239}Pu). These three elements are the main alpha emitters contained inside a package. Our technique is based on the detection of delayed gammas emitted by fission products. These latter are created by irradiation with the help of a neutron or photon beam. Performances of this method have been investigated after an Active Photon or Neutron Interrogation (INA or IPA). Three main objectives were fixed in the framework of this thesis. First, we measured many yields of photofission products to compensate the lack of data in the literature. Then, we studied experimental performances of this method to identify a given actinide ({sup 239}Pu in fission, {sup 235}U in photofission) present in an irradiated mixture. Finally, we assessed the application of this technique on different mock-up packages for both types of interrogation (118 l mock-up package containing EVA in fission, 220 l mock-up package with a wall of concrete in photofission). (author)

  6. Neutron background measurements at China Jinping underground laboratory with a Bonner multi-sphere spectrometer

    Science.gov (United States)

    Hu, Qingdong; Ma, Hao; Zeng, Zhi; Cheng, Jianping; Chen, Yunhua; He, Shengming; Li, Junli; Shen, Manbin; Wu, Shiyong; Yue, Qian; Yue, Jianfeng; Zhang, Hui

    2017-07-01

    The neutron background spectrum from thermal neutron to 20 MeV fast neutron was measured at the first experimental hall of China Jinping underground laboratory with a Bonner multi-sphere spectrometer. The measurement system was validated by a 252Cf source and inconformity was corrected. Due to micro charge discharge, the dataset was screened and background from the steel of the detectors was estimated by MC simulation. Based on genetic algorithm we obtained the energy distribution of the neutron and the total flux of neutron was (2.69±1.02) ×10-5 cm-2 s-1.

  7. Anisotropy of neutron sources of Neutron Metrology Laboratory, IRD, Brazil; Anisotropia de fontes de neutrons do Laboratorio de Metrologia de Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Silva, A.C.F.; Silva, F.S.; Leite, S.P.; Creazolla, P.G; Patrão, K.C.S.; Fonseca, E.S. da; Fernandes, S.S.; Pereira, W.W., E-mail: Alexander.camargo@oi.com.br, E-mail: s.felippesouza@gmail.com, E-mail: karla@ird.gov.br, E-mail: walsan@ird.gov.br, E-mail: evaldo@ird.gov.br, E-mail: simonesilvafernandes@gmail.com, E-mail: prycyllacreazolla@gmail.com, E-mail: leitesprk@gmail.com [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Laboratorio Nacional de Metrologia; Fundação Técnico Educacional Souza Marques (FTESM), Rio de Janeiro, RJ (Brazil)

    2017-11-01

    The anisotropy measurements have as main objective to define the emission of the radiation by different angles of an encapsulated neutron source. The measurements were performed using a Long Accuracy Counter (PLC) Detector in the Low Dispersion Room of the LNMRI / IRD with different neutron sources. Each measurement was made using a support for the source, emulated through an arduino system to rotate it. The carrier is marked with a variation of 5 °, ranging from 0 ° to 360 °, for the work in question only half, 0 ° to 180 ° is used for a total of nineteen steps. In this paper three sources of {sup 241}AmBe (α, n) 5.92 GBq (16 Ci) were used, neutron sources having the following dimensions: 105 mm in height and 31 mm in diameter. The PLC was positioned at a distance of 2 meters from the neutron source and has a radius of 15 cm for the detection area. The anisotropy factor of the {sup 241}AmBe source was 17%. The results in this work will focus mainly on the area of radioprotection and studies that will improve the process of routine measurements in laboratories and instrument calibrations. (author)

  8. Overview of the Neutron Radiography and Computed Tomography at the Oak Ridge National Laboratory and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Bilheux, Hassina Z [ORNL; Bilheux, Jean-Christophe [ORNL; Tremsin, Anton S [University of California, Berkeley; Santodonato, Louis J [ORNL; Dehoff, Ryan R [ORNL; Kirka, Michael M [ORNL; Bailey, William Barton [ORNL; Keener, Wylie S [ORNL; Herwig, Kenneth W [ORNL

    2015-01-01

    The Oak Ridge National Laboratory (ORNL) Neutron Sciences Directorate (NScD) has installed a neutron imaging (NI) beam line at the High Flux Isotope Reactor (HFIR) cold guide hall. The CG-1D beam line produces cold neutrons for a broad range of user research spanning from engineering to material research, additive manufacturing, vehicle technologies, archaeology, biology, and plant physiology. Recent efforts have focused on increasing flux and spatial resolution. A series of selected engineering applications is presented here. Historically and for more than four decades, neutron imaging (NI) facilities have been installed exclusively at continuous (i.e. reactor-based) neutron sources rather than at pulsed sources. This is mainly due to (1) the limited number of accelerator-based facilities and therefore the fierce competition for beam lines with neutron scattering instruments, (2) the limited flux available at accelerator-based neutron sources and finally, (3) the lack of high efficiency imaging detector technology capable of time-stamping pulsed neutrons with sufficient time resolution. Recently completed high flux pulsed proton-driven neutron sources such as the ORNL Spallation Neutron Source (SNS) at ORNL and the Japanese Spallation Neutron Source (JSNS) of the Japan Proton Accelerator Research Complex (J-PARC) in Japan produce high neutron fluxes that offer new and unique opportunities for NI techniques. Pulsed-based neutron imaging facilities RADEN and IMAT are currently being built at J-PARC and the Rutherford National Laboratory in the U.K., respectively. ORNL is building a pulsed neutron imaging beam line called VENUS to respond to the U.S. based scientific community. A team composed of engineers, scientists and designers has developed a conceptual design of the future VENUS imaging instrument at the SNS.

  9. Los Alamos National Laboratory Weapons Neutron Research Facility

    International Nuclear Information System (INIS)

    Woods, R.

    1981-01-01

    The Weapons Neutron Research (WNR) spallation neutron source utilizes 800-MeV protons from the Los Alamos Meson Physics linac. The proton beam transport system, the target systems, and the data acquisition and control system are described. Operating experience, present status, and planned improvements are discussed

  10. Progress report from the Studsvik Neutron Research Laboratory 1987-89

    International Nuclear Information System (INIS)

    Dahlborg, U.; Ebbsjoe, I.; Holmqvist, B.

    1993-01-01

    The present publication contains information from activities at the Studsvik Neutron Research Laboratory (NFL) and the Department of Neutron Research. NFL is the base for the research activities at the Studvik reactors. It is administrated by the University of Uppsala and is established to facilitate reactor based research. The laboratory is intended to, in co-operation with institutes and departments at universities in Sweden, develop, construct and maintain experimental equipment for this kind of research and to make it available for scientists at Swedish universitites and, if possible, also to scientists outside the universities. The research at the Studsvik facilities has during 1989 been performed by groups from Uppsala University, Royal Institute of Technology in Stockholm, Chalmers Technical University, Gothenburg, and by scientists at NFL. The research program of the groups is divided into three main areas, scattering of thermal neutrons, nuclear chemistry and nuclear physics, and neutron capture radiography. The program for subatomic physics, especially neutron physics, at the Department for Neutron Research, Uppsala University has also staff permanently placed at NFL but they are in their research using the facilities at the The Svedberg Laboratory, Uppsala. In addition to supporting research NFL has also put substantial efforts on creating facilities for training of undergraduate students. Thus a facility for practical exercises in neutron physics, activation analysis and radiography has recently been installed at the R2-0 reactor as a collaboration between NFL, Dept. of Neutron Research, Upppsala and Department for Reactor Physics, KTH

  11. Determination of the scattered radiation at the Neutron Calibration Laboratory of IPEN, SP, Brazil

    International Nuclear Information System (INIS)

    Alvarenga, Tallyson; Valeriano, Caio C.S.; Caldas, Linda V.E.; Federico, Claudio A.

    2016-01-01

    With the increased use of techniques using neutron radiation, there has been a considerable growth in the number of detectors for this kind of radiation. A neutron calibration laboratory with neutron radiation ( 241 AmBe) was designed. In practical situations of this type of laboratory, one of the main problems is related to the knowledge of scattered radiation. In order to evaluate this scattered radiation, simulations were carried out without the presence of structural elements and with the complete room. Fourteen measuring points were evaluated in different directions at various distances. (author)

  12. Use of cold neutrons for condensed matter research at the neutron guide laboratory ELLA in Juelich

    International Nuclear Information System (INIS)

    Schaetzler, R.; Monkenbusch, M.

    1998-01-01

    Cold neutrons produced in the FRJ-2 DIDO reactor are guided into the external hall ELLA. It hosts 10 instruments that are red by three major neutron guides. Cold neutrons allow for diffraction and small angle scattering experiments resolving mesoscopic structures (1 to 100 nm). Contrast variation by isotopic substitution in chemically identical species yields information uniquely accessible bi neutrons. Inelastic scattering of cold neutrons allows investigating slow molecular motions because the low neutron velocity results in large relative velocity changes even at small energy transfers. The SANS machines and the HADAS reflectometer serve as structure probes and the backscattering BSS1 and spin-echo spectrometers NSE as main dynamics probes. Besides this the diffuse scattering instrument DNS and the lattice parameter determination instrument LAP deal mainly with crystals and their defects. Finally the beta-NMR and the EKN position allow for methods other than scattering employing nuclear reactions for solid state physics, chemistry and biology/medicine. (author)

  13. SPES and the neutron facilities at Laboratori Nazionali di Legnaro

    Science.gov (United States)

    Silvestrin, L.; Bisello, D.; Esposito, J.; Mastinu, P.; Prete, G.; Wyss, J.

    2016-03-01

    The SPES Radioactive Ion Beam (RIB) facility, now in the construction phase at INFN-LNL, has the aim to provide high-intensity and high-quality beams of neutron-rich nuclei for nuclear physics research as well as to develop an interdisciplinary research center based on the cyclotron proton beam. The SPES system is based on a dual-exit high-current cyclotron, with tunable proton beam energy 35-70MeV and 0.20-0.75mA. The first exit is used as proton driver to supply an ISOL system with an UCx Direct Target able to sustain a power of 10kW. The expected fission rate in the target is of the order of 10^{13} fissions per second. The exotic isotopes will be re-accelerated by the ALPI superconducting LINAC at energies of 10 A MeV and higher, for masses around A=130 amu, with an expected beam intensity of 10^7 - 10^9 pps. The second exit will be used for applied physics: radioisotope production for medicine and neutrons for material studies. Fast neutron spectra will be produced by the proton beam interaction with a conversion target. A production rate in excess of 10^{14} n/s can be achieved: this opens up the prospect of a high-flux neutron irradiation facility (NEPIR) to produce both discrete and continuous energy neutrons. A direct proton beam line is also envisaged. NEPIR and the direct proton line would dramatically increase the wide range of irradiation facilities presently available at LNL. We also present LENOS, a proposed project dedicated to accurate neutron cross-sections measurements using intense, well-characterized, broad energy neutron beams. Other activities already in operation at LNL are briefly reviewed: the SIRAD facility for proton and heavy-ion irradiation at the TANDEM-ALPI accelerator and the BELINA test facility at CN van de Graaff accelerator.

  14. Characterization of the Neutron Fields in the Lawrence Livermore National Laboratory (LLNL) Radiation Calibration Laboratory Low Scatter Calibration Facility

    Energy Technology Data Exchange (ETDEWEB)

    Radev, R

    2009-09-04

    In June 2007, the Department of Energy (DOE) revised its rule on Occupational Radiation Protection, Part 10 CFR 835. A significant aspect of the revision was the adoption of the recommendations outlined in International Commission on Radiological Protection (ICRP) Report 60 (ICRP-60), including new radiation weighting factors for neutrons, updated internal dosimetric models, and dose terms consistent with the newer ICRP recommendations. ICRP-60 uses the quantities defined by the International Commission on Radiation Units and Measurements (ICRU) for personnel and area monitoring including the ambient dose equivalent H*(d). A Joint Task Group of ICRU and ICRP has developed various fluence-to-dose conversion coefficients which are published in ICRP-74 for both protection and operational quantities. In February 2008, Lawrence Livermore National Laboratory (LLNL) replaced its old pneumatic transport neutron irradiation system in the Radiation Calibration Laboratory (RCL) Low Scatter Calibration Facility (B255, Room 183A) with a Hopewell Designs irradiator model N40. The exposure tube for the Hopewell system is located close to, but not in exactly the same position as the exposure tube for the pneumatic system. Additionally, the sources for the Hopewell system are stored in Room 183A where, prior to the change, they were stored in a separate room (Room 183C). The new source configuration and revision of the 10 CFR 835 radiation weighting factors necessitate a re-evaluation of the neutron dose rates in B255 Room 183A. This report deals only with the changes in the operational quantities ambient dose equivalent and ambient dose rate equivalent for neutrons as a result of the implementation of the revised 10 CFR 835. In the report, the terms 'neutron dose' and 'neutron dose rate' will be used for convenience for ambient neutron dose equivalent and ambient neutron dose rate equivalent unless otherwise stated.

  15. Polarized 3He Neutron Spin Filters at Oak Ridge National Laboratory

    Science.gov (United States)

    Jiang, C. Y.; Tong, X.; Brown, D. R.; Lee, W. T.; Ambaye, H.; Craig, J. W.; Crow, L.; Culbertson, H.; Goyette, R.; Graves-Brook, M. K.; Hagen, M. E.; Kadron, B.; Lauter, V.; McCollum, L. W.; Robertson, J. L.; Winn, B.; Vandegrift, A. E.

    The unique advantages of using polarized 3He as neutron spin filters, such as broadband and wide angular acceptance of neutron beams, have made it widely used in most neutron facilities. Over the last several years, we have developed a polarized 3He program to meet the increasing needs of 3He based neutron spin filters at the Oak Ridge National Laboratory's (ORNL) High Flux Isotope Reactor (HFIR) and Spallation Neutron Source (SNS). At ORNL, polarized 3He is produced using Spin Exchange Optical Pumping (SEOP). We have constructed a 3He cell fabrication station to produce 3He cells of different pressures and dimensions. Two optical pumping stations have been built in the lab to perform ex situ pumping of 3He. A compact in situ3He analyzer has been constructed and installed for the Magnetism Reflectometer (MAGICS) at SNS. A novel polarized 3He filling station for the Hybrid Spectrometer (HYSPEC) at SNS is under development.

  16. An apparatus for studying spallation neutrons in the Aberdeen Tunnel laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Blyth, S.C. [Department of Electro-Optical Engineering, National United University, Miao-Li, Taiwan (China); Chan, Y.L.; Chen, X.C.; Chu, M.C. [Department of Physics, Chinese University of Hong Kong, Hong Kong (China); Hahn, R.L. [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Ho, T.H.; Hsiung, Y.B. [Department of Physics, National Taiwan University, Taipei, Taiwan (China); Hu, B.Z. [Institute of Physics, National Chiao-Tung University, Hsinchu, Taiwan (China); Kwan, K.K.; Kwok, M.W. [Department of Physics, Chinese University of Hong Kong, Hong Kong (China); Kwok, T., E-mail: goodtalent@gmail.com [Department of Physics, University of Hong Kong, Hong Kong (China); Lau, Y.P.; Lee, K.P.; Leung, J.K.C.; Leung, K.Y. [Department of Physics, University of Hong Kong, Hong Kong (China); Lin, G.L. [Institute of Physics, National Chiao-Tung University, Hsinchu, Taiwan (China); Lin, Y.C. [Department of Physics, Chinese University of Hong Kong, Hong Kong (China); Luk, K.B. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720 (United States); Luk, W.H. [Department of Physics, Chinese University of Hong Kong, Hong Kong (China); Ngai, H.Y. [Department of Physics, University of Hong Kong, Hong Kong (China); and others

    2013-09-21

    In this paper, we describe the design, construction and performance of an apparatus installed in the Aberdeen Tunnel laboratory in Hong Kong for studying spallation neutrons induced by cosmic-ray muons under a vertical rock overburden of 611 m water equivalent (m.w.e.). The apparatus comprises six horizontal layers of plastic-scintillator hodoscopes for determining the direction and position of the incident cosmic-ray muons. Sandwiched between the hodoscope planes is a neutron detector filled with 650 kg of liquid scintillator doped with about 0.06% of Gadolinium by weight for improving the efficiency of detecting the spallation neutrons. Performance of the apparatus is also presented.

  17. Neutron Imaging of Archaeological Bronzes at the Oak Ridge National Laboratory

    Science.gov (United States)

    Ryzewski, K.; Herringer, S.; Bilheux, H.; Walker, L.; Sheldon, B.; Voisin, S.; Bilheux, J.-C.; Finocchiaro, V.

    This article presents the initial results of 2-D and 3-D neutron imaging of bronze artifacts using the CG-1D prototype beamline at the High Flux Isotope Reactor (HFIR) located at the Oak Ridge National Laboratory (ORNL). Neutron imaging is a non-destructive technique capable of producing unprecedented three-dimensional information on archaeomaterials, including qualitative, quantitative, and visual data on impurities, composition change, voids, and structure at macro-scale levels. The initial results presented in this publication highlight how information from neutron imaging can provide otherwise inaccessible details about the methods and materials that ancient craftspeople used in creating bronze objects.

  18. Neutron Standards Laboratory of the CIEMAT; Laboratorio de Patrones Neutronicos del CIEMAT

    Energy Technology Data Exchange (ETDEWEB)

    Guzman G, K. A. [Universidad Politecnica de Madrid, C. Jose Gutierrez Abascal 2, 28006 Madrid (Spain); Mendez V, R. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Av. Complutense 40, 28040 Madrid (Spain); Vega C, H. R., E-mail: karen.guzman.garcia@alumnos.upm.es [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2014-08-15

    By means of a calculation series with Monte Carlo methods and the code MCNPX was characterized the neutrons field produced by the existent calibration sources in the Neutron Standards Laboratory of the Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT). The laboratory has two neutron calibration sources one of {sup 241}AmBe and other {sup 252}Cf that are stored in a water pool. A detailed three-dimensional model of the room was built with the base of stainless steel remarking in the selector to the sources that situates them to 4 m of the floor to be irradiated on the irradiation table and the storage pool. Each one of the sources was defined on the model in its double steel encapsulated. The spectra were calculated with different cases with the purpose of to calculate the contribution of each element that impacts to the neutrons transport. The spectra of the calibration sources were calculated to different distances regarding the source from 0, 15, 35, 50 to 300 cm on the base and in a same way the values of the ambient dose equivalent using the approaches of the ICRP-74. The results show clearly that the great contribution in the modification of the spectrum is attributed to the walls, and floor of the Neutron Standards Laboratory installations. (Author)

  19. Progress report from the Studsvik Neutron Research Laboratory 1990-91

    International Nuclear Information System (INIS)

    Dahlborg, U.; Ebbsjoe, I.; Holmqvist, B.

    1992-01-01

    The Studsvik Neutron Research Laboratory (NFL) is the base for the research activities at the Studsvik reactors. It is administrated by the University of Uppsala and is established to facilitate reactor based research. The laboratory is intended to, in co-operation with institutes and department at universities in Sweden, develop, construct and maintain experimental equipment for this kind of research and to make it available for scientists at Swedish universities and, if possible, also to scientists outside the universities. The research at the Studsvik facilities has during 1990 and 1991 been performed by groups form Uppsala University, Royal Institute of Technology, Stockholm, Chalmers Technical University, Gothenburg, and by scientists at NFL. The research programme of the groups is divided into three main areas, scattering of thermal neutrons, nuclear chemistry/nuclear physics, and neutron capture radiography

  20. Note on some quasielastic neutron scattering analysis programs on the Rutherford Laboratory IBM 360/195

    International Nuclear Information System (INIS)

    Richardson, R.M.

    1979-12-01

    A suite of programs for analysing neutron scattering data from time-of-flight spectrometers has been implemented on the Rutherford Laboratory IBM 360/195 computer system. The programs are intended for near inelastic and quasielastic data and operate by convoluting the measured instrumental resolution function with a model scattering function before fitting to the measured sample scattering law. (author)

  1. Monte Carlo analysis of the Neutron Standards Laboratory of the CIEMAT

    International Nuclear Information System (INIS)

    Vega C, H. R.; Mendez V, R.; Guzman G, K. A.

    2014-10-01

    By means of Monte Carlo methods was characterized the neutrons field produced by calibration sources in the Neutron Standards Laboratory of the Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT). The laboratory has two neutron calibration sources: 241 AmBe and 252 Cf which are stored in a water pool and are placed on the calibration bench using controlled systems at distance. To characterize the neutrons field was built a three-dimensional model of the room where it was included the stainless steel bench, the irradiation table and the storage pool. The sources model included double encapsulated of steel, as cladding. With the purpose of determining the effect that produces the presence of the different components of the room, during the characterization the neutrons spectra, the total flow and the rapidity of environmental equivalent dose to 100 cm of the source were considered. The presence of the walls, floor and ceiling of the room is causing the most modification in the spectra and the integral values of the flow and the rapidity of environmental equivalent dose. (Author)

  2. Neutron activation analysis in an industrial laboratory using an off-site nuclear reactor

    International Nuclear Information System (INIS)

    Osborn, T.W.; Broering, W.B.

    1977-01-01

    A multifunctional research laboratory, such as Procter and Gamble's Miami Valley Laboratories, requires elemental analyses on many materials. A general survey technique is important even if the information it provides is incomplete or is less precise than single element analyses. Procter and Gamble has developed neutron activation analysis (NAA) capabilities using a nuclear reactor several hundred miles away. The concentration of 40 to 50 elements can be determined in a variety of matrices. We have found NAA to be a powerful supplement to some of the more classical analytical techniques even without having an on-site neutron source. We have also found an automated data acquisition system to be essential for the successful application of NAA in an industrial laboratory

  3. Upgrade of detectors of neutron instruments at Neutron Physics Laboratory in Rez

    Czech Academy of Sciences Publication Activity Database

    Litvinenko, E. I.; Ryukhtin, Vasyl; Bogdzel, A. A.; Churakov, A. V.; Farkas, G.; Hervoches, Charles; Lukáš, Petr; Pilch, Jan; Šaroun, Jan; Strunz, Pavel; Zhuravlev, V. V.

    2017-01-01

    Roč. 841, JAN (2017), s. 5-11 ISSN 0168-9002 R&D Projects: GA MŠk LG14004; GA MŠk LM2015056; GA ČR GB14-36566G Institutional support: RVO:68378271 ; RVO:61389005 Keywords : neutron scattering * gaseous position-sensitive detector * delay line readout Subject RIV: BM - Solid Matter Physics ; Magnetism; JG - Metallurgy (FZU-D) OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.); Materials engineering (FZU-D) Impact factor: 1.362, year: 2016

  4. Determination of the scattered radiation at the Neutron Calibration Laboratory of IPEN, SP, Brazil; Determinacao da radiacao espalhada no Laboratorio de Calibracao com Neutrons do IPEN

    Energy Technology Data Exchange (ETDEWEB)

    Alvarenga, Tallyson; Valeriano, Caio C.S.; Caldas, Linda V.E., E-mail: talvarenga@ipen.br, E-mail: claudiofederico@ieav.cta.br, E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Federico, Claudio A. [Instituto de Estudos Avancados, Departamento de Ciencia e Tecnologia Aeroespacial (DCTA/IEAv), Sao Paulo, SP (Brazil)

    2016-07-01

    With the increased use of techniques using neutron radiation, there has been a considerable growth in the number of detectors for this kind of radiation. A neutron calibration laboratory with neutron radiation ({sup 241}AmBe) was designed. In practical situations of this type of laboratory, one of the main problems is related to the knowledge of scattered radiation. In order to evaluate this scattered radiation, simulations were carried out without the presence of structural elements and with the complete room. Fourteen measuring points were evaluated in different directions at various distances. (author)

  5. Study for correction of neutron scattering in the calibration of the albedo individual monitor from the Neutron Laboratory (LN), IRD/CNEN-RJ, Brazil

    International Nuclear Information System (INIS)

    Freitas, B.M.; Silva, A.X. da

    2014-01-01

    The Instituto de Radioprotecao e Dosimetria (IRD) runs a neutron individual monitoring service with albedo type monitor and thermoluminescent detectors (TLD). Moreover the largest number of workers exposed to neutrons in Brazil is exposed to 241 Am-Be fields. Therefore a study of the response of albedo dosemeter due to neutron scattering from 241 Am-Be source is important for a proper calibration. In this work, it has been evaluated the influence of the scattering correction in two distances at the Low Scattering Laboratory of the Neutron Laboratory of the Brazilian National Laboratory (Lab. Nacional de Metrologia Brasileira de Radiacoes Ionizantes) in the calibration of that albedo dosemeter for a 241 Am-Be source. (author)

  6. Design and verification of the shielding around the new Neutron Standards Laboratory (LPN) at CIEMAT.

    Science.gov (United States)

    Méndez-Villafañe, R; Guerrero, J E; Embid, M; Fernández, R; Grandio, R; Pérez-Cejuela, P; Márquez, J L; Alvarez, F; Ortego, P

    2014-10-01

    The construction of the new Neutron Standards Laboratory at CIEMAT (Laboratorio de Patrones Neutrónicos) has been finalised and is ready to provide service. The facility is an ∼8 m×8 m×8 m irradiation vault, following the International Organization for Standardization 8529 recommendations. It relies on several neutron sources: a 5-GBq (5.8× 10(8) s(-1)) (252)Cf source and two (241)Am-Be neutron sources (185 and 11.1 GBq). The irradiation point is located 4 m over the ground level and in the geometrical centre of the room. Each neutron source can be moved remotely from its storage position inside a water pool to the irradiation point. Prior to this, an important task to design the neutron shielding and to choose the most appropriate materials has been developed by the Radiological Security Unit and the Ionizing Radiations Metrology Laboratory. MCNPX was chosen to simulate the irradiation facility. With this information the walls were built with a thickness of 125 cm. Special attention was put on the weak points (main door, air conditioning system, etc.) so that the ambient dose outside the facility was below the regulatory limits. Finally, the Radiation Protection Unit carried out a set of measurements in specific points around the installation with an LB6411 neutron monitor and a Reuter-Stokes high-pressure ion chamber to verify experimentally the results of the simulation. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Measurements of the neutron spectrum in transit to Mars on the Mars Science Laboratory.

    Science.gov (United States)

    Köhler, J; Ehresmann, B; Zeitlin, C; Wimmer-Schweingruber, R F; Hassler, D M; Reitz, G; Brinza, D E; Appel, J; Böttcher, S; Böhm, E; Burmeister, S; Guo, J; Lohf, H; Martin, C; Posner, A; Rafkin, S

    2015-04-01

    The Mars Science Laboratory spacecraft, containing the Curiosity rover, was launched to Mars on 26 November 2011. Although designed for measuring the radiation on the surface of Mars, the Radiation Assessment Detector (RAD) measured the radiation environment inside the spacecraft during most of the 253-day, 560-million-kilometer cruise to Mars. An important factor for determining the biological impact of the radiation environment inside the spacecraft is the specific contribution of neutrons with their high biological effectiveness. We apply an inversion method (based on a maximum-likelihood estimation) to calculate the neutron and gamma spectra from the RAD neutral particle measurements. The measured neutron spectrum (12-436 MeV) translates into a radiation dose rate of 3.8±1.2 μGy/day and a dose equivalent of 19±5 μSv/day. Extrapolating the measured spectrum (0.1-1000 MeV), we find that the total neutron-induced dose rate is 6±2 μGy/day and the dose equivalent rate is 30±10 μSv/day. For a 360 day round-trip from Earth to Mars with comparable shielding, this translates into a neutron induced dose equivalent of about 11±4 mSv. Copyright © 2015 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.

  8. A Comparison of Neutron-Based Non-Destructive Assessment Methods for Chemical Warfare Materiel and High Explosives

    Science.gov (United States)

    Seabury, E. H.; Chichester, D. L.; Wharton, C. J.; Caffrey, A. J.

    2009-03-01

    Prompt Gamma Neutron Activation Analysis (PGNAA) systems employ neutrons as a probe to interrogate items, e.g. chemical warfare materiel-filled munitions. The choice of a neutron source in field-portable systems is determined by its ability to excite nuclei of interest, operational concerns such as radiological safety and ease-of-use, and cost. Idaho National Laboratory's PINS Chemical Assay System has traditionally used a 252Cf isotopic neutron source, but recently a deuterium-tritium (DT) electronic neutron generator (ENG) has been tested as an alternate neutron source. This paper presents the results of using both of these neutron sources to interrogate chemical warfare materiel (CWM) and high explosive (HE) filled munitions.

  9. Group knowledge in interrogative epistemology

    NARCIS (Netherlands)

    Baltag, A.; Boddy, R.; Smets, S.; van Ditmarsch, H.; Sandu, G.

    2018-01-01

    In this paper we formalize an approach to knowledge that we call Interrogative Epistemology, in the spirit of Hintikka’s “interrogative model” of knowledge. According to our approach, an agent’s knowledge is shaped and limited by her interrogative agenda (as defined by her fundamental questions or

  10. Determination of the scattered radiation at the Neutron Calibration Laboratory of IPEN using the shadow cone method

    Energy Technology Data Exchange (ETDEWEB)

    Alvarenga, Tallyson S.; Caldas, Linda V.E. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Freitas, Bruno M. [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Fonseca, Evaldo S.; Pereira, Walsan W., E-mail: talvarenga@ipen.br, E-mail: lcaldas@ipen.br, E-mail: bfreitas@con.ufrj.br, E-mail: walsan@ird.gov.br, E-mail: evaldo@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    Because of the increase in the demand for the calibration of neutron detectors, there is a need for new calibration services. In this context, the Calibration Laboratory of Instituto de Pesquisas Energéticas e Nucleares (IPEN), São Paulo, which already offers calibration services of radiation detectors with standard X, gamma, beta and alpha beams, has recently projected a new test laboratory for neutron detectors. This work evaluated the contribution of dispersed neutron radiation in this laboratory, using the cone shadow method and a Bonner sphere spectrometer to take the measurements at a distance of 100 cm from the neutron source. The dosimetric quantities H⁎(10) and H⁎(10) were obtained at the laboratory, allowing the calibration of detectors. (author)

  11. 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)

  12. 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)

  13. Phase 1 environmental report for the Advanced Neutron Source at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Blasing, T.J.; Brown, R.A.; Cada, G.F.; Easterly, C.; Feldman, D.L.; Hagan, C.W.; Harrington, R.M.; Johnson, R.O.; Ketelle, R.H.; Kroodsma, R.L.; McCold, L.N.; Reich, W.J.; Scofield, P.A.; Socolof, M.L.; Taleyarkhan, R.P.; Van Dyke, J.W.

    1992-02-01

    The US Department of Energy (DOE) has proposed the construction and operation of the Advanced Neutron Source (ANS), a 330-MW(f) reactor, at Oak Ridge National Laboratory (ORNL) to support neutron scattering and nuclear physics experiments. ANS would provide a steady-state source of neutrons that are thermalized to produce sources of hot, cold, and very coal neutrons. The use of these neutrons in ANS experiment facilities would be an essential component of national research efforts in basic materials science. Additionally, ANS capabilities would include production of transplutonium isotopes, irradiation of potential fusion and fission reactor materials, activation analysis, and production of medical and industrial isotopes such as 252 Cf. Although ANS would not require licensing by the US Nuclear Regulatory Commission (NRC), DOE regards the design, construction, and operation of ANS as activities that would produce a licensable facility; that is, DOE is following the regulatory guidelines that NRC would apply if NRC were licensing the facility. Those guidelines include instructions for the preparation of an environmental report (ER), a compilation of available data and preliminary analyses regarding the environmental impacts of nuclear facility construction and operation. The ER, described and outlined in NRC Regulatory Guide 4.2, serves as a background document to facilitate the preparation of environmental impact statements (EISs). Using Regulatory Guide 4.2 as a model, this ANS ER provides analyses and information specific to the ANS site and area that can be adopted (and modified, if necessary) for the ANS EIS. The ER is being prepared in two phases. Phase 1 ER includes many of the data and analyses needed to prepare the EIS but does not include data or analyses of alternate sites or alternate technologies. Phase 2 ER will include the additional data and analyses stipulated by Regulatory Guide 4.2

  14. Phase 1 environmental report for the Advanced Neutron Source at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Blasing, T.J.; Brown, R.A.; Cada, G.F.; Easterly, C.; Feldman, D.L.; Hagan, C.W.; Harrington, R.M.; Johnson, R.O.; Ketelle, R.H.; Kroodsma, R.L.; McCold, L.N.; Reich, W.J.; Scofield, P.A.; Socolof, M.L.; Taleyarkhan, R.P.; Van Dyke, J.W.

    1992-02-01

    The US Department of Energy (DOE) has proposed the construction and operation of the Advanced Neutron Source (ANS), a 330-MW(f) reactor, at Oak Ridge National Laboratory (ORNL) to support neutron scattering and nuclear physics experiments. ANS would provide a steady-state source of neutrons that are thermalized to produce sources of hot, cold, and very coal neutrons. The use of these neutrons in ANS experiment facilities would be an essential component of national research efforts in basic materials science. Additionally, ANS capabilities would include production of transplutonium isotopes, irradiation of potential fusion and fission reactor materials, activation analysis, and production of medical and industrial isotopes such as {sup 252}Cf. Although ANS would not require licensing by the US Nuclear Regulatory Commission (NRC), DOE regards the design, construction, and operation of ANS as activities that would produce a licensable facility; that is, DOE is following the regulatory guidelines that NRC would apply if NRC were licensing the facility. Those guidelines include instructions for the preparation of an environmental report (ER), a compilation of available data and preliminary analyses regarding the environmental impacts of nuclear facility construction and operation. The ER, described and outlined in NRC Regulatory Guide 4.2, serves as a background document to facilitate the preparation of environmental impact statements (EISs). Using Regulatory Guide 4.2 as a model, this ANS ER provides analyses and information specific to the ANS site and area that can be adopted (and modified, if necessary) for the ANS EIS. The ER is being prepared in two phases. Phase 1 ER includes many of the data and analyses needed to prepare the EIS but does not include data or analyses of alternate sites or alternate technologies. Phase 2 ER will include the additional data and analyses stipulated by Regulatory Guide 4.2.

  15. The method of Sample Management in Neutron Activation Analysis Laboratory-Serpong

    International Nuclear Information System (INIS)

    Elisabeth-Ratnawati

    2005-01-01

    In the testing laboratory used by neutron activation analysis method, sample preparation is the main factor and it can't be neglect. The error in the sample preparation can give result with lower accuracy. In this article is explained the scheme of sample preparation i.e sample receive administration, the separate of sample, fluid and solid sample preparation, sample grouping, irradiation, sample counting and holding the sample post irradiation. If the management of samples were good application based on Standard Operation Procedure, therefore each samples has good traceability. To optimize the management of samples is needed the trained and skilled personal and good facility. (author)

  16. Neutron activation analysis of alternative waste forms at the Savannah River Laboratory

    International Nuclear Information System (INIS)

    Johns, R.A.

    1981-01-01

    A remotely controlled system for neutron activation of candidate high-level waste (HLW) isolation forms was built by the Savannah River Laboratory at a Savannah River Plant reactor. With this system, samples can be irradiated for up to 24 hours and transferred through pneumatic tubing to a shielded repository unitl their activity is low enough for them to be handled in a radiobench. The principal use of the system is to support the Alternative Waste Forms Leach Testing (AWFLT) Program in which the comparative leachability of the various waste forms will be determined. The experimental method used in this work is based on neutron activation analysis techniques. Neutron irradiation of the solid waste form containing simulated HLW sludge activates elements in the sample. After suitable leaching of the solid matrix in standard solutions, the leachate and solid are assayed for gamma-emitting nuclides. From these measurements, the fraction of a specific element leached can be determined al half-lives with experimental ones, over a range of 24 orders of magnitude was obtained. This is a strong argument that the alpha decay could be considered a fission process with very high mass asymmetry and charge density asymmetry

  17. For boron neutron capture therapy,synthesizing boron-polymer compounds and testing in laboratory conditions

    International Nuclear Information System (INIS)

    2011-01-01

    The aim of this project is to establish a focus point at Turkish Atomic Energy Authority (TAEA) in the field of Boron Neutron Capture Therapy which is a binary radiotherapy method for brain tumours. Moreover in the scope of the project, a new alternative of 1 0B-carrier compounds will be synthesized, the neutron source will be determined and the infrastructure to start the clinical trials of BNCT in our country will be established. BNCT is a binary radiotherapy method and the successful of this method is depend on the synthesized boron compounds which have the selective targeting property with tumour cells and neutron optimization. The water-soluble polymer based boron compounds having biochemical and physiological properties will be synthesized and cell culture experiment will be done. In addition, after the neutron source is set up in our country, the infrastructure studies will be started in order to start the clinical trials of BNCT. In this project, there are three different groups as boron compounds, neutron physics and medical group. Neutron physics group is starting the calculations of neutron beam parameters using in BNCT application. But, medical group has no active studies yet. Boron compounds group has been carried out two different experimental studies. In the first experimental study, functional groups have been bound to boron containing polymers to enhance the selectively targeting property and characterized by various analysis methods. Later, cell culture experiment will be done. The first study has been carried out with Hacettepe University. Up to present, completed studies are listed as: -Maleic anhydride oligomer was synthesized and then 2-aminoethyl diphenyl borate (2-AEPB) and monomethoxy poly(ethylene glycol) (PEG) was bound to this oligomer, respectively. Thus, [MAH] n -g 1 -2-AEPB-g 2 -PEG was synthesized. -2-AEPB compound were bound to poly(acrylic acid) polymer at different three mole ratio.Then, the selected Poli(Ac)-g 1 -2-AEPB polymer

  18. Nuclear Material Detection by One-Short-Pulse-Laser-Driven Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Favalli, Andrea [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Aymond, F. [Univ. of Texas at Austin, TX (United States); Bridgewater, Jon S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Croft, Stephen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Deppert, O. [Technische Universitat Darmstadt (Germany); Devlin, Matthew James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Falk, Katerina [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Fernandez, Juan Carlos [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gautier, Donald Cort [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gonzales, Manuel A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Goodsell, Alison Victoria [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Guler, Nevzat [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hamilton, Christopher Eric [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hegelich, Bjorn Manuel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Henzlova, Daniela [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ianakiev, Kiril Dimitrov [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Iliev, Metodi [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Johnson, Randall Philip [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jung, Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kleinschmidt, Annika [Technische Universitat Darmstadt (Germany); Koehler, Katrina Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pomerantz, Ishay [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Roth, Markus [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Santi, Peter Angelo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Shimada, Tsutomu [Los Alamos National Laboratory; Swinhoe, Martyn Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Taddeucci, Terry Nicholas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wurden, Glen Anthony [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Palaniyappan, Sasikumar [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); McCary, E. [Univ. of Texas at Austin, TX (United States)

    2015-01-28

    Covered in the PowerPoint presentation are the following areas: Motivation and requirements for active interrogation of nuclear material; laser-driven neutron source; neutron diagnostics; active interrogation of nuclear material; and, conclusions, remarks, and future works.

  19. Interrogating personhood and dementia

    Science.gov (United States)

    Higgs, Paul; Gilleard, Chris

    2016-01-01

    ABSTRACT Objectives: To interrogate the concept of personhood and its application to care practices for people with dementia. Method: We outline the work of Tom Kitwood on personhood and relate this to conceptualisations of personhood in metaphysics and in moral philosophy. Results: The philosophical concept of personhood has a long history. The metaphysical tradition examines the necessary and sufficient qualities that make up personhood such as agency, consciousness, identity, rationality and second-order reflexivity. Alternative viewpoints treat personhood as a matter of degree rather than as a superordinate category. Within moral philosophy personhood is treated as a moral status applicable to some or to all human beings. Conclusion: In the light of the multiple meanings attached to the term in both metaphysics and moral philosophy, personhood is a relatively unhelpful concept to act as the foundation for developing models and standards of care for people with dementia. Care, we suggest, should concentrate less on ambiguous and somewhat abstract terms such as personhood and focus instead on supporting people's existing capabilities, while minimising the harmful consequences of their incapacities. PMID:26708149

  20. Containment performance analyses for the Advanced Neutron Source Reactor at the Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Kim, S.H.; Taleyarkhan, R.P.; Georgevich, V.

    1992-10-01

    This paper discusses salient aspects of methodology, assumptions, and modeling of various features related to estimation of source terms from two conservatively scoped severe accident scenarios in the Advanced Neutron Source (ANS) reactor at the Oak Ridge National Laboratory. Various containment configurations are considered for steaming-pool-type accidents and an accident involving molten core-concrete interaction. Several design features (such as rupture disks) are examined to study containment response during postulated severe accidents. Also, thermal-hydraulic response of the containment and radionuclide transport and retention in the containment are studied. The results are described as transient variations of source terms for each scenario, which are to be used for studying off-site radiological consequences and health effects for these postulated severe accidents. Also highlighted will be a comparison of source terms estimated by two different versions of the MELCOR code

  1. Structural Integrity Evaluation of Cold Neutron Laboratory Building by Design Change of Guide Shielding Room

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Sangik; Kim, Youngki; Kim, Harkrho

    2007-06-15

    This report summarizes the results of the structural integrity evaluation for the cold neutron laboratory building by design change of guide shielding room. The design of the guide shielding room was changed by making its structure members in normal concrete (2.3 g/cc) instead of heavy concrete (3.5 g/cc) because the heavy concrete could be not supplied to meet its design specification. Therefore, it was decided that the guide shielding room is made of the normal concrete. And, the shielding performance of the normal concrete was recalculated to confirm satisfying its design specification, which is of a 9000 zone according to HANARO radiation region classification. The change makes the shielding wall thicker than existing design, and then it is caused to qualify the structural integrity evaluation of the CNLB. Finally, the structural integrity of the CNLB was re-evaluated by considering the design change of the guide shielding room.

  2. A Large Neutrino Detector Facility at the Spallation Neutron Source at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Efremenko, Y.V.

    1999-01-01

    The ORLaND (Oak Ridge Large Neutrino Detector) collaboration proposes to construct a large neutrino detector in an underground experimental hall adjacent to the first target station of the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory. The main mission of a large (2000 ton) Scintillation-Cherenkov detector is to measure bar ν μ -> bar ν e neutrino oscillation parameters more accurately than they can be determined in other experiments, or significantly extending the covered parameter space below (sin'20 le 10 -4 ). In addition to the neutrino oscillation measurements, ORLaND would be capable of making precise measurements of sin 2 θ W , search for the magnetic moment of the muon neutrino, and investigate the anomaly in the KARMEN time spectrum, which has been attributed to a new neutral particle. With the same facility an extensive program of measurements of neutrino nucleus cross sections is also planned to support nuclear astrophysics

  3. Boron neutron capture therapy (BNCT) for glioblastoma multiforme (GBM), using the epithermal neutron beam at the Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Chadha, Manjeet; Capala, Jacek; Coderre, Jeffrey A.; Elowitz, Eric H.; Joel, Darrel D.; Hungyuan, B. Liu; Slatkin, Daniel N.; Chanana, Arjun D.

    1996-01-01

    Objective: BNCT is a binary treatment modality based on the nuclear reactions that occur when boron ( 10 B) is exposed to thermal neutrons. Preclinical studies have demonstrated the therapeutic efficacy of p-boronophenylalanine (BPA)-based BNCT. The objective of the Phase I/II trial was to evaluate BPA-fructose (BPA-F) as a boron delivery agent for GBM and to study the feasibility and safety of a single-fraction of BNCT. Materials and Methods: The trial design required i) a BPA-F biodistribution study performed at the time of craniotomy; and ii) BNCT within 4 weeks of the craniotomy. From September 94 to July 95, 10 patients with biopsy proven GBM were treated. All but 1 patient underwent a biodistribution study receiving IV BPA-F at the time of craniotomy. Multiple tissue samples and concurrent blood and urine samples were collected for evaluation of the boron concentration and clearance kinetics. For BNCT all patients received 250 mg/kgm of BPA-F (IV infusion over 2 hrs) followed by neutron irradiation. The blood 10 B concentration during irradiation was used to calculate the time of neutron exposure. The 3D treatment planning was done using the BNCT treatment planning software developed at the Idaho National Engineering Laboratory. The BNCT dose is expressed as the sum of the physical dose components corrected for both the RBE and the 10 B localization factor with the unit Gy-Eq. The photon-equivalent dose, where the thermal neutron fluence reaches a maximum, is the peak-dose equivalent. A single-fraction of BNCT was delivered prescribing 10.5 Gy-Eq (9 patients) and 13.8 Gy-Eq (1 patient) as the peak dose-equivalent to the normal brain. The peak dose rate was kept below 27 cGy-Eq/min. Results: Biodistribution data: The maximum blood 10 B concentration was observed at the end of the infusion and scaled as a linear function of the administered dose. The 10 B concentration in the scalp and in the GBM tissue was higher than in blood by 1.5 x and at least 3.5 x

  4. Proof-of-Concept Assessment of a Photofission-Based Interrogation System for the Detection of Shielded Nuclear Material

    Energy Technology Data Exchange (ETDEWEB)

    Jones, J. L.; Yoon, W. Y.; Harker, Y. D.; Hoggan, J. M.; Haskell, K. J.; VanAusdeln, L. A.

    2000-11-01

    A photonuclear interrogation method was experimentally assessed for the detection of shielded nuclear materials. Proof-of-Concept assessment was performed at the Los Alamos National Laboratory (LANL) TA-18 facility and used the INEEL VARITRON electron accelerator. Experiments were performed to assess and characterize the delayed neutron emission responses for different nuclear materials with various shield configurations using three ''nominal'' electron beam energies; 8-, 10-, and 11-MeV. With the exception of highly enriched uranium (HEU), the nuclear materials assessed represent material types commonly encountered in commerce. The specific nuclear materials studied include a solid 4.8-kg HEU sphere, a 5-kg multiple-object, depleted uranium (DU) [uranium with about 0.2% enrichment with U-235] target, and two 11-kg thorium disks. The shield materials selected include polyethylene, borated-polyethylene, and lead. Experimental results, supported with numerical predictions, have shown that the photonuclear interrogation technique is quite capable of detecting shielded nuclear material via the direct measurement of the photofission-induced delayed neutron emissions. To identify or discriminate between nuclear material types (i.e., depleted uranium, HEU, and thorium), a ratio of delayed neutron counts at two different beam energies is utilized. This latter method, referred to as the dual-beam energy ratio Figure-of-Merit, allows one to differentiate among the three nuclear material types.

  5. Current Status and Future Works of Neutron Scattering Laboratory at BATAN in Serpong

    International Nuclear Information System (INIS)

    Ikram, A.

