X-ray and neutron interrogation of air cargo for mobile applications

Energy Technology Data Exchange (ETDEWEB)

Van Liew, Seth

2015-06-01

A system for scanning break-bulk cargo for mobile applications is presented. This combines a 140 kV multi-view, multi-energy X-ray system with 2.5 MeV neutrons. The system uses dual energy X-ray radiography with neutron radiography. The X-ray and neutron systems were designed to be collocated in a mobile environment. Various materials were interrogated with the intent of distinguishing threat materials such as explosives from similar benign materials. In particular, the identification of threats and bengins with nearly identical effective atomic numbers has been demonstrated.

X-ray and neutron interrogation of air cargo for mobile applications

International Nuclear Information System (INIS)

Van Liew, Seth

2015-01-01

A system for scanning break-bulk cargo for mobile applications is presented. This combines a 140 kV multi-view, multi-energy X-ray system with 2.5 MeV neutrons. The system uses dual energy X-ray radiography with neutron radiography. The X-ray and neutron systems were designed to be collocated in a mobile environment. Various materials were interrogated with the intent of distinguishing threat materials such as explosives from similar benign materials. In particular, the identification of threats and bengins with nearly identical effective atomic numbers has been demonstrated

High-fidelity MCNP modeling of a D-T neutron generator for active interrogation of special nuclear material

International Nuclear Information System (INIS)

Katalenich, Jeff; Flaska, Marek; Pozzi, Sara A.; Hartman, Michael R.

2011-01-01

Fast and robust methods for interrogation of special nuclear material (SNM) are of interest to many agencies and institutions in the United States. It is well known that passive interrogation methods are typically sufficient for plutonium identification because of a relatively high neutron production rate from 240 Pu . On the other hand, identification of shielded uranium requires active methods using neutron or photon sources . Deuterium-deuterium (2.45 MeV) and deuterium-tritium (14.1 MeV) neutron-generator sources have been previously tested and proven to be relatively reliable instruments for active interrogation of nuclear materials . In addition, the newest generators of this type are small enough for applications requiring portable interrogation systems. Active interrogation techniques using high-energy neutrons are being investigated as a method to detect hidden SNM in shielded containers . Due to the thickness of some containers, penetrating radiation such as high-energy neutrons can provide a potential means of probing shielded SNM. In an effort to develop the capability to assess the signal seen from various forms of shielded nuclear materials, University of Michigan Neutron Science Laboratory's D-T neutron generator and its shielding were accurately modeled in MCNP. The generator, while operating at nominal power, produces approximately 1x10 10 neutrons/s, a source intensity which requires a large amount of shielding to minimize the dose rates around the generator. For this reason, the existing shielding completely encompasses the generator and does not include beam ports. Therefore, several MCNP simulations were performed to estimate the yield of uncollided 14.1-MeV neutrons from the generator for active interrogation experiments. Beam port diameters of 5, 10, 15, 20, and 25 cm were modeled to assess the resulting neutron fluxes. The neutron flux outside the beam ports was estimated to be approximately 2x10 4 n/cm 2 s.

Enhancing the performance of a tensioned metastable fluid detector based active interrogation system for the detection of SNM in 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

Integrated Box Interrogation System (IBIS) Preliminary Design Study

CERN Document Server

Croft, S; Chard-Mj, P; Estop, J R; Martancik, D; Sheila-Melton; Young, B

2003-01-01

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-nucli...

Signal predictions for a proposed fast neutron interrogation method

International Nuclear Information System (INIS)

Sale, K.E.

1992-12-01

We have applied the Monte Carlo radiation transport code COG) to assess the utility of a proposed explosives detection scheme based on neutron emission. In this scheme a pulsed neutron beam is generated by an approximately seven MeV deuteron beam incident on a thick Be target. A scintillation detector operating in the current mode measures the neutrons transmitted through the object as a function of time. The flight time of unscattered neutrons from the source to the detector is simply related to the neutron energy. This information along with neutron cross section excitation functions is used to infer the densities of H, C, N and O in the volume sampled. The code we have chosen to use enables us to create very detailed and realistic models of the geometrical configuration of the system, the neutron source and of the detector response. By calculating the signals that will be observed for several configurations and compositions of interrogated object we can investigate and begin to understand how a system that could actually be fielded will perform. Using this modeling capability many early on with substantial savings in time and cost and with improvements in performance. We will present our signal predictions for simple single element test cases and for explosive compositions. From these studies it is dear that the interpretation of the signals from such an explosives identification system will pose a substantial challenge