    2008-01-01

    Current status of neutron beam instruments using neutrons produced by the Multi Purpose Research Reactor--30MWth (MPR 30, RSG GA Siwabessy) located in Serpong is presented. Description of the reactor as the neutron source is mentioned briefly. There are six neutron beam tubes coming from the beryllium reflector surrounding half of the reactor core providing neutrons in the experimental hall of the reactor (XHR). Four of them are dedicated to R and D in materials science using neutron scattering techniques. Neutron Radiography Facility (NRF), Triple Axis Spectrometer (TAS) and Residual Stress Measurement (RSM) Diffractometer are installed respectively at beam tubes S2, S4 and S6. The largest neutron beam tube (S5) is exploited to accommodate two neutron guide tubes that transfer the neutrons to a neighbouring building called neutron guide hall (NGH). There are three other neutron beam instruments installed in this building, namely Small Angle Neutron Scattering (SANS) Spectrometer (SMARTer), High Resolution SANS (HRSANS) Spectrometer and High Resolution Powder Diffractometer (HRPD). In the XHR, a Four Circle and Texture Diffractometer (FCD/TD) is attached to one of the neutron guide tubes. These seven instruments were installed to utilize the neutrons for materials science research, and recently the RSM diffractometer has shown its capabilities in identifying different amount of stress left due to different treatments of welding in fuel cladding, while the SANS spectrometer is now gaining capabilities in identifying different sizes and shapes of macromolecules in polymers as well as investigations of magnetic samples. In the mean time, non-destructive tests using the NRF is gathering more confidence from some latest real time measurements eventhough there are still some shortcomings in the components and their alignments. Future works including improvement of each facility and its components, even replacement of some parts are necessary and have to be carried out

  6. 252Cf fission-neutron spectrum using a simplified time-of-flight setup: An advanced teaching laboratory experiment

    Science.gov (United States)

    Becchetti, F. D.; Febbraro, M.; Torres-Isea, R.; Ojaruega, M.; Baum, L.

    2013-02-01

    The removal of PuBe and AmBe neutron sources from many university teaching laboratories (due to heightened security issues) has often left a void in teaching various aspects of neutron physics. We have recently replaced such sources with sealed 252Cf oil-well logging sources (nominal 10-100 μCi), and developed several experiments using them as neutron sources. This includes a fission-neutron time-of-flight experiment using plastic scintillators, which utilizes the prompt γ rays emitted in 252Cf spontaneous fission as a fast timing start signal. The experiment can be performed with conventional nuclear instrumentation and a 1-D multi-channel pulse-height analyzer, available in most advanced teaching laboratories. Alternatively, a more sophisticated experiment using liquid scintillators and n/γ pulse-shape discrimination can be performed. Several other experiments using these neutron sources are also feasible. The experiments can introduce students to the problem of detecting the dark matter thought to dominate the universe and to the techniques used to detect contraband fissionable nuclear materials.

  7. Construction of a open-quotes black neutron detectorclose quotes at the University of Massachusetts-Lowell Accelerator Laboratory

    International Nuclear Information System (INIS)

    Bertone, P.F.; DeSimone, D.J.; Dugan, P.F.

    1992-01-01

    In many experiments involving fast neutrons generated in nuclear reactions initiated by accelerator produced charged particle beams, it is important to be able to determine accurately the neutron yield from the target. A detector suitable for such applications should have: a constant efficiency over a large energy range; a fast time response; and the ability to discriminate between gamma rays and neutrons. The authors have constructed a open-quotes black neutron detectorclose quotes based on the design of Poenitz that has these characteristics. At the Lowell Van de Graaff accelerator laboratory neutrons are produced via the 7 Li(p,n) 7 Be reaction using a pulsed proton beam which impinges on metallic lithium targets. The pulsed beam enables the detector to be used in a time-of-flight spectrometer. Use of BC501 liquid scintillator permits neutron-gamma discrimination. The scintillator is viewed by five RCA 48796 photo tubes. The detector is housed in a massive shield of lead, polyethylene and lithium carbonate. The characteristics and use of this detector will be discussed

  8. Laboratory of neutron activation analysis at the Nuclear Physics Institute ASCR, Řež

    Czech Academy of Sciences Publication Activity Database

    Kučera, Jan

    2011-01-01

    Roč. 21, č. 1 (2011), s. 30-35 ISSN 1061-9127 Institutional research plan: CEZ:AV0Z10480505 Keywords : Instrumental neutron activation analysis * epithermal neutron activation analysis * radiochemical neutron activation analysis * applications in science and technology Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  9. Photon interrogation annual report for FY-1980

    International Nuclear Information System (INIS)

    Nieschmidt, E.B.; Tsang, F.Y.; Lawrence, R.S.; Vegors, S.H. Jr.

    1980-12-01

    The Photon Interrogation Technique is being developed for the assay of transuranic materials. A description of source and detector geometry, die-away times and photon flux measurements is given. Considerable effort during FY-1980 was devoted to collimator construction and shielding materials and configurations. Boric acid was found to be a very efficient shielding material for this application. Descriptions and results of these efforts are presented. Results of photon flux determinations, system response to source position and their effects on accuracy are discussed. Changes in the detector system produced a considerable efficiency increase and instrumentation changes brought improved performance. The instrument system with additions can obtain neutron spectral information. A schedule for further development of the system is presented

  10. Performance of the upgraded ultracold neutron source at Los Alamos National Laboratory and its implication for a possible neutron electric dipole moment experiment

    Science.gov (United States)

    Ito, T. M.; Adamek, E. R.; Callahan, N. B.; Choi, J. H.; Clayton, S. M.; Cude-Woods, C.; Currie, S.; Ding, X.; Fellers, D. E.; Geltenbort, P.; Lamoreaux, S. K.; Liu, C.-Y.; MacDonald, S.; Makela, M.; Morris, C. L.; Pattie, R. W.; Ramsey, J. C.; Salvat, D. J.; Saunders, A.; Sharapov, E. I.; Sjue, S.; Sprow, A. P.; Tang, Z.; Weaver, H. L.; Wei, W.; Young, A. R.

    2018-01-01

    The ultracold neutron (UCN) source at Los Alamos National Laboratory (LANL), which uses solid deuterium as the UCN converter and is driven by accelerator spallation neutrons, has been successfully operated for over 10 years, providing UCN to various experiments, as the first production UCN source based on the superthermal process. It has recently undergone a major upgrade. This paper describes the design and performance of the upgraded LANL UCN source. Measurements of the cold neutron spectrum and UCN density are presented and compared to Monte Carlo predictions. The source is shown to perform as modeled. The UCN density measured at the exit of the biological shield was 184 (32 ) UCN /cm3 , a fourfold increase from the highest previously reported. The polarized UCN density stored in an external chamber was measured to be 39 (7 ) UCN /cm3 , which is sufficient to perform an experiment to search for the nonzero neutron electric dipole moment with a one-standard-deviation sensitivity of σ (dn) =3 ×10-27e cm .

  11. Neutron scattering at the high flux isotope reactor at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Yethiraj, M.; Fernandez-Baca, J.A.

    1995-03-01

    Since its beginnings in Oak Ridge and Argonne in the late 1940`s, neutron scattering has been established as the premier tool to study matter in its various states. Since the thermal neutron wavelength is of the same order of magnitude as typical atomic spacings and because they have comparable energies to those of atomic excitations in solids, both structure and dynamics of matter can be studied via neutron scattering. The High Flux Isotope Reactor (HFIR) provides an intense source of neutrons with which to carry out these measurements. This paper summarizes the available neutron scattering facilities at the HFIR.

  12. Characterization of the neutron irradiation system for use in the Low-Dose-Rate Irradiation Facility at Sandia National Laboratories.

    Energy Technology Data Exchange (ETDEWEB)

    Franco, Manuel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-08-01

    The objective of this work was to characterize the neutron irradiation system consisting of americium-241 beryllium (241AmBe) neutron sources placed in a polyethylene shielding for use at Sandia National Laboratories (SNL) Low Dose Rate Irradiation Facility (LDRIF). With a total activity of 0.3 TBq (9 Ci), the source consisted of three recycled 241AmBe sources of different activities that had been combined into a single source. The source in its polyethylene shielding will be used in neutron irradiation testing of components. The characterization of the source-shielding system was necessary to evaluate the radiation environment for future experiments. Characterization of the source was also necessary because the documentation for the three component sources and their relative alignment within the Special Form Capsule (SFC) was inadequate. The system consisting of the source and shielding was modeled using Monte Carlo N-Particle transport code (MCNP). The model was validated by benchmarking it against measurements using multiple techniques. To characterize the radiation fields over the full spatial geometry of the irradiation system, it was necessary to use a number of instruments of varying sensitivities. First, the computed photon radiography assisted in determining orientation of the component sources. With the capsule properly oriented inside the shielding, the neutron spectra were measured using a variety of techniques. A N-probe Microspec and a neutron Bubble Dosimeter Spectrometer (BDS) set were used to characterize the neutron spectra/field in several locations. In the third technique, neutron foil activation was used to ascertain the neutron spectra. A high purity germanium (HPGe) detector was used to characterize the photon spectrum. The experimentally measured spectra and the MCNP results compared well. Once the MCNP model was validated to an adequate level of confidence, parametric analyses was performed on the model to optimize for potential

  13. Proposed Californium-252 User Facility for Neutron Science at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Martin, R.C.; Laxson, R.R.; Knauer, J.B.

    1996-01-01

    The Radiochemical Engineering Development Center (REDC) at ORNL has petitioned to establish a Californium-252 User Facility for Neutron Science for academic, industrial, and governmental researchers. The REDC Californium Facility (CF) stores the national inventory of sealed 252 Cf neutron source for university and research loans. Within the CF, the 252 Cf storage pool and two uncontaminated hot cells currently in service for the Californium Program will form the physical basis for the User Facility. Relevant applications include dosimetry and experiments for neutron tumor therapy; fast and thermal neutron activation analysis of materials; experimental configurations for prompt gamma neutron activation analysis; neutron shielding and material damage studies; and hardness testing of radiation detectors, cameras, and electronics. A formal User Facility simplifies working arrangements and agreements between US DOE facilities, academia, and commercial interests

  14. Spallation Neutron Source (SNS)

    Data.gov (United States)

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

  15. Active interrogation of highly enriched uranium

    Science.gov (United States)

    Fairrow, Nannette Lea

    Safeguarding special nuclear material (SNM) in the Department of Energy Complex is vital to the national security of the United States. Active and passive nondestructive assays are used to confirm the presence of SNM in various configurations ranging from waste to nuclear weapons. Confirmation measurements for nuclear weapons are more challenging because the design complicates the detection of a distinct signal for highly enriched uranium. The emphasis of this dissertation was to investigate a new nondestructive assay technique that provides an independent and distinct signal to confirm the presence of highly enriched uranium (HEU). Once completed and tested this assay method could be applied to confirmation measurements of nuclear weapons. The new system uses a 14-MeV neutron source for interrogation and records the arrival time of neutrons between the pulses with a high efficiency detection system. The data is then analyzed by the Feynman reduced variance method. The analysis determined the amount of correlation in the data and provided a unique signature of correlated fission neutrons. Measurements of HEU spheres were conducted at Los Alamos with the new system. Then, Monte Carlo calculations were performed to verify hypothesis made about the behavior of the neutrons in the experiment. Comparisons of calculated counting rates by the Monte Carlo N-Particle Transport Code (MCNP) were made with the experimental data to confirm that the measured response reflected the desired behavior of neutron interactions in the highly enriched uranium. In addition, MCNP calculations of the delayed neutron build-up were compared with the measured data. Based on the results obtained from this dissertation, this measurement method has the potential to be expanded to include mass determinations of highly enriched uranium. Although many safeguards techniques exist for measuring special nuclear material, the number of assays that can be used to confirm HEU in shielded systems is

  16. Clinical trials of boron neutron capture therapy [in humans] [at Beth Israel Deaconess Medical Center][at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Wallace, Christine

    2001-01-01

    Assessment of research records of Boron Neutron Capture Therapy was conducted at Brookhaven National Laboratory and Beth Israel Deaconess Medical Center using the Code of Federal Regulations, FDA Regulations and Good Clinical Practice Guidelines. Clinical data were collected FR-om subjects' research charts, and differences in conduct of studies at both centers were examined. Records maintained at Brookhaven National Laboratory were not in compliance with regulatory standards. Beth Israel's records followed federal regulations. Deficiencies discovered at both sites are discussed in the reports

  17. Neutron activation analysis and ICP-AES to determine metal traces in antarctic krill. CNEA laboratories participation in the certification of a reference material

    International Nuclear Information System (INIS)

    Smichowski, Patricia N.; Farias, Silvia S.; Resnizky, Sara M.; Marrero, Julieta G.

    1999-01-01

    For the international certification of a reference material based on krill, As and Hg were determined by instrumental neutron activation analysis and Br, Co and Se by radiochemical neutron activation analysis. Inductive coupling plasma atomic emission spectrometry (ICP-AES) was used to determine Cu, Fe, Mn, and Zn. The results, which are in good agreement with those obtained by other laboratories, are discussed

  18. Automatization of the neutron activation analysis method in the nuclear analysis laboratory

    International Nuclear Information System (INIS)

    Gonzalez, N.R.; Rivero, D del C.; Gonzalez, M.A.; Larramendi, F.

    1993-01-01

    In the present paper the work done to automatice the Neutron Activation Analysis technic with a neutron generator is described. An interface between an IBM compatible microcomputer and the equipment in use to make this kind of measurement was developed. including the specialized software for this system

  19. Neutronic measurements of radioactive waste

    International Nuclear Information System (INIS)

    Perot, B.

    1997-01-01

    This document presents the general matters involved in the radioactive waste management and the different non destructive assays of radioactivity. The neutronic measurements used in the characterization of waste drums containing emitters are described with more details, especially the active neutronic interrogation assays with prompt or delayed neutron detection: physical principle, signal processing and evaluation of the detection limit. (author)

  20. Radiation damage at the Rotating Target Neutron Source (RTNS-I) facility at Lawrence Livermore Laboratory

    International Nuclear Information System (INIS)

    Logan, C.M.; Russell, E.W.

    1976-01-01

    Some of the basic computational features of a computer program used for modeling radiation damage at LLL's Rotating Target Neutron Source (RTNS-I) are presented. Input items required are material cross-section and angular distribution data, such as used for LLL neutron transport calculations, along with one particular neutron spectrum of interest. The nuclear reactions considered are elastic, neutron-emitting, and charged-particle-emitting. Classical and relativistic mechanics are used as required to calculate the resulting primary-recoil energy spectra and damage energy spectra. Calculative results are presented for the RTNS-I neutron spectra on aluminum, titanium, vanadium, iron, nickel, copper, zirconium, niobium, molybdenum, silver, tin, tantalum, tungsten, gold, and lead. 63 figures

  1. Characterization of the Neutron Fields in the Lawrence Livermore National Laboratory (LLNL) Radiation Calibration Laboratory Low Scatter Facility

    Energy Technology Data Exchange (ETDEWEB)

    Radev, Radoslav [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2009-08-20

    The issuance of Part 10 CFR 835 (2007) with revised radiation weighting factors and the installation of a new Hopewell N40 irradiator necessitated a re-characterization of the neutron fields in RCL's Low Scatter Calibration Facility (B255, Room 183 A). The emission rates of the RCL's two 252Cf calibration sources were re-evaluated and the updated emission rates are provided in Appendix A. The neutron dose rates from the new Hopewell N40 irradiator configuration were evaluated using three different instruments. the measurement methodology and the experimental set up as well as calibration of the instruments are discussed in detail.

  2. Neutron Scattering Facilities at the Oak Ridge National Laboratory High Flux Isotope Reactor

    International Nuclear Information System (INIS)

    Selby, D. L.

    2013-01-01

    This paper will address four aspects of the neutron scattering science utilization of the High Flux Isotope Reactor (HFIR): 1) Since the last IGORR meeting, two instruments (IMAGINE- a single crystal diffractometer and a polarized beam station) have been declared operational. In addition, cold neutron beam line CG-1D has been fully devoted to imaging studies. One specific characteristic that will be discussed will be the neutron optics mirror system that has been used for the IMAGINE instrument in lieu of a conventional neutron guide. 2) For the last 15 years there has been a focused effort to fully utilize the open neutron beam positions at the High Flux Isotope Reactor (HFIR). With the addition of the new instruments and plans to build a new spin echo test station at beam port CG-4B we will have filled out all 16 presently available beam instrument positions. Therefore, at HFIR we are starting to shift our focus to major upgrades of existing instruments. Many of these instruments are now over 10 years old and new technology, including advances in neutron optics techniques, can provide significant increases in the utilization of the existing neutron beams. In addition, upgrades will allow the use of new sample environment equipment that is presently prohibited because of geometry restrictions. The plans for these upgrades and expected gains in performance will be discussed. 3) Another proposal to increase the utilization capabilities at HFIR is to build a new building next to the HB-4 cold neutron guide hall that would provide space for 9 lab facilities. These labs would include magnet, sample environment, polarization, and sample preparation support capabilities for the neutron scattering instruments. In addition, there is still a proposal being discussed with the United States Department of Energy to build a second moderator and guide hall tied to the HB-2 beam line at HFIR. The status of these two proposed major projects will be addressed. 4) Finally, the

  3. Neutron Therapy Facility

    Data.gov (United States)

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

  4. The solid parahydrogen target for neutron research and the laboratory-scale installation for ortho-parahydrogen conversion

    International Nuclear Information System (INIS)

    Bazhenov, A.I.; Medvedev, V.I.; Pirozhkov, A.N.

    1991-08-01

    The solid parahydrogen target used in the physical experiment on vertical beam of cold polarized neutrons is described. Hydrogen is cooled by means of liquid helium from the supplementary vessel. The construction peculiarity is placing of hydrogen vessel in lateral appendix of cryostat at the 0.7 m distance from the helium vessel. The design of the simple laboratory-scale installation for ortho-parahydrogen conversion operating 'on-line' with target is given. The installation operating with conversion Fe(OH) 3 catalyst gives parahydrogen with content of ortho-component below 0.1%. The procedure of catalyst preparation is described. 7 refs.; 5 figs

  5. Monte Carlo Simulations Of The Response Of Shielded SNM To A Pulsed Neutron Source

    Science.gov (United States)

    Seabury, E. H.; Chichester, D. L.

    2011-06-01

    Active neutron interrogation has been used as a technique for the detection and identification of special nuclear material (SNM) for both proposed and field-tested systems. Idaho National Laboratory (INL) has been studying this technique for systems ranging from small systems employing portable electronic neutron generators to larger systems employing linear accelerators as high-energy photon sources for assessment of vehicles and cargo. In order to assess the feasibility of new systems, INL has undertaken a campaign of Monte Carlo simulations of the response of a variety of masses of SNM in multiple shielding configurations to a pulsed neutron source using the MCNPX code, with emphasis on the neutron and photon response of the system as a function of time after the initial neutron pulse. We present here some preliminary results from these calculations.

  6. 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.

  7. Activities of the neutron activation analysis laboratory of the radiochemistry division of IPEN - CNEN/SP

    International Nuclear Information System (INIS)

    Vasconcellos, M.B.A.

    1988-10-01

    Neutron activation analysis (NAA) is one of the relevant applications of nuclear research reactors. Due to the high neutron fluxes available in these reactors, an excellent sensitivity of analysis is attained for many elements. NAA is one of the most sensitive, precise and accurate analytical methods for trace element determination. NAA has been one of the main activities of the Radiochemistry Division of IPEN, since the beginning of the operation of the nuclear reactor IEA-R1. Most of the effort was devoted to research work, aimed to improvements in the method as well as to its applications to several kinds of matrixes (geological, biological, metallic, environmental, forensic). Besides, analytical services were also offered, to the CNEN, to industries, universities, mining companies and research institutes. In the present paper, a review is made of the research work being developed presently at the Radiochesmitry Division of IPEN. A discussion is also made of the planned expansion of the analytical services offered [pt

  8. Ion-induced gammas for photofission interrogation of HEU.

    Energy Technology Data Exchange (ETDEWEB)

    Doyle, Barney Lee (Sandia National Laboratories, Albuquerque, NM); Antolak, Arlyn J.; Morse, Daniel H.; Provencio, Paula Polyak (Sandia National Laboratories, Albuquerque, NM)

    2006-03-01

    High-energy photons and neutrons can be used to actively interrogate for heavily shielded special nuclear material (SNM), such as HEU (highly enriched uranium), by detecting prompt and/or delayed induced fission signatures. In this work, we explore the underlying physics for a new type of photon source that generates high fluxes of mono-energetic gamma-rays from low-energy (<500 keV) proton-induced nuclear reactions. The characteristic energies (4- to 18-MeV) of the gamma-rays coincide with the peak of the photonuclear cross section. The source could be designed to produce gamma-rays of certain selected energies, thereby improving the probability of detecting shielded HEU or providing a capability to determine enrichment inside sealed containers. The fundamental physics of such an interrogation source were studied in this LDRD through scaled ion accelerator experiments and radiation transport modeling. The data were used to assess gamma and neutron yields, background, and photofission-induced signal levels from several (p,{gamma}) target materials under consideration.

  9. Integrated Box Interrogation System (IBIS) Preliminary Design Study

    Energy Technology Data Exchange (ETDEWEB)

    DR. Stephen Croft; Mr. David Martancik; Dr. Brian Young; Dr. Patrick MJ Chard; Dr. Robert J Estop; Sheila Melton; Gaetano J. Arnone

    2003-01-13

    Canberra Industries has won the tendered solicitation, INEEL/EST-99-00121 for boxed waste Nondestructive Assay Development and Demonstration. Canberra will provide the Integrated Box Interrogation System (IBIS) which is a suite of assay instrumentation and a data reduction system that addresses the measurement needs for Boxed Wastes identified in the solicitation and facilitates the associated experimental program and demonstration of system capability. The IBIS system will consist of the next generation CWAM system, i.e. CWAM II, which is a Scanning Passive/Active Neutron interrogation system which we will call a Box Segmented Neutron Scanner (BSNS), combined with a physically separate Box Segmented Gamma-ray Scanning (BSGS) system. These systems are based on existing hardware designs but will be tailored to the large sample size and enhanced to allow the program to evaluate the following measurement criteria:Characterization and correction for matrix heterogeneity Characterization of non-uniform radio-nuclide and isotopic compositions Assay of high density matrices (both high-Z and high moderator contents)Correction for radioactive material physical form - such as self shielding or multiplication effects due to large accumulations of radioactive materials.Calibration with a minimal set of reference standards and representative matrices.THis document summarizes the conceptual design parameters of the IBIS and indicates areas key to the success of the project where development is to be centered. The work presented here is a collaborative effort between scientific staff within Canberra and within the NIS-6 group at LANL.

  10. The CG-1D Neutron Imaging Beamline at the Oak Ridge National Laboratory High Flux Isotope Reactor

    Science.gov (United States)

    Santodonato, Lou; Bilheux, Hassina; Bailey, Barton; Bilheux, Jean; Nguyen, Phong; Tremsin, Anton; Selby, Doug; Walker, Lakeisha

    The Oak Ridge National Laboratory Neutron Sciences Directorate has installed a neutron imaging beamline at the High Flux Isotope Reactor (HFIR) cold guide hall. CG-1D is one of the three instruments that make up the CG1 instrument suite. The beamline optics and detector have recently been upgraded to meet the needs of the neutron imaging community (better ;smoothing; of guide system artifacts, higher flux or spatial resolution). These upgrades comprise a new diffuser/aperture system, two new detectors, a He-filled flight tube and silicon (Si) windows. Shielding inside the flight tube, beam scrapers and a beam stop ensure that biological dose is less than 50 μSv/hr outside of the radiation boundary. A set of diffusers and apertures (pinhole geometry) has been installed at the exit of the guide system to allow motorized L/D variation. Samples sit on a translation/rotation stage for alignment and tomography purposes. Detectors for the CG-1D beamline are (1) an ANDOR DW936 charge coupled device (CCD) camera with a field of view of approximately 7 cm x 7 cm and ∼ 80 microns spatial resolution and 1 frame per second time resolution, (2) a new Micro-Channel Plate (MCP) detector with a 2.8 cm x 2.8 cm field of view and 55 microns spatial resolution, and 5 μs timing capability. 6LiF/ZnS scintillators of thickness varying from 50 to 200 microns are being used at this facility. An overview of the beamline upgrade and preliminary data is presented here.

  11. Estimation of neutron dose equivalent at the mezzanine of the Advanced Light Source and the laboratory boundary using the ORNL program MORSE.

    Science.gov (United States)

    Sun, R K

    1990-12-01

    To investigate the radiation effect of neutrons near the Advanced Light Source (ALS) at Lawrence Berkeley Laboratory (LBL) with respect to the neutron dose equivalents in nearby occupied areas and at the site boundary, the neutron transport code MORSE, from Oak Ridge National Laboratory (ORNL), was used. These dose equivalents result from both skyshine neutrons transported by air scattering and direct neutrons penetrating the shielding. The ALS neutron sources are a 50-MeV linear accelerator and its transfer line, a 1.5-GeV booster, a beam extraction line, and a 1.9-GeV storage ring. The most conservative total occupational-dose-equivalent rate in the center of the ALS mezzanine, 39 m from the ALS center, was found to be 1.14 X 10(-3) Sv y-1 per 2000-h "occupational" year, and the total environmental-dose-equivalent rate at the ALS boundary, 125 m from the ALS center, was found to be 3.02 X 10(-4) Sv y-1 per 8760-h calendar year. More realistic dose-equivalent rates, using the nominal (expected) storage-ring current, were calculated to be 1.0 X 10(-4) Sv y-1 and 2.65 X 10(-5) Sv y-1 occupational year and calendar year, respectively, which are much lower than the DOE reporting levels.

  12. Description and performance characteristics for the neutron Coincidence Collar for the verification of reactor fuel assemblies

    International Nuclear Information System (INIS)

    Menlove, H.O.

    1981-08-01

    An active neutron interrogation method has been developed for the measurement of 235 U content in fresh fuel assemblies. The neutron Coincidence Collar uses neutron interrogation with an AmLi neutron source and coincidence counting the induced fission reaction neutrons from the 235 U. This manual describes the system components, operation, and performance characteristics. Applications of the Coincidence Collar to PWR and BWR types of reactor fuel assemblies are described

  13. Plan for the future of neutron research on condensed matter: an Argonne National Laboratory report prepared in response to the Report of the Review Panel on Neutron Scattering

    International Nuclear Information System (INIS)

    1981-01-01

    The Review Panel on Neutron Scattering has recommended an expanded budget to allow systematic development of the field. An alternative plan for the future of neutron research on condensed matter is presented here, in case it is not possible to fund the expanded budget. This plan leads, in a rational and logical way, to a world-class neutron source that will ensure the vitality of the field and exploit the many benefits that state-of-the-art neutron facilities can bring to programs in the materials and biological sciences. 2 tables

  14. Measurement of actinide neutron cross sections

    International Nuclear Information System (INIS)

    Firestone, Richard B.; Nitsche, Heino; Leung, Ka-Ngo; Perry, DaleL.; English, Gerald

    2003-01-01

    The maintenance of strong scientific expertise is critical to the U.S. nuclear attribution community. It is particularly important to train students in actinide chemistry and physics. Neutron cross-section data are vital components to strategies for detecting explosives and fissile materials, and these measurements require expertise in chemical separations, actinide target preparation, nuclear spectroscopy, and analytical chemistry. At the University of California, Berkeley and the Lawrence Berkeley National Laboratory we have trained students in actinide chemistry for many years. LBNL is a leader in nuclear data and has published the Table of Isotopes for over 60 years. Recently, LBNL led an international collaboration to measure thermal neutron capture radiative cross sections and prepared the Evaluated Gamma-ray Activation File (EGAF) in collaboration with the IAEA. This file of 35, 000 prompt and delayed gamma ray cross-sections for all elements from Z=1-92 is essential for the neutron interrogation of nuclear materials. LBNL has also developed new, high flux neutron generators and recently opened a 1010 n/s D+D neutron generator experimental facility

  15. Analysis of traces at ORNL's new high-flux neutron activation laboratory

    International Nuclear Information System (INIS)

    Ricci, E.; Handley, T.H.; Dyer, F.F.

    1974-01-01

    The investigations are outlined, which are carried out in order to develop (preferably instrumental) methods for multielement analysis of various trace elements. For this reason a new High-Flux NAA Laboratory was constructed at ORNL's. A general review is given on the Laboratory, further some methods and applications are shown. In the field of comparator activation analysis comparative data are given on mercury determinations in various matrices, and on arsenic determination in grasshoppers. This later method was used to trace the transport of arsenic containing pesticides. Some data are given on absolute activation analysis of Na, Ci, Mn, Br, and Au, too. (K.A.)

  16. 32 CFR 637.21 - Recording interviews and interrogations.

    Science.gov (United States)

    2010-07-01

    ... ENFORCEMENT AND CRIMINAL INVESTIGATIONS MILITARY POLICE INVESTIGATION Investigations § 637.21 Recording interviews and interrogations. The recording of interviews and interrogations by military police personnel is...

  17. Metal metabolism in laboratory animals and human tissues as investigated by neutron activation analysis: current status and perspectives

    International Nuclear Information System (INIS)

    Sabbioni, E.; Pietra, R.; Marafante, E.

    1982-01-01

    The definition of dose-response relationships in man is the essential requisite to set scientifically health protection standards for the evaluation of a safe level exposure of humans to heavy metals. The derivation of these relationships requires sequential multidisciplinary informations including data on metabolic patterns and biochemical effects in mammals. Unfortunately, sufficient data are not available to establish dose-response curves expecially in long term-low level exposure conditions and a need exists to gather such informations for each metal on absorption, distribution and excretion in laboratory animals and humans. This paper: (1) discuss main problems related to the use of neutron activation analysis (NAA) in metallobiochemistry of present levels of trace elements; (2) report data on the current applications of NAA in metallobiochemistry in relation to the work carried out in the context of a project Heavy Metal Pollution of CEC JRC - Ispra. Applications deal with in vivo studies on laboratory animals, in vitro studies on biochemical systems and experiments on tissues of human origin; (3) discuss the perspectives of the use of the nuclear techniques in the environmental toxicology. (author)

  18. Monte Carlo analysis of the Neutron Standards Laboratory of the CIEMAT; Analisis Monte Carlo del Laboratorio de Patrones Neutronicos del CIEMAT

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Mendez V, R. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Av. Complutense 40, 28040 Madrid (Spain); Guzman G, K. A., E-mail: fermineutron@yahoo.com [Universidad Politecnica de Madrid, Departamento de Ingenieria Nuclear, C. Jose Gutierrez Abascal 2, 28006 Madrid (Spain)

    2014-10-15

    By means of Monte Carlo methods was characterized the neutrons field produced by calibration sources in the Neutron Standards Laboratory of the Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT). The laboratory has two neutron calibration sources: {sup 241}AmBe and {sup 252}Cf which are stored in a water pool and are placed on the calibration bench using controlled systems at distance. To characterize the neutrons field was built a three-dimensional model of the room where it was included the stainless steel bench, the irradiation table and the storage pool. The sources model included double encapsulated of steel, as cladding. With the purpose of determining the effect that produces the presence of the different components of the room, during the characterization the neutrons spectra, the total flow and the rapidity of environmental equivalent dose to 100 cm of the source were considered. The presence of the walls, floor and ceiling of the room is causing the most modification in the spectra and the integral values of the flow and the rapidity of environmental equivalent dose. (Author)

  19. Police interrogations through the prism of science

    Directory of Open Access Journals (Sweden)

    Igor Areh

    2016-03-01

    Full Text Available Several approaches can be employed for information gathering from human sources, differing in their theoretical basis, goals, realisation, and ethical acceptability. The paper critically presents and compares two prevalent approaches to suspect interrogation used by the police. The older, prevalent interrogation approach focuses on obtaining suspects’ incriminating statements and admissions, which severely elevates the risk of false confessions. Consequently, this interrogation approach is termed accusatorial or coercive since suspects are forced to admit to a crime. The newer interrogation approach is the information-gathering approach, also known as the investigative interview. It focuses on gathering accurate information in order to exclude or accuse a suspect in a criminal investigation. In comparison with coercive interrogation models, the information-gathering approach has a lower probability of false confessions since suspects are exposed to significantly lower levels of psychological pressure. Moreover, it is ethically more acceptable, has scientific grounds, enables the gathering of more accurate information, and has been found to be at least as effective as the coercive approach in criminal investigations. The investigative interview relies mainly on findings from social psychology. An analysis of coercive interrogation models reveals that they have no scientific basis and as such rely mainly on uncorroborated common-sense assumptions from authorities. In developed countries, coercive interrogation models are increasingly being replaced by the information-gathering approach, a trend connected with the enforcement of high human rights standards and a higher awareness of risks associated with coercive interrogation methods by the general public, academia, and professionals alike.

  20. Licensing of the new facility radioactive go-33: Laboratory of neutron patterns of the CIEMAT; Licenciamiento de la nueva instalacion radiactiva IR-33: Laboratorio de Patrones Neutronicos del CIEMAT

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Jimenez, R.; Mendez-Villafane, R.; Grandio, R.; Alvarez-Velarde, F.; Casado, P.; Embid, M.; Perez-Cejuela, P.; Guerrero, J. E.; Cano-Ott, D.; Martinez, T.; Mendoza, E.; Quinones, J.

    2013-07-01

    The construction of a laboratory of neutron patterns arises the necessity to establish a system of neutron calibrations in Spain backed by a national pattern. From the beginning they appeared numerous difficulties, change of location, redefinition of the project, preparation of technical specifications, mandatory documentation and operating procedures, reception of new neutron sources, verification of the results of the study of security, etc. The effort of all the professionals who participated in the project has resulted in the licensing of the NPL that will allow, for the first time in Spain, calibration neutron-measuring equipment, assign dose neutron and radiate materials and equipment with fluences or well known dose.

  1. 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.

  2. Comprehensive analysis of shielding effectiveness for HDPE, BPE and concrete as candidate materials for neutron shielding

    International Nuclear Information System (INIS)

    Dhang, Prosenjit; Verma, Rishi; Shyam, Anurag

    2015-01-01

    In the compact accelerator based DD neutron generator, the deuterium ions generated by the ion source are accelerated after the extraction and bombarded to a deuterated titanium target. The emitted neutrons have typical energy of ∼2.45MeV. Utilization of these compact accelerator based neutron generators of yield up to 10 9 neutron/second (DD) is under active consideration in many research laboratories for conducting active neutron interrogation experiments. Requirement of an adequately shielded laboratory is mandatory for the effective and safe utilization of these generators for intended applications. In this reference, we report the comprehensive analysis of shielding effectiveness for High Density Polyethylene (HDPE), Borated Polyethylene (BPE) and Concrete as candidate materials for neutron shielding. In shielding calculations, neutron induced scattering and absorption gamma dose has also been considered along with neutron dose. Contemporarily any material with higher hydrogenous concentration is best suited for neutron shielding. Choice of shielding material is also dominated by practical issues like economic viability and availability of space. Our computational analysis results reveal that utilization of BPE sheets results in minimum wall thickness requirement for attaining similar range of attenuation in neutron and gamma dose. The added advantage of using borated polyethylene is that it reduces the effect of both neutron and gamma dose by absorbing neutron and producing lithium and alpha particle. It has also been realized that for deciding upon optimum thickness determination of any shielding material, three important factors to be necessarily considered are: use factor, occupancy factor and work load factor. (author)

  3. In situ-observation of the vertical motion of soil waters by means of deuterated water using the gamma/neutron method: Laboratory and field

    International Nuclear Information System (INIS)

    Moutonnet, P.; Couchat, P.; Brissaud, F.; Puard, M.; Pappalardo, A.

    1978-01-01

    In order to study water movements in the field, the gamma/neutron method for measuring deuterated water was investigated. A laboratory device is presented which supplies measurements on 5 ml soil solution samples. A probe for in situ experiments is studied in all its performances: Background, calibration (count rate versus volumetric deuterated water content) and resolution. A dispersive transport of D 2 O pulses on soil column is presented and checked with a numerical simulation model. Then simultaneous measurement of soil water content and D 2 O concentration by neutron moisture gauge and gamma/neutron probe enable us to interpret the evolution of D 2 O pulse with an experimental field irrigation. (orig.) [de

  4. Study on the mercury evolution in a laboratory multi specific aquatic system by using instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Bubach, Debora; Guevara, Sergio Ribeiro; Arribere, Maria A.; Pechen de d'Angelo, Ana; Ferrari, Ana; Venturino, Andres

    1999-01-01

    A preliminary study on the evolution of mercury in the organisms of a laboratory multi specific aquatic system was performed using Instrumental Neutron Activation Analysis (INAA). Some of the possible effects of mercury toxicity were monitored by analyzing early biochemical indicators. The system consisted of an aquarium with bed sediments, aquatic macrophytes (Myriophyllum sp.), bivalves (Diplodom sp.) and exotic fish, simulating a long term contamination situation of unknown causes, where the sediments are the contaminant reservoir. Samples of the abiotic components of the system were analyzed at the beginning of the experiment, and again when the organisms were sampled. Fish carcass, kidney and liver samples, bivalve hepatopancreas, and whole macrophytes were extracted ana analyzed for mercury and other elements by INAA at the beginning of the experiment, and after 48 and 96 hours. Since some crustal elements such as Sc and La were detected in the hepatopancreas and macrophyte samples, enrichment factors for mercury, with respect to the <63 μm sediment fraction, were computed to discriminate the metabolized Hg content from that associated to the particulate. The hepatopancreas index, some indicators of oxidative stress (γ-Glutamyl-cysteinyl-glycine content and lipid peroxidation) and brain acetilcolinesterasa were measured as early indicators of toxicity. (author)

  5. Lawrence Livermore National Laboratory Experience Using 30-Gallon Drum Neutron Multiplicity Counter for Measuring Plutonium-Bearing Salts

    International Nuclear Information System (INIS)

    Dearborn, D M; Keeton, S C

    2004-01-01

    Lawrence Livermore National Laboratory (LLNL) has been performing accountability measurements of plutonium (Pu) -bearing items with the 30-gallon drum neutron multiplicity counter (NMC) since August 1998. A previous paper focused on the LLNL experience with Pu-bearing oxide and metal items. This paper expands on the LLNL experience with Pu-bearing salts containing low masses of Pu. All Pu-bearing salts used in this study were measured using calorimetry and gamma isotopic analyses (Cal/Iso) as well as the 30-gallon drum NMC. The Cal/Iso values were treated as being the true measure of Pu content because of the inherent high accuracy of the Cal/Iso technique, even at low masses of Pu, when measured over a sufficient period of time. Unfortunately, the long time period required to achieve high accuracy from Cal/Iso can impact other required accountability measurements. The 30-gallon drum NMC is a much quicker system for making accountability measurements of a Pu-bearing salt and might be a desirable tradeoff. The accuracy of 30-gallon drum NMC measurements of Pu-bearing salts, relative to that of Cal/Iso, is presented in relation to the mass range and alpha associated with each item. Conclusions drawn from the use of the 30-gallon drum NMC for accountability measurements of salts are also included

  6. Advances in associated-particle sealed-tube neutron probe diagnostics for substance detection

    International Nuclear Information System (INIS)

    Rhodes, E.; Dickerman, C.E.; Frey, M.

    1995-01-01

    The development and investigation of a small associated-particle sealed-tube neutron generator (APSTNG) shows potential to allow the associated-particle diagnostic method to be moved out of the laboratory into field applications. The APSTNG interrogates the inspected object with 14-MeV neutrons generated from the deuterium-tritium reaction and detects the alpha-particle associated with each neutron inside a cone encompassing the region of interest. Gamma-ray spectra of resulting neutron reactions identify many nuclides. Flight-times determined from detection times of the gamma-rays and alpha-particles can yield a separate coarse tomographic image of each identified nuclide, from a single orientation. Chemical substances are identified by comparing relative spectral line intensities with ratios of elements in reference compounds. The high-energy neutrons and gamma-rays penetrate large objects and dense materials. Generally no collimators or radiation shielding are needed. Proof-of-concept laboratory experiments have been successfully performed for simulated nuclear, chemical warfare, and conventional munitions. Most recently, inspection applications have been investigated for radioactive waste characterization, presence of cocaine in propane tanks, and uranium and plutonium smuggling. Based on lessons learned with the present APSTNG system, an advanced APSTNG tube (along with improved high voltage supply and control units) is being designed and fabricated that will be transportable and rugged, yield a substantial neutron output increase, and provide sufficiently improved lifetime to allow operation at more than an order of magnitude increase in neutron flux

  7. Using Instrumental Neutron Activation Analysis for geochemical analyses of terrestrial impact structures: Current analytical procedures at the University of Vienna Geochemistry Activation Analysis Laboratory

    International Nuclear Information System (INIS)

    Mader, Dieter; Koeberl, Christian

    2009-01-01

    The Instrumental Neutron Activation Analysis Gamma Spectroscopy Laboratory at the Department of Lithospheric Research, University of Vienna, has been upgraded in the year 2006. This paper describes the sample preparation, new instrumentation and data evaluation for hundreds of rock samples of two terrestrial impact structures. The measurement and data evaluation are done by using Genie TM 2000 and a custom-made batch software for the used analysis sequences.

  8. Micro elements for interrogating magnetoelastic sensors

    KAUST Repository

    Liang, Cai

    2011-11-01

    This paper reports a new approach for interrogating a magnetoelastic sensor\\'s resonant frequency. Previously, the frequency of a magnetoelastic sensor was measured by using a large-scale solenoid coil of at least some millimeters both in diameter and length. Planar structures of straight-line and rectangular spiral coil are designed, fabricated and tested to interrogate the resonant frequency of a magnetoelastic sensor. A sensor of 4 mm length is measured to have a resonant frequency of 551 kHz in air. The ability to interrogate a magnetoelastic sensor with such microscale elements is a step towards the miniaturization of a magnetoelastic sensor system and integration of such a system in a microfluidics device. © 2011 IEEE.

  9. Utilization of the Differential Die-Away Self-Interrogation Technique for Characterization and Verification of Spent Nuclear Fuel

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-27

    New nondestructive assay techniques are sought to better characterize spent nuclear fuel. One of the NDA instruments selected for possible deployment is differential die-away self-interrogation (DDSI). The proposed DDSI approach for spent fuel assembly assay utilizes primarily the spontaneous fission and (α, n) neutrons in the assemblies as an internal interrogating radiation source. The neutrons released in spontaneous fission or (α,n) reactions are thermalized in the surrounding water and induce fission in fissile isotopes, thereby creating a measurable signal from isotopes of interest that would be otherwise difficult to measure. The DDSI instrument employs neutron coincidence counting with 3He tubes and list-mode-based data acquisition to allow for production of Rossi-alpha distributions (RADs) in post-processing. The list-mode approach to data collection and subsequent construction of RADs has expanded the analytical possibilities, as will be demonstrated throughout this thesis. One of the primary advantages is that the measured signal in the form of a RAD can be analyzed in its entirety including determination of die-away times in different time domains. This capability led to the development of the early die-away method, a novel leakage multiplication determination method which is tested throughout the thesis on different sources in simulation space and fresh fuel experiments. The early die-away method is a robust, accurate, improved method of determining multiplication without the need for knowledge of the (α,n) source term. The DDSI technique and instrument are presented along with the many novel capabilities enabled by and discovered through RAD analysis. Among the new capabilities presented are the early die-away method, total plutonium content determination, and highly sensitive missing pin detection. Simulation of hundreds of different spent and fresh fuel assemblies were used to develop the analysis algorithms and the techniques were tested on a

  10. Advanced FBG sensing through rapid spectral interrogation

    Science.gov (United States)

    Kunzler, Wesley; Newman, Jason; Wilding, Daniel; Zhu, Zixu; Lowder, Tyson; Selfridge, Richard; Schultz, Stephen; Wirthlin, Michael

    2008-03-01

    A fiber Brag grating sensor interrogator has been developed which is capable of gathering vectors of information from individual fiber Bragg gratings by capturing the full optical spectrum 3 kHz. Using a field programmable gate array with high speed digital-to-analog converters and analog-to-digital components, plus a kilohertz rate MEMS optical filter, the optical spectrum can be scanned at rates in excess of 10 million nanometers per second, allowing sensor sampling rates of many kilohertz while maintaining the necessary resolution to understand sensor changes. The autonomous system design performs all necessary detection and processing of multiple sensors and allows spectral measurements to be exported as fast as Ethernet, USB, or RS232 devices can receive it through a memory mapped interface. The high speed - full spectrum - fiber Bragg grating sensor interrogator enables advanced interrogation of dynamic strain and temperature gradients along the length of a sensor, as well as the use of each sensor for multiple stimuli, such as in temperature compensation. Two examples are described, showing interrogation of rapid laser heating in an optical fiber, as well as complex strain effects in a beam that had an engineered defect.

  11. Rheo: Japanese Sound Art Interrogating Digital Mediality

    DEFF Research Database (Denmark)

    Vandsø, Anette

    2014-01-01

    THe article asks in what way the Japanese sound artist Ryoichi Kurokawa's audiovisual installation Rheo 5 Horisonz (2010) is 'digital'. Using Professor Lars Elleströms concept of 'mediality, the main claim in this article is that Rheo no only uses digital tehcnology, but also interrogates digital...

  12. Adaptive interrogation for 3D-PIV

    International Nuclear Information System (INIS)

    Novara, Matteo; Scarano, Fulvio; Ianiro, Andrea

    2013-01-01

    A method to adapt the shape and orientation of interrogation volumes for 3D-PIV motion analysis is introduced, aimed to increase the local spatial resolution. The main application of this approach is the detailed analysis of complex 3D and vortex-dominated flows that exhibit high vorticity in confined regions like shear layers and vortex filaments. The adaptive criterion is based on the analysis of the components of the local velocity gradient tensor, which returns the level of anisotropy of velocity spatial fluctuations. The principle to increase the local spatial resolution is based on the deformation of spherical isotropic interrogation regions, obtained by means of Gaussian weighting, into ellipsoids, with free choice of the principal axes and their directions. The interrogation region is contracted in the direction of the maximum velocity variation and elongated in the minimum one in order to maintain a constant interrogation volume. The adaptivity technique for three-dimensional PIV data takes advantage of the 3D topology of the flow, allowing increasing the spatial resolution not only in the case of shear layers, but also for vortex filaments, which is not possible for two-dimensional measurement in the plane normal to the vortex axis. The definition of the ellipsoidal interrogation region semi-axes is based on the singular values and singular directions of the local velocity gradient tensor as obtained by the singular values decomposition technique (SVD). The working principle is verified making use of numerical simulations of a shear layer and of a vortex filament. The application of the technique to data from a Tomo-PIV experiment conducted on a round jet, shows that the resolution of the shear layer at the jet exit can be considerably improved and an increase of about 25% in the vorticity peak is attained when the adaptive approach is applied. On the other hand, the peak vorticity description in the core of vortex rings is only slightly improved with

  13. Intonation and Duration Curve in Persian Interrogative Sentences

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Keyhani

    2012-03-01

    Full Text Available Background and Aim: prosody is a very important factor in communication and includes such parameters as: duration, intonation, pitch, stress, rhythm etc. Intonation is the pitch variation in one sentence. Duration is the time taken to utter a voice. The aim of the present study was to evaluate some parameters of prosody such as duration and intonation curve in interrogative sentences among normal Farsi speaking adults in order to determine the characteristics of this aspect of language with an emphasis on laboratory testing.Methods: This study was performed as a cross-sectional one. The participants included 134 male and female Farsi speaking individuals aging between 18-30 years. In this study two interrogative sentences with open and closed answers were used. The voice samples were analyzed by Dr.speech -real analysis software. Data analysis incorporated unilateral analysis of variance and an intonation curve was drawn for each sentence.Results: The parameter of duration among men and women was significantly different (p≤0.001. Duration in open questions was significantly longer than yes/no questions (p≤0.001. The intonation curve of the two groups were similar.Conclusion: Men and women use duration changes, for making difference in prosody. On the whole, duration among women is longer than men. In open questions, the duration of sentences is mostly due to the question word. The intonation curve in open questions has more amplitude. Women show much more changes in basic frequency for transferring interrogative state in their expressions.

  14. Performance of the Los Alamos National Laboratory spallation-driven solid-deuterium ultra-cold neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Saunders, A.; Makela, M.; Bagdasarova, Y.; Boissevain, J.; Bowles, T. J.; Currie, S. A.; Hill, R. E.; Hogan, G.; Morris, C. L.; Mortensen, R. N.; Ramsey, J.; Seestrom, S. J.; Sondheim, W. E.; Teasdale, W.; Wang, Z. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States); Back, H. O.; Broussard, L. J.; Hoagland, J.; Holley, A. T.; Pattie, R. W. Jr. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States); and others

    2013-01-15

    In this paper, we describe the performance of the Los Alamos spallation-driven solid-deuterium ultra-cold neutron (UCN) source. Measurements of the cold neutron flux, the very low energy neutron production rate, and the UCN rates and density at the exit from the biological shield are presented and compared to Monte Carlo predictions. The cold neutron rates compare well with predictions from the Monte Carlo code MCNPX and the UCN rates agree with our custom UCN Monte Carlo code. The source is shown to perform as modeled. The maximum delivered UCN density at the exit from the biological shield is 52(9) UCN/cc with a solid deuterium volume of {approx}1500 cm{sup 3}.

  15. Pneumatic sample-transfer system for use with the Lawrence Livermore National Laboratory rotating target neutron source (RTNS-I)

    International Nuclear Information System (INIS)

    Williams, R.E.

    1981-07-01

    A pneumatic sample-transfer system is needed to be able to rapidly retrieve samples irradiated with 14-MeV neutrons at the Rotating Target Neutron Source (RTNS-I). The rabbit system, already in place for many years, has been refurbished with modern system components controlled by an LSI-11 minicomputer. Samples can now be counted three seconds after an irradiation. There are many uses for this expanded 14-MeV neutron activation capability. Several fission products difficult to isolate from mixed fission fragments can be produced instead through (n,p) or (n,α) reactions with stable isotopes. Mass-separated samples of Nd, Mo, and Se, for example, can be irradiated to produce Pr, Nb, and As radionuclides sufficient for decay scheme studies. The system may also be used for multielement fast-neutron activation analysis because the neutron flux is greater than 2 x 10 11 n/cm 2 -sec. Single element analyses of Si and O are also possible. Finally, measurements of fast-neutron cross sections producing short-lived activation products can be performed with this system. A description of the rabbit system and instructions for its use are presented in this report

  16. Compact D-D/D-T neutron generators and their applications

    Energy Technology Data Exchange (ETDEWEB)

    Lou, Tak Pui [Univ. of California, Berkeley, CA (United States)

    2003-01-01

    Neutron generators based on the 2H(d,n)3He and 3H(d,n)4He fusion reactions are the most commonly available neutron sources. The applications of current commercial neutron generators are often limited by their low neutron yield and their short operational lifetime. A new generation of D-D/D-T fusion-based neutron generators has been designed at Lawrence Berkeley National Laboratory (LBNL) by using high current ion beams hitting on a self-loading target that has a large surface area to dissipate the heat load. This thesis describes the rationale behind the new designs and their potential applications. A survey of other neutron sources is presented to show their advantages and disadvantages compared to the fusion-based neutron generator. A prototype neutron facility was built at LBNL to test these neutron generators. High current ion beams were extracted from an RF-driven ion source to produce neutrons. With an average deuteron beam current of 24 mA and an energy of 100 keV, a neutron yield of >109 n/s has been obtained with a D-D coaxial neutron source. Several potential applications were investigated by using computer simulations. The computer code used for simulations and the variance reduction techniques employed were discussed. A study was carried out to determine the neutron flux and resolution of a D-T neutron source in thermal neutron scattering applications for condensed matter experiments. An error analysis was performed to validate the scheme used to predict the resolution. With a D-T neutron yield of 1014 n/s, the thermal neutron flux at the sample was predicted to be 7.3 x 105 n/cm2s. It was found that the resolution of cold neutrons was better than that of thermal neutrons when the duty factor is high. This neutron generator could be efficiently used for research and educational purposes at universities. Additional applications studied were positron production and

  17. Compact D-D/D-T neutron generators and their applications

    International Nuclear Information System (INIS)

    Lou, Tak Pui

    2003-01-01

    Neutron generators based on the 2 H(d,n) 3 He and 3 H(d,n) 4 He fusion reactions are the most commonly available neutron sources. The applications of current commercial neutron generators are often limited by their low neutron yield and their short operational lifetime. A new generation of D-D/D-T fusion-based neutron generators has been designed at Lawrence Berkeley National Laboratory (LBNL) by using high current ion beams hitting on a self-loading target that has a large surface area to dissipate the heat load. This thesis describes the rationale behind the new designs and their potential applications. A survey of other neutron sources is presented to show their advantages and disadvantages compared to the fusion-based neutron generator. A prototype neutron facility was built at LBNL to test these neutron generators. High current ion beams were extracted from an RF-driven ion source to produce neutrons. With an average deuteron beam current of 24 mA and an energy of 100 keV, a neutron yield of >10 9 n/s has been obtained with a D-D coaxial neutron source. Several potential applications were investigated by using computer simulations. The computer code used for simulations and the variance reduction techniques employed were discussed. A study was carried out to determine the neutron flux and resolution of a D-T neutron source in thermal neutron scattering applications for condensed matter experiments. An error analysis was performed to validate the scheme used to predict the resolution. With a D-T neutron yield of 10 14 n/s, the thermal neutron flux at the sample was predicted to be 7.3 x 10 5 n/cm 2 s. It was found that the resolution of cold neutrons was better than that of thermal neutrons when the duty factor is high. This neutron generator could be efficiently used for research and educational purposes at universities. Additional applications studied were positron production and Boron Neutron Capture Therapy (BNCT). The neutron flux required for positron

  18. Natural syntax : English interrogative main clauses

    Directory of Open Access Journals (Sweden)

    Janez Oresnik

    2007-12-01

    Full Text Available Natural Syntax is a developing deductive theory, a branch of Naturalness Theory. The naturalnessjudgements are couched in naturalness scales, whichfollow from the basic parameters (or «axioms» listed at the beginning of the paper. The predictions of the theory are calculated in deductions, whose chief components are apair of naturalness scales and the rules governing the alignment of corresponding naturalness values. Parallel and chiastic alignments are distinguished, in complementary distribution. Chiastic alignment is mandatory in deductions limited to unnatural environments. The paper deals with English interrogative main clauses. Within these, only the interrogatives containing wh-words exclusively insitu constitute an extremely unnatural environment and require chiastic alignment. Otherwiseparallel alignment is used. Earlier publications on Natural Syntax: Kavcic 2005a,b, Oresnik 1999, 2000a,b, 200la-f   2002, 2003a-c, 2002/03, 2004. This list cites only works written in English.

  19. Fast-neutron capture-cross-section measurements with the Argonne National Laboratory large-liquid-scintillator tank

    International Nuclear Information System (INIS)

    Poenitz, W.P.

    1982-01-01

    Measurements of the neutron-radioactive-capture cross sections of Y, Zr, Mo, Ag, Cd, In, Sb, La, Eu, Gd, Tb, Dy, Er, Yb, Hf, W, Re, and Pt in the 0.5 to 4.0-MeV-energy range are presented. A large-liquid-scintillator detector was used for detecting the capture events. A grey neutron detector was used as neutron monitor. The reported cross sections are relative to the capture cross section of gold at 0.5 MeV. Where prior data exist the present data are lower for most elements. However, good agreement was obtained with very recent results reported by the group from Bruyeres-le-Chatel

  20. Revenge versus rapport: Interrogation, terrorism, and torture.

    Science.gov (United States)

    Alison, Laurence; Alison, Emily

    2017-04-01

    This review begins with the historical context of harsh interrogation methods that have been used repeatedly since the Second World War. This is despite the legal, ethical and moral sanctions against them and the lack of evidence for their efficacy. Revenge-motivated interrogations (Carlsmith & Sood, 2009) regularly occur in high conflict, high uncertainty situations and where there is dehumanization of the enemy. These methods are diametrically opposed to the humanization process required for adopting rapport-based methods-for which there is an increasing corpus of studies evidencing their efficacy. We review this emerging field of study and show how rapport-based methods rely on building alliances and involve a specific set of interpersonal skills on the part of the interrogator. We conclude with 2 key propositions: (a) for psychologists to firmly maintain the Hippocratic Oath of "first do no harm," irrespective of perceived threat and uncertainty, and (b) for wider recognition of the empirical evidence that rapport-based approaches work and revenge tactics do not. Proposition (a) is directly in line with fundamental ethical principles of practice for anyone in a caring profession. Proposition (b) is based on the requirement for psychology to protect and promote human welfare and to base conclusions on objective evidence. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  1. Enrico Fermi's Discovery of Neutron-Induced Artificial Radioactivity:The Recovery of His First Laboratory Notebook

    Science.gov (United States)

    Acocella, Giovanni; Guerra, Francesco; Robotti, Nadia

    . We give a short description of the discovery of the first experimental notebook of Enrico Fermi (1901-1954) on his researches during March and April of 1934 on neutron-induced artificial radioactivity, and we point out its relevance for a proper historical and conceptual understanding of those researches.

  2. Hybrid Monte Carlo/Deterministic Methods for Accelerating Active Interrogation Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Peplow, Douglas E. [ORNL; Miller, Thomas Martin [ORNL; Patton, Bruce W [ORNL; Wagner, John C [ORNL

    2013-01-01

    The potential for smuggling special nuclear material (SNM) into the United States is a major concern to homeland security, so federal agencies are investigating a variety of preventive measures, including detection and interdiction of SNM during transport. One approach for SNM detection, called active interrogation, uses a radiation source, such as a beam of neutrons or photons, to scan cargo containers and detect the products of induced fissions. In realistic cargo transport scenarios, the process of inducing and detecting fissions in SNM is difficult due to the presence of various and potentially thick materials between the radiation source and the SNM, and the practical limitations on radiation source strength and detection capabilities. Therefore, computer simulations are being used, along with experimental measurements, in efforts to design effective active interrogation detection systems. The computer simulations mostly consist of simulating radiation transport from the source to the detector region(s). Although the Monte Carlo method is predominantly used for these simulations, difficulties persist related to calculating statistically meaningful detector responses in practical computing times, thereby limiting their usefulness for design and evaluation of practical active interrogation systems. In previous work, the benefits of hybrid methods that use the results of approximate deterministic transport calculations to accelerate high-fidelity Monte Carlo simulations have been demonstrated for source-detector type problems. In this work, the hybrid methods are applied and evaluated for three example active interrogation problems. Additionally, a new approach is presented that uses multiple goal-based importance functions depending on a particle s relevance to the ultimate goal of the simulation. Results from the examples demonstrate that the application of hybrid methods to active interrogation problems dramatically increases their calculational efficiency.

  3. Compact neutron generator

    Science.gov (United States)

    Leung, Ka-Ngo; Lou, Tak Pui

    2005-03-22

    A compact neutron generator has at its outer circumference a toroidal shaped plasma chamber in which a tritium (or other) plasma is generated. A RF antenna is wrapped around the plasma chamber. A plurality of tritium ion beamlets are extracted through spaced extraction apertures of a plasma electrode on the inner surface of the toroidal plasma chamber and directed inwardly toward the center of neutron generator. The beamlets pass through spaced acceleration and focusing electrodes to a neutron generating target at the center of neutron generator. The target is typically made of titanium tubing. Water is flowed through the tubing for cooling. The beam can be pulsed rapidly to achieve ultrashort neutron bursts. The target may be moved rapidly up and down so that the average power deposited on the surface of the target may be kept at a reasonable level. The neutron generator can produce fast neutrons from a T-T reaction which can be used for luggage and cargo interrogation applications. A luggage or cargo inspection system has a pulsed T-T neutron generator or source at the center, surrounded by associated gamma detectors and other components for identifying explosives or other contraband.

  4. Proceedings of the Oak Ridge National Laboratory/Brookhaven National Laboratory workshop on neutron scattering instrumentation at high-flux reactors

    International Nuclear Information System (INIS)

    McBee, M.R.; Axe, J.D.; Hayter, J.B.

    1990-07-01

    For the first three decades following World War II, the US, which pioneered the field of neutron scattering research, enjoyed uncontested leadership in the field. By the mid-1970's, other countries, most notably through the West European consortium at Institut Laue-Langevin (ILL) in Grenoble, France, had begun funding neutron scattering on a scale unmatched in this country. By the early 1980's, observers charged with defining US scientific priorities began to stress the need for upgrading and expansion of US research reactor facilities. The conceptual design of the ANS facility is now well under way, and line-item funding for more advanced design is being sought for FY 1992. This should lead to a construction request in FY 1994 and start-up in FY 1999, assuming an optimal funding profile. While it may be too early to finalize designs for instruments whose construction is nearly a decade removed, it is imperative that we begin to develop the necessary concepts to ensure state-of-the-art instrumentation for the ANS. It is in this context that this Instrumentation Workshop was planned. The workshop touched upon many ideas that must be considered for the ANS, and as anticipated, several of the discussions and findings were relevant to the planning of the HFBR Upgrade. In addition, this report recognizes numerous opportunities for further breakthroughs on neutron instrumentation in areas such as improved detection schemes (including better tailored scintillation materials and image plates, and increased speed in both detection and data handling), in-beam monitors, transmission white beam polarizers, multilayers and supermirrors, and more. Each individual report has been cataloged separately

  5. Neutrons for matter exploration: neutron spectroscopy in condensed matter physics

    International Nuclear Information System (INIS)

    Kahn, R.

    1997-01-01

    The physical properties and the various uses of neutrons for characterizing structures (through neutron diffraction) and condensed matter dynamics (through Doppler effect), are reviewed. Results and potential observations are given for the different methods: neutron diffraction, small angle scattering, reflectometry, neutron inelastic scattering. The two CEA laboratories where these studies may be carried out are presented

  6. Activities of the Laboratory of Neutron Activation Analysis in the Radiochemistry Division - IPEN/CNEN/SP/Brazil

    International Nuclear Information System (INIS)

    Vasconcellos, M.B.A.

    1988-01-01

    Neutron activation analysis (NAA) is one of the relevant applications of nuclear research reactors. Due to the high neutron fluxes available in these reactors, an excellent sensitivity of analysis is attained for many elements. NAA is one of the most sensitive, precise and accurate analytical methods for trace element determination. NAA has been one of the main activities of the Radiochemistry Division of IPEN, since the befinning of the operation of the nuclear reactor IEA-R1. Most of the effort was devoted to research work, aimed to improvements in the method as well as to its applications to several kinds of matrixes (geological, biological, metallic, environmental, forensic). Besides, analytical services were also offered, to the CNEN, to industries, universities, mining companies and research institutes. In the present paper, a review is made of the research work being developed presently at the Radiochemistry Division of IPEN. A discussion is also made of the planned expansion of the analytical services offered. (author) [pt

  7. Uses of advanced pulsed neutron sources. Report of a workshop held at Argonne National Laboratory October 21--24, 1975

    International Nuclear Information System (INIS)

    Carpenter, J.M.; Werner, S.A.

    1975-01-01

    The report contains the conclusions that were drawn by nine panels of scientists in the fields of Biology; Chemical Spectroscopy; Chemical Structures of Crystalline Solids; Chemical Structures of Disordered Solids and Inhomogeneous Systems; Dynamics of Solids, Liquids, Glasses and Gases; Magnetism; Neutron Sources; and Radiation Effects. The nine panel reports describe the applications found in these scientific areas, accompanying them with conceptual instruments designed for the measurements and with calculations to establish feasibility

  8. Neutron scattering. Lectures of the JCNS laboratory course held at Forschungszentrum Juelich and the research reactor FRM II of TU Munich

    International Nuclear Information System (INIS)

    Brueckel, T.; Heger, G.; Richter, D.; Zorn, R.

    2007-01-01

    The following topics are dealt with: Fourier transform, basic assumptions of quantum mechanics and the Born approximation, symmtery in crystals, neutron sources, neutron elastic scattering and properties, polarized neutron scattering, correlation functions measured by scattering experiments, grazing incidence neutron scattering, neutron diffractometers, small-angle scattewring inelastic crystal spectrometers, time-of-flight spectrometers using NSE, structure determination, inelastic neutron scattering with phonon and magnon excitations, structure of complex fluids and macromolecules, polymer dynamics, magnetism. (HSI)

  9. 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.

  10. First Deminsys (high speed FBG interrogator) flight

    Science.gov (United States)

    van Els, Thomas J.

    2009-03-01

    Deminsys is the world's fastest multi sensor / multi channel FBG interrogator, identifies one till four channels with typically 8 sensors per channel. The system is especially developed for the interrogation of signals up to 19,3 kHz for each sensor and the sample frequency is independent of the number of sensors. By having multiple sensors per fibre you can create a very compact network of sensors. Due to its revolutionary (light weight, compact and solid state) design, Deminsys seems to fit perfectly into (research) programs for aerospace, medic & life science, maritime, industrial, crash test and all other fast detection applications. Technobis Fibre Technologies (TFT) and NLR made a first test flight with the Deminsys optical fibre measurement system using the NLR test aircraft on October 24th 2008. This flight was a first step in the further development of the current system in order to make it suitable for operation on-board an aircraft and bring it from TRL3 towards TRL5, a functional model for aerospace applications.

  11. Neutron diffraction

    International Nuclear Information System (INIS)

    Heger, G.

    1996-01-01

    X-ray diffraction using conventional laboratory equipment and/or synchrotron installations is the most important method for structure analyses. The purpose of this paper is to discuss special cases, for which, in addition to this indispensable part, neutrons are required to solve structural problems. Even though the huge intensity of modern synchrotron sources allows in principle the study of magnetic X-ray scattering the investigation of magnetic structures is still one of the most important applications of neutron diffraction. (author) 15 figs., 1 tab., 10 refs

  12. Neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Heger, G. [Rheinisch-Westfaelische Technische Hochschule Aachen, Inst. fuer Kristallographie, Aachen (Germany)

    1996-12-31

    X-ray diffraction using conventional laboratory equipment and/or synchrotron installations is the most important method for structure analyses. The purpose of this paper is to discuss special cases, for which, in addition to this indispensable part, neutrons are required to solve structural problems. Even though the huge intensity of modern synchrotron sources allows in principle the study of magnetic X-ray scattering the investigation of magnetic structures is still one of the most important applications of neutron diffraction. (author) 15 figs., 1 tab., 10 refs.

  13. Health Interrogation for Space Structures (HISS), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Invocon's Health Interrogation for Space Structures (HISS) system provides a significant improvement over current alternatives for monitoring pressurized space...

  14. 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.

  15. 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

  16. Fission signal detection using helium-4 gas fast neutron scintillation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, J. M., E-mail: lewisj@ufl.edu; Kelley, R. P.; Jordan, K. A. [Nuclear Engineering Program, University of Florida, Gainesville, Florida 32611 (United States); Murer, D. [Arktis Radiation Detectors Ltd., 8045 Zurich (Switzerland)

    2014-07-07

    We demonstrate the unambiguous detection of the fission neutron signal produced in natural uranium during active neutron interrogation using a deuterium-deuterium fusion neutron generator and a high pressure {sup 4}He gas fast neutron scintillation detector. The energy deposition by individual neutrons is quantified, and energy discrimination is used to differentiate the induced fission neutrons from the mono-energetic interrogation neutrons. The detector can discriminate between different incident neutron energies using pulse height discrimination of the slow scintillation component of the elastic scattering interaction between a neutron and the {sup 4}He atom. Energy histograms resulting from this data show the buildup of a detected fission neutron signal at higher energies. The detector is shown here to detect a unique fission neutron signal from a natural uranium sample during active interrogation with a (d, d) neutron generator. This signal path has a direct application to the detection of shielded nuclear material in cargo and air containers. It allows for continuous interrogation and detection while greatly minimizing the potential for false alarms.

  17. Fission signal detection using helium-4 gas fast neutron scintillation detectors

    Science.gov (United States)

    Lewis, J. M.; Kelley, R. P.; Murer, D.; Jordan, K. A.

    2014-07-01

    We demonstrate the unambiguous detection of the fission neutron signal produced in natural uranium during active neutron interrogation using a deuterium-deuterium fusion neutron generator and a high pressure 4He gas fast neutron scintillation detector. The energy deposition by individual neutrons is quantified, and energy discrimination is used to differentiate the induced fission neutrons from the mono-energetic interrogation neutrons. The detector can discriminate between different incident neutron energies using pulse height discrimination of the slow scintillation component of the elastic scattering interaction between a neutron and the 4He atom. Energy histograms resulting from this data show the buildup of a detected fission neutron signal at higher energies. The detector is shown here to detect a unique fission neutron signal from a natural uranium sample during active interrogation with a (d, d) neutron generator. This signal path has a direct application to the detection of shielded nuclear material in cargo and air containers. It allows for continuous interrogation and detection while greatly minimizing the potential for false alarms.

  18. Phase I - Final report: Improved position sensitive detectors for thermal neutrons. Design, fabrication, and results of testing the Phase I - Proof-of-Principal Improved Position Sensitive Thermal Neutron Detector Prototype in the laboratory and at the Intense Pulsed Neutron Source (IPNS), Argonne National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Hull, Carter D.

    2001-04-06

    A position sensitive neutron detector was designed and fabricated with bundles of individual detector elements with diameters of 120 mm. These neutron scintillating fibers were coupled with optoelectronic arrays to produce a ''Fiber Detector.'' A fiber position sensitive detector was completed and tested with scattered and thermal neutrons. Deployment of improved 2D PSDs with high signal to noise ratios at lower costs per area was the overall objective of the project.

  19. Laser interrogation of latent vehicle registration number

    Energy Technology Data Exchange (ETDEWEB)

    Russo, R.E. [Lawrence Berkeley Lab., CA (United States). Energy and Environment Div.]|[Lawrence Livermore National Lab., CA (United States). Forensic Science Center; Pelkey, G.E. [City of Livermore Police Dept., CA (United States); Grant, P.; Whipple, R.E.; Andresen, B.D. [Lawrence Livermore National Lab., CA (United States). Forensic Science Center

    1994-09-01

    A recent investigation involved automobile registration numbers as important evidentiary specimens. In California, as in most states, small, thin metallic decals are issued to owners of vehicles each year as the registration is renewed. The decals are applied directly to the license plate of the vehicle and typically on top of the previous year`s expired decal. To afford some degree of security, the individual registration decals have been designed to tear easily; they cannot be separated from each other, but can be carefully removed intact from the metal license plate by using a razor blade. In September 1993, the City of Livermore Police Department obtained a blue 1993 California decal that had been placed over an orange 1992 decal. The two decals were being investigated as possible evidence in a case involving vehicle registration fraud. To confirm the suspicion and implicate a suspect, the department needed to known the registration number on the bottom (completely covered) 1992 decal. The authors attempted to use intense and directed light to interrogate the colored stickers. Optical illumination using a filtered white-light source partially identified the latent number. However, the most successful technique used a tunable dye laser pumped by a pulsed Nd:YAG laser. By selectively tuning the wavelength and intensity of the dye laser, backlit illumination of the decals permitted visualization of the underlying registration number through the surface of the top sticker. With optimally-tuned wavelength and intensity, 100% accuracy was obtained in identifying the sequence of latent characters. The advantage of optical techniques is their completely nondestructive nature, thus preserving the evidence for further interrogation or courtroom presentation.

  20. Fail-safe neutron shutter used for thermal neutron radiography

    International Nuclear Information System (INIS)

    Sachs, R.D.; Morris, R.A.

    1976-11-01

    A fail-safe, reliable, easy-to-use neutron shutter was designed, built, and put into operation at the Omega West Reactor, Los Alamos Scientific Laboratory. The neutron shutter will be used primarily to perform thermal neutron radiography, but is also available for a highly collimated source of thermal neutrons [neutron flux = 3.876 x 10 6 (neutrons)/(cm 2 .s)]. Neutron collimator sizes of either 10.16 by 10.16 cm or 10.16 by 30.48 cm are available

  1. Interrogator independence and challenges of his lack of ...

    African Journals Online (AJOL)

    The interrogator in criminal procedures is charged with important and momentous judicial tasks and for this reason, he should enjoy higher job security as in French law, an interrogator is not considered among the officials of public prosecutor's office and enjoys higher security. Code of Criminal Procedure of 2013 has ...

  2. Some Semantic Properties of Romanian Interrogatives: "Care" and "Cine."

    Science.gov (United States)

    Vasiliu, E.

    The aim of this paper is to account for some semantic properties of Romanian interrogatives "ce" and "cine" by establishing some definite correlations between various contextual restrictions governing the use of these interrogative particles and the "meaning" which might be assigned to each of these particles in any…

  3. Division of labor in the interpretation of declaratives and interrogatives

    NARCIS (Netherlands)

    Farkas, D.F.; Roelofsen, F.

    This article presents an account of the semantic content and conventional discourse effects of a range of sentence types in English, namely falling declaratives, polar interrogatives and certain kinds of rising declaratives and tag interrogatives. The account aims to divide the labor between

  4. Design of a 100 J Dense Plasma Focus Z-pinch Device as a Portable Neutron Source

    Science.gov (United States)

    Jiang, Sheng; Higginson, Drew; Link, Anthony; Liu, Jason; Schmidt, Andrea

    2015-11-01

    The dense plasma focus (DPF) Z-pinch devices are capable of accelerating ions to high energies through MV/mm-scale electric fields. When deuterium is used as the filling gas, neutrons are generated through beam-target fusion when fast D beams collide with the bulk plasma. The neutron yield on a DPF scales favorably with current, and could be used as portable sources for active interrogation. Past DPF experiments have been optimized empirically. Here we use the particle-in-cell (PIC) code LSP to optimize a portable DPF for high neutron yield prior to building it. In this work, we are designing a DPF device with about 100 J of energy which can generate 106 - 107 neutrons. The simulations are run in the fluid mode for the rundown phase and are switched to kinetic to capture the anomalous resistivity and beam acceleration process during the pinch. A scan of driver parameters, anode geometries and gas pressures are studied to maximize the neutron yield. The optimized design is currently under construction. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by the Laboratory Directed Research and Development Program (15-ERD-034) at LLNL.

  5. Study on severe accident fuel dispersion behavior in the Advanced Neutron Source reactor at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Kim, S.H.; Taleyarkhan, R.P.; Navarro-Valenti, S.; Georgevich, V.; Xiang, J.Y.

    1995-01-01

    Core flow blockage events are a leading contributor to core damage initiation risk in the Advanced Neutron Source (ANS) reactor. During such an accident, insufficient cooling of the fuel could result in core heatup and melting under full coolant flow condition. Coolant inertia forces acting on the melt surface would likely break up the melt into small particles. Under thermal-hydraulic conditions of ANS coolant channel, micro-fine melt particles are expected. Heat transfer between melt particle and coolant, which affects particle breakup, was studied. The study indicates that the thermal effect on melt fragmentation seems to be negligible because the time corresponding to the breakup due to hydrodynamic forces is much shorter than the time for the melt surface to solidify. The study included modeling and analyses to predict transient behavior and transport of debris particles throughout the coolant system. The transient model accounts for the surface forces acting on the particle that results from the pressure variation on the surface, inertia, virtual mass, viscous force due to relative motion of particle in the coolant, gravitation, and resistance due to inhomogenous coolant velocity radially across piping due to possible turbulent coolant motions. Results indicate that debris particles would reside longest in heat exchangers because of lower coolant velocity there. Also core debris tends to move together upon melting and entrainment

  6. Study on severe accident fuel dispersion behavior in the advanced neutron source reactor at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.H.; Taleyarkhan, R.P.; Navarro-Valenti, S. [Oak Ridge National Lab., TN (United States)] [and others

    1995-09-01

    Core flow blockage events have been determined to represent a leading contributor to core damage initiation risk in the Advanced Neutron Source (ANS) reactor. During such an accident, insufficient cooling of the fuel in a few adjacent blocked coolant channels out of several hundred channels, could also result in core heatup and melting under full coolant flow condition in other coolant channels. Coolant inertia forces acting on the melt surface would likely break up the melt into small particles. Under thermal-hydraulic conditions of ANS coolant channel, micro-fine melt particles are expected. Hat transfer between melt particle and coolant, which affects the particle breakup characteristics, was studied. The study indicates that the thermal effect on melt fragmentation seems to be negligible because the time corresponding to the breakup due to hydrodynamic forces is much shorter than the time for the melt surface to solidify. The study included modeling and analyses to predict transient behavior and transport of debris particles throughout the coolant system. The transient model accounts for the surface forces acting on the particle that results from the pressure variation on the surface, inertia, virtual mass, viscous force due to the relative motion of the particle in the coolant, gravitation, and resistance due to inhomogenous coolant velocity radially across piping due to possible turbulent coolant motions. The results indicate that debris particles would reside longest in heat exchangers because of lower coolant velocity there. Also they are entrained and move together in a cloud.

  7. Ultra-Cold Neutrons (UCN)

    Data.gov (United States)

    Federal Laboratory Consortium — Researchers working at the Los Alamos Neutron Science Center and eight other member institutions of an international collaboration are constructing the most intense...

  8. Prototype Neutron Energy Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Stephen Mitchell, Sanjoy Mukhopadhyay, Richard Maurer, Ronald Wolff

    2010-06-16

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

  9. Preliminary results for the k0-INAA methodology implementation at the Neutron Activation Analysis Laboratory, LAN-IPEN, using k0-IAEA software

    International Nuclear Information System (INIS)

    Mariano, Davi B.; Figueiredo, Ana Maria G.; Semmler, Renato

    2009-01-01

    The present paper presents the preliminary results obtained in the implementation of the k 0 standardization method at the Neutron Activation Laboratory (LAN) at IPEN, Sao Paulo, Brazil, using the program k 0 -IAEA, provided by The International Atomic Energy Agency (IAEA). This method is an important alternative for the comparative neutron activation analysis, which has been used for several years at LAN-IPEN. This quasiabsolute standardization method presents a great advantage with relation to the comparative method, since it does not require the preparation of accurate individual standards for each analysed element, which is very laborious and time-consuming. The k 0 method allows the determination of almost all elements whose gammaray peaks are present in the gamma spectrum. The analysis of gamma-ray spectra and the calculation of concentration are performed by the k 0 software, thus the analysis time is shortened: the time spent to calculate, for instance, the concentration of 25 elements in 10 samples takes about 5 minutes.The efficiency curve of one of the gamma-ray spectrometers used at LAN was determined by measuring calibrated radioactive sources at the usually utilised counting geometries. The parameters α and f were determined by irradiating a Certified Nuclear Reference Material IRMM-530R Al-0,1% Au alloys and high purity zirconium comparators at the IEA-R1 nuclear reactor of IPEN. In order to evaluate the efficiency of the methodology, the geological reference material basalt JB-1 (GSJ) was analysed. The preliminary results obtained showed promising results in spite of some discrepancies of the data in comparison to certified values. These preliminary results indicate that some improvements in the parameters required for the use of the k 0 -IAEA software should be made so that the k 0 - NAA software can be completely successful. (author)

  10. Update on Calibration of the Lawrence Livermore National Laboratory Passive-Active Neutron Drum Shuffler for Measurement of Highly Enriched Uranium Oxide

    International Nuclear Information System (INIS)

    Mount, M.; O'Connell, W.; Cochran, C.; Rinard, P.; Dearborn, D.; Endres, E.

    2002-01-01

    In October of 1999, Lawrence Livermore National Laboratory (LLNL) began an effort to calibrate the LLNL passive-active neutron (PAN) drum shuffler for measurement of highly enriched uranium (HEU) oxide. A single unit of certified reference material (CRM) 149 (Uranium (93% Enriched) Oxide - U 3 O 8 Standard for Neutron Counting Measurements) was used to (1) develop a mass calibration curve for HEU oxide in the nominal range of 393 g to 3144 g 235 U, and (2) perform a detailed axial and radial mapping of the detector response over a wide region of the PAN shuffler counting chamber. Results from these efforts were reported at the Institute of Nuclear Materials Management 4lSt Annual Meeting in July 2000. This paper describes subsequent efforts by LLNL to use a unit of CRM 146 (Uranium Isotopic Standard for Gamma Spectrometry Measurements) in consort with Monte Carlo simulations of the PAN shuffler response to CRM 149 and CRM 146 units and a selected set of containers with CRM 149-equivalent U 3 O 8 to (1) extend the low range of the reported mass calibration curve to 10 g 235 U, (2) evaluate the effect of U 3 O 8 density (2.4 g/cm 3 to 4.8 g/cm 3 ) and container size (5.24 cm to 12.17 cm inside diameter and 6.35 cm to 17.72 cm inside height) on the PAN shuffler response, and (3) develop mass calibration curves for U 3 O 8 enriched to 20.1 wt% 235 U and 52.5 wt% 235 U.

  11. Interrogative Utterances in Surah Al-Baqarah

    Directory of Open Access Journals (Sweden)

    Aly Bayoumy AIi Oteify

    1993-11-01

    Full Text Available The Qur’an is singularly distinctive in its style compared to any human composition. Human eloquence, with its remarkable history in the composition of poetry, has failed to compose even a single verse like that of the Qur'an. The Qur'anic composition is a living challenge for human beings to imitate its miraculous style. This inimitable aspect of the Qur'an, among other things, proves that it was revealed by Allah (SWT to Prophet Muhammad (SAAS. In addition, the miracle of its linguistic composition was a means to declare the faith based on monotheism and the introduction of a new order and a theo-centric guidance that was meant to unite humanity. Adopting the monotheistic faith gave rise to a new community, the Muslim ummah that was able to bridge the differences between human beings in culture, race, colour and geographical boundaries. Consequently, the unique style of the Qur’an deserves a careful study. The present study investigates the use of interrogative utterances in surah al-Baqarah and their contribution to the Qur'an's rhetorical style. Hopefully, the results of this study will be useful in later investigations of other parts of the Qur' an...

  12. Interrogations, confessions, and adolescent offenders' perceptions of the legal system.

    Science.gov (United States)

    Arndorfer, Andrea; Malloy, Lindsay C; Cauffman, Elizabeth

    2015-10-01

    The potential consequences of interrogations and false confessions have been discussed primarily in terms of the risk for wrongful conviction, especially among adolescents and other vulnerable populations. However, it is possible that such experiences influence adolescents' perceptions of the legal system more generally. In the present study, we examined whether incarcerated male juvenile offenders' (n = 193) perceptions of police and the courts were related to their confession and interrogation experiences. High-pressure interrogation experiences and self-reported false confessions to police were associated with more negative perceptions of police. However, self-reported true confessions were not significantly associated with youths' perceptions of the police. Neither interrogation nor confession experiences (true or false) were related to youths' perceptions of the courts. Results provide additional support for policy reform of interrogation practices with young suspects. A more developmentally appropriate approach to criminal interrogations with youth may simultaneously improve police-youth relations and protect vulnerable suspects in the interrogation room. (c) 2015 APA, all rights reserved).

  13. An adaptive sampling and windowing interrogation method in PIV

    Science.gov (United States)

    Theunissen, R.; Scarano, F.; Riethmuller, M. L.

    2007-01-01

    This study proposes a cross-correlation based PIV image interrogation algorithm that adapts the number of interrogation windows and their size to the image properties and to the flow conditions. The proposed methodology releases the constraint of uniform sampling rate (Cartesian mesh) and spatial resolution (uniform window size) commonly adopted in PIV interrogation. Especially in non-optimal experimental conditions where the flow seeding is inhomogeneous, this leads either to loss of robustness (too few particles per window) or measurement precision (too large or coarsely spaced interrogation windows). Two criteria are investigated, namely adaptation to the local signal content in the image and adaptation to local flow conditions. The implementation of the adaptive criteria within a recursive interrogation method is described. The location and size of the interrogation windows are locally adapted to the image signal (i.e., seeding density). Also the local window spacing (commonly set by the overlap factor) is put in relation with the spatial variation of the velocity field. The viability of the method is illustrated over two experimental cases where the limitation of a uniform interrogation approach appears clearly: a shock-wave-boundary layer interaction and an aircraft vortex wake. The examples show that the spatial sampling rate can be adapted to the actual flow features and that the interrogation window size can be arranged so as to follow the spatial distribution of seeding particle images and flow velocity fluctuations. In comparison with the uniform interrogation technique, the spatial resolution is locally enhanced while in poorly seeded regions the level of robustness of the analysis (signal-to-noise ratio) is kept almost constant.

  14. Neutron Resonance Transmission Analysis (NRTA): Initial Studies of a Method for Assaying Plutonium in Spent Fuel

    Energy Technology Data Exchange (ETDEWEB)

    David L. Chichester; James W. Sterbentz

    2011-05-01

    Neutron Resonance Transmission Analysis (NRTA) is an analytical technique that uses neutrons to assay the isotopic content of bulk materials. The technique uses a pulsed accelerator to produce an intense, short pulse of neutrons in a time-of-flight configuration. These neutrons, traveling at different speeds according to their energy, can be used to interrogate a spent fuel (SF) assembly to determine its plutonium content. Neutron transmission through the assembly is monitored as a function of neutron energy (time after the pulse), similar to the way neutron cross-section data is often collected. The transmitted neutron intensity is recorded as a function of time, with faster (higher-energy) neutrons arriving first and slower (lower-energy) neutrons arriving later. The low-energy elastic scattering and absorption resonances of plutonium and other isotopes modulate the transmitted neutron spectrum. Plutonium content in SF can be determined by analyzing this attenuation. Work is currently underway at Idaho National Laboratory, as a part of United States Department of Energy's Next Generation Safeguards Initiative (NGSI), to investigate the NRTA technique and to assess its feasibility for quantifying the plutonium content in SF and for determining the diversion of SF pins from assemblies. Preliminary results indicate that NRTA has great potential for being able to assay intact SF assemblies. Operating in the 1-40 eV range, it can identify four plutonium isotopes (239, 240, 241, & 242Pu), three uranium isotopes (235, 236, & 238U), and six resonant fission products (99Tc, 103Rh, 131Xe, 133Cs, 145Nd, and 152Sm). It can determine the areal density or mass of these isotopes in single- or multiple-pin integral transmission scans. Further, multiple observables exist to allow the detection of material diversion (pin defects) including fast-neutron and x-ray radiography, gross-transmission neutron counting, plutonium resonance absorption analysis, and fission

  15. Electronic instrumentation system for pulsed neutron measurements

    International Nuclear Information System (INIS)

    Burda, J.; Igielski, A.; Kowalik, W.

    1982-01-01

    An essential point of pulsed neutron measurement of thermal neutron parameters for different materials is the registration of the thermal neutron die-away curve after a fast neutron bursts have been injected into the system. An electronic instrumentation system which is successfully applied for pulsed neutron measurements is presented. An important part of the system is the control unit which has been designed and built in the Laboratory of Neutron Parameters of Materials. (author)

  16. Introductory theory of neutron scattering

    International Nuclear Information System (INIS)

    Gunn, J.M.F.

    1986-12-01

    The paper comprises a set of six lecture notes which were delivered to the summer school on 'Neutron Scattering at a pulsed source', Rutherford Laboratory, United Kingdom, 1986. The lectures concern the physical principles of neutron scattering. The topics of the lectures include: diffraction, incoherent inelastic scattering, connection with the Schroedinger equation, magnetic scattering, coherent inelastic scattering, and surfaces and neutron optics. (UK)

  17. Field and laboratory calibration of neutron probes for soil moisture measurements on a deep loess chernozem soil

    International Nuclear Information System (INIS)

    Schaecke, B.; Schaecke, E.

    1979-01-01

    In the case of a varying profile structure it is necessary to use different calibration curves and adequate correction factors, respectively. The bulk density of the soil had the greatest influence on the calibration. An increase in bulk density by 0.2 g/cm 3 at a clay content of 18% resulted in an apparent increase in the values of moisture measurements by 1.5 to 2.0% of the volume of water. In naturally stratified soil the humus content of the chernozem horizon, being 3% higher than that of the underlying loess horizon, was found to influence the measuring results obtained by the probe. The calibration curves determined for chernozem and loess horizons in the laboratory agreed well with those obtained in the field. The measured values read from the probe and the gravimetrically determined values of the soil moisture were of great significance in all measured depths of the profile. (author)

  18. 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

  19. Interrogating resilience in health systems development.

    Science.gov (United States)

    van de Pas, Remco; Ashour, Majdi; Kapilashrami, Anuj; Fustukian, Suzanne

    2017-11-01

    The Fourth Global Symposium on Health Systems Research was themed around 'Resilient and responsive health systems for a changing world.' This commentary is the outcome of a panel discussion at the symposium in which the resilience discourse and its use in health systems development was critically interrogated. The 2014-15 Ebola outbreak in West-Africa added momentum for the wider adoption of resilient health systems as a crucial element to prepare for and effectively respond to crisis. The growing salience of resilience in development and health systems debates can be attributed in part to development actors and philanthropies such as the Rockefeller Foundation. Three concerns regarding the application of resilience to health systems development are discussed: (1) the resilience narrative overrules certain democratic procedures and priority setting in public health agendas by 'claiming' an exceptional policy space; (2) resilience compels accepting and maintaining the status quo and excludes alternative imaginations of just and equitable health systems including the socio-political struggles required to attain those; and (3) an empirical case study from Gaza makes the case that resilience and vulnerability are symbiotic with each other rather than providing a solution for developing a strong health system. In conclusion, if the normative aim of health policies is to build sustainable, universally accessible, health systems then resilience is not the answer. The current threats that health systems face demand us to imagine beyond and explore possibilities for global solidarity and justice in health. © The Author 2017. Published by Oxford University Press in association with The London School of Hygiene and Tropical Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. Neutron beam experiments using nuclear research reactors: honoring the retirement of professor Bernard W. Wehring -II. 6. Nuclear Analytical Applications in a Semiconductor Materials Characterization Laboratory

    International Nuclear Information System (INIS)

    Hossain, Tim Z.

    2001-01-01

    A typical semiconductor materials characterization laboratory is heavily loaded with surface analytical tools such as SEM, TEM, TXRF, secondary ion mass spectrometry (SIMS), AFM, and XPS. However, there are analytical needs that cannot be addressed by the aforementioned methods and often require a bulk analysis technique such as ICP/MS. Nuclear analytical methods can play a very important complementary role and provide advantages over nonnuclear techniques because of higher sensitivity, simplicity of sample preparation, and highly quantitative answers. An overwhelming majority of the semiconductor industry uses silicon as the base material for the integrated circuit (IC) manufacturing, and silicon, incidentally, has very favorable nuclear parameters. Silicon, for example, does not have a high neutron capture cross section; thus, matrix activity induced during a neutron irradiation is not very high, and more importantly, the half-life of the major radioisotope 31 Si is only 2.6 h. This short half-life provides a good opportunity to study induced radioactivities of other impurities such as iron, zinc, and nickel. So, neutron activation analysis (NAA) can achieve a very high sensitivity with most transition metals and other important impurities such as copper, gold, and tungsten. NAA is very complementary to other methods of analysis in providing trace-level metals analysis of both silicon wafer and non-wafer samples such as quartz parts used in the diffusion furnaces. Data from NAA of quartz materials used in the diffusion furnaces will be described. In addition, the NAA techniques such as prompt gamma activation analysis are especially useful for the analysis of bulk hydrogen. Another nuclear method, nuclear reaction analysis (NRA), has also been widely used for this purpose. With NRA, a depth profile similar to the ones obtained by SIMS can be achieved. An important nuclear analysis in the semiconductor industry is the depth profiling of boron by neutron depth

  1. Miniaturized Interrogation System for Marsupial Rover Sensing Tether, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Luna proposes to continue development of its marsupial rover sensing tether (MaRS Tether) technology by miniaturizing the sensor's interrogation system. Luna is...

  2. Lawfulness of Interrogation Techniques under the Geneva Conventions

    National Research Council Canada - National Science Library

    Elsea, Jennifer K

    2004-01-01

    Allegations of abuse of Iraqi prisoners by U.S. soldiers at the Abu Ghraib prison in Iraq have raised questions about the applicability of the law of war to interrogations for military intelligence purposes...

  3. Fifty years of neutron physics

    International Nuclear Information System (INIS)

    Frank, I.M.

    1982-01-01

    A survey of neutron physics achievements during fifty years of its development beginning from neutron discovery in 1932 has been given. A complex of experimental and theoretical data collected by soviet and foreign laboratories in the nucleus fission physics has been considered retrospectively. Neutron methods of nucleus investigation have been described. Theoretical and eXperimental problems of reactor physics and technique arising during the chain nuclear process investigation have been discussed. Up-to-data problems of neutron physics have been considered in detail. A variety of neutron properties and spheres of neutron physics application have been noted

  4. An Ethical Framework for Physician Involvement in Detainee Interrogations

    Science.gov (United States)

    2006-03-15

    procedures to otherwise able-bodied human beings (i.e. cosmetic (vs. reconstructive) surgeries , bariatric intestinal redirecting surgeries , diet pills...process. The purpose should only be to ensure that the dignity of the detainee is not being violated and that interrogation techniques protect that...obtain information from patients or assist in the detainee management. a. Training and advising interrogators in interview techniques .43, 44 b. Observing

  5. Modeling and analysis framework for core damage propagation during flow-blockage-initiated accidents in the advanced neutron source reactor at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.H.; Taleyarkhan, R.P.; Navarro-Valenti, S.; Georgevich, V. [Oak Ridge National Lab., TN (United States)

    1995-09-01

    This paper describes modeling and analysis to evaluate the extent of core damage during flow blockage events in the Advanced Neutron Source (ANS) reactor planned to be built at the Oak Ridge National Laboratory (ORNL). Damage propagation is postulated to occur from thermal conduction between damaged and undamaged plates due to direct thermal contact. Such direct thermal contact may occur because of fuel plate swelling during fission product vapor release or plate buckling. Complex phenomena of damage propagation were modeled using a one-dimensional heat transfer model. A scoping study was conducted to learn what parameters are important for core damage propagation, and to obtain initial estimates of core melt mass for addressing recriticality and steam explosion events. The study included investigating the effect of the plate contact area, the convective heat transfer coefficient, thermal conductivity upon fuel swelling, and the initial temperature of the plate being contacted by the damaged plate. Also, the side support plates were modeled to account for their effects on damage propagation. The results provide useful insights into how various uncertain parameters affect damage propagation.

  6. Neutrons for probing matter

    International Nuclear Information System (INIS)

    Torres, F. Ed.; Mazzucchetti, D.

    2008-01-01

    The authors tell the story of the French Orphee reactor located in Saclay from the decision to build it in the seventies, to its commissioning in 1980, to its upgrading in the nineties and to its today's operating life. As early as its feasibility studies Orphee has been designed as a dual-purpose reactor: scientific research for instance in crystallography and magnetism, and industrial uses like neutron radiography, silicon doping or radionuclide production. This book is divided into 4 parts: 1) the neutron: an explorer of the matter, 2) the Orphee reactor: a neutron source, 3) the adventurers of the matter: Leon Brillouin laboratory's staff, and 4) the perspectives for neutrons

  7. Spectroscopic neutron detection using composite scintillators

    Science.gov (United States)

    Jovanovic, I.; Foster, A.; Kukharev, V.; Mayer, M.; Meddeb, A.; Nattress, J.; Ounaies, Z.; Trivelpiece, C.