Novel applications of fast neutron interrogation methods

International Nuclear Information System (INIS)

Gozani, Tsahi

1994-01-01

The development of non-intrusive inspection methods for contraband consisting primarily of carbon, nitrogen, oxygen, and hydrogen requires the use of fast neutrons. While most elements can be sufficiently well detected by the thermal neutron capture process, some important ones, e.g., carbon and in particular oxygen, cannot be detected by this process. Fortunately, fast neutrons, with energies above the threshold for inelastic scattering, stimulate relatively strong and specific gamma ray lines from these elements. The main lines are: 6.13 for O, 4.43 for C, and 5.11, 2.31 and 1.64 MeV for N. Accelerator-generated neutrons in the energy range of 7 to 15 MeV are being considered as interrogating radiations in a variety of non-intrusive inspection systems for contraband, from explosives to drugs and from coal to smuggled, dutiable goods. In some applications, mostly for inspection of small items such as luggage, the decision process involves a rudimentary imaging, akin to emission tomography, to obtain the localized concentration of various elements. This technique is called FNA - Fast Neutron Analysis. While this approach offers improvements over the TNA (Thermal Neutron Analysis), it is not applicable to large objects such as shipping containers and trucks. For these challenging applications, a collimated beam of neutrons is rastered along the height of the moving object. In addition, the neutrons are generated in very narrow nanosecond pulses. The point of their interaction inside the object is determined by the time of flight (TOF) method, that is measuring the time elapsed from the neutron generation to the time of detection of the stimulated gamma rays. This technique, called PFNA (Pulsed Fast Neutron Analysis), thus directly provides the elemental, and by inference, the chemical composition of the material at every volume element (voxel) of the object. The various neutron-based techniques are briefly described below. ((orig.))

INL Neutron Interrogation R and D: FY2010 MPACT End of Year Report

International Nuclear Information System (INIS)

Chichester, D.L.; Seabury, E.H.; Wharton, J.; Watson, S.M.

2010-01-01

Experiments have been carried out to investigate the feasibility and utility of using neutron interrogation and small-scale, portable prompt gamma-ray neutron activation analysis (PGNAA) instruments for assaying uranium for safeguards applications. Prior work has shown the potential of the PGNAA technique for assaying uranium using reactor-based neutron sources and high-yield electronic neutron generators (ENGs). In this project we adapted Idaho National Laboratory's portable isotopic neutron spectroscopy (PINS) PGNAA system for measuring natural-enrichment uranium yellowcake and metallic depleted uranium and highly enriched uranium. This work used 252Cf as well as deuterium-deuterium (DD) and deuterium-tritium (DT) ENGs. For PGNAA measurements a limiting factor when assaying large objects is the detector dead time due to fast-neutron scattering off of the uranium; this limits the maximum useable neutron source strength to O(107) neutrons per second. Under these conditions the low PGNAA reaction cross sections for uranium prohibited the collection of useful uranium PGNAA signatures from either the yellowcake or metallic uranium samples. Measurement of the decay product activation in these materials following irradiation in the PGNAA geometry similarly did not produce useful uranium activation product - fission product signatures. A customized irradiation geometry tailored to optimally thermalize the interrogation neutron source, intended only for generating long-lived activation products - fission products and not intended for PGNAA measurements, might be possible using small scale ENGs but an application need and a modeling simulation exercise would be recommended before advancing to experiments. Neutron interrogation PGNAA using a DT-ENG was found to be a quick and useful qualitative method for detecting the presence of oxygen in natural-enrichment uranium yellowcake. With a low effort of development work it would be reasonable to expect this measurement could be

Electronics system for transuranic waste assays using a photon interrogation technique

International Nuclear Information System (INIS)

Johnson, L.O.; Lawrence, R.S.

1979-12-01

This report documents the development of electronics for a neutron detection system used in experiments to demonstrate the feasibility of a photon interrogation technique for transuranic (TRU) waste assays. The system consists of the neutron detection and signal conditioning circuits, variable time-gate generators, and a data acquisition system. The data acquisition system is configured using commercially available scalers, timers, teletype, and control components. The remainder of the system, with the exception of the neutron detectors, uses components designed in-house. The neutron detection system consists of 3 He proportional counters installed in a polyethylene moderator assembly. The counters are direct-coupled to a high-count-rate, current-sensitive preamplifier. The preamplifier and an additional two-stage amplifier are also installed in the moderator assembly. Signal conditioning includes baseline restoration and fast discrimination. A variable time-gate generator with logic gates allows for separation of prompt and delayed neutron counts, and generation of prompt and delayed deadtimes. The 3 He proportional counters will detect not only the neutrons from the TRU waste sample, but also the high-energy photons used to induce fission in the sample. The burst of photons (gamma flash) tends to overload and paralyze the electronics. This system has been designed to recover from a worst-case gamma flash overload within 10 microseconds. The system has met all the requirements generated for the photon interrogation experiments