    2016-09-01

    Shielded special nuclear material (SNM), especially highly enriched uranium, is exceptionally difficult to detect without the use of active interrogation (AI). We are investigating the potential use of low-dose active interrogation to realize simultaneous high-contrast imaging and photofission of SNM using energetic gamma-rays produced by low-energy nuclear reactions, such as 11B(d,nγ)12C and 12C(p,p‧)12C. Neutrons produced via fission are one reliable signature of the presence of SNM and are usually identified by their unique timing characteristics, such as the delayed neutron die-away. Fast neutron spectroscopy may provide additional useful discriminating characteristics for SNM detection. Spectroscopic measurements can be conducted by recoil-based or thermalization and capture-gated detectors; the latter may offer unique advantages since they facilitate low-statistics and event-by-event neutron energy measurements without spectrum unfolding. We describe the results of the development and characterization of a new type of capture-gated spectroscopic neutron detector based on a composite of scintillating polyvinyltoluene and lithium-doped scintillating glass in the form of millimeter-thick rods. The detector achieves >108 neutron-gamma discrimination resulting from its geometric properties and material selection. The design facilitates simultaneous pulse shape and pulse height discrimination, despite the fact that no materials intrinsically capable of pulse shape discrimination have been used to construct the detector. Accurate single-event measurements of neutron energy may be possible even when the energy is relatively low, such as with delayed fission neutrons. Simulation and preliminary measurements using the new composite detector are described, including those conducted using radioisotope sources and the low-dose active interrogation system based on low-energy nuclear reactions.

  8. Neutrons and Nuclear Engineering

    International Nuclear Information System (INIS)

    Ekkebus, Allen E.

    2007-01-01

    Oak Ridge National Laboratory hosted two workshops in April 2007 relevant to nuclear engineering education. In the Neutron Stress, Texture, and Phase Transformation for Industry workshop (http://neutrons.ornl.gov/workshops/nst2/), several invited speakers gave examples of neutron stress mapping for nuclear engineering applications. These included John Root of National Research Council of Canada, Mike Fitzpatrick of the UK's Open University, and Yan Gao of GE Global Research on their experiences with industrial and academic uses of neutron diffraction. Xun-Li Wang and Camden Hubbard described the new instruments at ORNL that can be used for such studies. This was preceded by the Neutrons for Materials Science and Engineering educational symposium (http://neutrons.ornl.gov/workshops/edsym2007). It was directed to the broad materials science and engineering community based in universities, industry and laboratories who wish to learn what the neutron sources in the US can provide for enhancing the understanding of materials behavior, processing and joining. Of particular interest was the presentation of Donald Brown of Los Alamos about using 'Neutron diffraction measurements of strain and texture to study mechanical behavior of structural materials.' At both workshops, the ORNL neutron scattering instruments relevant to nuclear engineering studies were described. The Neutron Residual Stress Mapping Facility (NRSF2) is currently in operation at the High Flux Isotope Reactor; the VULCAN Engineering Materials Diffractometer will begin commissioning in 2008 at the Spallation Neutron Source. For characteristics of these instruments, as well as details of other workshops, meetings, capabilities, and research proposal submissions, please visit http://neutrons.ornl.gov. To submit user proposals for time on NRSF2 contact Hubbard at hubbardcratornl.gov

  9. k0-NAA implementation and application at IPEN neutron activation laboratory by using the k0-IAEA software: application to geological sample analysis

    International Nuclear Information System (INIS)

    Mariano, Davi Brigatto

    2011-01-01

    The Neutron Activation Analysis Laboratory (LAN-IPEN) has been analysing geological samples such as rocks, soils and sediments, for many years with the INAA comparative method, for geochemical and environmental research. This study presents the results obtained in the implementation of the k 0 -standardization method at LAN - IPEN, for geological sample analysis, by using the program k 0 - IAEA, provided by the International Atomic Energy Agency (IAEA). The thermal to epithermal flux ratio f and the shape factor α of the epithermal flux distribution of the IPEN IEA-R1 nuclear reactor were determined for the pneumatic irradiation facility and one selected irradiation position, for short and long irradiations, respectively. To obtain these factors, the 'are triple-monitor' method with 197 Au- 96 Zr- 94 Zr was used. In order to validate the methodology, the geological reference materials basalts JB-1 (GSJ) and BE-N (IWG-GIT), andesite AGV-1 (USGS), granite GS-N (ANRT), SOIL-7 (IAEA) and sediment Buffalo River Sediment (NIST - BRS-8704), which represent different geological matrices, were analysed. The concentration results obtained agreed with assigned values, with bias less than 10% except for Zn in AGV-1 (11.4%) and Mg in GS-N (13.4%). Three different scores were used to evaluate the results: z-score, zeta-score and Uscore. The z-score showed that the results can be considered satisfactory (z 3) for Mn in BE-N, Mg, Ce and La in GS-N, Mg in JB-1, and Th and Eu in Buffalo River Sediment. The U-score test showed that all results, except Mg in JB-1, were within 95% confidence interval. These results indicate excellent possibilities of using this parametric method at the LAN-IPEN for geological samples analysis in geochemical and environmental studies. (author)

  10. Interrogation zone determination in HF RFID systems with multiplexed antennas*

    Directory of Open Access Journals (Sweden)

    Jankowski-Mihułowicz Piotr

    2015-09-01

    Full Text Available The operation of an anti-collision RFID system is characterized by the interrogation zone which should be estimated in any direction of 3D space for a group of electronic transponders. The interrogation zone should be as large as possible. However, the many problems in this area are due to the fact that energy can be transferred to transponders only on a limited distance. The greatest flexibility in developing RFID applications and shaping the interrogation zone can be achieved using the system with an antenna multiplexer. Therefore the problem of the interrogation zone determination in HF RFID systems with two orthogonal RWD antennas is presented in the paper. The perceived issues have been effectively dealt with and the solution has been proposed on the basis of the elaborated model. Conducted studies have been used to develop the software tool JankoRFIDmuxHF in the Mathcad environment. The research results are analysed in an example system configuration. The specialized measuring stand has been used for experimental verification of the identification efficiency. The convergence of the measurements and calculations confirms a practical usefulness of the presented concept of interrogation zone determination in anti-collision systems. It also shows the practical utility of the developed model and software tools.

  11. Neutron scattering

    International Nuclear Information System (INIS)

    1991-02-01

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

  12. Superfluidity and Superconductivity in Neutron Stars

    Indian Academy of Sciences (India)

    Neutron stars, the compact stellar remnants of core-collapse supernova explosions, are unique cosmic laboratories for exploring novel phases of matter under extreme conditions. In particular, the occurrence of superfluidity and superconductivity in neutron stars will be briefly reviewed.

  13. Improved fission neutron energy discrimination with {sup 4}He detectors through pulse filtering

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ting, E-mail: ting.zhu@ufl.edu [University of Florida, Gainesville, FL (United States); Liang, Yinong; Rolison, Lucas; Barker, Cathleen; Lewis, Jason; Gokhale, Sasmit [University of Florida, Gainesville, FL (United States); Chandra, Rico [Arktis Radiation Detectors Ltd., Räffelstrasse 11, Zürich (Switzerland); Kiff, Scott [Sandia National Laboratories, CA (United States); Chung, Heejun [Korean Institute for Nuclear Nonproliferation and Control, 1534 Yuseong-daero, Yuseong-gu, Daejeon (Korea, Republic of); Ray, Heather; Baciak, James E.; Enqvist, Andreas; Jordan, Kelly A. [University of Florida, Gainesville, FL (United States)

    2017-03-11

    This paper presents experimental and computational techniques implemented for {sup 4}He gas scintillation detectors for induced fission neutron detection. Fission neutrons are produced when natural uranium samples are actively interrogated by 2.45 MeV deuterium-deuterium fusion reaction neutrons. Fission neutrons of energies greater than 2.45 MeV can be distinguished by their different scintillation pulse height spectra since {sup 4}He detectors retain incident fast neutron energy information. To enable the preferential detection of fast neutrons up to 10 MeV and suppress low-energy event counts, the detector photomultiplier gain is lowered and trigger threshold is increased. Pile-up and other unreliable events due to the interrogating neutron flux and background radiation are filtered out prior to the evaluation of pulse height spectra. With these problem-specific calibrations and data processing, the {sup 4}He detector's accuracy at discriminating fission neutrons up to 10 MeV is improved and verified with {sup 252}Cf spontaneous fission neutrons. Given the {sup 4}He detector's ability to differentiate fast neutron sources, this proof-of-concept active-interrogation measurement demonstrates the potential of special nuclear materials detection using a {sup 4}He fast neutron detection system.

  14. Delayed-neutron fraction in a pulsed spallation neutron source

    International Nuclear Information System (INIS)

    Carpenter, J.M.

    1980-02-01

    The fraction of delayed neutrons β (with T/sub 1/2/ greater than or equal to 0.025 s) in slow-neutron beams from a 238 U pulsed spallation neutron source is 0.0053 for 300 MeV protons. This measurement appears to be the first one of this quantity. The result indicates that, for most classes of measurements, the delayed-neutron background in time-of-flight instruments will be unimportant, and places constraints on the physics description of spallation targets. The measurement was performed at the prototype pulsed spallation neutron source, ZING-P', at Argonne National laboratory. 4 figures

  15. 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.)

  16. Interrogations And The Right To Remain Silent - A Comparative Approach

    Directory of Open Access Journals (Sweden)

    Bilalli Arta

    2015-12-01

    Full Text Available Interrogations are a very specific component of any criminal investigation. The answers gained through interrogative process provides information that are considered as direct evidences. In contemporary criminal procedure, the court is not absolved from gaining other evidences, even in cases when the defendant confesses his/her guiltiness. This is a mechanism for excluding the inquisitorial approach for extracting compulsory confessions. The modern procedure uses a variety of mechanisms to guarantee that the defendant will not be compelled to confess guilt.

  17. Lujan at Los Alamos Neutron Science Center (LANSCE)

    Data.gov (United States)

    Federal Laboratory Consortium — The Lujan Neutron Scattering Center (Lujan Center) at Los Alamos National Laboratory is an intense pulsed neutrons source operating at a power level of 80 -100 kW....

  18. Shielding around spallation neutron sources

    International Nuclear Information System (INIS)

    Fragopoulou, M; Manolopoulou, M; Stoulos, S; Brandt, R; Westmeier, W; Krivopustov, M; Sosnin, A; Golovatyuk, S; Zamani, M

    2006-01-01

    Spallation neutron sources provide more intense and harder neutron spectrum than nuclear reactors for which a substantial amount of shielding measurements have been performed. Although the main part of the cost for a spallation station is the cost of the shielding, measurements regarding shielding for the high energy neutron region are still very scarce. In this work calculation of the neutron interaction length in polyethylene moderator for different neutron energies is presented. Measurements which were carried out in Nuclotron accelerator at the Laboratory of High Energies (Joint Institute for Nuclear Research, Dubna) and comparison with calculation are also presented. The measurements were performed with Solid State Nuclear Track Detectors (SSNTDs)

  19. Neutron Stars and Pulsars

    CERN Document Server

    Becker, Werner

    2009-01-01

    Neutron stars are the most compact astronomical objects in the universe which are accessible by direct observation. Studying neutron stars means studying physics in regimes unattainable in any terrestrial laboratory. Understanding their observed complex phenomena requires a wide range of scientific disciplines, including the nuclear and condensed matter physics of very dense matter in neutron star interiors, plasma physics and quantum electrodynamics of magnetospheres, and the relativistic magneto-hydrodynamics of electron-positron pulsar winds interacting with some ambient medium. Not to mention the test bed neutron stars provide for general relativity theories, and their importance as potential sources of gravitational waves. It is this variety of disciplines which, among others, makes neutron star research so fascinating, not only for those who have been working in the field for many years but also for students and young scientists. The aim of this book is to serve as a reference work which not only review...

  20. Opportunities in Neutron Science

    Science.gov (United States)

    Fernandez-Baca, Jaime

    2010-03-01

    National Laboratories often have unique facilities that cannot be normally found at universities, and that provide unique opportunities to perform research using world class instrumentation in collaboration with teams of experts. This synergy of expertise and world-class facilities also offers unique opportunities for mentoring and training of students in settings different from the university environment. In this talk I will discuss the opportunities of scientific research, mentoring and training at the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. The SNS is the world's most intense pulsed accelerator-based neutron source, the HFIR is the highest flux reactor-based neutron source for condensed matter research in the United States, the combination of these provides neutron scattering capabilities unavailable anywhere else in the world. The SNS and the HFIR at ORNL are funded by the Division of Scientific User Facilities, Office of Basic Energy Sciences, US. Department of Energy.

  1. Neutrons in soft matter

    CERN Document Server

    Imae, Toyoko; Furusaka, Michihiro; Torikai, Naoya

    2011-01-01

    Neutron and synchrotron facilities, which are beyond the scale of the laboratory, and supported on a national level in countries throughout the world.  These tools for probing micro- and nano-structure research and on fast dynamics research of atomic location in materials have been key in the development of new polymer-based materials. Different from several existing professional books on neutron science, this book focuses on theory, instrumentation, an applications. The book is divided into five parts: Part 1 describes the underlying theory of neutron scattering. Part 2 desc

  2. 29 Interrogating Infanticide/ Child Euthanasia in the Roman ...

    African Journals Online (AJOL)

    NGOZI

    Monica Omoye Aneni* http://dx.doi.org/10.4314/ujah.v14i2.2. Abstract. The purpose of this paper is an attempt to examine infanticide practices in the Roman Christian era and interrogate infanticide and child euthanasia in the same era. It also attempts to point out infanticide practices in Abuja and makes a distinction ...

  3. Interrogating Infanticide/ Child Euthanasia in the Roman Christian ...

    African Journals Online (AJOL)

    The purpose of this paper is an attempt to examine infanticide practices in the Roman Christian era and interrogate infanticide and child euthanasia in the same era. It also attempts to point out infanticide practices in Abuja and makes a distinction between infanticide and child euthanasia in Abuja. The study employed ...

  4. Interrogating Your Wisdom of Practice to Improve Classroom Practices

    Science.gov (United States)

    Chappell, Philip

    2017-01-01

    This article presents a heuristic for language teachers to articulate and explore their fundamental theories of and philosophical stances towards language, language learning, and language teaching. It includes tools with which teachers can interrogate those theories, weighing them up against their actual classroom practices. Through presenting…

  5. Technology for Polymer Optical Fiber Bragg Grating Fabrication and Interrogation

    DEFF Research Database (Denmark)

    Ganziy, Denis

    The aim of this project is to develop a new, high-quality interrogator for FBG sensor systems, which combines high performance with costeffectiveness. The work includes the fields of optical system design, signal processing, and algorithm investigation. We present an efficient and fast peak detec...... by measuring optical resolution, wavelength fit resolution, accuracy, temperature and polarization dependable wavelength shift and use it to measure the strain response of a fewmode and a highly multimode FBG in a polymer fiber.......The aim of this project is to develop a new, high-quality interrogator for FBG sensor systems, which combines high performance with costeffectiveness. The work includes the fields of optical system design, signal processing, and algorithm investigation. We present an efficient and fast peak......) based interrogator, where the linear detector is replaced with a commercially available DMD, which leads to cost reduction and better performance. Original optical design, which utilizes advantages of a retro-reflect optical scheme, has been developed in Zemax. We test the presented interrogator...

  6. Patriarchy and social determinism: interrogating feminist agenda in ...

    African Journals Online (AJOL)

    This paper examines poems written in English by Tanzanians from a feminist perspective. Specifically, the paper examines how Tanzanian poets in English handle feminist ideas. It interrogates how the poets address issues of human rights, dignity and equality from a feminist perspective in a predominantly patriarchal ...

  7. On the aesthetics of mimicry and proliferation: interrogations of ...

    African Journals Online (AJOL)

    This article examines innovative modes of interrogating spectacles of State power in postcolonial dictatorship novels. Authoritarian power in the postcolonial public sphere perpetuates itself through practices that reiterate the prerogatives of State reason, national progress, national unity and the indispensability of the ...

  8. "Enhanced" interrogation of detainees: do psychologists and psychiatrists participate?

    Directory of Open Access Journals (Sweden)

    Halpern John H

    2008-09-01

    Full Text Available Abstract After revelations of participation by psychiatrists and psychologists in interrogation of prisoners at Guantánamo Bay and Central Intelligence Agency secret detention centers, the American Psychiatric Association and the American Psychological Association adopted Position Statements absolutely prohibiting their members from participating in torture under any and all circumstances, and, to a limited degree, forbidding involvement in interrogations. Some interrogations utilize very aggressive techniques determined to be torture by many nations and organizations throughout the world. This paper explains why psychiatrists and psychologists involved in coercive interrogations violate the Geneva Conventions and the laws of the United States. Whether done with ignorance of professional ethical obligations or not, these psychiatrists and psychologists have crossed an ethical barrier that may best be averted from re-occurring by teaching medical students and residents in all medical specialties about the ethics principles stemming from the 1946–1947 Nuremberg trials and the Geneva Conventions, together with the Ethics Codes of the World Medical Association and the American Medical Association; and, with regard to psychiatric residents and psychological trainees, by the teaching about The Principles of Medical Ethics With Annotations Especially Applicable to Psychiatry and the Ethical Principles of Psychologists and Code of Conduct, respectively. In this way, all physicians and psychologists will clearly understand that they have an absolute moral obligation to "First, do no harm" to the human beings they professionally encounter.

  9. Postmortem ICD interrogation in mode of death classification.

    Science.gov (United States)

    Nikolaidou, Theodora; Johnson, Miriam J; Ghosh, Justin M; Marincowitz, Carl; Shah, Saumil; Lammiman, Michael J; Schilling, Richard J; Clark, Andrew L

    2018-01-08

    The definition of sudden death due to arrhythmia relies on the time interval between onset of symptoms and death. However, not all sudden deaths are due to arrhythmia. In patients with an implantable cardioverter defibrillator (ICD), postmortem device interrogation may help better distinguish the mode of death compared to a time-based definition alone. This study aims to assess the proportion of "sudden" cardiac deaths in patients with an ICD that have confirmed arrhythmia. We conducted a literature search for studies using postmortem ICD interrogation and a time-based classification of the mode of death. A modified QUADAS-2 checklist was used to assess risk of bias in individual studies. Outcome data were pooled where sufficient data were available. Our search identified 22 studies undertaken between 1982 and 2015 with 23,600 participants. The pooled results (excluding studies with high risk of bias) suggest that ventricular arrhythmias are present at the time of death in 76% of "sudden" deaths (95% confidence interval [CI] 67-85; range 42-88). Postmortem ICD interrogation identifies 24% of "sudden" deaths to be nonarrhythmic. Postmortem device interrogation should be considered in all cases of unexplained sudden cardiac death. © 2018 Wiley Periodicals, Inc.

  10. Thoughts on the Police Interrogation of Individuals with Mental Retardation.

    Science.gov (United States)

    Perske, Robert

    1994-01-01

    This article presents 20 reasons why it is usually easy for police to get confessions from individuals with mental retardation. It urges that police training be seen as everyone's responsibility and that individuals with mental retardation be prepared for possible police interrogation. (DB)

  11. Interrogating Public Sphere and Popular Culture as Theoretical ...

    African Journals Online (AJOL)

    Because of its theoretical roots in Western liberal thinking, scholars in African studies such as Comaroffs, Mamdani and Ekeh have vigorously debated the extent to which the concept of civil society is useful in explaining and interrogating developments in Africa. However, the concept of the public sphere has been subjected ...

  12. Setup for polarized neutron imaging using in situ3He cells at the Oak Ridge National Laboratory High Flux Isotope Reactor CG-1D beamline.

    Science.gov (United States)

    Dhiman, I; Ziesche, Ralf; Wang, Tianhao; Bilheux, Hassina; Santodonato, Lou; Tong, X; Jiang, C Y; Manke, Ingo; Treimer, Wolfgang; Chatterji, Tapan; Kardjilov, Nikolay

    2017-09-01

    In the present study, we report a new setup for polarized neutron imaging at the ORNL High Flux Isotope Reactor CG-1D beamline using an in situ 3 He polarizer and analyzer. This development is very important for extending the capabilities of the imaging instrument at ORNL providing a polarized beam with a large field-of-view, which can be further used in combination with optical devices like Wolter optics, focusing guides, or other lenses for the development of microscope arrangement. Such a setup can be of advantage for the existing and future imaging beamlines at the pulsed neutron sources. The first proof-of-concept experiment is performed to study the ferromagnetic phase transition in the Fe 3 Pt sample. We also demonstrate that the polychromatic neutron beam in combination with in situ 3 He cells can be used as the initial step for the rapid measurement and qualitative analysis of radiographs.

  13. Setup for polarized neutron imaging using in situ 3He cells at the Oak Ridge National Laboratory High Flux Isotope Reactor CG-1D beamline

    Science.gov (United States)

    Dhiman, I.; Ziesche, Ralf; Wang, Tianhao; Bilheux, Hassina; Santodonato, Lou; Tong, X.; Jiang, C. Y.; Manke, Ingo; Treimer, Wolfgang; Chatterji, Tapan; Kardjilov, Nikolay

    2017-09-01

    In the present study, we report a new setup for polarized neutron imaging at the ORNL High Flux Isotope Reactor CG-1D beamline using an in situ 3He polarizer and analyzer. This development is very important for extending the capabilities of the imaging instrument at ORNL providing a polarized beam with a large field-of-view, which can be further used in combination with optical devices like Wolter optics, focusing guides, or other lenses for the development of microscope arrangement. Such a setup can be of advantage for the existing and future imaging beamlines at the pulsed neutron sources. The first proof-of-concept experiment is performed to study the ferromagnetic phase transition in the Fe3Pt sample. We also demonstrate that the polychromatic neutron beam in combination with in situ 3He cells can be used as the initial step for the rapid measurement and qualitative analysis of radiographs.

  14. Advanced plastic scintillators for fast neutron discrimination

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Patrick L [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Anstey, Mitchell [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Doty, F. Patrick [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Mengesha, Wondwosen [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2014-09-01

    The present work addresses the need for solid-state, fast neutron discriminating scintillators that possess higher light yields and faster decay kinetics than existing organic scintillators. These respective attributes are of critical importance for improving the gamma-rejection capabilities and increasing the neutron discrimination performance under high-rate conditions. Two key applications that will benefit from these improvements include large-volume passive detection scenarios as well as active interrogation search for special nuclear materials. Molecular design principles were employed throughout this work, resulting in synthetically tailored materials that possess the targeted scintillation properties.

  15. Reactor-neutron activation analysis

    International Nuclear Information System (INIS)

    Kucera, J.; Obrusnik, I.

    1977-01-01

    The principal operations are briefly described for both types of neutron activation analysis, i.e., instrumental and radiochemical, namely sampling and sample preparation, irradiation, measurement, and activity evaluation. Flow charts are shown of both types of neutron activation analysis from the point of view of instrumentation and laboratory equipment requirements. Their benefits and constraints are discussed. A few examples are given illustrating the wide scope of the neutron activation analysis applications in the national economy. (O.K.)

  16. Methods and systems using encapsulated tracers and chemicals for reservoir interrogation and manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Jeffery; Aines, Roger D; Duoss, Eric B; Spadaccini, Christopher M

    2014-11-04

    An apparatus, method, and system of reservoir interrogation. A tracer is encapsulating in a receptacle. The receptacle containing the tracer is injected into the reservoir. The tracer is analyzed for reservoir interrogation.

  17. Neutron radiography and neutron-induced autoradiography for the classroom

    International Nuclear Information System (INIS)

    Aderhold, H.C.

    1992-01-01

    The Cornell 500-kW MARK II TRIGA reactor at the Ward Laboratory of Nuclear Engineering has been used to illustrate the application of neutron radiography (NR) and neutron-induced autoradiography (NIAR) for solving problems in engineering as well as problems in art history. The applications are described in the paper

  18. Fresh Fuel Measurements With the Differential Die-Away Self-Interrogation Instrument

    Science.gov (United States)

    Trahan, Alexis C.; Belian, Anthony P.; Swinhoe, Martyn T.; Menlove, Howard O.; Flaska, Marek; Pozzi, Sara A.

    2017-07-01

    The purpose of the Next Generation Safeguards Initiative (NGSI)-Spent Fuel (SF) Project is to strengthen the technical toolkit of safeguards inspectors and/or other interested parties. The NGSI-SF team is working to achieve the following technical goals more easily and efficiently than in the past using nondestructive assay measurements of spent fuel assemblies: 1) verify the initial enrichment, burnup, and cooling time of facility declaration; 2) detect the diversion or replacement of pins; 3) estimate the plutonium mass; 4) estimate decay heat; and 5) determine the reactivity of spent fuel assemblies. The differential die-away self-interrogation (DDSI) instrument is one instrument that was assessed for years regarding its feasibility for robust, timely verification of spent fuel assemblies. The instrument was recently built and was tested using fresh fuel assemblies in a variety of configurations, including varying enrichment, neutron absorber content, and symmetry. The early die-away method, a multiplication determination method developed in simulation space, was successfully tested on the fresh fuel assembly data and determined multiplication with a root-mean-square (RMS) error of 2.9%. The experimental results were compared with MCNP simulations of the instrument as well. Low multiplication assemblies had agreement with an average RMS error of 0.2% in the singles count rate (i.e., total neutrons detected per second) and 3.4% in the doubles count rates (i.e., neutrons detected in coincidence per second). High-multiplication assemblies had agreement with an average RMS error of 4.1% in the singles and 13.3% in the doubles count rates.

  19. Importance of interrogation volume and full spectrum LIBS for measuring carbon in intact soil cores

    Science.gov (United States)

    Bricklemyer, R.; Brown, D. J.; Barefield, J.; Clegg, S. M.

    2011-12-01

    Laser-induced breakdown spectroscopy (LIBS) potentially provides a rapid method of measuring soil carbon (C) concentration in situ. In a previous study, we showed that 200-300 nm LIBS could be used to semi-quantitatively measure soil inorganic carbon (SIC) and total carbon (TC) in intact soil cores by utilizing stoichiometric relationships between C, Mg and Ca in partial least squares regression (PLSR2) models (Bricklemyer et al., 2011). We hypothesized that two problems might limit the accuracy of this technique: (1) the relatively small volume of soil interrogated by LIBS (~3 cm^3) might not be representative of larger core segments analyzed with standard laboratory procedures (~150 cm^3); and (2) a 200-300 nm LIBS instrument, capturing the C emission peak, may not provide enough elemental information (e.g. O, H, and N) to reliably discriminate using stoichiometry between soil organic carbon (SOC) and SIC. In the present study, 218 intact soil cores were extracted from nine Montana wheat fields. For 790 core segments (~150 cm^3) we determined TC, SIC and SOC using standard laboratory methods for both the core segment as a whole (dried and homogenized prior to subsampling for analysis) and one interrogation volume subsample (~3 cm^3) taken from the intact core segment prior to homogenization. A correlation analysis of core segment vs. interrogation volume yielded r^2 values of 0.83, 0.83, and 0.61 for TC, IC, and SOC, respectively. Measured TC and SOC concentrations differed significantly (paired t-test, α = 0.05) with mean bias = 0.69 g TC kg^-1 soil and 0.59 g SOC kg^-1. Using a custom LIBS-Core Scanning system to collect full spectrum LIBS data (200-800 nm), we interrogated 60 intact soil cores (50 cm depth) from six wheat fields following Bricklemyer et al. (2011). Predictive PLSR2 models were calibrated to laboratory determined TC, IC, and SOC using full (200-800 nm) and reduced (200-300 nm) spectrum LIBS data. Model quality was tested using independent

  20. Neutron cross sections

    CERN Document Server

    Hughes, Donald J; Dunworth, J V

    1957-01-01

    Neutron Cross Sections presents the principles of cross-section measurement and use, as well as sufficient theory so that the general behavior of cross sections is made understandable. This compilation is a direct result of experiences connected with the collection and evaluation of cross-section data during the past eight years at """"Sigma Centre"""", Brookhaven National Laboratory. Here, experimental results received from laboratories throughout the world are carefully evaluated and compiled in the curves and tables of the large volume Neutron Cross Sections, The most recent version of the

  1. Directed Neutron Beams From Inverse Kinematic Reactions

    Science.gov (United States)

    Vanhoy, J. R.; Guardala, N. A.; Glass, G. A.

    2011-06-01

    Kinematic focusing of an emitted fairly mono-energetic neutron beam by the use of inverse-kinematic reactions, i.e. where the projectile mass is greater than the target atom's mass, can provide for the utilization of a significant fraction of the fast neutron yield and also provide for a safer radiation environment. We examine the merit of various neutron production reactions and consider the practicalities of producing the primary beam using the suitable accelerator technologies. Preliminary progress at the NSWC-Carderock Positive Ion Accelerator Facility is described. Possible important applications for this type of neutron-based system can be both advanced medical imaging techniques and active "stand-off" interrogation of contraband items.

  2. Active neutron and gamma-ray imaging of highly enriched uranium for treaty verification.

    Science.gov (United States)

    Hamel, Michael C; Polack, J Kyle; Ruch, Marc L; Marcath, Matthew J; Clarke, Shaun D; Pozzi, Sara A

    2017-08-11

    The detection and characterization of highly enriched uranium (HEU) presents a large challenge in the non-proliferation field. HEU has a low neutron emission rate and most gamma rays are low energy and easily shielded. To address this challenge, an instrument known as the dual-particle imager (DPI) was used with a portable deuterium-tritium (DT) neutron generator to detect neutrons and gamma rays from induced fission in HEU. We evaluated system response using a 13.7-kg HEU sphere in several configurations with no moderation, high-density polyethylene (HDPE) moderation, and tungsten moderation. A hollow tungsten sphere was interrogated to evaluate the response to a possible hoax item. First, localization capabilities were demonstrated by reconstructing neutron and gamma-ray images. Once localized, additional properties such as fast neutron energy spectra and time-dependent neutron count rates were attributed to the items. For the interrogated configurations containing HEU, the reconstructed neutron spectra resembled Watt spectra, which gave confidence that the interrogated items were undergoing induced fission. The time-dependent neutron count rate was also compared for each configuration and shown to be dependent on the neutron multiplication of the item. This result showed that the DPI is a viable tool for localizing and confirming fissile mass and multiplication.

  3. Active Interrogation using Photofission Technique for Nuclear Materials Control and Accountability

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Haori [Oregon State Univ., Corvallis, OR (United States)

    2016-03-31

    Innovative systems with increased sensitivity and resolution are in great demand to detect diversion and to prevent misuse in support of nuclear materials management for the U.S. fuel cycle. Nuclear fission is the most important multiplicative process involved in non-destructive active interrogation. This process produces the most easily recognizable signature for nuclear materials. In addition to thermal or high-energy neutrons, high-energy gamma rays can also excite a nucleus and cause fission through a process known as photofission. Electron linear accelerators (linacs) are widely used as the interrogating photon sources for inspection methods involving photofission technique. After photofission reactions, prompt signals are much stronger than the delayed signals, but it is difficult to quantify them in practical measurements. Delayed signals are easily distinguishable from the interrogating radiation. Linac-based, advanced inspection techniques utilizing the delayed signals after photofission have been extensively studied for homeland security applications. Previous research also showed that a unique delayed gamma ray energy spectrum exists for each fissionable isotope. In this work, high-energy delayed γ-rays were demonstrated to be signatures for detection, identification, and quantification of special nuclear materials. Such γ-rays were measured in between linac pulses using independent data acquisition systems. A list-mode system was developed to measure low-energy delayed γ-rays after irradiation. Photofission product yields of 238U and 239Pu were determined based on the measured delayed γ-ray spectra. The differential yields of delayed γ-rays were also proven to be able to discriminate nuclear from non-nuclear materials. The measurement outcomes were compared with Monte Carlo simulation results. It was demonstrated that the current available codes have capabilities and limitations in the simulation of photofission process. A two

  4. Active Interrogation using Photofission Technique for Nuclear Materials Control and Accountability

    International Nuclear Information System (INIS)

    Yang, Haori

    2016-01-01

    Innovative systems with increased sensitivity and resolution are in great demand to detect diversion and to prevent misuse in support of nuclear materials management for the U.S. fuel cycle. Nuclear fission is the most important multiplicative process involved in non-destructive active interrogation. This process produces the most easily recognizable signature for nuclear materials. In addition to thermal or high-energy neutrons, high-energy gamma rays can also excite a nucleus and cause fission through a process known as photofission. Electron linear accelerators (linacs) are widely used as the interrogating photon sources for inspection methods involving photofission technique. After photofission reactions, prompt signals are much stronger than the delayed signals, but it is difficult to quantify them in practical measurements. Delayed signals are easily distinguishable from the interrogating radiation. Linac-based, advanced inspection techniques utilizing the delayed signals after photofission have been extensively studied for homeland security applications. Previous research also showed that a unique delayed gamma ray energy spectrum exists for each fissionable isotope. In this work, high-energy delayed γ-rays were demonstrated to be signatures for detection, identification, and quantification of special nuclear materials. Such γ-rays were measured in between linac pulses using independent data acquisition systems. A list-mode system was developed to measure low-energy delayed γ-rays after irradiation. Photofission product yields of 238 U and 239 Pu were determined based on the measured delayed γ-ray spectra. The differential yields of delayed γ-rays were also proven to be able to discriminate nuclear from non-nuclear materials. The measurement outcomes were compared with Monte Carlo simulation results. It was demonstrated that the current available codes have capabilities and limitations in the simulation of photofission process. A two-fold approach was

  5. 29 CFR 18.611 - Mode and order of interrogation and presentation.

    Science.gov (United States)

    2010-07-01

    ... interrogation and presentation effective for the ascertainment of the truth, (2) Avoid needless consumption of... 29 Labor 1 2010-07-01 2010-07-01 true Mode and order of interrogation and presentation. 18.611... of interrogation and presentation. (a) Control by judge. The judge shall exercise reasonable control...

  6. Scaling beta-delayed neutron measurements to large detector areas

    Science.gov (United States)

    Sutanto, F.; Nattress, J.; Jovanovic, I.

    2017-08-01

    We explore the performance of a cargo screening system that consists of two large-sized composite scintillation detectors and a high-energy neutron interrogation source by modeling and simulation. The goal of the system is to measure β-delayed neutron emission from an illicit special nuclear material by use of active interrogation. This task is challenging because the β-delayed neutron yield is small in comparison with the yield of the prompt fission secondary products, β-delayed neutrons are emitted with relatively low energies, and high neutron and gamma backgrounds are typically present. Detectors used to measure delayed neutron emission must exhibit high intrinsic efficiency and cover a large solid angle, which also makes them sensitive to background neutron radiation. We present a case study where we attempt to detect the presence of 5 kg-scale quantities of 235U in a standard air-filled cargo container using 14 MeV neutrons as a probe. We find that by using a total measurement time of ˜11.6 s and a dose equivalent of ˜1.7 mrem, the presence of 235U can be detected with false positive and false negative probabilities that are both no larger than 0.1%.

  7. Inexpensive, Rugged and Compact Tunable Laser with Simple Tuning Control for Airborne Fiber Optic Sensor (FOS) Interrogators, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Dryden (Armstrong) Flight Research Center has developed a 4-fiber interrogation system for Fiber Optic Smart Structures (FOSS) sensor networks interrogation....

  8. Inexpensive, Rugged and Compact Tunable Laser with Simple Tuning Control for Airborne Fiber Optic Sensor (FOS) Interrogators, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Dryden (Armstrong) Flight Research Center has developed a 4-fiber interrogation system for Fiber Optic Smart Structures (FOSS) sensor networks interrogation....

  9. Noncontact power/interrogation system for smart structures

    Science.gov (United States)

    Spillman, William B., Jr.; Durkee, S.

    1994-05-01

    The field of smart structures has been largely driven by the development of new high performance designed materials. Use of these materials has been generally limited due to the fact that they have not been in use long enough for statistical data bases to be developed on their failure modes. Real time health monitoring is therefore required for the benefits of structures using these materials to be realized. In this paper a non-contact method of powering and interrogating embedded electronic and opto-electronic systems is described. The technique utilizes inductive coupling between external and embedded coils etched on thin electronic circuit cards. The technique can be utilized to interrogate embedded sensors and to provide > 250 mW for embedded electronics. The system has been successfully demonstrated with a number of composite and plastic materials through material thicknesses up to 1 cm. An analytical description of the system is provided along with experimental results.

  10. The development of enabling technologies for producing active interrogation beams.

    Science.gov (United States)

    Kwan, Thomas J T; Morgado, Richard E; Wang, Tai-Sen F; Vodolaga, B; Terekhin, V; Onischenko, L M; Vorozhtsov, S B; Samsonov, E V; Vorozhtsov, A S; Alenitsky, Yu G; Perpelkin, E E; Glazov, A A; Novikov, D L; Parkhomchuk, V; Reva, V; Vostrikov, V; Mashinin, V A; Fedotov, S N; Minayev, S A

    2010-10-01

    A U.S./Russian collaboration of accelerator scientists was directed to the development of high averaged-current (∼1 mA) and high-quality (emittance ∼15 πmm mrad; energy spread ∼0.1%) 1.75 MeV proton beams to produce active interrogation beams that could be applied to counterterrorism. Several accelerator technologies were investigated. These included an electrostatic tandem accelerator of novel design, a compact cyclotron, and a storage ring with energy compensation and electron cooling. Production targets capable of withstanding the beam power levels were designed, fabricated, and tested. The cyclotron/storage-ring system was theoretically studied and computationally designed, and the electrostatic vacuum tandem accelerator at BINP was demonstrated for its potential in active interrogation of explosives and special nuclear materials.

  11. On Functional Potential of Interrogative Structures in Academic Linguistic Discourse

    Directory of Open Access Journals (Sweden)

    Sergey Trofimovich Nefedov

    2015-11-01

    Full Text Available The paper deals with the language of scientific communication in the field of linguistics, namely, with the functional potential of the interrogative structures in the form of direct and embedded questions. From a pragmatic perspective the interrogative structures does not seem to be compatible with the contexts of scientific interaction: scientists do not ask for information, but they offer their own solutions for the problem situations. This is reflected in the extremely low frequency of questions in academic research articles and monographs. Their text frequency works out a little over 2 % of the total number of the text predications and that of direct questions is about 1 %. Therefore, their place in verbalization of scientific knowledge in linguistics is metaphorically characterized in this article as «interrogative prohibition» by analogy with the «prohibitions» of Harald Weinrich who introduced several notions point to rarely used linguistic units: «prohibition of authorization» – das «Ich-Verbot», «narrative prohibition» – das «Erzähl-Verbot»; «prohibition of metaphors»– das «MetaphernVerbot». In its turn, low frequency makes the analyzed structures an effective tool to formulate the discussed problems, enables further argumentation, integrate the current text into overall linguistic discourse, control the development of the argumentation in scientific text and finally to draw the recipient's attention to a crucial or unexpected argument.

  12. Microwave Wire Interrogation Method Mapping Pressure under High Temperatures

    Directory of Open Access Journals (Sweden)

    Xiaoyong Chen

    2017-12-01

    Full Text Available It is widely accepted that wireless reading for in-situ mapping of pressure under high-temperature environments is the most feasible method, because it is not subject to frequent heterogeneous jointing failures and electrical conduction deteriorating, or even disappearing, under heat load. However, in this article, we successfully demonstrate an in-situ pressure sensor with wire interrogation for high-temperature applications. In this proof-of-concept study of the pressure sensor, we used a microwave resonator as a pressure-sensing component and a microwave transmission line as a pressure characteristic interrogation tunnel. In the sensor, the line and resonator are processed into a monolith, avoiding a heterogeneous jointing failure; further, microwave signal transmission does not depend on electrical conduction, and consequently, the sensor does not suffer from the heat load. We achieve pressure monitoring under 400 °C when employing the sensor simultaneously. Our sensor avoids restrictions that exist in wireless pressure interrogations, such as environmental noise and interference, signal leakage and security, low transfer efficiency, and so on.

  13. Convergent beam neutron crystallography

    Science.gov (United States)

    Gibson, Walter M.; Schultz, Arthur J.; Richardson, James W.; Carpenter, John M.; Mildner, David F. R.; Chen-Mayer, Heather H.; Miller, M. E.; Maxey, E.; Prask, Henry J.; Gnaeupel-Herold, Thomas H.; Youngman, Russell

    2004-01-01

    Applications of neutron diffraction for small samples (small fiducial areas are limited by the available neutron flux density. Recent demonstrations of convergent beam electron and x-ray diffraction and focusing of cold (λ>1 Å) neutrons suggest the possibility to use convergent beam neutron diffraction for small sample crystallography. We have carried out a systematic study of diffraction of both monoenergetic and broad bandwidth neutrons at the NIST Research Reactor and at the Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory. Combining convergent beams with time-of-flight Laue diffraction is particularly attractive for high efficiency small sample diffraction studies. We have studied single crystal and powder diffraction of neutrons with convergence angles as large as 15° and have observed diffracted peak intensity gains greater than 20. The convergent beam method (CBM) shows promise for crystallography on small samples of small to medium size molecules (potentially even for proteins), ultra-high pressure samples, and for mapping of strain and texture distributions in larger samples.

  14. Precision Polarization of Neutrons

    Science.gov (United States)

    Martin, Elise; Barron-Palos, Libertad; Couture, Aaron; Crawford, Christopher; Chupp, Tim; Danagoulian, Areg; Estes, Mary; Hona, Binita; Jones, Gordon; Klein, Andi; Penttila, Seppo; Sharma, Monisha; Wilburn, Scott

    2009-05-01

    Determining polarization of a cold neutron beam to high precision is required for the next generation neutron decay correlation experiments at the SNS, such as the proposed abBA and PANDA experiments. Precision polarimetry measurements were conducted at Los Alamos National Laboratory with the goal of determining the beam polarization to the level of 10-3 or better. The cold neutrons from FP12 were polarized using optically polarized ^3He gas as a spin filter, which has a highly spin-dependent absorption cross section. A second ^ 3He spin filter was used to analyze the neutron polarization after passing through a resonant RF spin rotator. A discussion of the experiment and results will be given.

  15. The synchronous active neutron detection assay system

    International Nuclear Information System (INIS)

    Pickrell, M.M.; Kendall, P.K.

    1994-01-01

    We have begun to develop a novel technique for active neutron assay of fissile material in spent nuclear fuel. This approach will exploit a 14-MeV neutron generator developed by Schlumberger. The technique, termed synchronous active neutron detection (SAND), follows a method used routinely in other branches of physics to detect very small signals in presence of large backgrounds. Synchronous detection instruments are widely available commercially and are termed ''lock-in'' amplifiers. We have implemented a digital lock-in amplifier in conjunction with the Schlumberger neutron generator to explore the possibility of synchronous detection with active neutrons. The Schlumberger system can operate at up to a 50% duty factor, in effect, a square wave of neutron yield. Results are preliminary but promising. The system is capable of resolving the fissile material contained in a small fraction of the fuel rods in a cold fuel assembly; it also appears resilient to background neutron interference. The interrogating neutrons appear to be non-thermal and penetrating. Work remains to fully explore relevant physics and optimize instrument design

  16. Neutron supermirrors and application to neutron guides

    International Nuclear Information System (INIS)

    Ballot, B.; Samuel, F.; Farnoux, B.

    1994-01-01

    Metallic multilayers are now commonly used in many neutron optics devices like supermirrors. Supermirrors are made of stacks of aperiodic bilayers, and present a reflection coefficient close to one for angles much larger than the critical angle of nickel. We show here the results of investigation of neutron reflectometry of such supermirrors. They have been prepared by magnetron sputtering and are made of 25 layers of NiC and Ti, thicknesses of which were determined using the Hayter's algorithm [1]. This enables us to obtain on large surfaces 5x50 cm 2 , an effective critical angle of 1.9 times the critical angle of natural nickel. These supermirrors have been used in the construction of a new neutron guide on the ORPHEE reactor in the Leon Brillouin Laboratory of Saclay. The use of supermirrors enables us to enhance the transmission of the short wavelength by the guide, and so to increase the transmitted flux. ((orig.))

  17. Commercial applications of neutron scattering

    International Nuclear Information System (INIS)

    Hutchings, M.T.

    1993-01-01

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

  18. Reactor neutrons in nuclear astrophysics

    OpenAIRE

    Reifarth, R.; Glorius, J.; Gobel, K.; Heftrich, T.; Jentschel, M.; Jurado, B.; Käppeler, F.; Köster, U.; Langer, C.; Litvinov, Y.A.; Weigand, M.

    2017-01-01

    The huge neutron fluxes offer the possibility to use research reactors to produce isotopes of interest, which can be investigated afterwards. An example is the half-lives of long-lived isotopes like 129I. A direct usage of reactor neutrons in the astrophysical energy regime is only possible, if the corresponding ions are not at rest in the laboratory frame. The combination of an ion storage ring with a reactor and a neutron guide could open the path to direct measurements of neutron-induced c...

  19. Software for Manipulating and Embedding Data Interrogation Algorithms into Integrated Systems: Special Application to Structural Health Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Allen, David W. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2004-12-01

    In this study a software package for easily creating and embedding structural health monitoring (SHM) data interrogation processes in remote hardware is presented. The software described herein is comprised of two pieces. The first is a client to allow graphical construction of data interrogation processes. The second is node software for remote execution of processes on remote sensing and monitoring hardware. The client software is created around a catalog of data interrogation algorithms compiled over several years of research at Los Alamos National Laboratory known as DIAMOND II. This study also includes encapsulating the DIAMOND II algorithms into independent interchangeable functions and expanding the catalog with work in feature extraction and statistical discrimination. The client software also includes methods for interfacing with the node software over an Internet connection. Once connected, the client software can upload a developed process to the integrated sensing and processing node. The node software has the ability to run the processes and return results. This software creates a distributed SHM network without individual nodes relying on each other or a centralized server to monitor a structure.

  20. Polarized neutron scattering on HYSPEC: the HYbrid SPECtrometer at SNS

    Energy Technology Data Exchange (ETDEWEB)

    Zaliznyak, Igor [Brookhaven National Laboratory (BNL); Savici, Andrei T [ORNL; Garlea, Vasile O [ORNL; Winn, Barry L [ORNL; Schneelock, John [Brookhaven National Laboratory (BNL); Tranquada, John M. [Brookhaven National Laboratory (BNL); Gu, G. D. [Brookhaven National Laboratory (BNL); Wang, Aifeng [Brookhaven National Laboratory (BNL); Petrovic, C [Brookhaven National Laboratory (BNL)

    2017-01-01

    We describe some of the first polarized neutron scattering measurements performed at HYSPEC spectrometer at the Spallation Neutron Source, Oak Ridge National Laboratory. We discuss details of the instrument setup and the experimental procedures in the mode with the full polarization analysis. Examples of the polarized neutron diffraction and the polarized inelastic neutron data obtained on single crystal samples are presented.

  1. Calibration of the IRD two-component TLD albedo neutron dosemeter in some moderated neutron fields

    International Nuclear Information System (INIS)

    Freitas, Bruno M.; Silva, Ademir X. da

    2015-01-01

    In some stray neutron fields, like those found in practices involving the handling of radionuclide sources, the neutron calibration factor for albedo neutron dosemeter can vary widely compared to the factor for bare sources. This is the case for well logging, which is the area with the largest number of workers exposed to neutrons in Brazil. The companies employ routinely 241 Am-Be neutron sources. The albedo response variation is mainly due to the presence of scattered and moderated neutrons. This paper studies the response variation of the two-component TLD albedo neutron dosemeter used in the neutron individual monitoring service of Instituto de Radioprotecao e Dosimetria, in different radionuclide neutron source beams. The neutron spectra were evaluated applying a Bonner sphere spectrometer with a 6 LiI(Eu) detector in the Brazilian National Metrology Neutron Laboratory. Standard neutron sources of 241 Am-Be and 252 Cf were employed, besides 238 Pu-Be. Measurements were also made with scattered and moderated neutron beams, including 252 Cf(D 2 O) reference spectrum, 241 Am-Be moderated with paraffin and silicone and a thermal neutron flux facility. New neutron calibration factors, as a function of the incident to albedo neutron ratio, were proposed for use in the albedo algorithm for occupational fields where the primary neutron beam is one of those studied sources. (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 guide

    Science.gov (United States)

    Greene, Geoffrey L.

    1999-01-01

    A neutron guide in which lengths of cylindrical glass tubing have rectangular glass plates properly dimensioned to allow insertion into the cylindrical glass tubing so that a sealed geometrically precise polygonal cross-section is formed in the cylindrical glass tubing. The neutron guide provides easier alignment between adjacent sections than do the neutron guides of the prior art.

  4. neutron transmission through crystalline materials

    International Nuclear Information System (INIS)

    El Mesiry, M.S.

    2011-01-01

    The aim of the present work is to study the neutron transmission through crystalline materials. Therefore a study of pyrolytic graphite (PG) as a highly efficient selective thermal neutron filter and Iron single crystal as a whole one, as well as the applicability of using their polycrystalline powders as a selective cold neutron filters is given. Moreover, the use of PG and iron single crystal as an efficient neutron monochromator is also investigated. An additive formula is given which allows calculating the contribution of the total neutron cross-section including the Bragg scattering from different )(hkl planes to the neutron transmission through crystalline iron and graphite. The formula takes into account their crystalline form. A computer CFe program was developed in order to provide the required calculations for both poly- and single-crystalline iron. The validity of the CFe program was approved from the comparison of the calculated iron cross-section data with the available experimental ones. The CFe program was also adapted to calculate the reflectivity from iron single crystal when it used as a neutron monochromator The computer package GRAPHITE, developed in Neutron Physics laboratory, Nuclear Research Center, has been used in order to provide the required calculations for crystalline graphite in the neutron energy range from 0.1 meV to 10 eV. A Mono-PG code was added to the computer package GRAPHITE in order to calculate the reflectivity from PG crystal when it used as a neutron monochromator.

  5. Cooperative effort between Consorcio European Spallation Source--Bilbao and Oak Ridge National Laboratory spallation neutron source for manufacturing and testing of the JEMA-designed modulator system

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, David E [ORNL

    2017-01-02

    The JEMA modulator was originally developed for the European Spallation Source (ESS) when Spain was under consideration as a location for the ESS facility. Discussions ensued and the Spallation Neutron Source Research Accelerator Division agreed to form a collaboration with ESS-Bilbao (ESS-B) consortium to provide services for specifying the requirements for a version of the modulator capable of operating twelve 550 kW klystrons, monitoring the technical progress on the contract with JEMA, installing and commissioning the modulator at SNS, and performing a 30 day full power test. This work was recently completed, and this report discusses those activities with primary emphasis on the installation and testing activities.

  6. Cooperative effort between Consorcio European Spallation Source--Bilbao and Oak Ridge National Laboratory spallation neutron source for manufacturing and testing of the JEMA-designed modulator system

    International Nuclear Information System (INIS)

    Anderson, David E.

    2017-01-01

    The JEMA modulator was originally developed for the European Spallation Source (ESS) when Spain was under consideration as a location for the ESS facility. Discussions ensued and the Spallation Neutron Source Research Accelerator Division agreed to form a collaboration with ESS-Bilbao (ESS-B) consortium to provide services for specifying the requirements for a version of the modulator capable of operating twelve 550 kW klystrons, monitoring the technical progress on the contract with JEMA, installing and commissioning the modulator at SNS, and performing a 30 day full power test. This work was recently completed, and this report discusses those activities with primary emphasis on the installation and testing activities.

  7. Measurement for skyshine of neutron generated by the K-600 neutron generator

    International Nuclear Information System (INIS)

    Zhen Huazhi; Li Guisheng; Wu Jingmin; Li Jianping

    1988-01-01

    The attenuation low of neutron scattering in atmosphere that generated by K-600 neutron generator at IMP was measured in order to evaluate the effect of the neutron generator to surroundings. The attenuation lenth λ = 396m was obtained and this result is in aggreement with the measured data at some laboratories abroad

  8. INTERCONNECTION AND INTERACTION OF INTERROGATIVE SENTENCES IN THE ENGLISH LANGUAGE

    Directory of Open Access Journals (Sweden)

    Natalia Sklyarova

    2013-12-01

    Full Text Available Normal 0 false false false RU X-NONE X-NONE MicrosoftInternetExplorer4 This paper presents the results of research devoted to one of significant aspects of interrogative sentences. The precise definitions of interconnection and interaction and the application of these terms to the language units helped to distinguish between interconnection and interaction of interrogative sentences in English. The existence of two different kinds of relations in the language, namely paradigmatic and syntagmatic, provided the basis for singling out two corresponding forms of interaction of English interrogative sentences. Contextual and distributional analyses of the material from authentic sources enabled to characterize the range and degree of their paradigmatic and syntagmatic interaction. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Обычная таблица"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  9. Sealed operation of a rf driven ion source for a compact neutron generator to be used for associated particle imaging.

    Science.gov (United States)

    Wu, Y; Hurley, J P; Ji, Q; Kwan, J W; Leung, K N

    2010-02-01

    We present the recent development of a prototype compact neutron generator to be used in conjunction with the method of associated particle imaging for the purpose of active neutron interrogation. In this paper, the performance and device specifications of these compact generators that employ rf driven ion sources will be discussed. Initial measurements of the generator performance include a beam spot size of 1 mm in diameter and a neutron yield of 2x10(5) n/s with air cooling.

  10. Neutron scattering in Australia

    International Nuclear Information System (INIS)

    Knott, R.B.

    1994-01-01

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

  11. Source Correlated Prompt Neutron Activation Analysis for Material Identification and Localization

    Science.gov (United States)

    Canion, Bonnie; McConchie, Seth; Landsberger, Sheldon

    2017-07-01

    This paper investigates the energy spectrum of photon signatures from an associated particle imaging deuterium tritium (API-DT) neutron generator interrogating shielded uranium. The goal is to investigate if signatures within the energy spectrum could be used to indirectly characterize shielded uranium when the neutron signature is attenuated. By utilizing the correlated neutron cone associated with each pixel of the API-DT neutron generator, certain materials can be identified and located via source correlated spectrometry of prompt neutron activation gamma rays. An investigation is done to determine if fission neutrons induce a significant enough signature within the prompt neutron-induced gamma-ray energy spectrum in shielding material to be useful for indirect nuclear material characterization. The signature deriving from the induced fission neutrons interacting with the shielding material was slightly elevated in polyethylene-shielding depleted uranium (DU), but was more evident in some characteristic peaks from the aluminum shielding surrounding DU.

  12. Review of pipe-break probability assessment methods and data for applicability to the advanced neutron source project for Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Fullwood, R.R.

    1989-04-01

    The Advanced Neutron Source (ANS) (Difilippo, 1986; Gamble, 1986; West, 1986; Selby, 1987) will be the world's best facility for low energy neutron research. This performance requires the highest flux density of all non-pulsed reactors with concomitant low thermal inertial and fast response to upset conditions. One of the primary concerns is that a flow cessation of the order of a second may result in fuel damage. Such a flow stoppage could be the result of break in the primary piping. This report is a review of methods for assessing pipe break probabilities based on historical operating experience in power reactors, scaling methods, fracture mechanics and fracture growth models. The goal of this work is to develop parametric guidance for the ANS design to make the event highly unlikely. It is also to review and select methods that may be used in an interactive IBM-PC model providing fast and reasonably accurate models to aid the ANS designers in achieving the safety requirements. 80 refs., 7 figs

  13. Neutron physics

    CERN Document Server

    Reuss, Paul

    2008-01-01

    Originally just an offshoot of nuclear physics, neutron physics soon became a branch of physics in its own right. It deals with the movement of neutrons in nuclear reactors and ail the nuclear reactions they trigger there, particularly the fission of heavy nuclei which starts a chain reaction to produce energy. Neutron Physics covers the whole range of knowledge of this complex science, discussing the basics of neutron physics and some principles of neutron physics calculations. Because neutron physics is the essential part of reactor physics, it is the main subject taught to students of Nuclear Engineering. This book takes an instructional approach for that purpose. Neutron Physics is also intended for ail physicists and engineers involved in development or operational aspects of nuclear power.

  14. RETRACTED: Fast neutron interrogation system development for the detection of explosive materials

    Science.gov (United States)

    Sim, Cheul Muu; Kim, Yi Kyung; Kim, Tae Joo; Hong, Kwang Pyo; Em, V. T.; Lee, Kye Hong; Kim, Young Jin; Kim, Jeong Uk

    2009-06-01

    This article has been removed at the request of the Editor-in-Chief and Authors. Please see Elsevier Policy on Article Withdrawal ( http://www.elsevier.com/locate/withdrawalpolicy). Reason: this article has been retracted at the request of the Editor-in-Chief and authors as it contains serious errors. This proceedings paper did not fully provide readers with the whole process of the experiment because of page limitations. This short paper resulted in prejudiced texts as well as absurd figures in regard with public information of detecting explosive materials against terrorism. The authors will revise the paper after a comprehensive discussion with the co-authors before resubmitting formally an article to NIMA.

  15. Neutron-based portable drug probe

    International Nuclear Information System (INIS)

    Womble, P. C.; Vourvopoulos, G.; Ball Howard, J.; Paschal, J.

    1999-01-01

    Based on previous measurements, a probe prototype for contraband detection utilizing the neutron technique of Pulsed Fast-Thermal Neutron Analysis (PFTNA) is being constructed. The prototype weighs less than 45 kg and is composed of a probe (5 cm diameter), a power pack and a data acquisition and display system. The probe is designed to be inserted in confined spaces such as the boiler of a ship or a tanker truck filled with liquid. The probe provides information on a) the elemental content, and b) the density variations of the interrogated object. By measuring elemental content, the probe can differentiate between innocuous materials and drugs. Density variations can be found through fast neutron transmission. In all cases, hidden drugs are identified through the measurement of the elemental content of the object, and the comparison of expected and measured elemental ratios

  16. Remotely Interrogated Passive Polarizing Dosimeter (RIPPeD).

    Energy Technology Data Exchange (ETDEWEB)

    Kemme, Shanalyn A.; Buller, Daniel L.; Dirk, Shawn M.; Boye, Robert R.; Samora, Sally; Washburn, Cody M.; Wheeler, David Roger

    2008-09-01

    Conductive polymers have become an extremely useful class of materials for many optical applications. We have developed an electrochemical growth method for depositing highly conductive ({approx}100 S/cm) polypyrrole. Additionally, we have adapted advanced fabrication methods for use with the polypyrrole resulting in gratings with submicron features. This conductive polymer micro-wire grid provides an optical polarizer with unique properties. When the polymer is exposed to ionizing radiation, its conductivity is affected and the polarization properties of the device, specifically the extinction ratio, change in a corresponding manner. This change in polarization properties can be determined by optically interrogating the device, possibly from a remote location. The result is a passive radiation-sensitive sensor with very low optical visibility. The ability to interrogate the device from a safe standoff distance provides a device useful in potentially dangerous environments. Also, the passive nature of the device make it applicable in applications where external power is not available. We will review the polymer deposition, fabrication methods and device design and modeling. The characterization of the polymer's sensitivity to ionizing radiation and optical testing of infrared polarizers before and after irradiation will also be presented. These experimental results will highlight the usefulness of the conductive infrared polarizer to many security and monitoring applications.

  17. Inside interrogation: the lie, the bluff, and false confessions.

    Science.gov (United States)

    Perillo, Jennifer T; Kassin, Saul M

    2011-08-01

    Using a less deceptive variant of the false evidence ploy, interrogators often use the bluff tactic, whereby they pretend to have evidence to be tested without further claiming that it necessarily implicates the suspect. Three experiments were conducted to assess the impact of the bluff on confession rates. Using the Kassin and Kiechel (Psychol Sci 7:125-128, 1996) computer crash paradigm, Experiment 1 indicated that bluffing increases false confessions comparable to the effect produced by the presentation of false evidence. Experiment 2 replicated the bluff effect and provided self-reports indicating that innocent participants saw the bluff as a promise of future exoneration which, paradoxically, made it easier to confess. Using a variant of the Russano et al. (Psychol Sci 16:481-486, 2005) cheating paradigm, Experiment 3 replicated the bluff effect on innocent suspects once again, though a ceiling effect was obtained in the guilty condition. Results suggest that the phenomenology of innocence can lead innocents to confess even in response to relatively benign interrogation tactics.

  18. Accelerating fissile material detection with a neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Rowland, Mark S.; Snyderman, Neal J.

    2018-01-30

    A neutron detector system for discriminating fissile material from non-fissile material wherein a digital data acquisition unit collects data at high rate, and in real-time processes large volumes of data directly to count neutrons from the unknown source and detecting excess grouped neutrons to identify fission in the unknown source. The system includes a Poisson neutron generator for in-beam interrogation of a possible fissile neutron source and a DC power supply that exhibits electrical ripple on the order of less than one part per million. Certain voltage multiplier circuits, such as Cockroft-Walton voltage multipliers, are used to enhance the effective of series resistor-inductor circuits components to reduce the ripple associated with traditional AC rectified, high voltage DC power supplies.

  19. NELIS - a Neutron Inspection System for Detection of Illicit Drugs

    International Nuclear Information System (INIS)

    Barzilov, Alexander P.; Womble, Phillip C.; Vourvopoulos, George

    2003-01-01

    NELIS (Neutron ELemental Inspection System) is currently being developed to inspect cargo pallets for illicit drugs. NELIS must be used in conjunction with an x-ray imaging system to optimize the inspection capabilities at ports of entry. Pulsed fast-thermal neutron analysis is utilized to measure the major and minor chemical elements in a non-destructive and non-intrusive manner. Fourteen-MeV neutrons produced with a pulsed d-T neutron generator are the interrogating particles. NELIS analyzes the characteristic gamma rays emitted from the object that are produced by nuclear reactions from fast and thermal neutrons. These gamma rays have different energies for each chemical element, and act as their fingerprints. Since the elemental composition of illicit drugs is quite different from that of innocuous materials, drugs hidden in pallets are identified through the comparison of expected and measured elemental composition and ratios. Results of tests of the system will be discussed

  20. Elemental analysis using temporal gating of a pulsed neutron generator

    Science.gov (United States)

    Mitra, Sudeep

    2018-02-20

    Technologies related to determining elemental composition of a sample that comprises fissile material are described herein. In a general embodiment, a pulsed neutron generator periodically emits bursts of neutrons, and is synchronized with an analyzer circuit. The bursts of neutrons are used to interrogate the sample, and the sample outputs gamma rays based upon the neutrons impacting the sample. A detector outputs pulses based upon the gamma rays impinging upon the material of the detector, and the analyzer circuit assigns the pulses to temporally-based bins based upon the analyzer circuit being synchronized with the pulsed neutron generator. A computing device outputs data that is indicative of elemental composition of the sample based upon the binned pulses.

  1. Neutron radiography

    International Nuclear Information System (INIS)

    Hiraoka, Eiichi

    1988-01-01

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

  2. Initial Neutronics Analyses for HEU to LEU Fuel Conversion of the Transient Reactor Test Facility (TREAT) at the Idaho National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Kontogeorgakos, D. [Argonne National Lab. (ANL), Argonne, IL (United States); Derstine, K. [Argonne National Lab. (ANL), Argonne, IL (United States); Wright, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Bauer, T. [Argonne National Lab. (ANL), Argonne, IL (United States); Stevens, J. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2013-06-01

    The purpose of the TREAT reactor is to generate large transient neutron pulses in test samples without over-heating the core to simulate fuel assembly accident conditions. The power transients in the present HEU core are inherently self-limiting such that the core prevents itself from overheating even in the event of a reactivity insertion accident. The objective of this study was to support the assessment of the feasibility of the TREAT core conversion based on the present reactor performance metrics and the technical specifications of the HEU core. The LEU fuel assembly studied had the same overall design, materials (UO2 particles finely dispersed in graphite) and impurities content as the HEU fuel assembly. The Monte Carlo N–Particle code (MCNP) and the point kinetics code TREKIN were used in the analyses.

  3. Compact neutron generators for environmental recovery applications

    International Nuclear Information System (INIS)

    Leung, K. N.; Firestone, R. B.; Lou, T. P.; Reijonen, J.; Vujic, J. Lj.

    2002-01-01

    New generations of compact neutron sources are being developed at the Lawrence Berkeley National Laboratory (LBNL). The D-D or D-T neutron generators can be used to perform precise elemental analysis by Prompt Gamma-Ray Activation Analysis (PGAA) in place of a nuclear reactor. The neutron generators will be composed of an ion source, from which a 1.5 A deuterium beam will be extracted and accelerated to about 150 keV onto a target loaded with deuterium. Based on the D-D nuclear reaction, the neutron generator will yield approximately 10 12 n/s (10 14 n/s for D-T reaction). With this neutron output, thermal and cold neutron fluxes of 10 7 n/s cm 2 and 6 x 10 6 n/s cm 2 have been estimated using neutron moderators designed by the neutron transport simulation code MCNP. (author)

  4. Neutron gamma fraction imaging: Detection, location and identification of neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Gamage, K.A.A., E-mail: k.gamage@lancaster.ac.uk [Department of Engineering, University of Lancaster , Lancaster LA1 4YR (United Kingdom); Taylor, G.C. [National Physical Laboratory, Hampton Road,Teddington, Middlesex TW11 0LW (United Kingdom)

    2015-07-11

    In this paper imaging of neutron sources and identification and separation of a neutron source from another neutron source is described. The system is based upon organic liquid scintillator detector, tungsten collimator, bespoke fast digitiser and adjustable equatorial mount. Three environments have been investigated with this setup corresponding to an AmBe neutron source, a {sup 252}Cf neutron source and both sources together separated in space. In each case, events are detected, digitised, discriminated and radiation images plotted corresponding to the area investigated. The visualised neutron count distributions clearly locate the neutron source and, relative gamma to neutron (or neutron to gamma) fraction images aid in discriminating AmBe sources from {sup 252}Cf source. The measurements were performed in the low scatter facility of the National Physical Laboratory, Teddington, UK.

  5. Non-Destructive Evaluation of Materials Using Pulsed Microwave Interrogating Signals and Acoustic Wave Induced Reflections

    National Research Council Canada - National Science Library

    Albanese, R

    2002-01-01

    A class of inverse problems is formulated for the estimation of material dielectric parameters using reflections of pulsed microwave interrogating signals from moving acoustic interfaces in the dielectric...

  6. Characteristics and theory of operation of the controlatron neutron tube

    International Nuclear Information System (INIS)

    Volk, R.D.

    1977-01-01

    The Controlatron (or Type 26E) neutron tube was developed by General Electric under contract to Sandia Laboratories in 1961 to be used in a neutron activation analysis experiment on the lunar surface. It was subsequently employed as a very stable laboratory neutron source for neutron detector calibration within the ERDA complex. The Controlatron is a gas filled neutron tube using a titanium target, Penning type cold cathode ion source, and self-contained reservoir. The general theory of operation of this type of neutron tube utilizing the D-T nuclear reaction is presented

  7. High sensitivity MOSFET-based neutron dosimetry

    International Nuclear Information System (INIS)

    Fragopoulou, M.; Konstantakos, V.; Zamani, M.; Siskos, S.; Laopoulos, T.; Sarrabayrouse, G.

    2010-01-01

    A new dosemeter based on a metal-oxide-semiconductor field effect transistor sensitive to both neutrons and gamma radiation was manufactured at LAAS-CNRS Laboratory, Toulouse, France. In order to be used for neutron dosimetry, a thin film of lithium fluoride was deposited on the surface of the gate of the device. The characteristics of the dosemeter, such as the dependence of its response to neutron dose and dose rate, were investigated. The studied dosemeter was very sensitive to gamma rays compared to other dosemeters proposed in the literature. Its response in thermal neutrons was found to be much higher than in fast neutrons and gamma rays.

  8. Neutron detector

    Science.gov (United States)

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

    2011-04-05

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

  9. Fusion neutronics

    CERN Document Server

    Wu, Yican

    2017-01-01

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

  10. The neutron

    International Nuclear Information System (INIS)

    Cheetham, A.K.

    1990-01-01

    In 1932, when Chadwick obtained the first unambiguous evidence for the existence of the neutron, his discovery confirmed the widely held belief that there existed a particle with zero charge and a mass similar to that of the proton. Indeed, as early as 1920, Lord Rutherford had suggested such a possibility in a lecture to the Royal Society. The discovery of the neutron had an immediate and dramatic impact in several areas. The nucleus, which had hitherto been regarded, somewhat unsatisfactorily, as a combination of protons and electrons, was now seen as comprising of protons and neutrons. This in turn lead to a proper understanding of the nature of isotopes and provided a fresh basis for nuclear theories. This paper examines the nature and properties of the neutron, and describes some facets of its remarkable role in contemporary science and technology. The aspects covered are its properties, the production and detection of neutrons, the reactions between neutrons and nuclei, fission reactions, neutron scattering, pulsed neutron scattering and neutron spectroscopy. (author)

  11. Atmospheric neutrons

    International Nuclear Information System (INIS)

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

    1976-01-01

    Additional calibrations of the University of California double-scatter neutron and additional analysis corrections lead to the slightly changed neutron fluxes reported here. The theoretical angular distributions of Merker (1975) are in general agreement with our experimental fluxes but do not give the peaks for vertical upward and downward moving neutrons. The theoretical neutron escape current J 2 /sub pi/ (Merker, 1972; Armstrong et al., 1973) is in agreement with the experimental values from 10 to 100 MeV. Our experimental fluxes agree with those of the Kanbach et al. (1974) in the overlap region from 70 to 100 MeV

  12. RPC for thermal neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Arnaldi, R [INFN Torino and Dip. di Fisica Sperimentale dell' Universita di Torino (Italy); Chiavassa, E [INFN Torino and Dip. di Fisica Sperimentale dell' Universita di Torino (Italy); Colla, A [INFN Torino and Dip. di Fisica Sperimentale dell' Universita di Torino (Italy); Cortese, P [INFN Alessandria and Universita del Piemonte Orientale ' Amedeo Avogadro' , Alessandria (Italy); Dellacasa, G [INFN Alessandria and Universita del Piemonte Orientale ' Amedeo Avogadro' , Alessandria (Italy); Marco, N De [INFN Torino and Dip. di Fisica Sperimentale dell' Universita di Torino (Italy); Ferretti, A [INFN Torino and Dip. di Fisica Sperimentale dell' Universita di Torino (Italy); Gagliardi, M [INFN Torino and Dip. di Fisica Sperimentale dell' Universita di Torino (Italy); Gallio, M [INFN Torino and Dip. di Fisica Sperimentale dell' Universita di Torino (Italy); Gemme, R [INFN Torino and Dip. di Fisica Sperimentale dell' Universita di Torino (Italy); Musso, A [INFN Torino and Dip. di Fisica Sperimentale dell' Universita di Torino (Italy); Oppedisano, C [INFN Torino and Dip. di Fisica Sperimentale dell' Universita di Torino (Italy); Piccotti, A [INFN Torino and Dip. di Fisica Sperimentale dell' Universita di Torino (Italy); Poggio, F [INFN Torino and Dip. di Fisica Sperimentale dell' Universita di Torino (Italy); Scomparin, E [INFN Torino and Dip. di Fisica Sperimentale dell' Universita di Torino (Italy); Vercellin, E [INFN Torino and Dip. di Fisica Sperimentale dell' Universita di Torino (Italy)

    2006-05-15

    The possibility to detect thermal neutrons with single gap Resistive Plate Chambers has been investigated. To detect neutrons a {sup 10}B{sub 4}C thin coating on the inner surface of one RPC electrode is used as thermal neutron converter. The RPC detects the charged particles generated by neutrons via the (n, {alpha}) reaction on Boron. Tests on converter samples have been performed with a thermalized {sup 252}Cf source in order to evaluate the conversion efficiency: a good agreement between experimental results and simulation has been achieved. A detector prototype has been developed and tested on a low energy neutron beam at the European laboratories JRC in Belgium. A detailed description of the detector and the experimental test results are presented.

  13. Advanced ultrasonic measurement methodology for non-invasive interrogation and identification of fluids in sealed containers

    Science.gov (United States)

    Tucker, Brian J.; Diaz, Aaron A.; Eckenrode, Brian A.

    2006-03-01

    Government agencies and homeland security related organizations have identified the need to develop and establish a wide range of unprecedented capabilities for providing scientific and technical forensic services to investigations involving hazardous chemical, biological, and radiological materials, including extremely dangerous chemical and biological warfare agents. Pacific Northwest National Laboratory (PNNL) has developed a prototype portable, hand-held, hazardous materials acoustic inspection prototype that provides noninvasive container interrogation and material identification capabilities using nondestructive ultrasonic velocity and attenuation measurements. Due to the wide variety of fluids as well as container sizes and materials encountered in various law enforcement inspection activities, the need for high measurement sensitivity and advanced ultrasonic measurement techniques were identified. The prototype was developed using a versatile electronics platform, advanced ultrasonic wave propagation methods, and advanced signal processing techniques. This paper primarily focuses on the ultrasonic measurement methods and signal processing techniques incorporated into the prototype. High bandwidth ultrasonic transducers combined with an advanced pulse compression technique allowed researchers to 1) obtain high signal-to-noise ratios and 2) obtain accurate and consistent time-of-flight (TOF) measurements through a variety of highly attenuative containers and fluid media. Results of work conducted in the laboratory have demonstrated that the prototype experimental measurement technique also provided information regarding container properties, which will be utilized in future container-independent measurements of hidden liquids.

  14. Compact neutron generator development at LBNL

    International Nuclear Information System (INIS)

    Reijonen, J.; English, G.; Firestone, R.; Giquel, F.; King, M.; Leung, K-N.; Sun, M.

    2003-01-01

    A wide variety of applications ranging from medical (BNCT, Boron Neutron Capture Therapy) and basic science (neutron imaging, material studies) to homeland security (explosive detection and nuclear material non-proliferation) are in need of compact, high flux neutron generators. The Plasma and Ion Source Technology Group in the Lawrence Berkeley National Laboratory is developing various neutron generators for these applications. These neutron generators employed either the D-D or the D-T fusion reaction for the neutron production. The deuterium or deuterium-tritium gas mixture is ionized in an RF-driven plasma source. The ions are then accelerated to ∼100 keV energy using high current, high voltage DC-power supply to a target where the 2.45 MeV (for D-D reaction) or 14 MeV (for the D-T reaction) neutrons are generated. The development of two different types of neutron tubes are being discussed in this presentation, namely compact, pulsed operation neutron generators and cw, high yield neutron generators. These generators are currently operating at D-D neutron yields of 108 n/s and 109 n/s respectively. A facility, incorporating the larger neutron generator, has been constructed for Prompt Gamma Activation Analysis (PGAA) and Neutron Activation Analysis (NAA) measurements

  15. Utilization of a pulsed D-T neutron generator

    International Nuclear Information System (INIS)

    Vilaithong, T.; Singkarat, S.; Tippawan, U.

    2000-01-01

    In the past two decades the IAEA has supported the establishment of neutron laboratories in many developing countries by providing small D-T neutron generators. The neutron generator is basically a low energy (100-400 keV) ion accelerator capable of producing a continuous beam of deuterons with a current in the range between 1-2.5 mA. These neutron generators are primarily intended to be used for fast neutron activation analysis. This paper describes the utilization of a 14 MeV neutron generator in continuous and pulsed beam modes in applied neutron physics program at Chiang Mai University. (author)

  16. A Contrastive Analysis of Interrogative Sentences in English and Indonesian

    Directory of Open Access Journals (Sweden)

    Mashlihatul Umami

    2016-04-01

    Full Text Available The aim of this paper is to investigate the forms of questions in English and Indonesian in order to identify the similarities and differences between them. CA may look at linguistic structures in a twofold way: predictability power and wash back effect (Cheng, Watanabe & Curtis, 2004. The former deals with foreseeing the areas of problems the English learners may commit and the latter refers to the effect of diagnostic value of CA on improvement of teaching processes. In this case, the researcher emphasizes her study in analyzing CA based on the first perspective; this study focuses on interrogative sentences which are in the form of questions which play an important role in learning English among junior English students. This study has found the differences and similarities between Indonesian and English. Recognizing this will contribute to the accuracy of English questions made by the students.

  17. The Advanced Neutron Source

    International Nuclear Information System (INIS)

    Peretz, F.J.

    1990-01-01

    The Advanced Neutron Source (ANS) is to be a multipurpose neutron research center, constructed around a high-flux reactor now being designed at the Oak Ridge National Laboratory (ORNL). Its primary purpose is to place the United States in the forefront of neutron scattering in the twenty-first century. Other research programs include nuclear and fundamental physics, isotope production, materials irradiation, and analytical chemistry. The ANS will be a unique and invaluable research tool because of the unprecedented neutron flux available from the high-intensity research reactor. But this reactor would be ineffective without world-class research facilities that allow the fullest utilization of the available neutrons. And, in turn, those research facilities will not produce new and exciting science without a broad population of users from all parts of the nation and the world, placed in a stimulating environment in which experiments can be effectively conducted and in which scientific exchange is encouraged. This paper discusses the measures being taken to ensure that the design of the ANS focuses not only on the reactor, but on providing the experiment and user support facilities needed to allow its effective use

  18. Coaxial Mono-Energetic Gamma Generator for Active Interrogation

    Energy Technology Data Exchange (ETDEWEB)

    Ludewigt, Bernhard A.; Antolak, A.J.; Henestroza, E.; Leitner, M.; Leung, K.-N.; Waldron, W.; Wilde, S.; Kwan, J.W.

    2008-08-01

    Compact mono-energetic photon sources are sought for active interrogation systems to detect shielded special nuclear materials in, for example, cargo containers, trucks and other vehicles. A prototype gamma interrogation source has been designed and built that utilizes the 11B(p,gamma)12C reaction to produce 12 MeV gamma-rays which are near the peak of the photofission cross section. In particular, the 11B(p,gamma)12C resonance at 163 kV allows the production of gammas at low proton acceleration voltages, thus keeping the design of a gamma generator comparatively small and simple. A coaxial design has been adopted with a toroidal-shaped plasma chamber surrounding a cylindrical gamma production target. The plasma discharge is driven by a 2 MHz rf-power supply (capable up to 50 kW) using a circular rf-antenna. Permanent magnets embedded in the walls of the plasma chamber generate a multi-cusp field that confines the plasma and allows higher plasma densities and lower gas pressures. About 100 proton beamlets are extracted through a slotted plasma electrode towards the target at the center of the device that is at a negative 180 kV. The target consists of LaB6 tiles that are brazed to a water-cooled cylindrical structure. The generator is designed to operate at 500 Hz with 20 mu s long pulses, and a 1percent duty factor by pulsing the ion source rf-power. A first-generation coaxial gamma source has been built for low duty factor experiments and testing.

  19. Interrogated with Intellectual Disabilities: The Risks of False Confession.

    Science.gov (United States)

    Schatz, Samson J

    2018-02-01

    False confessions happen. At least 245 people have been exonerated from convictions in cases featuring confessions that were simply not true. Confessions offer a narrative that allows law enforcement, and society in general, to neatly resolve cases with apparent clarity and closure. And yet the pressures officers place on suspects to provide that closure weigh disproportionately on the vulnerable, including individuals with intellectual disabilities. These individuals are disadvantaged at every step of the custodial interrogation, and they face heightened risks of falsely confessing. Moreover, the principal judicial safeguards against false confessions--assessing a suspect's Miranda waiver and determining whether a confession was voluntarily given within the bounds of the Fourteenth Amendment’s Due Process Clause--provide little protection for the innocent with intellectual disabilities. Few pieces of scholarship focus specifically on the heightened risks faced by individuals with intellectual disabilities throughout the process of police interrogation. This Note describes the various ways these individuals are disadvantaged. And it offers an additional data point illustrating the vulnerability of people with intellectual disabilities. This Note analyzes the 245 individuals (as of June 2, 2017) on the National Registry of Exonerations who have falsely confessed. Over one-quarter of them display indicia of intellectual disability. This percentage dwarfs the prevalence of people with intellectual disabilities in the general population and even exceeds most estimates of the proportion of the prison population suffering from intellectual disabilities. This Note concludes with several policy and doctrinal suggestions to better protect individuals with intellectual disabilities from the risks of false confession.

  20. Interrogating transcriptional regulatory sequences in Tol2-mediated Xenopus transgenics.

    Directory of Open Access Journals (Sweden)

    Gabriela G Loots

    Full Text Available Identifying gene regulatory elements and their target genes in vertebrates remains a significant challenge. It is now recognized that transcriptional regulatory sequences are critical in orchestrating dynamic controls of tissue-specific gene expression during vertebrate development and in adult tissues, and that these elements can be positioned at great distances in relation to the promoters of the genes they control. While significant progress has been made in mapping DNA binding regions by combining chromatin immunoprecipitation and next generation sequencing, functional validation remains a limiting step in improving our ability to correlate in silico predictions with biological function. We recently developed a computational method that synergistically combines genome-wide gene-expression profiling, vertebrate genome comparisons, and transcription factor binding-site analysis to predict tissue-specific enhancers in the human genome. We applied this method to 270 genes highly expressed in skeletal muscle and predicted 190 putative cis-regulatory modules. Furthermore, we optimized Tol2 transgenic constructs in Xenopus laevis to interrogate 20 of these elements for their ability to function as skeletal muscle-specific transcriptional enhancers during embryonic development. We found 45% of these elements expressed only in the fast muscle fibers that are oriented in highly organized chevrons in the Xenopus laevis tadpole. Transcription factor binding site analysis identified >2 Mef2/MyoD sites within ~200 bp regions in 6 of the validated enhancers, and systematic mutagenesis of these sites revealed that they are critical for the enhancer function. The data described herein introduces a new reporter system suitable for interrogating tissue-specific cis-regulatory elements which allows monitoring of enhancer activity in real time, throughout early stages of embryonic development, in Xenopus.

  1. Analysis of containment performance and radiological consequences under severe accident conditions for the Advanced Neutron Source Reactor at the Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.H.; Taleyarkhan, R.P.

    1994-01-01

    A severe accident study was conducted to evaluate conservatively scoped source terms and radiological consequences to support the Advanced Neutron Source (ANS) Conceptual Safety Analysis Report (CSAR). Three different types of severe accident scenarios were postulated with a view of evaluating conservatively scoped source terms. The first scenario evaluates maximum possible steaming loads and associated radionuclide transport, whereas the next scenario is geared towards evaluating conservative containment loads from releases of radionuclide vapors and aerosols with associated generation of combustible gases. The third scenario follows the prescriptions given by the 10 CFR 100 guidelines. It was included in the CSAR for demonstrating site-suitability characteristics of the ANS. Various containment configurations are considered for the study of thermal-hydraulic and radiological behaviors of the ANS containment. Severe accident mitigative design features such as the use of rupture disks were accounted for. This report describes the postulated severe accident scenarios, methodology for analysis, modeling assumptions, modeling of several severe accident phenomena, and evaluation of the resulting source term and radiological consequences.

  2. Analysis of containment performance and radiological consequences under severe accident conditions for the Advanced Neutron Source Reactor at the Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Kim, S.H.; Taleyarkhan, R.P.

    1994-01-01

    A severe accident study was conducted to evaluate conservatively scoped source terms and radiological consequences to support the Advanced Neutron Source (ANS) Conceptual Safety Analysis Report (CSAR). Three different types of severe accident scenarios were postulated with a view of evaluating conservatively scoped source terms. The first scenario evaluates maximum possible steaming loads and associated radionuclide transport, whereas the next scenario is geared towards evaluating conservative containment loads from releases of radionuclide vapors and aerosols with associated generation of combustible gases. The third scenario follows the prescriptions given by the 10 CFR 100 guidelines. It was included in the CSAR for demonstrating site-suitability characteristics of the ANS. Various containment configurations are considered for the study of thermal-hydraulic and radiological behaviors of the ANS containment. Severe accident mitigative design features such as the use of rupture disks were accounted for. This report describes the postulated severe accident scenarios, methodology for analysis, modeling assumptions, modeling of several severe accident phenomena, and evaluation of the resulting source term and radiological consequences

  3. Neutron guides on pulsed sources

    International Nuclear Information System (INIS)

    Carlile, C.J.; Johnson, M.W.; Williams, W.G.

    1979-11-01

    A survey of the physics of neutron guides has been applied to their installation on pulsed neutron sources, particularly the Spallation Neutron Source (SNS) at the Rutherford Laboratory. Guides on pulsed sources generally view smaller source areas than those on continuous sources, and furthermore their lengths are fixed primarily by time-of-flight resolution requirements. These differences have been accounted for in the design of guides for two SNS instruments A Monte Carlo computer code has been used in the optimisation and simulation of the guide geometries. (author)

  4. Neutron scattering science in Australia

    International Nuclear Information System (INIS)

    Knott, Robert

    1999-01-01

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

  5. Neutron scattering science in Australia

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-10-01

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

  6. Measure of uranium enrichment by 14 MeV neutron irradiation

    International Nuclear Information System (INIS)

    Rezende, H.R.

    1987-01-01

    A non-destructive technique for the determination of uranium in UO 2 samples was developed, marking use of the change in the fission cross of a nuclide with the neutron energy. The active interrogation method was used by irradiating the samples with pulsed 14 MeV neutrons and furtherdetection of delayed fission neutrons. In order to descriminated U-238 from U-235 the neutron energy was tailored by means of two concentric cylinders of lead and paraffin/poliethylene, 11 and 4 cm thick. Between neutron pulses, delayed neutrons from fission were detected by a long counter built with five BF 3 proportional counters. Calibration curves for enrichment and total mass versus delayed neutron response were obtained using available UO 2 pellets of Known enrichment. Enrichment detection limit, obtained with 95% confidence level by the the Student distribution was estimated to be 0.33%. The minimal detectable mass was estimated to be 4.4 g. (Author) [pt

  7. Measurement of neutron diffraction with compact neutron source RANS

    Science.gov (United States)

    Ikeda, Y.; Takamura, M.; Taketani, A.; Sunaga, H.; Otake, Y.; Suzuki, H.; Kumagai, M.; Oba, Y.; Hama, T.

    2016-11-01

    Diffraction is used as a measurement technique for crystal structure. X-rays or electron beam with wavelength that is close to the lattice constant of the crystal is often used for the measurement. They have sensitivity in surface (0.01mm) of heavy metals due to the mean free path for heavy ions. Neutron diffraction has the probe of the internal structure of the heavy metals because it has a longer mean free path than that of the X-rays or the electrons. However, the neutron diffraction measurement is not widely used because large facilities are required in the many neutron sources. RANS (Riken Accelerator-driven Compact Neutron Source) is developed as a neutron source which is usable easily in laboratories and factories. In RANS, fast neutrons are generated by 7MeV protons colliding on a Be target. Some fast neutrons are moderated with polyethylene to thermal neutrons. The thermal neutrons of 10meV which have wavelength of 10nm can be used for the diffraction measurement. In this study, the texture evolution in steels was measured with RANS and the validity of the compact neutron source was proved. The texture of IF steel sheets with the thickness of 1.0mm was measured with 10minutes run. The resolution is 2% and is enough to analyze a evolution in texture due to compression/tensile deformation or a volume fraction of two phases in the steel sample. These results have proven the possibility to use compact neutron source for the analysis of mesoscopic structure of metallic materials.

  8. Neutron activation analysis

    International Nuclear Information System (INIS)

    Taure, I.; Riekstina, D.; Veveris, O.

    2004-01-01

    Neutron activation analysis (NAA) in Latvia began to develop after 1961 when nuclear reactor in Salaspils started to work. It provided a powerful neuron source, which is necessary for this analytical method. In 1963 at Institute of Physics of the Latvian Academy of Sciences the Laboratory of Neutron Activation Analysis was formed. At the first stage of development the main tasks were of theoretical and technical aspects of NAA. Later the NAA was used to solve problems in technology, biology, and medicine. In the beginning of the 80-ties more attention was focussed to the use of NAA in the environmental research. Environmental problems stayed the main task till the closing the nuclear reactor in Salaspils in 1998 that ceased the main the existence of the laboratory and of NAA, this significant and powerful analytical method in Latvia and Baltic in general. (authors)

  9. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1993-12-31

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

  10. 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

  11. Neutronic reactor

    International Nuclear Information System (INIS)

    Wende, C.W.J.

    1976-01-01

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

  12. 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)

  13. 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.)

  14. High Intensity, Pulsed, D-D Neutron Generator

    International Nuclear Information System (INIS)

    Williams, D.L.; Vainionpaa, J.H.; Jones, G.; Piestrup, M.A.; Gary, C.K.; Harris, J.L.; Fuller, M.J.; Cremer, J.T.; Ludewigt, Bernhard A.; Kwan, J.W.; Reijonen, J.; Leung, K.-N.; Gough, R.A.

    2008-01-01

    Single ion-beam RF-plasma neutron generators are presented as a laboratory source of intense neutrons. The continuous and pulsed operations of such a neutron generator using the deuterium-deuterium fusion reaction are reported. The neutron beam can be pulsed by switching the RF plasma and/or a gate electrode. These generators are actively vacuum pumped so that a continuous supply of deuterium gas is present for the production of ions and neutrons. This contributes to the generator's long life. These single-beam generators are capable of producing up to 1E10 n/s. Previously, Adelphi and LBNL have demonstrated these generators applications in fast neutron radiography, Prompt Gamma Neutron Activation Analysis (PGNAA) and Neutron Activation Analysis (NAA). Together with an inexpensive compact moderator, these high-output neutron generators extend useful applications to home laboratory operations.

  15. 76 FR 44282 - Defense Federal Acquisition Regulation Supplement; Prohibition on Interrogation of Detainees by...

    Science.gov (United States)

    2011-07-25

    ...-AG88 Defense Federal Acquisition Regulation Supplement; Prohibition on Interrogation of Detainees by.... It also allows the Secretary of Defense to waive the prohibition for a limited period of time, with... Defense to waive the prohibition on contractor interrogations for up to 60 days on the grounds of national...

  16. And I Want to Thank You Barbie: Barbie as a Site for Cultural Interrogation.

    Science.gov (United States)

    Mitchell, Claudia; Reid-Walsh, Jacqueline

    1995-01-01

    Barbie is presented as the perfect cultural site for interrogating margins, borders, and contradictions in females' lives. This article illuminates such issues by interrogating the "cumulative cultural text of Barbie." Texts criticized are: Barbie collector cards; "Barbie" and "Barbie Fashion" comic books;…

  17. On velocity space interrogation regions of fast-ion collective Thomson scattering at ITER

    DEFF Research Database (Denmark)

    Salewski, Mirko; Nielsen, Stefan Kragh; Bindslev, Henrik

    2011-01-01

    the collective scattering in well-defined regions in velocity space, here dubbed interrogation regions. Since the CTS instrument measures entire spectra of scattered radiation, many different interrogation regions are probed simultaneously. We here give analytic expressions for weight functions describing...

  18. The Development of Interrogative Forms and Functions in Early Childhood Cantonese

    Science.gov (United States)

    Li, Hui; Tse, Shek Kam; Sin Wong, Jessie Ming; Mei Wong, Eileen Chin; Leung, Shing On

    2013-01-01

    This study investigated question acquisition in Cantonese-speaking young children with a focus on the development of interrogative forms and functions. Data from a child Cantonese corpus (492 children aged 36, 48 and 60 months) were analysed. The main results were that: (1) all the interrogative forms and functions were produced by the three age…

  19. Diagnostic yield of device interrogation in the evaluation of syncope in an elderly population.

    Science.gov (United States)

    D'Angelo, Robert N; Pickett, Christopher C

    2017-06-01

    Device interrogation has become a standard part of the syncope evaluation for patients admitted with permanent pacemakers (PPM) or implantable cardiac defibrillators (ICD), although few studies have shown interrogation yields clinically useful data. The purpose of this study is to determine the diagnostic yield of device interrogation as well as other commonly performed tests in the workup of unexplained syncope in patients with previously implanted PPMs or ICDs. We retrospectively reviewed records of 88 patients admitted to our medical center for syncope with previously implanted pacemakers between January 1, 2005 and January 1, 2015 using ICD-9 billing data. Pacemaker interrogation demonstrated an arrhythmia as the cause for syncope in 4 patients (4%) and evidence of device failure secondary to perforation in 1 patient (1%). The cause of syncope was unknown in 34 patients (39%). Orthostatic hypotension was the most commonly identified cause of syncope (26%), followed by vasovagal syncope (13%), autonomic dysfunction (5%), ventricular arrhythmia (3%), atrial arrhythmia (2%), congestive heart failure (2%), stroke (2%), and other less common causes (8%). History was the most important determinant of syncope (36%), followed by orthostatic vital signs (14%), device interrogations (4%), head CT (2%), and transthoracic echocardiogram (1%). Device interrogation is rarely useful for elucidating a cause of syncope without concerning physical exam, telemetry, or EKG findings. Interrogation may occasionally yield paroxysmal arrhythmias responsible for syncopal episode, but these rarely alter clinical outcomes. Interrogation appears to be more useful in patients with syncope after recent device placement. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  20. Neutron tubes

    Science.gov (United States)

    Leung, Ka-Ngo [Hercules, CA; Lou, Tak Pui [Berkeley, CA; Reijonen, Jani [Oakland, CA

    2008-03-11

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

  1. Neutron source

    Science.gov (United States)

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

    1975-10-21

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

  2. 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...

  3. Neutron source

    International Nuclear Information System (INIS)

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

    1975-01-01

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

  4. New prospect in neutron radiography

    International Nuclear Information System (INIS)

    Cluzeau, S.

    1991-01-01

    Neutron radiography is a very useful non-destructive testing (NDT) method which frequently complements classical X-ray inspection. Numerous inspections in some fields are currently performed at reactor-based neutron radiography facilities but many other interesting applications in different fields are at present not considered because the objects to be tested cannot be moved to a reactor. It is the goal of the DIANE project, to allow the utilization of this NDT method in industrial facilities by developing a safe and convenient neutron radiography equipment using an ''on-off'' neutron source. As a result of the efforts of the four European partners, a first laboratory demonstration model is currently in operation in Germany and a fully mobile second one is expected by the end of 1992. Good radiographs are obtained with exposure times in the range of a few seconds to ten minutes using an electronic imaging system. The fast neutron generator uses a sealed neutron tube delivering 5.10 11 neutrons.cm -2 .s -1 in 4 π steradian; with a collimator ratio of about 12, the fluence rate onto the object is then close to 1,5.10 5 thermal neutrons.cm -2 .s -1 . (author)

  5. Neutron Scattering for the Nuclear Industry

    International Nuclear Information System (INIS)

    Rogge, Ronald B.

    1999-01-01

    The National Research Council's (NRC's) Neutron Program for Materials Research is in the fortunate circumstance of being located at the primary research facility for Canada's nuclear industry, Atomic Energy of Canada Limited (AECL). The National Research Universal (NRU) Reactor located at the Chalk River Laboratories is the source of neutrons for NRC's neutron beam laboratory. The NRC provides access to neutrons in two ways: (a) as an international user facility, participating in collaborative research projects with university, industry, and government laboratories, and (b) on a fee-for-service basis, obtaining proprietary information for Canadian and foreign industries. Consequently, neutron-scattering techniques can be applied to problems that span the range from fundamental research on the properties and behavior of materials to manufacturing processes and failure analysis

  6. Lectures on magnetism and neutron scattering

    International Nuclear Information System (INIS)

    Gunn, J.M.F.