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

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)

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)

Scoping studies - photon and low energy neutron interrogation

Energy Technology Data Exchange (ETDEWEB)

Becker, G.; Harker, Y.; Jones, J. [LMITCo, Idaho Falls, ID (United States); Harmon, F. [Idaho State Univ., Pocatello, ID (United States)

1997-11-01

High energy photon interrogation of waste containers, with the aim of producing photo nuclear reactions, in specific materials, holds the potential of good penetration and rapid analysis. Compact high energy ({le} 10 MeV) photon sources in the form of electron linacs producing bremstrahlung radiation are readily available. Work with the Varitron variable energy accelerator at ISU will be described. Advantages and limitations of the technique will be discussed. Using positive ion induced neutron producing reactions, it is possible to generate neutrons in a specific energy range. By this means, variable penetration and specific reactions can be excited in the assayed material. Examples using the {sup 3}H(p,n) and {sup 7}Li(p,n) reactions as neutron sources will be discussed. 4 refs., 7 figs.

Fissile materials in solution concentration measured by active neutron interrogation

International Nuclear Information System (INIS)

Romeyer Dherbey, J.; Passard, Ch.; Cloue, J.; Bignan, G.

1993-01-01

The use of the active neutron interrogation to measure the concentration of plutonium contained in flow solutions is particularly interesting for fuel reprocessing plants. Indeed, this method gives a signal which is in a direct relation with the fissile materials concentration. Moreover, it is less sensitive to the gamma dose rate than the other nondestructive methods. Two measure methods have been evolved in CEA. Their principles are given into details in this work. The first one consists to detect fission delayed neutrons induced by a 252 Cf source. In the second one fission prompt neutrons induced by a neutron generator of 14 MeV are detected. (O.M.)

Measurement of uranium and plutonium in solid waste by passive photon or neutron counting and isotopic neutron source interrogation

Energy Technology Data Exchange (ETDEWEB)

Crane, T.W.

1980-03-01

A summary of the status and applicability of nondestructive assay (NDA) techniques for the measurement of uranium and plutonium in 55-gal barrels of solid waste is reported. The NDA techniques reviewed include passive gamma-ray and x-ray counting with scintillator, solid state, and proportional gas photon detectors, passive neutron counting, and active neutron interrogation with neutron and gamma-ray counting. The active neutron interrogation methods are limited to those employing isotopic neutron sources. Three generic neutron sources (alpha-n, photoneutron, and /sup 252/Cf) are considered. The neutron detectors reviewed for both prompt and delayed fission neutron detection with the above sources include thermal (/sup 3/He, /sup 10/BF/sub 3/) and recoil (/sup 4/He, CH/sub 4/) proportional gas detectors and liquid and plastic scintillator detectors. The instrument found to be best suited for low-level measurements (< 10 nCi/g) is the /sup 252/Cf Shuffler. The measurement technique consists of passive neutron counting followed by cyclic activation using a /sup 252/Cf source and delayed neutron counting with the source withdrawn. It is recommended that a waste assay station composed of a /sup 252/Cf Shuffler, a gamma-ray scanner, and a screening station be tested and evaluated at a nuclear waste site. 34 figures, 15 tables.

Design of a neutron interrogation cell based on an electron accelerator and performance assessment on 220 liter nuclear waste mock-up drums

International Nuclear Information System (INIS)

Sari, A.; Carrel, F.; Laine, F.; Lyoussi, A.