    1983-12-01

    The paper contains six lectures given to the Neutron Division of the Rutherford Appleton laboratory in 1983. The aim was to explain fundamental physics of neutron scattering and basic magnetism to the non-specialist scientist. The text includes: origin of neutron's magnetic moment and spin-dependent interactions with electrons and nuclei, why are solids magnetic, magnetic anistropy and domain structure, phenomenological spin waves, magnetic phase transitions and electronic excitations in magnets. (U.K.)

  7. Neutron spectrometer for improved SNM search.

    Energy Technology Data Exchange (ETDEWEB)

    Vance, Andrew L.; Aigeldinger, Georg

    2007-03-01

    With the exception of large laboratory devices with very low sensitivities, a neutron spectrometer have not been built for fission neutrons such as those emitted by special nuclear materials (SNM). The goal of this work was to use a technique known as Capture Gated Neutron Spectrometry to develop a solid-state device with this functionality. This required modifications to trans-stilbene, a known solid-state scintillator. To provide a neutron capture signal we added lithium to this material. This unique triggering signal allowed identification of neutrons that lose all of their energy in the detector, eliminating uncertainties that arise due to partial energy depositions. We successfully implemented a capture gated neutron spectrometer and were able to distinguish an SNM like fission spectrum from a spectrum stemming from a benign neutron source.

  8. Spectral unfolding of fast neutron energy distributions

    Science.gov (United States)

    Mosby, Michelle; Jackman, Kevin; Engle, Jonathan

    2015-10-01

    The characterization of the energy distribution of a neutron flux is difficult in experiments with constrained geometry where techniques such as time of flight cannot be used to resolve the distribution. The measurement of neutron fluxes in reactors, which often present similar challenges, has been accomplished using radioactivation foils as an indirect probe. Spectral unfolding codes use statistical methods to adjust MCNP predictions of neutron energy distributions using quantified radioactive residuals produced in these foils. We have applied a modification of this established neutron flux characterization technique to experimentally characterize the neutron flux in the critical assemblies at the Nevada National Security Site (NNSS) and the spallation neutron flux at the Isotope Production Facility (IPF) at Los Alamos National Laboratory (LANL). Results of the unfolding procedure are presented and compared with a priori MCNP predictions, and the implications for measurements using the neutron fluxes at these facilities are discussed.

  9. Research opportunities with compact accelerator-driven neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, I.S. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Andreani, C., E-mail: carla.andreani@uniroma2.it [Università degli Studi di Roma “Tor Vergata”, Physics Department and NAST Centre, Via della Ricerca Scientifica 1, 00133 Roma (Italy); CNR-IPCF Sezione di Messina, Messina (Italy); Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Roma (Italy); Carpenter, J.M. [Argonne National Laboratory, Argonne, IL (United States); Festa, G., E-mail: giulia.festa@uniroma2.it [Università degli Studi di Roma “Tor Vergata”, Physics Department and NAST Centre, Via della Ricerca Scientifica 1, 00133 Roma (Italy); Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Roma (Italy); Gorini, G. [Università degli Studi di Milano—Bicocca, Milano (Italy); Loong, C.-K. [Università degli Studi di Roma “Tor Vergata”, Centro NAST, Via della Ricerca Scientifica 1, 00133 Roma (Italy); Senesi, R. [Università degli Studi di Roma “Tor Vergata”, Physics Department and NAST Centre, Via della Ricerca Scientifica 1, 00133 Roma (Italy); CNR-IPCF Sezione di Messina, Messina (Italy); Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Roma (Italy)

    2016-10-13

    Since the discovery of the neutron in 1932 neutron beams have been used in a very broad range of applications, As an aging fleet of nuclear reactor sources is retired the use of compact accelerator-driven neutron sources (CANS) is becoming more prevalent. CANS are playing a significant and expanding role in research and development in science and engineering, as well as in education and training. In the realm of multidisciplinary applications, CANS offer opportunities over a wide range of technical utilization, from interrogation of civil structures to medical therapy to cultural heritage study. This paper aims to provide the first comprehensive overview of the history, current status of operation, and ongoing development of CANS worldwide. The basic physics and engineering regarding neutron production by accelerators, target–moderator systems, and beam line instrumentation are introduced, followed by an extensive discussion of various evolving applications currently exploited at CANS.

  10. 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

  11. Computer-automated neutron activation analysis system

    International Nuclear Information System (INIS)

    Minor, M.M.; Garcia, S.R.

    1983-01-01

    An automated delayed neutron counting and instrumental neutron activation analysis system has been developed at Los Alamos National Laboratory's Omega West Reactor (OWR) to analyze samples for uranium and 31 additional elements with a maximum throughput of 400 samples per day. 5 references

  12. Probing thermonuclear burning on accreting neutron stars

    NARCIS (Netherlands)

    Keek, L.

    2008-01-01

    Neutron stars are the most compact stars that can be directly observed, which makes them ideal laboratories to study physics at extreme densities. Neutron stars in low-mass X-ray binaries accrete hydrogen and helium from a lower-mass companion star through Roche lobe overflow. This matter undergoes

  13. Portable system for periodical verification of area monitors for neutrons

    International Nuclear Information System (INIS)

    Souza, Luciane de R.; Leite, Sandro Passos; Lopes, Ricardo Tadeu; Patrao, Karla C. de Souza; Fonseca, Evaldo S. da; Pereira, Walsan W.

    2009-01-01

    The Neutrons Laboratory develops a project viewing the construction of a portable test system for verification of functioning conditions of neutron area monitors. This device will allow to the users the verification of the calibration maintenance of his instruments at the use installations, avoiding the use of an inadequate equipment related to his answer to the neutron beam response

  14. A Point Kinetics Model for Estimating Neutron Multiplication of Bare Uranium Metal in Tagged Neutron Measurements

    Science.gov (United States)

    Tweardy, Matthew C.; McConchie, Seth; Hayward, Jason P.

    2017-07-01

    An extension of the point kinetics model is developed to describe the neutron multiplicity response of a bare uranium object under interrogation by an associated particle imaging deuterium-tritium (D-T) measurement system. This extended model is used to estimate the total neutron multiplication of the uranium. Both MCNPX-PoliMi simulations and data from active interrogation measurements of highly enriched and depleted uranium geometries are used to evaluate the potential of this method and to identify the sources of systematic error. The detection efficiency correction for measured coincidence response is identified as a large source of systematic error. If the detection process is not considered, results suggest that the method can estimate total multiplication to within 13% of the simulated value. Values for multiplicity constants in the point kinetics equations are sensitive to enrichment due to (n, xn) interactions by D-T neutrons and can introduce another significant source of systematic bias. This can theoretically be corrected if isotopic composition is known a priori. The spatial dependence of multiplication is also suspected of introducing further systematic bias for high multiplication uranium objects.

  15. Spectroscopy of high rate events during active interrogation

    International Nuclear Information System (INIS)

    Yang, H.; Wehe, D.K.; Bartels, D.M.

    2009-01-01

    Pulsed accelerators are being used for radiographic inspections in homeland security applications. Adding spectroscopic detection capability enables additional information to be extracted but challenges signal processing hardware. This work compares two approaches to cost-effective digital spectroscopy systems designed to handle these high rate scenarios. In the first system, the signal from a PMT is directly digitized and then deconvolved on a PC using standard techniques. Bypassing the preamplifier, this system can handle high count rates (>10 6 cps) from an LaCl 3 detector with no dead time and an energy resolution of 5% at 1.33 MeV. Spectra acquired from fission product gamma rays between interrogation pulses are shown. At higher rates, this approach is limited by the DAQ transfer rate to the PC. Instead, we tested a fast ADC (125 MSPS) and an FPGA that performed onboard, real-time digital signal processing (DSP). The energy spectrum is generated on the FPGA board during the measurement and transferred later. This system was tested in nuclear resonance fluorescence (NRF) experiments. Resonance peaks from NRF reactions are shown.

  16. Molecular techniques to interrogate and edit the Chlamydomonas nuclear genome.

    Science.gov (United States)

    Jinkerson, Robert E; Jonikas, Martin C

    2015-05-01

    The success of the green alga Chlamydomonas reinhardtii as a model organism is to a large extent due to the wide range of molecular techniques that are available for its characterization. Here, we review some of the techniques currently used to modify and interrogate the C. reinhardtii nuclear genome and explore several technologies under development. Nuclear mutants can be generated with ultraviolet (UV) light and chemical mutagens, or by insertional mutagenesis. Nuclear transformation methods include biolistic delivery, agitation with glass beads, and electroporation. Transforming DNA integrates into the genome at random sites, and multiple strategies exist for mapping insertion sites. A limited number of studies have demonstrated targeted modification of the nuclear genome by approaches such as zinc-finger nucleases and homologous recombination. RNA interference is widely used to knock down expression levels of nuclear genes. A wide assortment of transgenes has been successfully expressed in the Chlamydomonas nuclear genome, including transformation markers, fluorescent proteins, reporter genes, epitope tagged proteins, and even therapeutic proteins. Optimized expression constructs and strains help transgene expression. Emerging technologies such as the CRISPR/Cas9 system, high-throughput mutant identification, and a whole-genome knockout library are being developed for this organism. We discuss how these advances will propel future investigations. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

  17. Neutron scattering

    International Nuclear Information System (INIS)

    Furrer, A.

    1993-01-01

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

  18. Rattling nucleons: New developments in active interrogation of special nuclear material

    International Nuclear Information System (INIS)

    Runkle, Robert C.; Chichester, David L.; Thompson, Scott J.

    2012-01-01

    Active interrogation is a vigorous area of research and development due to its promise of offering detection and characterization capabilities of special nuclear material in environments where passive detection fails. The primary value added by active methods is the capability to penetrate shielding - special nuclear material itself, incidental materials, or intentional shielding - and advocates hope that active interrogation will provide a solution to the problem of detecting shielded uranium, which is at present the greatest obstacle to interdiction efforts. The technique also provides a unique benefit for quantifying nuclear material in high background-radiation environments, an area important for nuclear material safeguards and material accountancy. Progress has been made in the field of active interrogation on several fronts, most notably in the arenas of source development, systems integration, and the integration and exploitation of multiple fission and non-fission signatures. But penetration of interrogating radiation often comes at a cost, not only in terms of finance and dose but also in terms of induced backgrounds, system complexity, and extended measurement times (including set up and acquisition). These costs make the calculus for deciding to implement active interrogation more subtle than may be apparent. The purpose of this review is thus to examine existing interrogation methods, compare and contrast their attributes and limitations, and identify missions where active interrogation may hold the most promise.

  19. The Risks of Interrogation with the Help of an Interpreter in the Criminal Procedure

    Directory of Open Access Journals (Sweden)

    Hati Csilla

    2017-03-01

    Full Text Available During the criminal procedure, the process of verification includes the reconstruction of past events for the sake of establishing the statement of facts. When it comes to exploring the events in the past, great significance can be attributed to personal evidence. In order to prevent the influencing of the interrogated person, many provisions of guarantee had been established in the criminal procedure. In such an interrogatory situation, the most difficult practical problem is how to word the question so that the interrogation would aim at the exploration of the mind of the witness or accused, and at the helping of the recalling of the memories. During the criminal procedure however, interrogation with the assistance of an interpreter could also result in the communication of the statements of the accused or the witness about their perceptions and original knowledge with modified contents. Another significant factor at interpreter-assisted interrogations is to avoid the will of either the interrogator or the interpreter being projected on the interrogated person, as that would threaten with the witness, the accused, or the interrogated person giving a confession that is different form their original content of consciousness.

  20. Research possibilities with an intense neutron generator

    International Nuclear Information System (INIS)

    Bartholomew, G.A.

    1966-01-01

    As the title suggests this paper will depart somewhat from the general topic of this session and will be concerned more with applications of accelerators than with accelerators them elves. The particular application of interest at our laboratory concerns the use of a high current intermediate energy proton accelerator as the basis for a versatile intense neutron source. Chalk River's entry into the intermediate energy accelerator field with neutron production as the primary motivation is somewhat unusual. Although neutron production is also being explored by other laboratories interested in intermediate energy accelerators, e.g., Oak Ridge National Laboratory and Los Alamos Scientific Laboratory, it has not been the major motivation. Our initial motivation was in fact the production of thermal neutrons and this interest has remained foremost in our ING program. We are currently writing a proposal for this project. Our target is to have a proton beam in 1973. (author)

  1. Study on the mercury evolution in a laboratory multi specific aquatic system by using instrumental neutron activation analysis; Estudio de la evolucion del mercurio en un sistema acuatico de laboratorio multiespecifico utilizando analisis por activacion neutronica instrumental

    Energy Technology Data Exchange (ETDEWEB)

    Bubach, Debora; Guevara, Sergio Ribeiro; Arribere, Maria A. [Comision Nacional de Energia Atomica, San Carlos de Bariloche (Argentina). Centro Atomico Bariloche. Lab. de Analisis por Activacion Nautronica; Pechen de d`Angelo, Ana; Ferrari, Ana; Venturino, Andres [Universidad Nacional del Comahue, Neuquen (Argentina). Facultad de Ingenieria

    1999-11-01

    A preliminary study on the evolution of mercury in the organisms of a laboratory multi specific aquatic system was performed using Instrumental Neutron Activation Analysis (INAA). Some of the possible effects of mercury toxicity were monitored by analyzing early biochemical indicators. The system consisted of an aquarium with bed sediments, aquatic macrophytes (Myriophyllum sp.), bivalves (Diplodom sp.) and exotic fish, simulating a long term contamination situation of unknown causes, where the sediments are the contaminant reservoir. Samples of the abiotic components of the system were analyzed at the beginning of the experiment, and again when the organisms were sampled. Fish carcass, kidney and liver samples, bivalve hepatopancreas, and whole macrophytes were extracted ana analyzed for mercury and other elements by INAA at the beginning of the experiment, and after 48 and 96 hours. Since some crustal elements such as Sc and La were detected in the hepatopancreas and macrophyte samples, enrichment factors for mercury, with respect to the <63 {mu}m sediment fraction, were computed to discriminate the metabolized Hg content from that associated to the particulate. The hepatopancreas index, some indicators of oxidative stress ({gamma}-Glutamyl-cysteinyl-glycine content and lipid peroxidation) and brain acetilcolinesterasa were measured as early indicators of toxicity. (author) 23 refs., 4 tabs.

  2. Monte Carlo Simulation of an Active Neutron Counter for Fissile Material Accounting

    International Nuclear Information System (INIS)

    Ahn, Seong-Kyu; Lee, Tae-Hoon; Shin, Hee-Sung; Kim, Ho-Dong

    2008-01-01

    Passive neutron coincidence counters have been developed for the measurement of special nuclear materials by the Korea Atomic Energy Research Institute (KAERI). Those passive-mode counters are based on spontaneous fission from plutonium or curium in special nuclear materials. Therefore, uranium and other fissile materials can not be assayed by a passive mode because of its very low spontaneous fission yield. An active neutron counting method is one of the possible ways to measure fissile material, in which a neutron interrogation source is adapted for induced fission. Passive neutron counter could be used in an active-mode with some appropriate modifications and interrogation sources. Preliminary research had been performed for an active-mode operation of a DUPIC safeguards neutron counter, which was developed as a passive counter, using a cadmium shutter and total neutron counting. In this paper, MCNP simulation result for active neutron coincidence counting has been described and discussed. The result could be applied to determine the possibility and necessary modification for an active mode operation of a developed neutron counter

  3. Radioisotopes produced by neutron irradiation of food.

    Science.gov (United States)

    Albright, S; Seviour, R

    2016-04-01

    The use of neutrons for cargo interrogation has the potential to drastically improve threat detection. Previous research has focussed on the production of (24)Na, based on the isotopes produced in pharmaceuticals and medical devices. For both the total activity and the ingestion dose we show that a variety of isotopes contribute and that (24)Na is only dominant under certain conditions. The composition of the foods has a strong influence on the resulting activity and ingestion dose suggesting that the pharmaceuticals and medical devices considered initially are not a viable analogue for foodstuffs. There is an energy dependence to the isotopes produced due to the cross-sections of different reactions varying with neutron energy. We show that this results in different isotopes dominating the ingestion dose at different energies, which has not been considered in the previous literature. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Neutron induced gamma spectrometry for on-line compositional analysis in coal conversion and fluidized-bed combustion plants

    International Nuclear Information System (INIS)

    Herzenberg, C.L.; O'Fallon, N.M.; Yarlagadda, B.S.; Doering, R.W.; Cohn, C.E.; Porges, K.G.; Duffey, D.

    1977-01-01

    Nuclear techniques involving relatively penetrating radiation may offer the possibility of non-invasive, continuous on-line instrumental monitoring which is representative of the full process stream. Prompt gamma rays following neutron capture are particularly attractive because the penetrating power of the neutrons and the, typically several MeV, capture gammas makes possible interrogation of material within a pipe. We are evaluating neutron capture gamma techniques for this application, both for elemental composition monitoring and for mass-flow measurement purposes, and this paper will present some recent work on composition analysis by neutron induced gamma spectrometry

  5. Nuclear physics and fundamental physics explored with neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, Yasuhiro [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

    1995-08-01

    This Japan Hadron Project workshop was held on May 19 and 20, 1995, at Institute for Nuclear Study, University of Tokyo. The Neutron Arena planned in JHP is the facility that uses the spallation neutrons generated by high energy protons, and its utilization is planned in wide research fields. On the other hand, in the neutron scattering facility in the booster utilization facility of National Laboratory for High Energy Physics, the researches of verifying parity nonconservation and time reversal break have been carried out so far. It is necessary to accurately measure the reaction cross section of neutrons in low energy region. This workshop was planned for examining the Neutron Arena by the researchers related to elementary particles and atomic nuclei. In the workshop, lectures were given on the break of the reversal symmetry of time and space in neutron-atomic nucleus reaction, neutrino physics, neutron capture and celestial nuclear physics, neutron-induced nucleosynthesis, development and utilization of very cold neutron interferometer using multi-layer film mirror, research on gravity using neutron interferometer, electric polarizability of neutrons, {beta} decay of neutrons, possibility of research on basic symmetry problem at E-arena, {beta} decay in storage ring, neutron electric dipole moment using ultracold neutrons, magnetic confinement and control of ultracold neutrons, and outline of JHP neutron source. (K.I.)

  6. Nuclear physics and fundamental physics explored with neutrons

    International Nuclear Information System (INIS)

    Masuda, Yasuhiro

    1995-08-01

    This Japan Hadron Project workshop was held on May 19 and 20, 1995, at Institute for Nuclear Study, University of Tokyo. The Neutron Arena planned in JHP is the facility that uses the spallation neutrons generated by high energy protons, and its utilization is planned in wide research fields. On the other hand, in the neutron scattering facility in the booster utilization facility of National Laboratory for High Energy Physics, the researches of verifying parity nonconservation and time reversal break have been carried out so far. It is necessary to accurately measure the reaction cross section of neutrons in low energy region. This workshop was planned for examining the Neutron Arena by the researchers related to elementary particles and atomic nuclei. In the workshop, lectures were given on the break of the reversal symmetry of time and space in neutron-atomic nucleus reaction, neutrino physics, neutron capture and celestial nuclear physics, neutron-induced nucleosynthesis, development and utilization of very cold neutron interferometer using multi-layer film mirror, research on gravity using neutron interferometer, electric polarizability of neutrons, β decay of neutrons, possibility of research on basic symmetry problem at E-arena, β decay in storage ring, neutron electric dipole moment using ultracold neutrons, magnetic confinement and control of ultracold neutrons, and outline of JHP neutron source. (K.I.)

  7. Neutron Scattering

    International Nuclear Information System (INIS)

    Fayer, Michael J.; Gee, Glendon W.

    2005-01-01

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

  8. A Fibre Bragg Grating Interrogation Technique Based on High Birefringence Fibre Loop Mirror and WDM

    Directory of Open Access Journals (Sweden)

    Zhang Xun

    2016-01-01

    Full Text Available In this paper, a fibre Bragg grating (FBG interrogation technique based on high Birefringence fibre loop mirror (Hi-Bi FLM and wavelength division multiplexer (WDM is proposed and demonstrated. The approximate linear edge of the transmittance of the Hi-Bi FLM, which is a sinusoidal function of wavelength, is used to interrogate the sensing FBGs and WDMs is used to realize wavelength discrimination .Suitable for both static and dynamic sensing, this interrogation method has the advantages of all fibre design and high stability.

  9. FOREWORD: Neutron metrology Neutron metrology

    Science.gov (United States)

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

    2011-12-01

    The International Committee for Weights and Measures (CIPM) has consultative committees covering various areas of metrology. The Consultative Committee for Ionizing Radiation (CCRI) differs from the others in having three sections: Section (I) deals with radiation dosimetry, Section (II) with radionuclide metrology and Section (III) with neutron metrology. In 2003 a proposal was made to publish special issues of Metrologia covering the work of the three Sections. Section (II) was the first to complete their task, and their special issue was published in 2007, volume 44(4). This was followed in 2009 by the special issue on radiation dosimetry, volume 46(2). The present issue, volume 48(6), completes the trilogy and attempts to explain neutron metrology, the youngest of the three disciplines, the neutron only having been discovered in 1932, to a wider audience and to highlight the relevance and importance of this field. When originally approached with the idea of this special issue, Section (III) immediately saw the value of a publication specifically on neutron metrology. It is a topic area where papers tend to be scattered throughout the literature in journals covering, for example, nuclear instrumentation, radiation protection or radiation measurements in general. Review articles tend to be few. People new to the field often ask for an introduction to the various topics. There are some excellent older textbooks, but these are now becoming obsolete. More experienced workers in specific areas of neutron metrology can find it difficult to know the latest position in related areas. The papers in this issue attempt, without presenting a purely historical outline, to describe the field in a sufficiently logical way to provide the novice with a clear introduction, while being sufficiently up-to-date to provide the more experienced reader with the latest scientific developments in the different topic areas. Neutron radiation fields obviously occur throughout the nuclear

  10. Materials for spallation neutron sources

    International Nuclear Information System (INIS)

    Sommer, W.F.; Daemen, L.L.

    1996-03-01

    The Workshop on Materials for Spallation Neutron Sources at the Los Alamos Neutron Science Center, February 6 to 10, 1995, gathered scientists from Department of Energy national laboratories, other federal institutions, universities, and industry to discuss areas in which work is needed, successful designs and use of materials, and opportunities for further studies. During the first day of the workshop, speakers presented overviews of current spallation neutron sources. During the next 3 days, seven panels allowed speakers to present information on a variety of topics ranging from experimental and theoretical considerations on radiation damage to materials safety issues. An attempt was made to identify specific problems that require attention within the context of spallation neutron sources. This proceedings is a collection of summaries from the overview sessions and the panel presentations

  11. The synchronous active neutron detection system for spent fuel assay

    International Nuclear Information System (INIS)

    Pickrell, M.M.; Kendall, P.K.

    1994-01-01

    The authors have begun to develop a novel technique for active neutron assay of fissile material in spent nuclear fuel. This approach will exploit the unique operating features of a 14-MeV neutron generator developed by Schlumberger. This generator and a novel detection system will be applied to the direct measurement of the fissile material content in spent fuel in place of the indirect measures used at present. The technique they are investigating is termed synchronous active neutron detection (SAND). It closely follows a method that has been used routinely in other branches of physics to detect very small signals in the presence of large backgrounds. Synchronous detection instruments are widely available commercially and are termed open-quotes lock-inclose quotes amplifiers. The authors have implemented a digital lock-in amplifier in conjunction with the Schlumberger neutron generator to explore the possibility of synchronous detection with active neutrons. This approach is possible because the Schlumberger system can operate at up to a 50% duty factor, in effect, a square wave of neutron yield. The results to date are preliminary but quite promising. The system is capable of resolving the fissile material contained in a small fraction of the fuel rods in a cold fuel assembly. It also appears to be quite resilient to background neutron interference. The interrogating neutrons appear to be nonthermal and penetrating. Although a significant amount of work remains to fully explore the relevant physics and optimize the instrument design, the underlying concept appears sound

  12. Implementation of the active neutron Coincidence Collar for the verification of unirradiated PWR and BWR fuel assemblies

    International Nuclear Information System (INIS)

    Menlove, H.O.; Keddar, A.

    1982-01-01

    An active neutron interrogation technique has been developed for the measurement of the 235 U content in fresh fuel assemblies. The method employs an AmLi neutron source to induce fission reactions in the fuel assembly and coincidence counting of the resulting fission reaction neutrons. When no interrogation source is present, the passive neutron coincidence rate gives a measure of the 238 U by the spontaneous fission reactions. The system can be applied to the fissile content determination in fresh fuel assemblies for accountability, criticality control, and safeguards purposes. Field tests have been performed by International Atomic Energy Agency (IAEA) staff using the Coincidence Collar to verify the 235 U content in light-water-reactor fuel assemblies. The results gave an accuracy of 1 to 2% in the active mode ( 235 U) and 2 to 3% in the passive mode ( 238 U) under field conditions

  13. 14 MeV neutrons physics and applications

    CERN Document Server

    Valkovic, Vladivoj

    2015-01-01

    Despite the often difficult and time-consuming effort of performing experiments with fast (14 MeV) neutrons, these neutrons can offer special insight into nucleus and other materials because of the absence of charge. 14 MeV Neutrons: Physics and Applications explores fast neutrons in basic science and applications to problems in medicine, the environment, and security.Drawing on his more than 50 years of experience working with 14 MeV neutrons, the author focuses on:Sources of 14 MeV neutrons, including laboratory size accelerators, small and sealed tube generators, well logging sealed tube ac

  14. PLANS FOR A NEUTRON EDM EXPERIMENT AT SNS

    Energy Technology Data Exchange (ETDEWEB)

    ITO, TAKEYASU [Los Alamos National Laboratory

    2007-01-31

    The electric dipole moment of the neutron, leptons, and atoms provide a unique window to Physics Beyond the Standard Model. They are currently developing a new neutron EDM experiment (the nEDM Experiment). This experiment, which will be run at the 8.9 {angstrom} Neutron Line at the Fundamental Neutron Physics Beamline (FNPB) at the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory, will search for the neutron EDM with a sensitivity two orders of magnitude higher than the present limit. In this paper, the motivation for the experiment, the experimental method, and the present status of the experiment are discussed.

  15. Neutron science opportunities at pulsed spallation neutron sources

    International Nuclear Information System (INIS)

    Carpenter, J.M.

    1996-01-01

    Using the IPNS Upgrade plan developed at Argonne National Laboratory as a worked example of the design of a pulsed spallation neutron source, this paper explores some of the scientific applications of an advanced facility for materials science studies and the instrumentation for those purposes

  16. Neutron scattering in ORNL's calibration facility

    International Nuclear Information System (INIS)

    Liu, J.C.; Sims, C.S.; Casson, W.H.; Murakami, H.

    1991-01-01

    Room scattering corrections for several common neutron detectors in a new neutron calibration facility at the Oak Ridge National Laboratory were measured. Results for three radioisotopic sources in ground scattering and enclosed room scattering situations are compared with two model calculations, and the agreement is good. A personnel neutron spectrometer was used to examine further the spectral variation inside the enclosed neutron room. Scattered fluence and scattered dose equivalent results from the spectral measurements indicate that the scattering predictions using models hold only for small-source-to-detector distances. Additional observations from this study are also presented. (author)

  17. Neutron matter, neutron pairing, and neutron drops based on chiral effective field theory interactions

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, Thomas

    2016-10-19

    The physics of neutron-rich systems is of great interest in nuclear and astrophysics. Precise knowledge of the properties of neutron-rich nuclei is crucial for understanding the synthesis of heavy elements. Infinite neutron matter determines properties of neutron stars, a final stage of heavy stars after a core-collapse supernova. It also provides a unique theoretical laboratory for nuclear forces. Strong interactions are determined by quantum chromodynamics (QCD). However, QCD is non-perturbative at low energies and one presently cannot directly calculate nuclear forces from it. Chiral effective field theory circumvents these problems and connects the symmetries of QCD to nuclear interactions. It naturally and systematically includes many-nucleon forces and gives access to uncertainty estimates. We use chiral interactions throughout all calculation in this thesis. Neutron stars are very extreme objects. The densities in their interior greatly exceed those in nuclei. The exact composition and properties of neutron stars is still unclear but they consist mainly of neutrons. One can explore neutron stars theoretically with calculations of neutron matter. In the inner core of neutron stars exist very high densities and thus maybe exotic phases of matter. To investigate whether there exists a phase transition to such phases even at moderate densities we study the chiral condensate in neutron matter, the order parameter of chiral symmetry breaking, and find no evidence for a phase transition at nuclear densities. We also calculate the more extreme system of spin-polarised neutron matter. With this we address the question whether there exists such a polarised phase in neutron stars and also provide a benchmark system for lattice QCD. We find spin-polarised neutron matter to be an almost non-interacting Fermi gas. To understand the cooling of neutron stars neutron pairing is of great importance. Due to the high densities especially triplet pairing is of interest. We

  18. Conceptual design of collective ion acceleration for pulsed neutron source

    International Nuclear Information System (INIS)

    Deng Renpei; Yang Maorong

    1998-12-01

    Theoretical and experimental analysis of the collective acceleration of ions (CIA) by an electron beam to obtain pulse neutron source in an evacuated drift tube are presented. The progress and development in the world laboratories are given too. According to the requirement, the plan of neutron source produced by CIA is investigated, with Marx generator, water dielectric Blumlein line, low impedance diode and drift tube. These devices' main parameters for neutron intensity of 10 9 neutrons/pulse are given

  19. Interrogating the Practice of Image Making in a Budding Context

    Directory of Open Access Journals (Sweden)

    Ashraf M. Salama

    2014-11-01

    Full Text Available Image making is a continuous worldwide practice of architects and designers whose concern is to create meaningful environments. Such a practice results in expressions that either reflect the regional context or mirror the wider global culture. This paper aims at interrogating image making practices in the city of Doha, which has experienced rapid urban transformations, associated with building large scale work and learning environments, mixed use developments, and cultural and sport facilities. Contextualizing current debate on Doha’s architecture and urbanism, a critical analysis of geo-cultural politics and on the notion of the ‘scapes of flows’ is undertaken. Based on contextual, critical, and perceptual approaches image-making practices in the city were discerned.  Different types of efforts were categorized and critically analyzed underlying the contextual and critical approaches. The analysis reveals that efforts range from utilizing symbolism in contemporary imaging, to manifesting tradition-modernity in search for image identity, to addressing the global condition towards image making. The perceptual approach established empirical evidence by investigating users’ reactions to three notable office buildings that their design attempts to evoke a unique image.  This was supported by statements made by CEOs of architectural firms and development companies that reflected a promise towards image making in the architecture of Doha. A concluding critique is introduced to elucidate that while there are incessant attempts at image making, the practice of ‘cutting and pasting’ dominates in the absence of critical consciousness. Such a critique calls for avoiding ‘case by case decision making’ the urban governance in the city still adopts while engaging effective place making strategies.

  20. Interrogating the topological robustness of gene regulatory circuits by randomization.

    Directory of Open Access Journals (Sweden)

    Bin Huang

    2017-03-01

    Full Text Available One of the most important roles of cells is performing their cellular tasks properly for survival. Cells usually achieve robust functionality, for example, cell-fate decision-making and signal transduction, through multiple layers of regulation involving many genes. Despite the combinatorial complexity of gene regulation, its quantitative behavior has been typically studied on the basis of experimentally verified core gene regulatory circuitry, composed of a small set of important elements. It is still unclear how such a core circuit operates in the presence of many other regulatory molecules and in a crowded and noisy cellular environment. Here we report a new computational method, named random circuit perturbation (RACIPE, for interrogating the robust dynamical behavior of a gene regulatory circuit even without accurate measurements of circuit kinetic parameters. RACIPE generates an ensemble of random kinetic models corresponding to a fixed circuit topology, and utilizes statistical tools to identify generic properties of the circuit. By applying RACIPE to simple toggle-switch-like motifs, we observed that the stable states of all models converge to experimentally observed gene state clusters even when the parameters are strongly perturbed. RACIPE was further applied to a proposed 22-gene network of the Epithelial-to-Mesenchymal Transition (EMT, from which we identified four experimentally observed gene states, including the states that are associated with two different types of hybrid Epithelial/Mesenchymal phenotypes. Our results suggest that dynamics of a gene circuit is mainly determined by its topology, not by detailed circuit parameters. Our work provides a theoretical foundation for circuit-based systems biology modeling. We anticipate RACIPE to be a powerful tool to predict and decode circuit design principles in an unbiased manner, and to quantitatively evaluate the robustness and heterogeneity of gene expression.

  1. Massively Parallel Interrogation of Aptamer Sequence, Structure and Function

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, N O; Tok, J B; Tarasow, T M

    2008-02-08

    Optimization of high affinity reagents is a significant bottleneck in medicine and the life sciences. The ability to synthetically create thousands of permutations of a lead high-affinity reagent and survey the properties of individual permutations in parallel could potentially relieve this bottleneck. Aptamers are single stranded oligonucleotides affinity reagents isolated by in vitro selection processes and as a class have been shown to bind a wide variety of target molecules. Methodology/Principal Findings. High density DNA microarray technology was used to synthesize, in situ, arrays of approximately 3,900 aptamer sequence permutations in triplicate. These sequences were interrogated on-chip for their ability to bind the fluorescently-labeled cognate target, immunoglobulin E, resulting in the parallel execution of thousands of experiments. Fluorescence intensity at each array feature was well resolved and shown to be a function of the sequence present. The data demonstrated high intra- and interchip correlation between the same features as well as among the sequence triplicates within a single array. Consistent with aptamer mediated IgE binding, fluorescence intensity correlated strongly with specific aptamer sequences and the concentration of IgE applied to the array. The massively parallel sequence-function analyses provided by this approach confirmed the importance of a consensus sequence found in all 21 of the original IgE aptamer sequences and support a common stem:loop structure as being the secondary structure underlying IgE binding. The microarray application, data and results presented illustrate an efficient, high information content approach to optimizing aptamer function. It also provides a foundation from which to better understand and manipulate this important class of high affinity biomolecules.

  2. Toward multi-area distributed network of implanted neural interrogators

    Science.gov (United States)

    Powell, Marc P.; Hou, Xiaoxiao; Galligan, Craig; Ashe, Jeffrey; Borton, David A.

    2017-08-01

    As we aim to improve our understanding of the brain, it is critical that researchers have simultaneous multi-area, large-scale access to the brain. Information processing in the brain occurs through close and distant coupling of functional sub-domains, as opposed to within isolated single neurons. However, commercially available neural interfaces capable of sensing electrophysiology of single neurons, currently allow access to only a small, mm3 volume of cortical cells, are not scalable to recording from orders of magnitude more neurons, and leverage bulky, skull mounted hardware and cabling sensitive to relative movements of the skull and brain. In this work, we propose a system capable of recording from many individual distributed neural interrogator nodes, untethered from any external electronics. Using an array of epidural inductive coils to wirelessly power the implanted electronics, the system is intended to be agnostic to the surgical placement of any individual node. Here, we demonstrate the ability to transmit nearly 15mW of power with greater than 50% power transfer efficiency, benchtop testing of individual subcircuit system components showing successful digitization of neural signals, and wireless transmission currently supporting a data rate of 3.84Mbps. We leverage a software defined radio based RF receiver to demodulate the data which can be stored in memory for later retrieval. Finally, we introduce a packaging technology capable of isolating active electronics from the surrounding tissue while providing capability for electrical feed-through assemblies for external neural interfacing. We expect, based on the presented preliminary findings, that the system can be integrated into a platform technology for the study of the intricate interactions between cortical domains.

  3. Promotion COPERNIC Energy and Society the interrogations on the world demand evolution; Promotion COPERNIC Energie et Societe les interrogations sur l'evolution de la demande mondiale

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-12-15

    In the framework of a prospective reflexion emergence on the energy demand, this document presents an analysis of the prospective approach and of recent studies: challenges, interests, limits, validity of the models and hypothesis and results relevance. With this analysis, the authors aim to identify the main interrogations bond to the world energy demand evolution. They then analyse these interrogations in the framework of a sectoral approach (agriculture, industry, transports, residential) in order to detail the demand and to forecast the evolution. Facing the consumption attitudes, they also suggest some new action avenues to favor a sustainable growth. (A.L.B.)

  4. A multiplex bead-based suspension array assay for interrogation of phylogenetically informative single nucleotide polymorphisms for Bacillus anthracis

    DEFF Research Database (Denmark)

    Thierry, Simon; Hamidjaja, Raditijo A.; Girault, Guillaume

    2013-01-01

    Single nucleotide polymorphisms (SNPs) are abundant in genomes of all species and represent informative DNA markers extensively used to analyze phylogenetic relationships between strains. Medium to high throughput, open methodologies able to test many SNPs in a minimum time are therefore in great...... been modified and adapted for simultaneous interrogation of 13 biallelic canonical SNPs in a 13-plex assay. Changes made to the originally published method include the design of allele-specific dual-priming-oligonucleotides (DPOs) as competing detection probes (MOLigo probes) and use of asymmetric PCR...... laboratories. While cost-effective compared to other singleplex methods, the present MOL-PCR method offers a high degree of flexibility and scalability. It can easily accommodate newly identified SNPs to increase resolving power to the canSNP typing of B. anthracis....

  5. The History of MIS-Y: U.S. Strategic Interrogation During World War II

    National Research Council Canada - National Science Library

    Kleinman, Steven M

    2002-01-01

    As World War II unfolded, the strategic interrogation programs established by the British, German, and American forces evolved into robust collection entities that proved to be a unique source of critical intelligence...

  6. Microwave-Interrogated Embedded Sensor System for Nondestructive Evaluation (NDE) of Complex Structures, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. and Lawrence Livermore National Lab propose to develop a new class of microwave-interrogated embedded sensors for nondestructive evaluation...

  7. The phase interrogation method for optical fiber sensor by analyzing the fork interference pattern

    Science.gov (United States)

    Lv, Riqing; Qiu, Liqiang; Hu, Haifeng; Meng, Lu; Zhang, Yong

    2018-02-01

    The phase interrogation method for optical fiber sensor is proposed based on the fork interference pattern between the orbital angular momentum beam and plane wave. The variation of interference pattern with phase difference between the two light beams is investigated to realize the phase interrogation. By employing principal component analysis method, the features of the interference pattern can be extracted. Moreover, the experimental system is designed to verify the theoretical analysis, as well as feasibility of phase interrogation. In this work, the Mach-Zehnder interferometer was employed to convert the strain applied on sensing fiber to the phase difference between the reference and measuring paths. This interrogation method is also applicable for the measurements of other physical parameters, which can produce the phase delay in optical fiber. The performance of the system can be further improved by employing highlysensitive materials and fiber structures.

  8. Ultraviolet Raman Spectral Signatures in Support of Lisa (Laser Interrogation of Surface Agents)

    National Research Council Canada - National Science Library

    Sedlacek, III, Arthur J; Finfrock, Charles C; Christesen, Steve; Chyba, Tom; Higdon, Scott

    2003-01-01

    ... (Laser Interrogation of Surface Agents). This engineering, testing and evaluation effort uses a novel mini-Raman lidar technique for on-the-move, short-range, non-contact detection and identification of chemical agents on the battlefield...

  9. Adaptive image interrogation for PIV : Application to compressible flows and interfaces

    NARCIS (Netherlands)

    Theunissen, R.

    2010-01-01

    As an experimental tool, Particle Image Velocimetry has quickly superseded traditional point-wise measurements. The inherent image processing has become standardized though the performances are strongly dependent on user experience. Moreover, the arduously selected image interrogation parameters are

  10. Neutron transfer reactions: Surrogates for neutron capture for basic and applied nuclear science

    Energy Technology Data Exchange (ETDEWEB)

    Cizewski, J. A. [Rutgers University; Jones, K. L. [University of Tennessee; Kozub, R. L. [Tennessee Technological University; Pain, Steven D [ORNL; Peters, W. A. [Rutgers University; Adekola, Aderemi S [ORNL; Allen, J. [Rutgers University; Bardayan, Daniel W [ORNL; Becker, J. [Lawrence Livermore National Laboratory (LLNL); Blackmon, Jeff C [ORNL; Chae, K. Y. [University of Tennessee; Chipps, K. [Colorado School of Mines, Golden; Erikson, Luke [Colorado School of Mines, Golden; Gaddis, A. L. [Furman University; Harlin, Christopher W [ORNL; Hatarik, Robert [Rutgers University; Howard, Joshua A [ORNL; Jandel, M. [Los Alamos National Laboratory (LANL); Johnson, Micah [ORNL; Kapler, R. [University of Tennessee; Krolas, W. [University of Warsaw; Liang, J Felix [ORNL; Livesay, Jake [ORNL; Ma, Zhanwen [ORNL; Matei, Catalin [Oak Ridge Associated Universities (ORAU); Matthews, C. [Rutgers University; Moazen, Brian [University of Tennessee; Nesaraja, Caroline D [ORNL; O' Malley, Patrick [Rutgers University; Patterson, N. P. [University of Surrey, UK; Paulauskas, Stanley [University of Tennessee; Pelham, T. [University of Surrey, UK; Pittman, S. T. [University of Tennessee, Knoxville (UTK); Radford, David C [ORNL; Rogers, J. [Tennessee Technological University; Schmitt, Kyle [University of Tennessee; Shapira, Dan [ORNL; ShrinerJr., J. F. [Tennessee Technological University; Sissom, D. J. [Tennessee Technological University; Smith, Michael Scott [ORNL; Swan, T. P. [University of Surrey, UK; Thomas, J. S. [Rutgers University; Vieira, D. J. [Los Alamos National Laboratory (LANL); Wilhelmy, J. B. [Los Alamos National Laboratory (LANL); Wilson, Gemma L [ORNL

    2009-04-01

    Neutron capture reactions on unstable nuclei are important for both basic and applied nuclear science. A program has been developed at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory to study single-neutron transfer (d,p) reactions with rare isotope beams to provide information on neutron-induced reactions on unstable nuclei. Results from (d,p) studies on {sup 130,132}Sn, {sup 134}Te and {sup 75}As are discussed.

  11. 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

  12. 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

  13. Hardware embedded fiber sensor interrogation system using intensive digital signal processing

    OpenAIRE

    Wang, Yujuan; Negri, Lucas H.; Kalinowski, Hypolito J.; Mattos, Daniel S.; Negri, Gabriel H.; Paterno, Aleksander S.

    2014-01-01

    The description of an interrogation system for fiber Bragg grating sensors is reported. The full implementation in hardware of the required signal processing is proposed and made publicly available. The hardware description is implemented in a field programmable gate array (FPGA) development kit and the processing units allow one to control an optoelectronic interrogation system that uses the tunable filter method. Since the signal that drives the used Fabry-Perot filter (FFP) using a digital...

  14. Are the American Psychological Association?s Detainee Interrogation Policies Ethical and Effective?

    OpenAIRE

    Pope, Kenneth S.

    2011-01-01

    After 9?11, the United States began interrogating detainees at settings such as Abu Ghraib, Bagram, and Guantanamo. The American Psychological Association (APA) supported psychologists? involvement in interrogations, adopted formal policies, and made an array of public assurances. This article?s purpose is to highlight key APA decisions, policies, procedures, documents, and public statements in urgent need of rethinking and to suggest questions that may be useful in a serious assessment, such...

  15. Intelligence, previous convictions and interrogative suggestibility: a path analysis of alleged false-confession cases.

    Science.gov (United States)

    Sharrock, R; Gudjonsson, G H

    1993-05-01

    The main purpose of this study was to investigate the relationship between interrogative suggestibility and previous convictions among 108 defendants in criminal trials, using a path analysis technique. It was hypothesized that previous convictions, which may provide defendants with interrogative experiences, would correlate negatively with 'shift' as measured by the Gudjonsson Suggestibility Scale (Gudjonsson, 1984a), after intelligence and memory had been controlled for. The hypothesis was partially confirmed and the theoretical and practical implications of the findings are discussed.

  16. Silicon Photomultipliers for Compact Neutron Scatter Cameras

    Science.gov (United States)

    Ruch, Marc L.

    The ability to locate and identify special nuclear material (SNM) is critical for treaty verification and emergency response applications. SNM is used as the nuclear explosive in a nuclear weapon. This material emits neutrons, either spontaneously or when interrogated. The ability to form an image of the neutron source can be used for characterization and/or to confirm that the item is a weapon by determining whether its shape is consistent with that of a weapon. Additionally, treaty verification and emergency response applications might not be conducive to non-portable instruments. In future weapons treaties, for example, it is unlikely that host countries will make great efforts to facilitate large, bulky, and/or fragile inspection equipment. Furthermore, inspectors and especially emergency responders may need to access locations not easily approachable by vehicles. Therefore, there is a considerable need for a compact, human-portable neutron imaging system. Of the currently available neutron imaging technologies, only neutron scatter cameras (NSCs) can be made truly compact because aperture-based imagers, and time-encoded imagers, rely on large amounts of materials to modulate the neutron signal. NSCs, in contrast, can be made very small because most of the volume of the imager can be filled with active detector material. Also, unlike other neutron imaging technologies, NSCs have the inherent ability to act as neutron spectrometers which gives them an additional means of identifying a neutron source. Until recently, NSCs have relied on photomultiplier tubes (PMT) readouts, which are bulky and fragile, require high voltage, and are very sensitive to magnetic fields. Silicon photomultipliers (SiPMs) do not suffer from these drawbacks and are comparable to PMTs in many respects such as gain, and cost with better time resolution. Historically, SiPMs have been too noisy for these applications; however, recent advancements have greatly reduced this issue and they have

  17. Evolution of Neutron Stars and Observational Constraints

    Directory of Open Access Journals (Sweden)

    Lattimer J.

    2010-10-01

    Full Text Available The structure and evolution of neutron stars is discussed with a view towards constraining the properties of high density matter through observations. The structure of neutron stars is illuminated through the use of several analytical solutions of Einstein’s equations which, together with the maximally compact equation of state, establish extreme limits for neutron stars and approximations for binding energies, moments of inertia and crustal properties as a function of compactness. The role of the nuclear symmetry energy is highlighted and constraints from laboratory experiments such as nuclear masses and heavy ion collisions are presented. Observed neutron star masses and radius limits from several techniques, such as thermal emissions, X-ray bursts, gammaray flares, pulsar spins and glitches, spin-orbit coupling in binary pulsars, and neutron star cooling, are discussed. The lectures conclude with a discusson of proto-neutron stars and their neutrino signatures.

  18. ANL--LASL workshop on advanced neutron detection systems

    International Nuclear Information System (INIS)

    Kitchens, T.A.

    1979-06-01

    A two-day workshop on advanced neutron detectors and associated electronics was held in Los Alamos on April 5--6, 1979, as a part of the Argonne National Laboratory--Los Alamos Scientific Laboratory Coordination on neutron scattering instrumentation. This report contains an account of the information presented and conclusions drawn at the workshop

  19. Aerial Neutron Detection: Neutron Signatures for Nonproliferation and Emergency Response Applications

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, Richard J.; Stampahar, Thomas G.; Smith, Ethan X.; Mukhopadhyay, Sanjoy; Wolff, Ronald S.; Rourke, Timothy J.; LeDonne, Jeffrey P.; Avaro, Emanuele; Butler, D. Andre; Borders, Kevin L.; Stampahar, Jezabel; Schuck, William H.; Selfridge, Thomas L.; McKissack, Thomas M.; Duncan, William W.; Hendricks, Thane J.

    2012-10-17

    From 2007 to the present, the Remote Sensing Laboratory has been conducting a series of studies designed to expand our fundamental understanding of aerial neutron detection with the goal of designing an enhanced sensitivity detection system for long range neutron detection. Over 35 hours of aerial measurements in a helicopter were conducted for a variety of neutron emitters such as neutron point sources, a commercial nuclear power reactor, nuclear reactor spent fuel in dry cask storage, depleted uranium hexafluoride and depleted uranium metal. The goals of the project were to increase the detection sensitivity of our instruments such that a 5.4 × 104 neutron/second source could be detected at 100 feet above ground level at a speed of 70 knots and to enhance the long-range detection sensitivity for larger neutron sources, i.e., detection ranges above 1000 feet. In order to increase the sensitivity of aerial neutron detection instruments, it is important to understand the dynamics of the neutron background as a function of altitude. For aerial neutron detection, studies have shown that the neutron background primarily originates from above the aircraft, being produced in the upper atmosphere by galactic cosmic-ray interactions with air molecules. These interactions produce energetic neutrons and charged particles that cascade to the earth’s surface, producing additional neutrons in secondary collisions. Hence, the neutron background increases as a function of altitude which is an impediment to long-range neutron detection. In order to increase the sensitivity for long range detection, it is necessary to maintain a low neutron background as a function of altitude. Initial investigations show the variation in the neutron background can be decreased with the application of a cosmic-ray shield. The results of the studies along with a representative data set are presented.

  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. 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)

  2. CVD polycrystalline diamond. A novel neutron detector and applications

    International Nuclear Information System (INIS)

    Mongkolnavin, R.

    1998-07-01

    Chemical Vapour Deposition (CVD) Polycrystalline Diamond film has been investigated as a low noise sensor for beta particles, gammas and neutrons using High Energy Physics technologies. Its advantages and disadvantages have been explored in comparison with other particle detectors such as silicon detector and other plastic scintillators. The performance and characteristic of the diamond detector have been fully studied and discussed. These studies will lead to a better understanding of how CVD diamonds perform as a detector and how to improve their performance under various conditions. A CVD diamond detector model has been proposed which is an attempt to explain the behaviour of such an extreme detector material. A novel neutron detector is introduced as a result of these studies. A good thermal and fast neutron detector can be fabricated with CVD diamond with new topologies. This detector will perform well without degradation in a high neutron radiation environment, as diamond is known to be radiation-hard. It also offers better neutrons and gammas discrimination for high gamma background applications compared to other semiconductor detectors. A full simulation of the detector has also been done using GEANT, a Monte Carlo simulation program for particle detectors. Simulation results show that CVD diamond detectors with this novel topology can detect neutrons with great directionality. Experimental work has been done on this detector in a nuclear reactor environment and accelerator source. A novel neutron source which offers a fast pulse high-energy neutrons has also been studied. With this detector, applications in neutron spectrometry for low-Z material have been pursued with various neutron detection techniques. One of these is a low-Z material identification system. The system has been designed and simulated for contraband luggage interrogation using the detector and the novel neutron source. (author)

  3. Neutronics of pulsed spallation neutron sources

    CERN Document Server

    Watanabe, N

    2003-01-01

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

  4. 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)

  5. Radiation Generation from Ultra Intense Laser Plasma Interactions with Solid Density Plasmas for Active Interrogation of Nuclear Materials

    Science.gov (United States)

    Zulick, Calvin Andrew

    The development of short pulse high power lasers has led to interest in laser based particle accelerators. Laser produced plasmas have been shown to support quasi-static TeV/m acceleration gradients which are more than four orders of magnitude stronger than conventional accelerators. These high gradients have the potential to allow compact particle accelerators for active interrogation of nuclear material. In order to better understand this application, several experiments have been conducted at the HERCULES and Lambda Cubed lasers as the Center for Ultrafast Optical Science at the University of Michigan. Electron acceleration and bremsstrahlung generation were studied on the Lambda Cubed laser. The scaling of the intensity, angular, and material dependence of bremsstrahlung radiation from an intense (I > 10 18 W/cm2 ) laser-solid interaction has been characterized at energies between 100 keV and 1 MeV. These were the first high resolution (lambda / d lambda > 100) measurements of bremsstrahlung photons from a relativistic laser plasma interaction. The electron populations and bremsstrahlung temperatures were modeled in the particle-in-cell code OSIRIS and the Monte Carlo code MCNPX and were in good agreement with the experimental results. Proton acceleration was studied on the HERCULES laser. The effect of three dimensional perturbations of electron sheaths on proton acceleration was investigated through the use of foil, grid, and wire targets. Hot electron density, as measured with an imaging Cu Kalpha crystal, increased as the target surface area was reduced and was correlated to an increase in the temperature of the accelerated proton beam. Additionally, experiments at the HERCULES laser facility have produced directional neutron beams with energies up to 16.8 (+/-0.3) MeV using (d,n) and (p,n) reactions. Efficient (d,n) reactions required the selective acceleration of deuterons through the introduction of a deuterated plastic or cryogenically frozen D2O layer

  6. Neutron scattering: Revealing the structure of matter

    International Nuclear Information System (INIS)

    Zeyher, A.

    1996-01-01

    Neutrons are being used to explore materials and biological molecules in a growing number of applications, such as advanced steels and other materials, polymer films, complex molecular structures, and magnetic behavior. open-quotes Virtually all we know about the structure of the new high-transition temperature superconductors was determined using neutron scattering,close quotes said Bill Appleton, associate director for advanced materials, physical, and neutron sciences at Oak Ridge National Laboratory, in Oak Ridge, Tennessee. Neutrons are the only way to see what happens inside superconductors because of the neutron's penetrating power and its magnetic moment. Penetrating power means that neutrons can look up to several centimetres below the surface of a material without damaging it; the neutron's magnetic moment means that it is sensitive to the magnetic fields inside a material. Research in high-temperature superconductivity is only one example of the power of neutrons to illuminate, without disturbing, the structure and behavior of matter at the atomic or molecular scale. In many applications, neutron scattering serves as a complement to X-ray diffraction. In others, neutrons are the only nondestructive probe for looking inside materials or processes

  7. The University of Texas Cold Neutron Source

    International Nuclear Information System (INIS)

    Uenlue, Kenan; Rios-Martinez, Carlos; Wehring, B.W.

    1994-01-01

    A cold neutron source has been designed, constructed, and tested by the Nuclear Engineering Teaching Laboratory (NETL) at The University of Texas at Austin. The Texas Cold Neutron Source (TCNS) is located in one of the beam ports of the NETL 1-MW TRIGA Mark II research reactor. The main components of the TCNS are a cooled moderator, a heat pipe, a cryogenic refrigerator, and a neutron guide. 80 ml of mesitylene moderator are maintained at about 30 K in a chamber within the reactor graphite reflector by the heat pipe and cryogenic refrigerator. The heat pipe is a 3-m long aluminum tube that contains neon as the working fluid. The cold neutrons obtained from the moderator are transported by a curved 6-m long neutron guide. This neutron guide has a radius of curvature of 300 m, a 50x15 mm cross-section, 58 Ni coating, and is separated into three channels. The TCNS will provide a low-background subthermal neutron beam for neutron capture and scattering research. After the installation of the external portion of the neutron guide, a neutron focusing system and a Prompt Gamma Activation Analysis facility will be set up at the TCNS. ((orig.))

  8. Compact neutron generator development and applications

    International Nuclear Information System (INIS)

    Leung, Ka-Ngo; Reijonen, Jani; Gicquel, Frederic; Hahto, Sami; Lou, Tak-Pui

    2004-01-01

    The Plasma and Ion Source Technology Group at the Lawrence Berkeley National Laboratory has been engaging in the development of high yield compact neutron generators for the last ten years. Because neutrons in these generators are formed by using either D-D, T-T or D-T fusion reaction, one can produce either mono-energetic (2.4 MeV or 14 MeV) or white neutrons. All the neutron generators being developed by our group utilize 13.5 MHz RF induction discharge to produce a pure deuterium or a mixture of deuterium-tritium plasma. As a result, ion beams with high current density and almost pure atomic ions can be extracted from the plasma source. The ion beams are accelerated to ∼100 keV and neutrons are produced when the beams impinge on a titanium target. Neutron generators with different configurations and sizes have been designed and tested at LBNL. Their applications include neutron activation analysis, oil-well logging, boron neutron capture therapy, brachytherapy, cargo and luggage screening. A novel small point neutron source has recently been developed for radiography application. The source size can be 2 mm or less, making it possible to examine objects with sharper images. The performance of these neutron generators will be described in this paper

  9. A dense plasma focus-based neutron source for a single-shot detection of illicit materials and explosives by a nanosecond neutron pulse

    Energy Technology Data Exchange (ETDEWEB)

    Gribkov, V A; Latyshev, S V [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Miklaszewski, R A; Chernyshova, M [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Drozdowicz, K; Wiacek, U [Institute of Nuclear Physics, Krakow (Poland); Tomaszewski, K [ACS Ltd, Warsaw (Poland); Lemeshko, B D [N L Dukhov All-Russian Institute of Automation, Moscow (Russian Federation)], E-mail: gribkovv@yahoo.com

    2010-03-15

    Recent progress in a single-pulse Nanosecond Impulse Neutron Investigation System (NINIS) intended for interrogation of hidden objects by means of measuring elastically scattered neutrons is presented in this paper. The method uses very bright neutron pulses having duration of the order of 10 ns only, which are generated by dense plasma focus (DPF) devices filled with pure deuterium or DT mixture as a working gas. The small size occupied by the neutron bunch in space, number of neutrons per pulse and mono-chromaticity ({delta}E/E{approx}1%) of the neutron spectrum provides the opportunity to use a time-of-flight (TOF) technique with flying bases of about a few metres. In our researches we used DPF devices having bank energy in the range 2-7 kJ. The devices generate a neutron yield of the level of 10{sup 8}-10{sup 9} 2.45 MeV and 10{sup 10}-10{sup 11} 14 MeV neutrons per pulse with pulse duration {approx}10-20 ns. TOF base in the tests was 2.2-18.5 m. We have demonstrated the possibility of registering of neutrons scattered by the substances under investigation-1 litre bottles with methanol (CH{sub 3}OH), phosphoric (H{sub 2}PO{sub 4}) and nitric (HNO{sub 3}) acids as well as a long object-a 1 m gas tank filled with deuterium at high pressure. It is shown that the above mentioned short TOF bases and relatively low neutron yields are enough to distinguish different elements' nuclei composing the substance under interrogation and to characterize the geometry of lengthy objects in some cases. The wavelet technique was employed to 'clean' the experimental data registered. The advantages and restrictions of the proposed and tested NINIS technique in comparison with other methods are discussed.

  10. A dense plasma focus-based neutron source for a single-shot detection of illicit materials and explosives by a nanosecond neutron pulse

    International Nuclear Information System (INIS)

    Gribkov, V A; Latyshev, S V; Miklaszewski, R A; Chernyshova, M; Drozdowicz, K; Wiacek, U; Tomaszewski, K; Lemeshko, B D

    2010-01-01

    Recent progress in a single-pulse Nanosecond Impulse Neutron Investigation System (NINIS) intended for interrogation of hidden objects by means of measuring elastically scattered neutrons is presented in this paper. The method uses very bright neutron pulses having duration of the order of 10 ns only, which are generated by dense plasma focus (DPF) devices filled with pure deuterium or DT mixture as a working gas. The small size occupied by the neutron bunch in space, number of neutrons per pulse and mono-chromaticity (ΔE/E∼1%) of the neutron spectrum provides the opportunity to use a time-of-flight (TOF) technique with flying bases of about a few metres. In our researches we used DPF devices having bank energy in the range 2-7 kJ. The devices generate a neutron yield of the level of 10 8 -10 9 2.45 MeV and 10 10 -10 11 14 MeV neutrons per pulse with pulse duration ∼10-20 ns. TOF base in the tests was 2.2-18.5 m. We have demonstrated the possibility of registering of neutrons scattered by the substances under investigation-1 litre bottles with methanol (CH 3 OH), phosphoric (H 2 PO 4 ) and nitric (HNO 3 ) acids as well as a long object-a 1 m gas tank filled with deuterium at high pressure. It is shown that the above mentioned short TOF bases and relatively low neutron yields are enough to distinguish different elements' nuclei composing the substance under interrogation and to characterize the geometry of lengthy objects in some cases. The wavelet technique was employed to 'clean' the experimental data registered. The advantages and restrictions of the proposed and tested NINIS technique in comparison with other methods are discussed.

  11. A dense plasma focus-based neutron source for a single-shot detection of illicit materials and explosives by a nanosecond neutron pulse

    Science.gov (United States)

    Gribkov, V. A.; Latyshev, S. V.; Miklaszewski, R. A.; Chernyshova, M.; Drozdowicz, K.; Wiącek, U.; Tomaszewski, K.; Lemeshko, B. D.

    2010-03-01

    Recent progress in a single-pulse Nanosecond Impulse Neutron Investigation System (NINIS) intended for interrogation of hidden objects by means of measuring elastically scattered neutrons is presented in this paper. The method uses very bright neutron pulses having duration of the order of 10 ns only, which are generated by dense plasma focus (DPF) devices filled with pure deuterium or DT mixture as a working gas. The small size occupied by the neutron bunch in space, number of neutrons per pulse and mono-chromaticity (ΔE/E~1%) of the neutron spectrum provides the opportunity to use a time-of-flight (TOF) technique with flying bases of about a few metres. In our researches we used DPF devices having bank energy in the range 2-7 kJ. The devices generate a neutron yield of the level of 108-109 2.45 MeV and 1010-1011 14 MeV neutrons per pulse with pulse duration ~10-20 ns. TOF base in the tests was 2.2-18.5 m. We have demonstrated the possibility of registering of neutrons scattered by the substances under investigation—1 litre bottles with methanol (CH3OH), phosphoric (H2PO4) and nitric (HNO3) acids as well as a long object—a 1 m gas tank filled with deuterium at high pressure. It is shown that the above mentioned short TOF bases and relatively low neutron yields are enough to distinguish different elements' nuclei composing the substance under interrogation and to characterize the geometry of lengthy objects in some cases. The wavelet technique was employed to 'clean' the experimental data registered. The advantages and restrictions of the proposed and tested NINIS technique in comparison with other methods are discussed.

  12. Etude des formes interrogatives en francais chez les enfants de trois ans (Study of the Interrogative Forms in French in Three-Year-Olds)

    Science.gov (United States)

    Redard, Francoise

    1976-01-01

    A study of the acquisition of interrogative forms in children of high socioeconomic status reveals that utterances belong more to the colloquial than to the standard range. It is concluded that disadvantaged children would show similar usage, leading to the suggestion that teachers teach language as they use it. (Text is in French.) (CDSH/CLK)

  13. Methods for Characterization of Batteries Using Acoustic Interrogation

    Science.gov (United States)

    Bhadra, Shoham

    Batteries are a ubiquitous form of electrochemical energy storage, but thus far the methods for measuring the mechanical properties of batteries and their component materials in operando have lagged far behind the methods for measuring the corresponding electrical properties. In this thesis, I demonstrate methods for determining the changes in materials properties of an electrochemical energy storage cell both ex situ and in operando.. I begin by establishing the impact of micro-scale morphology changes on the macro-scale dynamic mechanical response in commercial alkaline AA cells. Using a bounce test, the coefficient of restitution (COR) of the cell is shown to increase non-linearly as a function of state of charge (SOC). I show that the reason for the increase in the COR stems from the spatially-dependent oxidation of the Zn anode, with an initial increase corresponding to the formation of a percolation pathway of ZnO-clad Zn particles spanning the radius of the anode. The subsequent saturation of the COR is shown to result from the ultimate solidification and desiccation of the Zn anode. Building from this, I present a generalized in operando solution for materials characterization in batteries using ultrasonic interrogation. The materials properties of battery components change during charge and discharge, resulting in a change in the sound speed of the materials. By attaching transducers to a battery during cycling and sending ultrasonic pulses through each cell I observe the changes in the time of flight (ToF) of the pulses, both in reflection and transmission. I show that the changes in ToF correspond to both SOC and state of health (SOH) in a variety of battery chemistries and geometries, and detail a corresponding acoustic conservation law model framework. Finally, I perform these electrochemical acoustic time of flight (EAToF) experiments on commercial alkaline AA cells. By correlating the results with energy dispersive x-ray diffraction (EDXRD) data and

  14. High flux compact neutron generators

    International Nuclear Information System (INIS)

    Reijonen, J.; Lou, T.-P.; Tolmachoff, B.; Leung, K.-N.; Verbeke, J.; Vujic, J.

    2001-01-01

    Compact high flux neutron generators are developed at the Lawrence Berkeley National Laboratory. The neutron production is based on D-D or D-T reaction. The deuterium or tritium ions are produced from plasma using either a 2 MHz or 13.56 MHz radio frequency (RF) discharge. RF-discharge yields high fraction of atomic species in the beam which enables higher neutron output. In the first tube design, the ion beam is formed using a multiple hole accelerator column. The beam is accelerated to energy of 80 keV by means of a three-electrode extraction system. The ion beam then impinges on a titanium target where either the 2.4 MeV D-D or 14 MeV D-T neutrons are generated. The MCNP computation code has predicted a neutron flux of ∼10 11 n/s for the D-D reaction at beam intensity of 1.5 A at 150 kV. The neutron flux measurements of this tube design will be presented. Recently new compact high flux tubes are being developed which can be used for various applications. These tubes also utilize RF-discharge for plasma generation. The design of these tubes and the first measurements will be discussed in this presentation

  15. Neutronic reactor

    International Nuclear Information System (INIS)

    Wende, C.W.J.

    1976-01-01

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

  16. Neutronic reactor

    International Nuclear Information System (INIS)

    Carleton, J.T.

    1977-01-01

    A graphite-moderated nuclear reactor includes channels between blocks of graphite and also includes spacer blocks between adjacent channeled blocks with an axis of extension normal to that of the axis of elongation of the channeled blocks to minimize changes in the physical properties of the graphite as a result of prolonged neutron bombardment. 3 claims, 6 figures

  17. 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.

  18. Neutron angular distribution in plutonium-240 spontaneous fission

    Energy Technology Data Exchange (ETDEWEB)

    Marcath, Matthew J., E-mail: mmarcath@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109 (United States); Shin, Tony H.; Clarke, Shaun D. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109 (United States); Peerani, Paolo [European Commission at the Joint Research Centre, Ispra (Italy); Pozzi, Sara A. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109 (United States)

    2016-09-11

    Nuclear safeguards applications require accurate fission models that exhibit prompt neutron anisotropy. In the laboratory reference frame, an anisotropic neutron angular distribution is observed because prompt fission neutrons carry momentum from fully accelerated fission fragments. A liquid organic scintillation detector array was used with pulse shape discrimination techniques to produce neutron-neutron cross-correlation time distributions and angular distributions from spontaneous fission in a {sup 252}Cf, a 0.84 g {sup 240}Pu{sub eff} metal, and a 1.63 g {sup 240}Pu{sub eff} metal sample. The effect of cross-talk, estimated with MCNPX-PoliMi simulations, is removed from neutron-neutron coincidences as a function of the angle between detector pairs. Fewer coincidences were observed at detector angles near 90°, relative to higher and lower detector angles. As light output threshold increases, the observed anisotropy increases due to spectral effects arising from fission fragment momentum transfer to emitted neutrons. Stronger anisotropy was observed in Cf-252 spontaneous fission prompt neutrons than in Pu-240 neutrons. - Highlights: • Pu-240 prompt fission fast-neutron anisotropy was quantified for the first time. • MCNPX-PoliMi and MPPost codes were used to remove cross-talk neutron detections from experiment results. • Cf-252 spontaneous fission neutrons were found to be more anisotropic than Pu-240 neutrons.

  19. Neutron Stars: Laboratories for Fundamental Physics Under ...

    Indian Academy of Sciences (India)

    DEBADES BANDYOPADHYAY

    2017-09-07

    Sep 7, 2017 ... American Physical Society in 1933, Baade & Zwicky ... of pulsars and black holes using the SKA and LIGO-. India along with other ..... a black hole. Different groups investigated the problem of stability of a PNS for short times. When a PNS is made up of nucleons and leptons, it has a slightly smaller max-.

  20. Neutron Stars: Laboratories for Fundamental Physics Under ...

    Indian Academy of Sciences (India)

    Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately.

  1. Data acquisition system for the neutron scattering instruments at the intense pulsed neutron source

    International Nuclear Information System (INIS)

    Crawford, R.K.; Daly, R.T.; Haumann, J.R.; Hitterman, R.L.; Morgan, C.B.; Ostrowski, G.E.; Worlton, T.G.

    1981-01-01

    The Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory is a major new user-oriented facility which is now coming on line for basic research in neutron scattering and neutron radiation damage. This paper describes the data-acquisition system which will handle data acquisition and instrument control for the time-of-flight neutron-scattering instruments at IPNS. This discussion covers the scientific and operational requirements for this system, and the system architecture that was chosen to satisfy these requirements. It also provides an overview of the current system implementation including brief descriptions of the hardware and software which have been developed

  2. Magnetic Nanotweezers for Interrogating Biological Processes in Space and Time.

    Science.gov (United States)

    Kim, Ji-Wook; Jeong, Hee-Kyung; Southard, Kaden M; Jun, Young-Wook; Cheon, Jinwoo

    2018-04-17

    The ability to sense and manipulate the state of biological systems has been extensively advanced during the past decade with the help of recent developments in physical tools. Unlike standard genetic and pharmacological perturbation techniques-knockdown, overexpression, small molecule inhibition-that provide a basic on/off switching capability, these physical tools provide the capacity to control the spatial, temporal, and mechanical properties of the biological targets. Among the various physical cues, magnetism offers distinct advantages over light or electricity. Magnetic fields freely penetrate biological tissues and are already used for clinical applications. As one of the unique features, magnetic fields can be transformed into mechanical stimuli which can serve as a cue in regulating biological processes. However, their biological applications have been limited due to a lack of high-performance magnetism-to-mechanical force transducers with advanced spatiotemporal capabilities. In this Account, we present recent developments in magnetic nanotweezers (MNTs) as a useful tool for interrogating the spatiotemporal control of cells in living tissue. MNTs are composed of force-generating magnetic nanoparticles and field generators. Through proper design and the integration of individual components, MNTs deliver controlled mechanical stimulation to targeted biomolecules at any desired space and time. We first discuss about MNT configuration with different force-stimulation modes. By modulating geometry of the magnetic field generator, MNTs exert pulling, dipole-dipole attraction, and rotational forces to the target specifically and quantitatively. We discuss the key physical parameters determining force magnitude, which include magnetic field strength, magnetic field gradient, magnetic moment of the magnetic particle, as well as distance between the field generator and the particle. MNTs also can be used over a wide range of biological time scales. By simply

  3. Fission neutron spectra measurements at LANSCE - status and plans

    Energy Technology Data Exchange (ETDEWEB)

    Haight, Robert C [Los Alamos National Laboratory; Noda, Shusaku [Los Alamos National Laboratory; Nelson, Ronald O [Los Alamos National Laboratory; O' Donnell, John M [Los Alamos National Laboratory; Devlin, Matt [Los Alamos National Laboratory; Chatillon, Audrey [CEA-FRANCE; Granier, Thierry [CEA-FRANCE; Taieb, Julien [CEA-FRANCE; Laurent, Benoit [CEA-FRANCE; Belier, Gilbert [CEA-FRANCE; Becker, John A [LLNL; Wu, Ching - Yen [LLNL

    2009-01-01

    A program to measure fission neutron spectra from neutron-induced fission of actinides is underway at the Los Alamos Neutron Science Center (LANSCE) in a collaboration among the CEA laboratory at Bruyeres-le-Chatel, Lawrence Livermore National Laboratory and Los Alamos National Laboratory. The spallation source of fast neutrons at LANSCE is used to provide incident neutron energies from less than 1 MeV to 100 MeV or higher. The fission events take place in a gas-ionization fission chamber, and the time of flight from the neutron source to that chamber gives the energy of the incident neutron. Outgoing neutrons are detected by an array of organic liquid scintillator neutron detectors, and their energies are deduced from the time of flight from the fission chamber to the neutron detector. Measurements have been made of the fission neutrons from fission of {sup 235}U, {sup 238}U, {sup 237}Np and {sup 239}Pu. The range of outgoing energies measured so far is from 1 MeV to approximately 8 MeV. These partial spectra and average fission neutron energies are compared with evaluated data and with models of fission neutron emission. Results to date will be presented and a discussion of uncertainties will be given in this presentation. Future plans are to make significant improvements in the fission chambers, neutron detectors, signal processing, data acquisition and the experimental environment to provide high fidelity data including mea urements of fission neutrons below 1 MeV and improvements in the data above 8 MeV.

  4. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-01

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

  5. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  6. Pulsed neutron generator

    International Nuclear Information System (INIS)

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

    1986-03-01

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

  7. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  8. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  9. Development of an Optical Fiber Sensor Interrogation System for Vibration Analysis

    Directory of Open Access Journals (Sweden)

    Alfredo Lamberti

    2016-01-01

    Full Text Available Since the introduction of dynamic optical fiber sensor interrogation systems on the market it has become possible to perform vibration measurements at frequencies up to a few kHz. Nevertheless, the use of these sensors in vibration analysis has not become a standard practice yet. This is mainly caused by the fact that interrogators are stand-alone systems which focus on strain measurements while other types of signals are also required for vibration analysis (e.g., force signals. In this paper, we present a fiber Bragg grating (FBG interrogation system that enables accurate strain measurement simultaneously with other signals (e.g., excitation forces. The system is based on a Vertical Cavity Surface Emitting Laser (VCSEL and can easily be assembled with relatively low-cost off-the-shelf components. Dynamic measurements up to a few tens of kHz with a dynamic precision of around 3 nanostrain per square-root Hz can be performed. We evaluate the proposed system on two measurement examples: a steel beam with FBG sensors glued on top and a composite test specimen with a fiber sensor integrated within the material. We show that in the latter case the results of the interrogation system are superior in quality compared to a state-of-the-art commercially available interrogation system.

  10. Analysis and Validation of Contactless Time-Gated Interrogation Technique for Quartz Resonator Sensors.

    Science.gov (United States)

    Baù, Marco; Ferrari, Marco; Ferrari, Vittorio

    2017-06-02

    A technique for contactless electromagnetic interrogation of AT-cut quartz piezoelectric resonator sensors is proposed based on a primary coil electromagnetically air-coupled to a secondary coil connected to the electrodes of the resonator. The interrogation technique periodically switches between interleaved excitation and detection phases. During the excitation phase, the resonator is set into vibration by a driving voltage applied to the primary coil, whereas in the detection phase, the excitation signal is turned off and the transient decaying response of the resonator is sensed without contact by measuring the voltage induced back across the primary coil. This approach ensures that the readout frequency of the sensor signal is to a first order approximation independent of the interrogation distance between the primary and secondary coils. A detailed theoretical analysis of the interrogation principle based on a lumped-element equivalent circuit is presented. The analysis has been experimentally validated on a 4.432 MHz AT-cut quartz crystal resonator, demonstrating the accurate readout of the series resonant frequency and quality factor over an interrogation distance of up to 2 cm. As an application, the technique has been applied to the measurement of liquid microdroplets deposited on a 4.8 MHz AT-cut quartz crystal. More generally, the proposed technique can be exploited for the measurement of any physical or chemical quantities affecting the resonant response of quartz resonator sensors.

  11. Sequential interrogation of multiple FBG sensors using LPG modulation and an artificial neural network

    International Nuclear Information System (INIS)

    Basu, Mainak; Ghorai, S K

    2015-01-01

    Interrogating multiple fiber Bragg gratings (FBG) requires highly sensitive spectrum scanning equipment such as optical spectrum analyzers, tunable filters, acousto-optic tunable filters etc, which are expensive, bulky and time consuming. In this paper, we present a new approach for multiple FBG sensor interrogation using long-period gratings and an artificial neural network. The reflection spectra of the multiplexed FBGs are modulated by two long period gratings separately and the modulated optical intensities were detected by two photodetectors. The outputs of the detectors are then used as input in a previously trained artificial neural network to interrogate the FBG sensors. Simulations have been performed to determine the strain and wavelength shift using two and four sensors. The interrogation system has also been demonstrated experimentally for two sensors using simply supported beams in the range of 0–350 μstrain. The proposed interrogation scheme has been found to identify the perturbed FBG, and to determine strain and wavelength shift with reasonable accuracy. (paper)

  12. Narrowband interrogation of plasmonic optical fiber biosensors based on spectral combs

    Science.gov (United States)

    González-Vila, Álvaro; Kinet, Damien; Mégret, Patrice; Caucheteur, Christophe

    2017-11-01

    Gold-coated tilted fiber Bragg gratings can probe surface Plasmon polaritons with high resolution and sensitivity. In this work, we report two configurations to interrogate such plasmonic biosensors, with the aim of providing more efficient alternatives to the widespread spectrometer-based techniques. To this aim, the interrogation is based on measuring the optical power evolution of the cladding modes with respect to surrounding refractive index changes instead of computing their wavelength shift. Both setups are composed of a broadband source and a photodiode and enable a narrowband interrogation around the cladding mode that excites the surface Plasmon resonance. The first configuration makes use of a uniform fiber Bragg grating to filter the broadband response of the source in a way that the final interrogation is based on an intensity modulation measured in transmission. The second setup uses a uniform fiber grating too, but located beyond the sensor and acting as a selective optical mirror, so the interrogation is carried out in reflection. Both configurations are compared, showing interesting differential features. The first one exhibits a very high sensitivity while the second one has an almost temperature-insensitive behavior. Hence, the choice of the most appropriate method will be driven by the requirements of the target application.

  13. EXCISING TAGS: DISTINGUISHING BETWEEN INTERROGATIVE SFPS AND TAG QUESTIONS IN TAIWANESE

    Directory of Open Access Journals (Sweden)

    Seng-Hian Lau

    2010-06-01

    Full Text Available This paper serves as an investigation into the differences between interrogative sentence-final particles (SFPs and tag questions (tags in Taiwanese. What we are concerned with is the discrepancies found among the lists of interrogative SFPs in the literature. To distinguish tags from the interrogative particles (PRTs, a testing procedure is devised based on the proposal for testing negative particles (NEG-PRTs in Hsieh (2001. We conclude that buē, bē, bô, m, honn, m̄, ma, nih are interrogative SFPs and hiòo, m-me(me, sī--bô, sī-m̄ (sìm and sioh are tag questions. Among the interrogative SFPs, buē, bē, bô, and m are negative-particles which occur under IP, honn, m̄, ma, and nih are particles which perch higher, under CP. We believe that distinguishing SFPs from tags is the foundation of a solid investigation into SFPs.

  14. Ion beam-induced formation and interrogation of Au nanoclusters

    Czech Academy of Sciences Publication Activity Database

    Karmakar, P.; Liu, G. F.; Šroubek, Zdeněk; Yarmoff, J. A.

    2007-01-01

    Roč. 98, č. 21 (2007), s. 215502.1-215502.4 ISSN 0031-9007 Grant - others:U. S. Army Research Laboratory and U. S. Army Research Office(US) 46686-PH-H Institutional research plan: CEZ:AV0Z20670512 Source of funding: V - iné verejné zdroje Keywords : thin films * nanostructured materials * erosion * geomorphology Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 6.944, year: 2007

  15. Radiation carcinogenesis, laboratory studies

    International Nuclear Information System (INIS)

    Shellabarger, C.J.

    1974-01-01

    Laboratory studies on radioinduced carcinogenesis are reviewed. Some topics discussed are: radioinduced neoplasia in relation to life shortening; dose-response relationships; induction of skin tumors in rats by alpha particles and electrons; effects of hormones on tumor response; effects of low LET radiations delivered at low dose-rates; effects of fractionated neutron radiation; interaction of RBE and dose rate effects; and estimates of risks for humans from animal data. (U.S.)

  16. Optical measuring system with an interrogator and a polymer-based single-mode fibre optic sensor system

    DEFF Research Database (Denmark)

    2017-01-01

    The present invention relates to an optical measuring system comprising a polymer-based single-mode fibre-optic sensor system (102), an optical interrogator (101), and an optical arrangement (103) interconnecting the optical interrogator (101) and the polymer-based single-mode fibre-optic sensor...... system (102). The invention further relates to an optical interrogator adapted to be connected to a polymer-based single-mode fibre-optic sensor system via an optical arrangement. The interrogator comprises a broadband light source arrangement (104) and a spectrum analysing arrangement which receives...... and analyses light reflected from the polymer-based single- mode fibre-optic sensor system....

  17. Compact Neutron Generators for Medical, Home Land Security, and Planetary Exploration

    CERN Document Server

    Reijonen, Jani

    2005-01-01

    The Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory has developed various types of advanced D-D (neutron energy 2.5 MeV), D-T (14 MeV) and T-T (0 - 9 MeV) neutron generators for wide range of applications. These applications include medical (Boron Neutron Capture Therapy), homeland security (Prompt Gamma Activation Analysis, Fast Neutron Activation Analysis and Pulsed Fast Neutron Transmission Spectroscopy) and planetary exploration in form of neutron based, sub-surface hydrogen detection systems. These neutron generators utilize RF induction discharge to ionize the deuterium/tritium gas. This discharge method provides high plasma density for high output current, high atomic species from molecular gases, long life operation and versatility for various discharge chamber geometries. Three main neutron generator developments are discussed here: high neutron output co-axial neutron generator for BNCT applications, point neutron generator for security applications, compact and sub-c...

  18. S’interroger sur la météo, c’est s’interroger sur soi-même

    OpenAIRE

    Becker, Karin

    2018-01-01

    S’interroger sur la météo, c’est s’interroger sur soi-même. Car dans la perspective des sciences humaines, c’est le temps vécu qui est placé au centre de l’intérêt dans l’étude des météores, c’est-à-dire le ressenti corporel et mental sur le plan individuel et sur le plan collectif. Autrement dit, l’attention des chercheurs porte sur la « perception du climat », pour reprendre la dénomination du réseau interdisciplinaire dirigé par l’ethnologue Martin de la Soudière, la géographe climatologue...

  19. Interrogation in Teacher-Student Interaction in Bahasa Indonesia Learning at Elementary School

    Directory of Open Access Journals (Sweden)

    Akmal Hamsa

    2014-08-01

    Full Text Available Interrogation in Teacher-Student Interaction in Bahasa Indonesia Learning at Elementary School. This study aimed to describe the form, function, and questioning strategies teachers in teacher-student interrogation in Bahasa Indonesia learning in elementary school. Data sourced from four teacher of elementary school, SDN Tamangapa and SD Inpres Tamangapa. Data were obtained by (1 recording, (2 documentation, (3 field notes, (4 interview. The results showed that: (1 the form of questioning the teacher in the teacher-student interaction in Bahasa Indonesia learning in primary schools generally examined the low-level thinking skills, (2 functions of teacher questions are generally intended to check student understanding, and (3 teachers utilize a variety of strategies in addressing student answers correctly and the apparent hesitation. Some disadvantages are indicated teachers in providing interrogation.

  20. High-Speed Interrogation for Large-Scale Fiber Bragg Grating Sensing

    Directory of Open Access Journals (Sweden)

    Chenyuan Hu

    2018-02-01

    Full Text Available A high-speed interrogation scheme for large-scale fiber Bragg grating (FBG sensing arrays is presented. This technique employs parallel computing and pipeline control to modulate incident light and demodulate the reflected sensing signal. One Electro-optic modulator (EOM and one semiconductor optical amplifier (SOA were used to generate a phase delay to filter reflected spectrum form multiple candidate FBGs with the same optical path difference (OPD. Experimental results showed that the fastest interrogation delay time for the proposed method was only about 27.2 us for a single FBG interrogation, and the system scanning period was only limited by the optical transmission delay in the sensing fiber owing to the multiple simultaneous central wavelength calculations. Furthermore, the proposed FPGA-based technique had a verified FBG wavelength demodulation stability of ±1 pm without average processing.

  1. Characterization of a FBG sensor interrogation system based on a mode-locked laser scheme.

    Science.gov (United States)

    Madrigal, Javier; Fraile-Peláez, Francisco Javier; Zheng, Di; Barrera, David; Sales, Salvador

    2017-10-02

    This paper is focused on the characterization of a fiber Bragg grating (FBG) sensor interrogation system based on a fiber ring laser with a semiconductor optical amplifier as the gain medium, and an in-loop electro-optical modulator. This system operates as a switchable active (pulsed) mode-locked laser. The operation principle of the system is explained theoretically and validated experimentally. The ability of the system to interrogate an array of different FBGs in wavelength and spatial domain is demonstrated. Simultaneously, the influence of several important parameters on the performance of the interrogation technique has been investigated. Specifically, the effects of the bandwidth and the reflectivity of the FBGs, the SOA gain, and the depth of the intensity modulation have been addressed.

  2. Bioassay Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Bioassay Laboratory is an accredited laboratory capable of conducting standardized and innovative environmental testing in the area of aquatic ecotoxicology. The...

  3. HYDROMECHANICS LABORATORY

    Data.gov (United States)

    Federal Laboratory Consortium — Naval Academy Hydromechanics LaboratoryThe Naval Academy Hydromechanics Laboratory (NAHL) began operations in Rickover Hall in September 1976. The primary purpose of...

  4. International workshop on cold neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Russell, G.J.; West, C.D. (comps.) (Los Alamos National Lab., NM (United States))

    1991-08-01

    The first meeting devoted to cold neutron sources was held at the Los Alamos National Laboratory on March 5--8, 1990. Cosponsored by Los Alamos and Oak Ridge National Laboratories, the meeting was organized as an International Workshop on Cold Neutron Sources and brought together experts in the field of cold-neutron-source design for reactors and spallation sources. Eighty-four people from seven countries attended. Because the meeting was the first of its kind in over forty years, much time was spent acquainting participants with past and planned activities at reactor and spallation facilities worldwide. As a result, the meeting had more of a conference flavor than one of a workshop. The general topics covered at the workshop included: Criteria for cold source design; neutronic predictions and performance; energy deposition and removal; engineering design, fabrication, and operation; material properties; radiation damage; instrumentation; safety; existing cold sources; and future cold sources.

  5. International workshop on cold neutron sources

    International Nuclear Information System (INIS)

    Russell, G.J.; West, C.D.

    1991-08-01

    The first meeting devoted to cold neutron sources was held at the Los Alamos National Laboratory on March 5--8, 1990. Cosponsored by Los Alamos and Oak Ridge National Laboratories, the meeting was organized as an International Workshop on Cold Neutron Sources and brought together experts in the field of cold-neutron-source design for reactors and spallation sources. Eighty-four people from seven countries attended. Because the meeting was the first of its kind in over forty years, much time was spent acquainting participants with past and planned activities at reactor and spallation facilities worldwide. As a result, the meeting had more of a conference flavor than one of a workshop. The general topics covered at the workshop included: Criteria for cold source design; neutronic predictions and performance; energy deposition and removal; engineering design, fabrication, and operation; material properties; radiation damage; instrumentation; safety; existing cold sources; and future cold sources

  6. The neutron long counter NERO for studies of β-delayed neutron emission in the r-process

    International Nuclear Information System (INIS)

    Pereira, J.; Hosmer, P.; Lorusso, G.; Santi, P.; Couture, A.; Daly, J.; Del Santo, M.; Elliot, T.

    2010-01-01

    The neutron long counter NERO was built at the National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, for measuring β-delayed neutron-emission probabilities. The detector was designed to work in conjunction with a β-delay implantation station, so that β decays and β-delayed neutrons emitted from implanted nuclei can be measured simultaneously. The high efficiency of about 40%, for the range of energies of interest, along with the small background, are crucial for measuring β-delayed neutron emission branchings for neutron-rich r-process nuclei produced as low intensity fragmentation beams in in-flight separator facilities.

  7. Neutron structure analysis using neutron imaging plate

    International Nuclear Information System (INIS)

    Karasawa, Yuko; Minezaki, Yoshiaki; Niimura, Nobuo

    1997-01-01

    Neutron is complementary against X-ray and is dispensable for structure analysis. However, because of the lack of the neutron intensity, it was not so common as X-ray. In order to overcome the intensity problem, a neutron imaging plate (NIP) has been successfully developed. The NIP has opened the door of neutron structure biology, where all the hydrogen atoms and bound water molecules of protein are determined, and contributed to development of other fields such as neutron powder diffraction and neutron radiography, too. (author)

  8. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  9. REFRACTIVE NEUTRON LENS

    OpenAIRE

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

    2013-01-01

    Compound concave refractive lenses are used for focusing neutron beam. Investigations of spectral and focusing properties of a refractive neutron lens are presented. Resolution of the imaging system on the base of refractive neutron lenses depends on material properties and parameters of neutron source. Model of refractive neutron lens are proposed. Results of calculation diffraction resolution and focal depth of refractive neutron lens are discussed.

  10. High energy neutron radiography

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  11. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  12. Promotion COPERNIC Energy and Society the interrogations on the world demand evolution

    International Nuclear Information System (INIS)

    2001-12-01

    In the framework of a prospective reflexion emergence on the energy demand, this document presents an analysis of the prospective approach and of recent studies: challenges, interests, limits, validity of the models and hypothesis and results relevance. With this analysis, the authors aim to identify the main interrogations bond to the world energy demand evolution. They then analyse these interrogations in the framework of a sectoral approach (agriculture, industry, transports, residential) in order to detail the demand and to forecast the evolution. Facing the consumption attitudes, they also suggest some new action avenues to favor a sustainable growth. (A.L.B.)

  13. The Lawyer in the Dutch Interrogation Room: Influence on Police and Suspect

    OpenAIRE

    Verhoeven, W.J.; Stevens, L.

    2012-01-01

    textabstractIn many European countries, providing a suspect in custody with legal aid before the first police interrogation is a heavily debated issue. In this paper, we report on an exploratory study on the use of coercion by the police and the use of the right to silence by suspects in 70 Dutch homicide cases and their relation to prior consultation and presence of a lawyer. Analysis of the data indicates that there is a relation between the presence of a lawyer in the interrogation room an...

  14. On the actual bandwidth of some dynamic fiber optic strain/temperature interrogators

    Science.gov (United States)

    Preizler, Rotem R.; Davidi, R.; Motil, Avi; Botsev, Yakov; Hahami, Meir; Tur, Moshe

    2017-04-01

    The measurement accuracy of dynamic fiber-optic sensing interrogators, which use frequency scanning to determine the value of the measured, err as either the event bandwidth approaches half the instrument sampling frequency or when the event dynamic range comes close to the instrument designed value. One main source of error is the common practice of assigning sampling at a non-uniform grid to a uniform one. Harmonics higher than -20 dB are observed for signal frequencies exceeding 25% of the sampling rate and/or for signal amplitudes higher than 15% of the instrument dynamic range. These findings have applications to fiber-Bragg-grating and Brillouin interrogators.

  15. Compact, low-cost, and high-resolution interrogation unit for optical sensors

    International Nuclear Information System (INIS)

    Kiesel, Peter; Schmidt, Oliver; Mohta, Setu; Johnson, Noble; Malzer, Stefan

    2006-01-01

    Compact wavelength detectors that resolve wavelength changes in the subpicometer range over a broad spectral range are presented. A photodiode array or position sensor device is coated with a linear variable filter that converts the wavelength of the incident light into a spatial intensity distribution. The centroid of the spatial distribution is determined by a differential readout of the two elements of the photodiode array or the position sensor device. The device can interrogate any optical sensor that produces a wavelength shift in response to a stimulus. The potential of this device was tested by interrogating fiber-Bragg-grating sensors

  16. Interrogating adhesion using fiber Bragg grating sensing technology

    Science.gov (United States)

    Rasberry, Roger D.; Rohr, Garth D.; Miller, William K.; Udd, Eric; Blach, Noah T.; Davis, Ryan A.; Olson, Walter R.; Calkins, David; Roach, Allen R.; Walsh, David S.; McElhanon, James R.

    2015-05-01

    The assurance of the integrity of adhesive bonding at substrate interfaces is paramount to the longevity and sustainability of encapsulated components. Unfortunately, it is often difficult to non-destructively evaluate these materials to determine the adequacy of bonding after manufacturing and then later in service. A particularly difficult problem in this regard is the reliable detection/monitoring of regions of weak bonding that may result from poor adhesion or poor cohesive strength, or degradation in service. One promising and perhaps less explored avenue we have recently begun to investigate for this purpose centers on the use of (chirped) fiber Bragg grating sensing technology. In this scenario, a grating is patterned into a fiber optic such that a (broadband) spectral reflectance is observed. The sensor is highly sensitive to local and uniform changes across the length of the grating. Initial efforts to evaluate this approach for measuring adhesive bonding defects at substrate interfaces are discussed. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  17. Dosimetry intercomparisons between fast neutron radiotherapy facilities

    International Nuclear Information System (INIS)

    Almond, P.R.; Smith, A.R.; Smathers, J.B.; Otte, V.A.

    1975-01-01

    Neutron dosimetry intercomparisons have been made between M.D. Anderson Hospital and Tumor Institute, Naval Research Laboratory, University of Washington Hospital, and Hammersmith Hospital. The parameters that are measured during these visits are: tissue kerma in air, tissue dose at depth of dose maximum, depth dose, beam profiles, neutron/gamma ratios and photon calibrations of ionization chambers. A preliminary report of these intercomparisons will be given including a comparison of the calculation and statement of tumor doses for each institution

  18. Guidelines on calibration of neutron measuring devices

    International Nuclear Information System (INIS)

    Burger, G.

    1988-01-01

    The International Atomic Energy Agency and the World Health Organization have agreed to establish an IAEA/WHO Network of Secondary Standard Dosimetry Laboratories (SSDLs) in order to improve accuracy in applied radiation dosimetry throughout the world. These SSDLs must be equipped with, and maintain, secondary standard instruments, which have been calibrated against primary standards, and must be nominated by their governments for membership of the network. The majority of the existing SSDLs were established primarily to work with photon radiation (X-rays and gamma rays). Neutron sources are, however, increasingly being applied in industrial processes, research, nuclear power development and radiation biology and medicine. Thus, it is desirable that the SSDLs in countries using neutron sources on a regular basis should also fulfil the minimum requirements to calibrate neutron measuring devices. It is the primary purpose of this handbook to provide guidance on calibration of instruments for radiation protection. A calibration laboratory should also be in a position to calibrate instrumentation being used for the measurement of kerma and absorbed dose and their corresponding rates. This calibration is generally done with photons. In addition, since each neutron field is usually contaminated by photons produced in the source or by scatter in the surrounding media, neutron protection instrumentation has to be tested with respect to its intrinsic photon response. The laboratory will therefore need to possess equipment for photon calibration. This publication deals primarily with methods of applying radioactive neutron sources for calibration of instrumentation, and gives an indication of the space, manpower and facilities needed to fulfil the minimum requirements of a calibration laboratory for neutron work. It is intended to serve as a guide for centres about to start on neutron dosimetry standardization and calibration. 94 refs, 8 figs, 12 tabs

  19. Research activities at the Finnish TRIGA Laboratory

    International Nuclear Information System (INIS)

    Jauho, P.