2013-01-01

Radiological characterization of nuclear waste drums is an important task for the nuclear industry. The amount of actinides, such as 235 U or 239 Pu, contained in a package can be determined using non-destructive active methods based on the fission process. One of these techniques, known as neutron interrogation, uses a neutron beam to induce fission reactions on the actinides. Optimization of the neutron flux is an important step towards improving this technique. Electron accelerators enable to achieve higher neutron flux intensities than the ones delivered by deuterium-tritium generators traditionally used on neutron interrogation industrial facilities. In this paper, we design a neutron interrogation cell based on an electron accelerator by MCNPX simulation. We carry out photoneutron interrogation measurements on uranium samples placed at the center of 220 liter nuclear waste drums containing different types of matrices. We quantify impact of the matrix on the prompt neutron signal, on the ratio between the prompt and delayed neutron signals, and on the interrogative neutron half-life time. We also show that characteristics of the conversion target of the electron accelerator enable to improve significantly measurement performances. (authors)

Assay of fissionable isotopes in aqueous solution by pulsed neutron interrogation

International Nuclear Information System (INIS)

Campbell, P.; Gardy, E.M.; Boase, D.G.

1978-04-01

Non-destructive assay of uranium-235 and thorium-232 in aqueous nitric acid solutions has been accomplished by irradiation with pulses of neutrons from a 14-MeV Cockcroft-Walton neutron generator, and counting of the delayed neutrons emitted from the fissions induced. Design of the delayed neutron detector assemblies is described, together with the neutron pulse timing and counting systems. The effects of irradiation time, counting time, neutron moderation, detector design and sample geometry on the delayed neutron response from uranium-235 and 238 and thorium-232 are discussed. By using polyethylene to moderate the interrogating neutrons, solutions can be analyzed for both uranium-235 and thorium. Comparative analyses with chemical and γ-spectrometric methods show good agreement. The neutron method is rapid and is shown to be unaffected by the presence in solution of impurities such as iron, nickel, chromium, and aluminum. With the experimental equipment described, detection limits of 0.6 mg of 235 U and 9 mg of 232 Th in a sample volume of 25 mL have been achieved. Analyses of highly radioactive samples may be done easily since the measurements are not affected by the presence of large amounts of βγ radiation. Samples can be enclosed in small lead-shielded flasks during analysis to protect the analyst. The potential of the technique to on-line analysis applications is explored briefly. (author)

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

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

APSTNG: Neutron interrogation for detection of nuclear and CW weapons, explosives, and drugs

International Nuclear Information System (INIS)

Rhodes, E.; Dickerman, C.E.; De Volpi, A.; Peters, C.W.

1992-01-01

A recently developed neutron diagnostic probe system has the potential to satisfy a significant number of van-mobile and fixed- portal requirements for nondestructive verification of sealed munitions and detection of contraband explosives and drugs. The probe is based on a unique associated-particle sealed-tube neutron generator (APSTNG) that interrogates the object of interest with a low-intensity beam of 14-MeV neutrons generated from the deuterium-tritium reaction and that detects the alpha-particle associated with each neutron. Gamma-ray spectra of resulting neutron inelastic scattering and fission reactions identify nuclides associated with all major chemicals in chemical warfare agents, explosives, and drugs, as well as many pollutants and fissile and fertile special nuclear material. Flight times determined from determined from detection times of the gamma-rays and alpha-particles yield a separate tomographic image of each identified nuclide. The APSTNG also forms the basis for a compact fast-neutron transmission imaging system that can be used along with or instead of the emission imaging system; a collimator is not required since scattered neutrons are removed by ''electronic collimation'' (detected neutrons not having the proper flight time to be uncollided are discarded). The small and relatively inexpensive APSTNG exhibits high reliability and can be quickly replaced. Proof-of-concept experiments have been performed under laboratory conditions for simulated nuclear and chemical warfare munitions and for explosives and drugs

Integrated Box Interrogation System (IBIS) Preliminary Design Study

International Nuclear Information System (INIS)

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

2003-01-01

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

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.

Radioactive waste package assay facility. Volume 2. Investigation of active neutron and active gamma interrogation

International Nuclear Information System (INIS)

Bailey, M.; Bunce, L.J.; Findlay, D.J.S.; Jolly, J.E.; Parsons, T.V.; Sene, M.R.; Swinhoe, M.T.

1992-01-01

Volume 2 of this report describes the theoretical and experimental work carried out at Harwell on active neutron and active gamma interrogation of 500 litre cemented intermediate level waste drums. The design of a suitable neutron generating target in conjunction with a LINAC was established. Following theoretical predictions of likely neutron responses, an experimental assay assembly was built. Responses were measured for simulated drums of ILW, based on CAGR, Magnox and PCM wastes. Good correlations were established between quantities of 235 -U, nat -U and D 2 O contained in the drums, and the neutron signals. Expected sensitivities are -1g of fissile actinide and -100g of total actinide. A measure of spatial distribution is obtainable. The neutron time spectra obtained during neutron interrogation were more complex than expected, and more analysis is needed. Another area of discrepancy is the difference between predicted and measured thermal neutron flux in the drum. Clusters of small 3 He proportional counters were found to be much superior for fast neutron detection than larger diameter counters. It is necessary to ensure constancy of electron beam position relative to target(s) and drum, and prudent to measure the target neutron or gamma output as appropriate. 59 refs., 77 figs., 11 tabs

Detection of Special Nuclear Material in Cargo Containers Using Neutron Interrogation

International Nuclear Information System (INIS)

Slaughter, D.; Accatino, M.; Bernstein, A.; Candy, J.; Dougan, A.; Hall, J.; Loshak, A.; Manatt, D.; Meyer, A.; Pohl, B.; Prussin, S.; Walling, R.; Weirup, D.

2003-01-01

The goal of the work reported here is to develop a concept for an active neutron interrogation system that can detect small targets of SNM contraband in cargo containers, roughly 5 kg HEU or 1 kg Pu, even when well shielded by a thick cargo. It is essential that the concept be reliable and have low false-positive and false-negative error rates. It also must be rapid to avoid interruption of commerce, completing the analysis in minutes. A new radiation signature unique to SNM has been identified that utilizes high-energy (E γ = 3-7 MeV) fission product γ-ray emission. Fortunately, this high-energy γ-ray signature is robust in that it is very distinct compared to normal background radiation where there is no comparable high-energy γ-ray radiation. Equally important, it has a factor of 10 higher yield than delayed neutrons that are the basis of classical interrogation technique normally used on small unshielded specimens of SNM. And it readily penetrates two meters of low-Z and high-Z cargo at the expected density of ∼ 0.5 gm/cm 3 . Consequently, we expect that in most cases the signature flux at the container wall is at least 2-3 decades more intense than delayed neutron signals used historically and facilitates the detection of SNM even when shielded by thick cargo. Experiments have verified this signature and its predicted characteristics. However, they revealed an important interference due to the activation of 16 O by the 16 O(n,p) 16 N reaction that produces a 6 MeV γ-ray following a 7-sec β-decay of the 16 N. This interference is important when irradiating with 14 MeV neutrons but is eliminated when lower energy neutron sources are utilized since the reaction threshold for 16 O(n,p) 16 N is 10 MeV. The signature γ-ray fluxes exiting a thick cargo can be detected in large arrays of scintillation detectors to produce useful signal count rates of 2-4 x 10 4 cps. That is high enough to quickly identify SNM fission by its characteristic high energy �

APSTNG: Neutron interrogation for detection of explosives and drugs and nuclear and CW materials

International Nuclear Information System (INIS)

Rhodes, E.; Peters, C.W.

1993-01-01

A recently developed neutron diagnostic probe system has the potential to satisfy a significant number of van-mobile and fixed-portal requirements for nondestructive detection, including monitoring of contraband explosives, drugs, and weapon materials, and treaty verification of sealed munitions. The probe is based on a unique associated-particle sealed-tube neutron generator (APSTNG) that interrogates the object of interest with a low-intensity beam of 14-MeV neutron generated from the deuterium-tritium reaction and that detects the alpha-particle associated with each neutron. Gamma-ray spectra of resulting neutron reactions identify nuclides associated with all major chemicals in explosives, drugs, and chemical warfare agents, as well as many pollutants and fissile and fertile special nuclear material. Flight times determined from detection times of the gamma rays and alpha-particles yield a separate coarse tomographic image of each identified nuclide. The APSTNG also forms the basis for a compact fast-neutron transmission imaging system that can be used along with or instead of the emission imaging system. Proof-of-concept experiments have been performed under laboratory conditions for simulated nuclear and chemical warfare munitions and for explosives and drugs. The small and relatively inexpensive APSTNG exhibits high reliability and can be quickly replaced. Surveillance systems based on APSTNG technology can avoid the large physical size, high capital and operating expenses, and reliability problems associated with complex accelerators

Monte Carlo Simulation for LINAC Standoff Interrogation of Nuclear Material

International Nuclear Information System (INIS)

Clarke, Shaun D.; Flaska, Marek; Miller, Thomas Martin; Protopopescu, Vladimir A.; Pozzi, Sara A.