    1970-01-01

    Short descriptions will be given of the following projects: Cold neutron facility redesign, texture studies with neutron diffraction, capture gamma ray studies for analytical purposes using Bi-filtered beam, neutron radiography, nuclear spectroscopy work, positron research, nuclear noise analysis, activities of the reactor code group. As a separate part the projects of the Isotope Technical Division of the laboratory will be described. These include neutron source based activation analysis, X-ray- fluorescence instruments for industrial use, tracer studies of industrial processes, labelling of compounds for medical use, activation analysis applications. Some planned projects will also be mentioned. (author)

  20. 233U Assay A Neutron NDA System

    Energy Technology Data Exchange (ETDEWEB)

    Hensley, D.C.; Lucero, A.J.; Pierce, L.

    1998-11-17

    The assay of highly enriched {sup 233}U material presents some unique challenges. Techniques which apply to the assay of materials of Pu or enriched {sup 235}U do not convert easily over to the assay of {sup 233}U. A specialized neutron assay device is being fabricated to exploit the singles neutron signal, the weak correlated neutron signal, and an active correlated signal. These pieces of information when combined with {gamma} ray isotopics information should give a good overall determination of {sup 233}U material now stored in bldg. 3019 at the Oak Ridge National Laboratory.

  1. Assessment of cold neutron radiography capability

    International Nuclear Information System (INIS)

    McDonald, T.E. Jr.; Roberts, J.A.

    1998-01-01

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The authors goals were to demonstrate and assess cold neutron radiography techniques at the Los Alamos Neutron Science Center (LANSCE), Manual Lujan Neutron Scattering Center (Lujan Center), and to investigate potential applications of the capability. The authors have obtained images using film and an amorphous silicon detector. In addition, a new technique they have developed allows neutron radiographs to be made using only a narrow range of neutron energies. Employing this approach and the Bragg cut-off phenomena in certain materials, they have demonstrated material discrimination in radiography. They also demonstrated the imaging of cracks in a sample of a fire-set case that was supplied by Sandia National Laboratory, and they investigated whether the capability could be used to determine the extent of coking in jet engine nozzles. The LANSCE neutron radiography capability appears to have applications in the DOE stockpile maintenance and science-based stockpile stewardship (SBSS) programs, and in industry

  2. Neutron microdosimetry

    International Nuclear Information System (INIS)

    Kliauga, P.

    1987-01-01

    A major effort was made during the past year to do precision microdosimetry of neutrons at the RARAF facility. By precision microdosimetry the authors mean a special effort to understand, better than previously, some of the factors which go into the limitation of the accuracy and precision of microdosimetric measurements of neutrons. That such factors are still not clearly understood, or at least accounted for, is immediately evident upon examination of published microdosimetric measurements. What becomes immediately apparent upon examination of, say, the dose mean lineal energies reported, is that the spread of reported values for exceeds the reported experimental uncertainty, commonly taken as about 5%. Differences of 50% are not uncommon. It is easy to make the mistake that since classical microdosimetry uses a well-established experimental tool, the proportional counter, that sources of error should also be well understood. However, microdosimetry makes use of the proportional counter in a way which is quite different from its origins as a low-energy photon spectroscopy device. Microdosimetric spectra, particularly of neutrons, span 5 to 6 decades of event sizes. It is by no means certain that proportionality extends over such a range, and in fact it has been pointed out that it probably does not. Data analysis techniques vary from one experimenter to another, and can substantially affect mean values as well as spectral shape. The authors are examining these parameters, as well as others, such as calibration errors, but they are especially concentrating on the effect of counter design and performance on the resultant spectra which the counter measures

  3. Portable system for periodical verification of area monitors for neutrons; Sistema portatil para verificacao periodica de monitores de area para neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Luciane de R.; Leite, Sandro Passos; Lopes, Ricardo Tadeu, E-mail: rluciane@ird.gov.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEN/COPPE/UFRJ), RJ (Brazil). Programa de Energia Nuclear; Patrao, Karla C. de Souza; Fonseca, Evaldo S. da; Pereira, Walsan W., E-mail: karla@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. Nacional de Metrologia das Radiacoes Ionizantes (LNMRI). Lab. de Neutrons

    2009-07-01

    The Neutrons Laboratory develops a project viewing the construction of a portable test system for verification of functioning conditions of neutron area monitors. This device will allow to the users the verification of the calibration maintenance of his instruments at the use installations, avoiding the use of an inadequate equipment related to his answer to the neutron beam response

  4. Development of high flux thermal neutron generator for neutron activation analysis

    International Nuclear Information System (INIS)

    Vainionpaa, Jaakko H.; Chen, Allan X.; Piestrup, Melvin A.; Gary, Charles K.; Jones, Glenn; Pantell, Richard H.

    2015-01-01

    The new model DD110MB neutron generator from Adelphi Technology produces thermal (<0.5 eV) neutron flux that is normally achieved in a nuclear reactor or larger accelerator based systems. Thermal neutron fluxes of 3–5 · 10 7 n/cm 2 /s are measured. This flux is achieved using four ion beams arranged concentrically around a target chamber containing a compact moderator with a central sample cylinder. Fast neutron yield of ∼2 · 10 10 n/s is created at the titanium surface of the target chamber. The thickness and material of the moderator is selected to maximize the thermal neutron flux at the center. The 2.5 MeV neutrons are quickly thermalized to energies below 0.5 eV and concentrated at the sample cylinder. The maximum flux of thermal neutrons at the target is achieved when approximately half of the neutrons at the sample area are thermalized. In this paper we present simulation results used to characterize performance of the neutron generator. The neutron flux can be used for neutron activation analysis (NAA) prompt gamma neutron activation analysis (PGNAA) for determining the concentrations of elements in many materials. Another envisioned use of the generator is production of radioactive isotopes. DD110MB is small enough for modest-sized laboratories and universities. Compared to nuclear reactors the DD110MB produces comparable thermal flux but provides reduced administrative and safety requirements and it can be run in pulsed mode, which is beneficial in many neutron activation techniques

  5. Development of high flux thermal neutron generator for neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Vainionpaa, Jaakko H., E-mail: hannes@adelphitech.com [Adelphi Technology, 2003 E Bayshore Rd, Redwood City, CA 94063 (United States); Chen, Allan X.; Piestrup, Melvin A.; Gary, Charles K. [Adelphi Technology, 2003 E Bayshore Rd, Redwood City, CA 94063 (United States); Jones, Glenn [G& J Jones Enterprice, 7486 Brighton Ct, Dublin, CA 94568 (United States); Pantell, Richard H. [Department of Electrical Engineering, Stanford University, Stanford, CA (United States)

    2015-05-01

    The new model DD110MB neutron generator from Adelphi Technology produces thermal (<0.5 eV) neutron flux that is normally achieved in a nuclear reactor or larger accelerator based systems. Thermal neutron fluxes of 3–5 · 10{sup 7} n/cm{sup 2}/s are measured. This flux is achieved using four ion beams arranged concentrically around a target chamber containing a compact moderator with a central sample cylinder. Fast neutron yield of ∼2 · 10{sup 10} n/s is created at the titanium surface of the target chamber. The thickness and material of the moderator is selected to maximize the thermal neutron flux at the center. The 2.5 MeV neutrons are quickly thermalized to energies below 0.5 eV and concentrated at the sample cylinder. The maximum flux of thermal neutrons at the target is achieved when approximately half of the neutrons at the sample area are thermalized. In this paper we present simulation results used to characterize performance of the neutron generator. The neutron flux can be used for neutron activation analysis (NAA) prompt gamma neutron activation analysis (PGNAA) for determining the concentrations of elements in many materials. Another envisioned use of the generator is production of radioactive isotopes. DD110MB is small enough for modest-sized laboratories and universities. Compared to nuclear reactors the DD110MB produces comparable thermal flux but provides reduced administrative and safety requirements and it can be run in pulsed mode, which is beneficial in many neutron activation techniques.

  6. Utilization of low voltage D-T neutron generators in neutron physics studies

    Energy Technology Data Exchange (ETDEWEB)

    Singkarat, S.

    1995-08-01

    In a small nuclear laboratory of a developing country a low voltage D-T neutron generator can be a very useful scientific apparatus. Such machines have been used successfully for more than 40 years in teaching and scientific research. The original continuous mode 150-kV D-T neutron generator has been modified to have also a capability of producing 2-ns pulsed neutrons. Together with a carefully designed 10 m long flight path collimator and shielding of a 25 cm diameter {center_dot} 10 cm thick BC-501 neutron detector, the pulsing system was successfully used for measuring the double differential cross-section (DDX) of natural iron for 14.1-MeV neutron from the angle of 30 deg to 150 deg in 10 deg steps. In order to extend the utility of the generator, two methods for converting the almost monoenergetic 14-MeV neutrons to monoenergetic neutrons of lower energy were proposed and tested. The first method uses a pulsed neutron generator and the second method uses an ordinary continuous mode generator. The latter method was successfully used to measure the scintillation light output of a 1.4 cm diameter spherical NE-213 scintillation detector. The neutron generator has also been used in the continuous search for improved neutron detection techniques. There is a proposal, based on Monte Carlo calculations, of using a scintillation fiber for a fast neutron spectrometer. Due to the slender shape of the fiber, the pattern of produced light gives a peak in the pulse height spectrum instead of the well-known rectangular-like distribution, when the fiber is bombarded end-on by a beam of 14-MeV neutrons. Experimental investigations were undertaken. Detailed investigations on the light transportation property of a short fiber were performed. The predicted peak has not yet been found but the fiber detector may be developed as a directional discrimination fast neutron detector. 18 refs.

  7. Introduction - Chadwick discovers the neutron

    International Nuclear Information System (INIS)

    Hendry, J.

    1984-01-01

    The background to Chadwick's discovery in 1932 of the neutron predicted by Rutherford is chronicled. In the same year Cockcroft and Walton split the atom, and the story of this event is told. 1932 also saw the demonstration by Blackett and Occhialini of the existence of the positron. These important contributions to nuclear physics were all made at the Cavendish Laboratory in Cambridge. Photographs, extracts from experimental notebooks and circuit diagrams illustrate this introduction. (UK)

  8. Bulk media assay using backscattered Pu-Be neutrons

    CERN Document Server

    Csikai, J

    1999-01-01

    Spectral yields of elastically backscattered Pu-Be neutrons measured for graphite, water, polyethylene, liquid nitrogen, paraffin oil, SiO sub 2 , Al, Fe, and Pb slabs show a definite correlation with the energy dependence of the elastic scattering cross sections, sigma sub E sub L (E sub n). The C, N and O can be identified by the different structures in their sigma sub E sub L (E sub n) functions. The integrated spectral yields versus thickness exhibit saturation for each sample. The interrogated volume is limited by the presence of hydrogen in the sample. (author)

  9. The Dense Plasma Focus Opportunities in Detection of Hidden Objects by Using Nanosecond Impulse Neutron Inspection System (NINIS)

    International Nuclear Information System (INIS)

    Gribkov, V.; Karpinski, L.; Miklaszewski, R.; Paduch, M.; Scholz, M.; Strzyzewski, P.; Tomaszewski, K.; Dubrovsky, A.

    2006-01-01

    Dense Plasma Focus device is proposed for use as a neutron source to generate very powerful pulses of neutrons in the nanosecond (ns) range of its duration. Our devices PF-6, recently put into operation at the Institute of Plasma Physics and Laser Microfusion, Warsaw, Poland, and PF-10 belonging to the Institute for Theoretical and Experimental Physics, Moscow, Russia, have energy storages in its capacitor banks 7.4 kJ and 13 kJ as a maximum. Operated with the DPF chambers of a special design they have a current maximum up to ∼760 kA with a quarter period of the discharge equal to 1 microsecond. They generate circa 109 of 2.5-MeV neutrons in one pulse of congruent with 10-ns duration when working with deuterium, what permit to expect 1011 14-MeV neutrons at their operation with DT-mixture. This feature gives a principal possibility to create a ''single-shot detection system'' for interrogation of hidden objects. It means that all necessary information will be received during a single bright pulse of neutrons having duration in a nanosecond range by means of the time-of-flight technique with a short flight base. It might be a base for the creation of the Nanosecond Impulse Neutron Inspection System (NINIS). These characteristics of the neutron source open a number of opportunities while interrogation time in this case would now depend only on the data-processing system

  10. The Dense Plasma Focus Opportunities in Detection of Hidden Objects by Using Nanosecond Impulse Neutron Inspection System (NINIS)

    Science.gov (United States)

    Gribkov, V.; Dubrovsky, A.; Karpiński, L.; Miklaszewski, R.; Paduch, M.; Scholz, M.; StrzyŻewski, P.; Tomaszewski, K.

    2006-12-01

    Dense Plasma Focus device is proposed for use as a neutron source to generate very powerful pulses of neutrons in the nanosecond (ns) range of its duration. Our devices PF-6, recently put into operation at the Institute of Plasma Physics and Laser Microfusion, Warsaw, Poland, and PF-10 belonging to the Institute for Theoretical and Experimental Physics, Moscow, Russia, have energy storages in its capacitor banks 7.4 kJ and 13 kJ as a maximum. Operated with the DPF chambers of a special design they have a current maximum up to ˜760 kA with a quarter period of the discharge equal to 1 microsecond. They generate circa 109 of 2.5-MeV neutrons in one pulse of ≅ 10-ns duration when working with deuterium, what permit to expect 1011 14-MeV neutrons at their operation with DT-mixture. This feature gives a principal possibility to create a "single-shot detection system" for interrogation of hidden objects. It means that all necessary information will be received during a single bright pulse of neutrons having duration in a nanosecond range by means of the time-of-flight technique with a short flight base. It might be a base for the creation of the Nanosecond Impulse Neutron Inspection System (NINIS). These characteristics of the neutron source open a number of opportunities while interrogation time in this case would now depend only on the data-processing system.

  11. Neutrons and carcinogenesis: a cautionary tale

    International Nuclear Information System (INIS)

    Hall, E.J.

    1996-01-01

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

  12. Intercomparison of high energy neutron personnel dosimeters

    International Nuclear Information System (INIS)

    McDonald, J.C.; Akabani, G.; Loesch, R.M.

    1993-03-01

    An intercomparison of high-energy neutron personnel dosimeters was performed to evaluate the uniformity of the response characteristics of typical neutron dosimeters presently in use at US Department of Energy (DOE) accelerator facilities. It was necessary to perform an intercomparison because there are no national or international standards for high-energy neutron dosimetry. The testing that is presently under way for the Department of Energy Laboratory Accreditation Program (DOELAP) is limited to the use of neutron sources that range in energy from about 1 keV to 2 MeV. Therefore, the high-energy neutron dosimeters presently in use at DOE accelerator facilities are not being tested effectively. This intercomparison employed neutrons produced by the 9 Be(p,n) 9 B interaction at the University of Washington cyclotron, using 50-MeV protons. The resulting neutron energy spectrum extended to a maximum of approximately 50-MeV, with a mean energy of about 20-MeV. Intercomparison results for currently used dosimeters, including Nuclear Type A (NTA) film, thermoluminescent dosimeter (TLD)-albedo, and track-etch dosimeters (TEDs), indicated a wide variation in response to identical doses of high-energy neutrons. Results of this study will be discussed along with a description of plans for future work

  13. Miniature and low cost fiber bragg grating interrogator for structural monitoring in nano-satellites

    NARCIS (Netherlands)

    Toet, P.M.; Hagen, R.A.J.; Hakkesteegt, H.C.; Lugtenburg, J.; Maniscalco, M.P.

    2014-01-01

    In this paper we present a newly developed Fiber Optic measurement system, consisting of Fiber Bragg Grating (FBG) sensors and an FBG interrogator. The development of the measuring system is part of the PiezoElectric Assisted Smart Satellite Structure (PEASSS) project, which was initiated at the

  14. Asking for Action or Information? Crosslinguistic Comparison of Interrogative Functions in Early Child Cantonese and Mandarin

    Science.gov (United States)

    Li, Hui; Wong, Eileen Chin Mei; Tse, Shek Kam; Leung, Shing On; Ye, Qianling

    2015-01-01

    Request for information (RfI) is believed to be the universally dominant function of young children's questioning, whereas request for action (RfA) has been reported to be the leading interrogative form used in early child Cantonese. The possibility of crosslinguistic variability prompts further research and comparison with additional languages.…

  15. “Please let me shape my fate” : Interrogating the contemporary in ...

    African Journals Online (AJOL)

    These writers are concerned with the fate of their countries, and so we can argue that the purpose of writing is the desire to shape the fate of the society. This is what we have termed “let me know my fate”. Another concern in this paper is how effectively and successfully can a contemporary writer interrogate a contemporary ...

  16. An Evaluation of "Miranda" Rights and Interrogation in Autism Spectrum Disorders

    Science.gov (United States)

    Salseda, Lindsay M.; Dixon, Dennis R.; Fass, Tracy; Miora, Deborah; Leark, Robert A.

    2011-01-01

    The primary deficits present in autism spectrum disorders (ASD) may lead to increased susceptibility to involvement in the criminal justice system. The same deficits may also cause individuals with ASD to be more vulnerable to interrogation techniques and other aspects of the legal system. Due to the increased level of vulnerability as well as…

  17. The Lawyer in the Dutch Interrogation Room: Influence on Police and Suspect

    NARCIS (Netherlands)

    W-J. Verhoeven (Willem-Jan); L. Stevens (Lonneke)

    2012-01-01

    textabstractIn many European countries, providing a suspect in custody with legal aid before the first police interrogation is a heavily debated issue. In this paper, we report on an exploratory study on the use of coercion by the police and the use of the right to silence by suspects in 70 Dutch

  18. The Lawyer in the Dutch Interrogation Room: Influence on Police and Suspect

    NARCIS (Netherlands)

    Verhoeven, W.J.; Stevens, L.

    2012-01-01

    In many European countries, providing a suspect in custody with legal aid before the first police interrogation is a heavily debated issue. In this paper, we report on an exploratory study on the use of coercion by the police and the use of the right to silence by suspects in 70 Dutch homicide cases

  19. Interferometric interrogation of π-phase shifted fiber Bragg grating sensors

    Science.gov (United States)

    Srivastava, Deepa; Tiwari, Umesh; Das, Bhargab

    2018-03-01

    Interferometric interrogation technique realized for conventional fiber Bragg grating (FBG) sensors is historically known to offer the highest sensitivity measurements, however, it has not been yet explored for π-phase-shifted FBG (πFBG) sensors. This, we believe, is due to the complex nature of the reflection/transmission spectrum of a πFBG, which cannot be directly used for interferometric interrogation purpose. Therefore, we propose here an innovative as well as simple concept towards this direction, wherein, the transmission spectrum of a πFBG sensor is optically filtered using a specially designed fiber grating. The resulting filtered spectrum retains the entire characteristics of a πFBG sensor and hence the filtered spectrum can be interrogated with interferometric principles. Furthermore, due to the extremely narrow transmission notch of a πFBG sensor, a fiber interferometer can be realized with significantly longer path difference. This leads to substantially enhanced detection limit as compared to sensors based on a regular FBG of similar length. Theoretical analysis demonstrates that high resolution weak dynamic strain measurement down to 4 pε /√{ Hz } is easily achievable. Preliminary experimental results are also presented as proof-of-concept of the proposed interrogation principle.

  20. 75 FR 67632 - Defense Federal Acquisition Regulation Supplement; Prohibition on Interrogation of Detainees by...

    Science.gov (United States)

    2010-11-03

    ...D Instruction 1100.22, Policy and Procedures for Determining Workforce Mix ( http://www.dtic.mil/whs... ( http://www.dtic.mil/whs/directives/corres/pdf/231001p.pdf ); and DoD Directive 3115.09, DoD Intelligence Interrogations, Detainee Debriefings, and Tactical Questioning ( http://www.dtic.mil/whs...

  1. The recognition of acted interpersonal stance in police interrogations and the influence of actor proficiency

    NARCIS (Netherlands)

    Bruijnes, Merijn; op den Akker, Hendrikus J.A.; Spitters, Sophie; Sanders, Merijn; Fu, Quihua

    2015-01-01

    This paper reports on judgement studies regarding the perception of interpersonal stances taken by humans playing the role of a suspect in a police interrogation setting. Our project aims at building believable embodied conversational characters to play the role of suspects in a serious game for

  2. French Interrogative Structures: A New Pedagogical Norm for the 21st-Century Classroom

    Science.gov (United States)

    Antes, Theresa A.

    2016-01-01

    This study investigated interrogative structures most frequently used by native speakers of French, in an attempt to reconcile differences between language forms taught in the French as a foreign language classroom and those that are encountered in authentic input. Radio, television, and magazine interviews provided multiple examples of…

  3. Advice-Implicative Interrogatives: Building "Client-Centered" Support in a Children's Helpline

    Science.gov (United States)

    Butler, Carly W.; Potter, Jonathan; Danby, Susan; Emmison, Michael; Hepburn, Alexa

    2010-01-01

    Interactional research on advice giving has described advice as normative and asymmetric. In this paper we examine how these dimensions of advice are softened by counselors on a helpline for children and young people through the use of questions. Through what we term "advice-implicative interrogatives," counselors ask clients about the…

  4. 25 CFR 11.303 - Notification of rights prior to custodial interrogation.

    Science.gov (United States)

    2010-04-01

    ... COURTS OF INDIAN OFFENSES AND LAW AND ORDER CODE Criminal Procedure § 11.303 Notification of rights prior... 25 Indians 1 2010-04-01 2010-04-01 false Notification of rights prior to custodial interrogation... following rights: (a) That he or she has the right to remain silent. (b) That any statements made by him or...

  5. Multi-Messenger Observations of Neutron Rich Matter

    Energy Technology Data Exchange (ETDEWEB)

    Horowitz, C. J. [UTK/ORNL/Indiana University

    2012-01-01

    At very high densities, electrons react with protons to form neutron rich matter. This material is central to many fundamental questions in nuclear physics and astrophysics. Moreover, neutron rich matter is being studied with an extraordinary variety of new tools such as the Facility for Rare Isotope Beams (FRIB) and the Laser Interferometer Gravitational Wave Observatory (LIGO). We describe the Lead Radius Experiment (PREX) that uses parity violating electron scattering to measure the neutron radius in 208Pb. This has important implications for neutron stars and their crusts. We discuss X-ray observations of neutron star radii. These also have important implications for neutron rich matter. Gravitational waves (GW) open a new window on neutron rich matter. They come from sources such as neutron star mergers, rotating neutron star mountains, and collective r-mode oscillations. Using large scale molecular dynamics simulations, we find neutron star crust to be very strong. It can support mountains on rotating neutron stars large enough to generate detectable gravitational waves. We believe that combing astronomical observations using photons, GW, and neutrinos, with laboratory experiments on nuclei, heavy ion collisions, and radioactive beams will fundamentally advance our knowledge of compact objects in the heavens, the dense phases of QCD, the origin of the elements, and of neutron rich matter.

  6. Application of neutron/gamma transport codes for the design of explosive detection systems

    International Nuclear Information System (INIS)

    Elias, E.; Shayer, Z.

    1994-01-01

    Applications of neutron and gamma transport codes to the design of nuclear techniques for detecting concealed explosives material are discussed. The methodology of integrating radiation transport computations in the development, optimization and analysis phases of these new technologies is discussed. Transport and Monte Carlo codes are used for proof of concepts, guide the system integration, reduce the extend of experimental program and provide insight into the physical problem involved. The paper concentrates on detection techniques based on thermal and fast neutron interactions in the interrogated object. (authors). 6 refs., 1 tab., 5 figs

  7. Petrophysical quantities from high resolution gamma-ray spectra arising from energetic neutron bombardment

    Science.gov (United States)

    Mellor, D. W.; Underwood, M. C.

    A logging tool comprising a 5 Curie Am241-Be neutron source and n-type intrinsic germanium gamma ray detector was developed. A large calibration tank, in simulated well-bore geometry, comprising oil and water saturated sand, was constructed and was interrogated using the tool. In a separate experiment, oil zone material was irradiated using 14 MeV neutrons. An interpretational model that allows the porosity, oil and water saturation, matrix composition, and water salinity to be inferred is presented. This confirms that under strictly controlled experimental conditions, major petrophysical properties can be inferred from high resolution gamma ray spectra.

  8. Studies of neutron irradiation effects at IPNS-REF

    International Nuclear Information System (INIS)

    Kirk, M.A.

    1983-09-01

    Neutron irradiation effects studies at the Radiation Effects Facility (REF) at the Intense Pulsed Neutron Source (IPNS) located at Argonne National Laboratory (ANL) are reviewed. A brief history of the development of this user facility is followed by an overview of the scientific program. Experiments unique to a spallation neutron source are covered in more detail. Future direction of research at this facility is suggested

  9. Polarisation modulated crosscorrelation spectroscopy on a pulsed neutron source

    International Nuclear Information System (INIS)

    Cywinski, R.; Williams, W.G.

    1984-07-01

    A crosscorrelation technique is introduced by which a total scattering polarisation analysis spectrometer on a pulsed neutron source can be modified to give full neutron polarisation and energy analysis without changing the physical configuration of the instrument. Its implementation on the proposed POLARIS spectrometer at the Rutherford Appleton Laboratory Spallation Neutron Source is described, and the expected dynamic (Q, ω) range and resolution evaluated. (author)

  10. Neutron-Activated Gamma-Emission: Technology Review

    Science.gov (United States)

    2012-01-01

    complex in implementation. The lower energy neutrons from californium - 252 (0.7–4 MeV) and deuterium-on-deuterium (D-D) electronic neutron generators (ENG...for production of californium is centered at Oak Ridge National Laboratory (ORNL) high-flux- reactor (HIFR). Californium is used to start up new power...achievable Am americium API associated particle imaging B boron Be beryllium BNCT boron neutron capture therapy C carbon Cf californium Cl

  11. Manufacturing of NAA laboratory clean room

    International Nuclear Information System (INIS)

    Suwoto; Hasibuan, Djaruddin

    2001-01-01

    The ''NAA laboratory clean room'' has been built in the Reactor Serba Guna G.A. Siwabessy building. The erection of ''AAN laboratory clean room'' doing by started of preparation of the ''manufacturing procedure'' refer to ''Design and manufacturing neutron activation analysis clean room laboratory''. Manufacturing process and erection doing refer to procedures makes. By providing of the ''AAN laboratory clean room'' can be cocluded that the research activity and the user sevises in P2TRR well meet to be done

  12. Measurements of the thermal neutron flux for an accelerator-based photoneutron source.

    Science.gov (United States)

    Taheri, Ali; Pazirandeh, Ali

    2016-12-01

    To have access to an appropriate neutron source is one of the most demanding requirements for neutron studies. This is important specially in laboratory and clinical applications, which need more compact and accessible sources. The most known neutron sources are fission reactors and natural isotopes, but there is an increasing interest for using accelerator based neutron sources because of their advantages. In this paper, we shall present a photo-neutron source prototype which is designed and fabricated to be used for different neutron researches including in-laboratory neutron activation analysis and neutron imaging, and also preliminary studies in boron neutron capture therapy (BNCT). Series of experimental tests were conducted to examine the intensity and quality of the neutron field produced by this source. Monte-Carlo simulations were also utilized to provide more detailed evaluation of the neutron spectrum, and determine the accuracy of the experiments. The experiments demonstrated a thermal neutron flux in the order of 10 7 (n/cm 2 .s), while simulations affirmed this flux and showed a neutron spectrum with a sharp peak at thermal energy region. According to the results, about 60 % of produced neutrons are in the range of thermal to epithermal neutrons.

  13. Neutron matter, symmetry energy and neutron stars

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-01

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

  14. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  15. Neutron generator control system

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  16. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  17. Improvements in PIE-techniques at the IFE hot-laboratory. 'Neutron radiography, three dimensional profilometry and image compilation of PIE data for visualization in an image based user-interface'

    International Nuclear Information System (INIS)

    Jenssen, H.K.; Oberlaender, B.C.

    2002-01-01

    The PIE-techniques used at IFE are continuously improved through upgrading of equipment and methods, e.g. image handling techniques and components utilized in data acquisition and editing techniques. To improve the quality or spatial resolution of neutron radiographs the normal technique was complemented with another method, i.e. the dysprosium foil/X ray film technique is supplemented with a track-etch recorder consisting of a cellulose nitrate film. For further examination of the neutron radiographs the cellulose nitrate film can be digitized to allow electronic image treatment. Promising results were obtained with this technique on neutron radiographs, namely higher spatial resolution compared to the normal technique, high contrast and sharp neutron radiography images. The traditional uniaxial profilometry of fuel rods was modified so that diameter/bow measurements are possible at several angular orientations during one acquisition sequence. This extension is very useful in several ways, for instance the built-in data symmetry of the method is used to check the correctness of the measurement results. Diameter and bow measurements give information of cladding irregularities and fuel rod profiles. Implementation of electronic image handling techniques is particularly useful in PIE when data are collected and compiled in an image file. Inspection and examination of the file contents (examination results) are possible through an ideal user-interface, i.e. Adobe Photoshop software with navigator possibilities. Examples incorporating PIE data acquired from neutron radiography, visual inspection and ceramography are utilized for illustration of the user-interface and some of its possibilities. (author)

  18. Performances of a β-delayed neutron detection array at Peking University

    Science.gov (United States)

    Lou, Jianling; Li, Zhihuan; Ye, Yanlin; Hua, Hui; Faisal, Q. J.; Jiang, Dongxing; Li, Xiangqing; Zhang, Shuangquan; Zheng, Tao; Ge, Yucheng; Kong, Zan; Song, Yushou; Lv, Linhui; Li, Chen; Lu, Fei; Fan, Fengying; Li, Zhongyu; Cao, Zhongxin; Ma, Liying; Li, Qite; Xiao, Jun

    2009-07-01

    A β-delayed neutron detection array composed of a neutron sphere and two neutron walls was constructed in the State Key Laboratory of Nuclear Physics and Technology at Peking University. Recently the performances of this detection array were largely improved and tested with a Co60 source, cosmic rays and C16 and N17 radioactive beams. The Tyvek 1056D paper and silicone grease were chosen for the reflection and coupling materials, respectively. For the neutron sphere with large detection solid angle (30% of 4π steradian), the intrinsic efficiency is about 14.1% at a neutron energy of 1 MeV and the detection threshold is about 350 keV; for the neutron walls with flexible setup, these values are 36.5% and 200 keV, respectively. The combined array of neutron sphere and neutron walls has successfully been applied to measure the β-delayed neutrons emitted from neutron-rich unstable nuclei.

  19. Police training in interviewing and interrogation methods: A comparison of techniques used with adult and juvenile suspects.

    Science.gov (United States)

    Cleary, Hayley M D; Warner, Todd C

    2016-06-01

    Despite empirical progress in documenting and classifying various interrogation techniques, very little is known about how police are trained in interrogation methods, how frequently they use various techniques, and whether they employ techniques differentially with adult versus juvenile suspects. This study reports the nature and extent of formal (e.g., Reid Technique, PEACE, HUMINT) and informal interrogation training as well as self-reported technique usage in a diverse national sample (N = 340) of experienced American police officers. Officers were trained in a variety of different techniques ranging from comparatively benign pre-interrogation strategies (e.g., building rapport, observing body language or speech patterns) to more psychologically coercive techniques (e.g., blaming the victim, discouraging denials). Over half the sample reported being trained to use psychologically coercive techniques with both adults and juveniles. The majority (91%) receive informal, "on the job" interrogation training. Technique usage patterns indicate a spectrum of psychological intensity where information-gathering approaches were used most frequently and high-pressure tactics less frequently. Reid-trained officers (56%) were significantly more likely than officers without Reid training to use pre-interrogation and manipulation techniques. Across all analyses and techniques, usage patterns were identical for adult and juvenile suspects, suggesting that police interrogate youth in the same manner as adults. Overall, results suggest that training in specific interrogation methods is strongly associated with usage. Findings underscore the need for more law enforcement interrogation training in general, especially with juvenile suspects, and highlight the value of training as an avenue for reducing interrogation-induced miscarriages of justice. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  20. 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.

  1. 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

  2. Non-destructive assay of mechanical components using gamma-rays and thermal neutrons

    Science.gov (United States)

    Souza, Erica Silvani; de Almeida, Gevaldo L.; Souza, Maria Ines S.; Avelino, Mila R.

    2013-05-01

    This work presents the results obtained in the inspection of several mechanical components through neutron and gamma-ray transmission radiography. The 4.46 × 105 n.cm-2.s-1 thermal neutron flux available at the main port of the Argonauta research reactor in Instituto de Engenharia Nuclear has been used as source for the neutron radiographic imaging. The 412 keV γ-ray emitted by 198Au, also produced in that reactor, has been used as interrogation agent for the gamma radiography. Imaging Plates - IP specifically designed to operate with thermal neutrons or with X-rays have been employed as detectors and storage devices for each of these radiations.

  3. Neutron collar calibration for assay of LWR [light-water reactor] fuel assemblies

    International Nuclear Information System (INIS)

    Menlove, H.O.; Pieper, J.E.

    1987-03-01

    The neutron-coincidence collar is used for the verification of the uranium content in light-water reactor fuel assemblies. An AmLi neutron source is used to give an active interrogation of the fuel assembly to measure the 235 U content, and the 238 U content is verified from a passive neutron-coincidence measurement. This report gives the collar calibration data of pressurized-water reactor and boiling-water reactor fuel assemblies. Calibration curves and correction factors are presented for neutron absorbers (burnable poisons) and different fuel assembly sizes. The data were collected at Exxon Nuclear, Franco-Belge de Fabrication de Combustibles, ASEA-Atom, and other nuclear fuel fabrication facilities

  4. Fast neutron inspection of sea containers for the presence of 'dirty bomb'

    International Nuclear Information System (INIS)

    Valkovic, V.; Sudac, D.; Blagus, S.; Nad, K.; Obhodas, J.; Vekic, B.; Nebbia, G.; Pesente, S.

    2007-01-01

    The possibility of the detection of 'dirty bomb' presence inside sea containers is evaluated. The method proposed for explosive and fissile material detection makes use of two sensors (X-rays and neutrons). A commercial imaging device based on the X-ray radiography performs a fast scan of the container, identifies a 'suspect' region and provides its coordinates to the neutron based device for the final 'confirmatory' inspection. In this two sensor system a 14 MeV neutron beam defined by the detection of associated alpha particles is used for interrogation of only volume elements marked by X-ray sensor. The object's nature is determined from passive and neutron induced, gamma energy spectra measurements. Experimental results (time-of-flight and gamma energy spectra) obtained for the irradiation 30 kg of TNT, depleted uranium and other materials hidden inside the container are presented

  5. The D-D Neutron Generator as an Alternative to Am(Li) Isotopic Neutron Source in the Active Well Coincidence Counter

    Energy Technology Data Exchange (ETDEWEB)

    McElroy, Robert Dennis [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cleveland, Steven L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-03-01

    The 235U mass assay of bulk uranium items, such as oxide canisters, fuel pellets, and fuel assemblies, is not achievable by traditional gamma-ray assay techniques due to the limited penetration of the item by the characteristic 235U gamma rays. Instead, fast neutron interrogation methods such as active neutron coincidence counting must be used. For international safeguards applications, the most commonly used active neutron systems, the Active Well Coincidence Counter (AWCC), Uranium Neutron Collar (UNCL) and 252Cf Shuffler, rely on fast neutron interrogation using an isotopic neutron source [i.e., 252Cf or Am(Li)] to achieve better measurement accuracies than are possible using gamma-ray techniques for high-mass, high-density items. However, the Am(Li) sources required for the AWCC and UNCL systems are no longer manufactured, and newly produced systems rely on limited supplies of sources salvaged from disused instruments. The 252Cf shuffler systems rely on the use of high-output 252Cf sources, which while still available have become extremely costly for use in routine operations and require replacement every five to seven years. Lack of a suitable alternative neutron interrogation source would leave a potentially significant gap in the safeguarding of uranium processing facilities. In this work, we made use of Oak Ridge National Laboratory’s (ORNL’s) Large Volume Active Well Coincidence Counter (LV-AWCC) and a commercially available deuterium-deuterium (D-D) neutron generator to examine the potential of the D-D neutron generator as an alternative to the isotopic sources. We present the performance of the LV-AWCC with D-D generator for the assay of 235U based on the results of Monte Carlo N-Particle (MCNP) simulations and measurements of depleted uranium (DU), low enriched uranium (LEU), and highly enriched uranium (HEU) items.

  6. Effective vibration isolation system for perfect-crystal neutron interferometry

    International Nuclear Information System (INIS)

    Arthur, J.

    1985-01-01

    Perfect-crystal neutron interferometers are subject to degradation of their performance caused by vibrational accelerations. It is shown that the most seriously offending accelerations are rotational, and an effective and simple vibration isolation system that has been developed at the MIT Neutron Diffraction Laboratory is described

  7. Data acquisition and instrument control system for neutron ...

    Indian Academy of Sciences (India)

    A personal computer (PC)-based data acquisition and instrument control system has been developed for neutron spectrometers in Dhruva reactor hall and Guide Tube laboratory. Efforts have been made to make the system versatile so that it can be used for controlling various neutron spectrometers using single end-on ...

  8. Neutrons in science and technology

    International Nuclear Information System (INIS)

    Bromley, D.A.

    1984-01-01

    Occasionally to the fiftieth anniversy of the discovery of the neutron the author presents a historical review about the impact of this discovery on different fields at physics. Especially considered are nuclear physics, the neutron as an elementary particles, ultracold neutrons, condensed matter physics, radiation damage induced by neutrons, neutron activation analysis, imaging and radiography by neutrons, neutrons in mining operations, track etching, the use of intense gamma sources, gauging systems, neutron holography and neutron stars. (HSI)

  9. Physics of enriched uranyl fluoride deposit characterizations using active neutron and gamma interrogation techniques with 252Cf

    International Nuclear Information System (INIS)

    Wyatt, M.S.; Hannon, T.F.

    1998-01-01

    A method was developed and successfully applied to characterize large uranyl fluoride (UO 2 F 21 ) deposits at the former Oak Ridge Gaseous Diffusion Plant. These deposits were formed by a wet air in-leakage into the UF 6 process gas lines over a period of years. The resulting UO 2 F 2 is hygroscopic, readily absorbing moisture from the air to form hydrates as UO 2 F 2 -nH 2 O. The ratio of hydrogen to uranium, denoted H/U, can vary from 0--16, and has significant nuclear criticality safety impacts for large deposits. In order to properly formulate the required course of action, a non-intrusive characterization of the distribution of the fissile material within the pipe, its total mass, and amount of hydration was needed. The Nuclear Weapons Identification System (NWIS) previously developed at the Oak Ridge Y-12 Plant for identification of uranium weapons components in storage containers was used to successfully characterize the distribution, hydration, and total mass of these deposits

  10. Characterization of neutron optics elements using neutron multireflections experiment

    International Nuclear Information System (INIS)

    Ballot, B.; Menelle, A.; Samuel, F.; Al Usta, K.; Farnoux, B.

    1994-01-01

    Metallic multilayers are more and more used in the fabrication of efficient neutron optics elements. Neutron reflectivity is the ideal tool for the characterization of these multilayer devices. However, for these developments, the most interesting part of the reflectivity curve is situated in regions where the reflectivity coefficient R is close to one. In that part of the curve, a good precision in the measurement of the reflectivity is difficult to obtain using the classical one reflection measurements since differences between the incoming and the reflected beams are weak. At the Leon Brillouin Laboratory in Saclay, we have developed a neutron multireflections experiment. Compared with one reflection measurement, it enables us to increase the accuracy on the deviation from 1 of the reflectivity by a factor up to 12. This technique has been used on classical 58 Ni neutron guide elements as well as on two multilayer systems. These new measurements have been compared with classical reflectivity experiments performed on the same elements. ((orig.))

  11. Monte Carlo calculations of the neutron coincidence gate utilisation factor for passive neutron coincidence counting

    CERN Document Server

    Bourva, L C A

    1999-01-01

    The general purpose neutron-photon-electron Monte Carlo N-Particle code, MCNP sup T sup M , has been used to simulate the neutronic characteristics of the on-site laboratory passive neutron coincidence counter to be installed, under Euratom Safeguards Directorate supervision, at the Sellafield reprocessing plant in Cumbria, UK. This detector is part of a series of nondestructive assay instruments to be installed for the accurate determination of the plutonium content of nuclear materials. The present work focuses on one aspect of this task, namely, the accurate calculation of the coincidence gate utilisation factor. This parameter is an important term in the interpretative model used to analyse the passive neutron coincidence count data acquired using pulse train deconvolution electronics based on the shift register technique. It accounts for the limited proportion of neutrons detected within the time interval for which the electronics gate is open. The Monte Carlo code MCF, presented in this work, represents...

  12. Recent high-accuracy measurements of the 1S0 neutron-neutron scattering length

    International Nuclear Information System (INIS)

    Howell, C.R.; Chen, Q.; Gonzalez Trotter, D.E.; Salinas, F.; Crowell, A.S.; Roper, C.D.; Tornow, W.; Walter, R.L.; Carman, T.S.; Hussein, A.; Gibbs, W.R.; Gibson, B.F.; Morris, C.; Obst, A.; Sterbenz, S.; Whitton, M.; Mertens, G.; Moore, C.F.; Whiteley, C.R.; Pasyuk, E.; Slaus, I.; Tang, H.; Zhou, Z.; Gloeckle, W.; Witala, H.

    2000-01-01

    This paper reports two recent high-accuracy determinations of the 1 S 0 neutron-neutron scattering length, a nn . One was done at the Los Alamos National Laboratory using the π - d capture reaction to produce two neutrons with low relative momentum. The neutron-deuteron (nd) breakup reaction was used in other measurement, which was conducted at the Triangle Universities Nuclear Laboratory. The results from the two determinations were consistent with each other and with previous values obtained using the π - d capture reaction. The value obtained from the nd breakup measurements is a nn = -18.7 ± 0.1 (statistical) ± 0.6 (systematic) fm, and the value from the π - d capture experiment is a nn = -18.50 ± 0.05 ± 0.53 fm. The recommended value is a nn = -18.5 ± 0.3 fm. (author)

  13. Calibration of a neutron polarimeter in the 0.2-1.1GeV region

    International Nuclear Information System (INIS)

    Semenov, A.Yu.; Zhang, W.M.; Madey, R.; Ahmidouch, A.; Anderson, B.D.; Assamagan, K.; Avery, S.; Baldwin, A.R.; Crowell, A.S.; Eden, T.; Manley, D.M.; Markowitz, P.; Milleret, G.; Prout, D.; Reichelt, T.; Semenova, I.A.; Ulmer, P.E.; Voutier, E.; Watson, J.W.; Wells, S.P.

    2006-01-01

    We measured the analyzing power and the efficiency of a neutron polarimeter at the Saturne National Laboratory in France with central energies of the neutron beam of 261,533,752,922, and 1057MeV. This polarimeter was a prototype designed to measure G E n , the neutron electric form factor, at the Thomas Jefferson National Accelerator Facility

  14. Neutron-scattering study of the vibrational behavior of trehalose aqueous solutions

    CERN Document Server

    Branca, C; Migliardo, F; Romeo, G; Villari, V; Wanderlingh, U; Colognesi, D

    2002-01-01

    Neutron spectra for hydrated trehalose samples have been obtained by using the time-of-flight spectrometer TOSCA at the ISIS Pulse Neutron Facility (Rutherford Appleton Laboratory, Chilton, UK). Neutron spectra have been compared to the absorbance spectra obtained by Fourier-transform infrared spectroscopy. Finally, a comparison with findings obtained by density functional theory has been performed. 3 Refs.

  15. Neutronic Analyses in Support of the HFIR Beamline Modifications and Lifetime Extension

    Science.gov (United States)

    Remec, I.; Blakeman, E. D.

    2009-08-01

    At the High Flux Isotope Reactor, in operation since 1966 at the Oak Ridge National Laboratory, a larger HB-2 beam tube was installed to enhance capabilities for neutron science research. Neutronic analyses, including dosimetry measurements, radiation transport simulations, and simultaneous neutron and gamma spectrum adjustment calculations, performed to assess the impact of modifications on the PV lifetime are presented.

  16. Prompt γ rays and neutrons from fission

    Science.gov (United States)

    Kwan, E.; Wu, C. Y.; Chyzh, A.; Gostic, J.; Henderson, R.; Haight, R. C.; Lee, H. Y.; O'Donnell, J. M.; Perdue, B. A.; Taddeucci, T. N.

    2011-10-01

    Nuclear data are needed to test the accuracy of calculations from nuclear reaction codes. Information on the prompt γ-ray distributions from fission is sparse and only a handful of published experiments data that measured the prompt γ-ray distribution above incident neutron energies of 1 MeV can be found. In addition, improvement on the accuracy and shape of neutron spectrum from the fission of actinides been requested by the nuclear data community. An investigation on the shapes of the neutron and γ-ray distributions from the spontaneous fission of 252Cf and the neutron-induced fission of 235U was undertaken using the Chi-Nu detector array at the Weapons Neutron Research Facility of the Los Alamos Neutron Science Center. Preliminary results will be presented. This work is performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and the Los Alamos National Laboratory under Contract DE-AC52-06NA25396.

  17. Improving Neutron Measurement Capabilities; Expanding the Limits of Correlated Neutron Counting

    Energy Technology Data Exchange (ETDEWEB)

    Santi, Peter Angelo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Geist, William H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dougan, Arden [National Nuclear Security Administration (NNSA), Washington, DC (United States)

    2015-11-05

    A number of technical and practical limitations exist within the neutron correlated counting techniques used in safeguards, especially within the algorithms that are used to process and analyze the detected neutron signals. A multi-laboratory effort is underway to develop new and improved analysis and data processing algorithms based on fundamental physics principles to extract additional or more accurate information about nuclear material bearing items.

  18. Neutron Detection via Bubble Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, David V.; Ely, James H.; Peurrung, Anthony J.; Bond, Leonard J.; Collar, J. I.; Flake, Matthew; Knopf, Michael A.; Pitts, W. K.; Shaver, Mark W.; Sonnenschein, Andrew; Smart, John E.; Todd, Lindsay C.

    2005-10-06

    The results of a Pacific Northwest National Laboratory (PNNL) exploratory research project investigating the feasibility of fast neutron detection using a suitably prepared and operated, pressure-cycled bubble chamber are described. The research was conducted along two parallel paths. Experiments with a slow pressure-release Halon chamber at the Enrico Fermi Institute at the University of Chicago showed clear bubble nucleation sensitivity to an AmBe neutron source and insensitivity to the 662 keV gammas from a 137Cs source. Bubble formation was documented via high-speed (1000 frames/sec) photography, and the acoustic signature of bubble formation was detected using a piezo-electric transducer element mounted on the base of the chamber. The chamber’s neutron sensitivity as a function of working fluid temperature was mapped out. The second research path consisted of the design, fabrication, and testing of a fast pressure-release Freon-134a chamber at PNNL. The project concluded with successful demonstrations of the PNNL chamber’s AmBe neutron source sensitivity and 137Cs gamma insensitivity. The source response tests of the PNNL chamber were documented with high-speed photography.

  19. Photometrics Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose:The Photometrics Laboratory provides the capability to measure, analyze and characterize radiometric and photometric properties of light sources and filters,...

  20. Blackroom Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Enables evaluation and characterization of materials ranging from the ultraviolet to the longwave infrared (LWIR).DESCRIPTION: The Blackroom Laboratory is...