2007-01-01

The development of new techniques for the interrogation of shielded nuclear materials relies on the use of Monte Carlo codes to accurately simulate the entire system, including the interrogation source, the fissile target and the detection environment. The objective of this modeling effort is to develop analysis tools and methods-based on a relevant scenario-which may be applied to the design of future systems for active interrogation at a standoff. For the specific scenario considered here, the analysis will focus on providing the information needed to determine the type and optimum position of the detectors. This report describes the results of simulations for a detection system employing gamma rays to interrogate fissile and nonfissile targets. The simulations were performed using specialized versions of the codes MCNPX and MCNP-PoliMi. Both prompt neutron and gamma ray and delayed neutron fluxes have been mapped in three dimensions. The time dependence of the prompt neutrons in the system has also been characterized For this particular scenario, the flux maps generated with the Monte Carlo model indicate that the detectors should be placed approximately 50 cm behind the exit of the accelerator, 40 cm away from the vehicle, and 150 cm above the ground. This position minimizes the number of neutrons coming from the accelerator structure and also receives the maximum flux of prompt neutrons coming from the source. The lead shielding around the accelerator minimizes the gamma-ray background from the accelerator in this area. The number of delayed neutrons emitted from the target is approximately seven orders of magnitude less than the prompt neutrons emitted from the system. Therefore, in order to possibly detect the delayed neutrons, the detectors should be active only after all prompt neutrons have scattered out of the system. Preliminary results have shown this time to be greater than 5 ?s after the accelerator pulse. This type of system is illustrative of a

Epithermal interrogation of fissile waste

International Nuclear Information System (INIS)

Coop, K.L.; Hollas, C.L.

1996-01-01

Self-shielding of interrogating thermal neutrons in lumps of fissile material can be a major source of error in transuranic waste assay using the widely employed differential dieaway technique. We are developing a new instrument, the combined thermal/epithermal neutron (CTEN) interrogation instrument to detect the occurrence of self- shielding and mitigate its effects. Neutrons are moderated in the graphite walls of the CTEN instrument to provide an interrogating flux of epithermal and thermal neutrons. The induced prompt fission neutrons are detected in proportional counters. We report the results of measurements made with the CTEN instrument, using minimal and highly self-shielding plutonium and uranium sources in 55 gallon drums containing a variety of mock waste matrices. Fissile isotopes and waste forms for which the method is most applicable, and limitations associated with the hydrogen content of the waste package/matrix are described

Photon interrogation for bulk measurement of transuranic materials

International Nuclear Information System (INIS)

Nieschmidt, E.B.

1981-01-01

Investigation and assay of high atomic number materials may be accomplished in near real-time through use of photon interrogation. Photon interrogation, as used here, involves the use of high-energy photons to induce fission and then detect neutrons associated with the fission. This technique has the advantage that the interrogating particle and the detected particle are different. The discussion here will include: (1) neutron production; (2) photon production; (3) neutron counting; (4) sensitivity; and (5) problems associated with large containers. In summary, the attributes and limitations of photon interrogation can be stated as: near real-time accountability; interrogating particle different than detected particle; ability to count prompt or delayed neutrons depending on matrix; radiography or therapy accelerators available; cannot distinguish between fission and fertile material; and interrogated material must be well characterized to obtain safeguards quality results

Fissile materials in solution concentration measured by active neutron interrogation; Mesure de concentration en matiere fissile dans les liquides par interrogation neutronique active

Energy Technology Data Exchange (ETDEWEB)

Romeyer Dherbey, J.; Passard, Ch.; Cloue, J.; Bignan, G.

1993-12-31

The use of the active neutron interrogation to measure the concentration of plutonium contained in flow solutions is particularly interesting for fuel reprocessing plants. Indeed, this method gives a signal which is in a direct relation with the fissile materials concentration. Moreover, it is less sensitive to the gamma dose rate than the other nondestructive methods. Two measure methods have been evolved in CEA. Their principles are given into details in this work. The first one consists to detect fission delayed neutrons induced by a {sup 252} Cf source. In the second one fission prompt neutrons induced by a neutron generator of 14 MeV are detected. (O.M.). 6 refs.

The simultaneous neutron and photon interrogation method for fissile and non-fissile element separation in radioactive waste drums

International Nuclear Information System (INIS)

Jallu, F.; Lyoussi, A.; Passard, C.; Payan, E.; Recroix, H.; Nurdin, G.; Buisson, A.; Allano, J.

2000-01-01

Measuring α-emitters such as ( 234,235,236,238 U, 238,239,240,242,244 Pu, 237 Np, 241,243 Am, ...), in solid radioactive waste allows us to quantify the α-activity in a drum and then to classify it. The simultaneous photon and neutron interrogation experiment (SIMPHONIE) method dealt with in this paper, combines both active neutron interrogation and induced photofission interrogation techniques simultaneously. Its purpose is to quantify fissile ( 235 U, 239,241 Pu, ...) and non-fissile ( 236,238 U, 238,240 Pu, ...) elements separately in only one measurement. This paper presents the principle of the method, the experimental setup, and the first experimental results obtained using the DGA/ETCA Linac and MiniLinatron pulsed linear electron accelerators located at Arcueil, France. First studies were carried out with U and Pu bare samples

Development and application of a hybrid transport methodology for active interrogation systems

Energy Technology Data Exchange (ETDEWEB)

Royston, K.; Walters, W.; Haghighat, A. [Nuclear Engineering Program, Department of Mechanical Engineering, Virginia Tech., 900 N Glebe Rd., Arlington, VA 22203 (United States); Yi, C.; Sjoden, G. [Nuclear and Radiological Engineering, Georgia Tech, 801 Ferst Drive, Atlanta, GA 30332 (United States)

2013-07-01

A hybrid Monte Carlo and deterministic methodology has been developed for application to active interrogation systems. The methodology consists of four steps: i) neutron flux distribution due to neutron source transport and subcritical multiplication; ii) generation of gamma source distribution from (n, 7) interactions; iii) determination of gamma current at a detector window; iv) detection of gammas by the detector. This paper discusses the theory and results of the first three steps for the case of a cargo container with a sphere of HEU in third-density water cargo. To complete the first step, a response-function formulation has been developed to calculate the subcritical multiplication and neutron flux distribution. Response coefficients are pre-calculated using the MCNP5 Monte Carlo code. The second step uses the calculated neutron flux distribution and Bugle-96 (n, 7) cross sections to find the resulting gamma source distribution. In the third step the gamma source distribution is coupled with a pre-calculated adjoint function to determine the gamma current at a detector window. The AIMS (Active Interrogation for Monitoring Special-Nuclear-Materials) software has been written to output the gamma current for a source-detector assembly scanning across a cargo container using the pre-calculated values and taking significantly less time than a reference MCNP5 calculation. (authors)

SIMULATION OF CARGO CONTAINER INTERROGATION BY D-D NEUTRONS

International Nuclear Information System (INIS)

Lou, Tak Pui; Antolak, Arlyn

2007-01-01

High fidelity, three-dimensional computer models based on a CAD drawing of an intermodal cargo container, representative payload objects, and detector array panels were developed to simulate the underlying physical events taking place during active interrogation. These computer models are used to assess the performance of interrogation systems with different sources and detection schemes. In this presentation, we will show that the use oversimplified models, such as analyzing homogenized payloads only, can lead to errors in determining viable approaches for interrogation

Correcting the effects of the matrix using capture gamma-ray spectrometry: Application to measurement by Active Neutron Interrogation

International Nuclear Information System (INIS)

Baudry, G.

2003-11-01

In the field of the measurement of low masses of fissile material ( 235 U, 239 Pu, 241 Pu) in radioactive waste drums, the Active Neutron Interrogation is a non-destructive method achieving good results. It does however remain reliant upon uncertainties related to the matrix effects on interrogation and fission neutrons. The aim of this thesis is to develop a correction method able to take into account these matrix effects by quantifying the amount of absorbent materials (chlorine and hydrogen) in a 118- liter homogeneous matrix. The main idea is to use the gamma-ray spectrometry of gamma emitted by neutron captures to identify and quantify the composition of the matrix. An indicator from its chlorine content is then deduced in order to choose the calibration coefficient which best represents the real composition of the matrix. This document firstly presents the needs of control and characterization of radioactive objects, and the means used in the field of nuclear measurement. Emphases is put in particular on the Active Neutron Interrogation method. The matrices of interest are those made of light technological waste (density ≤ 0,4 g/cm 3 ) containing hydrogenated and chlorinated materials. The advantages of gamma-rays emitted by neutron captures for the determination of a chlorine content indicator of the matrices and the principles of the correction method are then explained. Measurements have been firstly realized with an existing Neutron Interrogation device (PROMETHEE 6). Such measurements have proven its inadequacy: no signal from the matrix hydrogen was detected, due to an intense signal from the polyethylene contained in some cell elements. Moreover, the matrix chlorine content appeared difficult to be measured. A new and specific device, named REGAIN and dedicated to active gamma-rays spectrometry, was defined with the Monte-Carlo N-Particle (MCNP) code. The experiments conducted with this new device made it possible to detect the hydrogen from the

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

Science.gov (United States)

Bélanger-Champagne, Camille; Vainionpää, Hannes; Peura, Pauli; Toivonen, Harri; Eerola, Paula; Dendooven, Peter

2017-01-01

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.

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.

Dose profile modeling of Idaho National Laboratory's active neutron interrogation laboratory

Energy Technology Data Exchange (ETDEWEB)

Chichester, D.L. [Idaho National Laboratory, 2525 N. Fremont Avenue, Idaho Falls, ID 83415 (United States)], E-mail: david.chichester@inl.gov; Seabury, E.H.; Zabriskie, J.M.; Wharton, J.; Caffrey, A.J. [Idaho National Laboratory, 2525 N. Fremont Avenue, Idaho Falls, ID 83415 (United States)

2009-06-15

A new laboratory has been commissioned at Idaho National Laboratory for performing active neutron interrogation research and development. The facility is designed to provide radiation shielding for deuterium-tritium (DT) fusion (14.1 MeV) neutron generators (2x10{sup 8} n/s), deuterium-deuterium (DD) fusion (2.5 MeV) neutron generators (1x10{sup 7} n/s), and {sup 252}Cf spontaneous fission neutron sources (6.96x10{sup 7} n/s, 30 {mu}g). Shielding at the laboratory is comprised of modular concrete shield blocks 0.76 m thick with tongue-in-groove features to prevent radiation streaming, arranged into one small and one large test vault. The larger vault is designed to allow operation of the DT generator and has walls 3.8 m tall, an entrance maze, and a fully integrated electrical interlock system; the smaller test vault is designed for {sup 252}Cf and DD neutron sources and has walls 1.9 m tall and a simple entrance maze. Both analytical calculations and numerical simulations were used in the design process for the building to assess the performance of the shielding walls and to ensure external dose rates are within required facility limits. Dose rate contour plots have been generated for the facility to visualize the effectiveness of the shield walls and entrance mazes and to illustrate the spatial profile of the radiation dose field above the facility and the effects of skyshine around the vaults.

Monte carlo feasibility study of an active neutron assay technique for full-volume UF{sub 6} cylinder assay using a correlated interrogation source

Energy Technology Data Exchange (ETDEWEB)

Miller, Karen A., E-mail: kamiller@lanl.gov [Los Alamos National Laboratory, Los Alamos, P.O. Box 1663 MS E540, NM 87545 (United States); Menlove, Howard O.; Swinhoe, Martyn T.; Marlow, Johnna B. [Los Alamos National Laboratory, Los Alamos, P.O. Box 1663 MS E540, NM 87545 (United States)

2013-03-01

Uranium cylinder assay plays an important role in the nuclear material accounting at gas centrifuge enrichment plants. The Passive Neutron Enrichment Meter (PNEM) was designed to determine uranium mass and enrichment in 30B and 48Y cylinders using total neutron and coincidence counting in the passive mode. 30B and 48Y cylinders are used to hold bulk UF{sub 6} feed, product, and tails at enrichment plants. In this paper, we report the results of a Monte-Carlo-based feasibility study for an active uranium cylinder assay system based on the PNEM design. There are many advantages of the active technique such as a shortened count time and a more direct measure of {sup 235}U content. The active system is based on a modified PNEM design and uses a {sup 252}Cf source as the correlated, active interrogation source. We show through comparison with a random AmLi source of equal strength how the use of a correlated driver significantly boosts the active signal and reduces the statistical uncertainty. We also discuss ways in which an active uranium cylinder assay system can be optimized to minimize background from {sup 238}U fast-neutron induced fission and direct counts from the interrogation source.

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)

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)

Unexploded Ordnance identification—A gamma-ray spectral analysis method for Carbon, Nitrogen and Oxygen signals following tagged neutron interrogation

International Nuclear Information System (INIS)

Mitra, S.; Dioszegi, I.

2012-01-01

A novel gamma-ray spectral analysis method has been demonstrated to optimally extract the signals of the signature elements of explosives, carbon (C), nitrogen (N) and oxygen (O) from 57–155 mm projectiles following tagged neutron interrogation with 14 MeV neutrons. The method was implemented on Monte Carlo simulated, synthetic spectra of Unexploded Ordnance (UXO) that contained high explosive fillers (Composition B, TNT or Explosive D) within steel casings of appropriate thicknesses. The analysis technique defined three broad regions-of-interest (ROI) between 4–7.5 MeV of a spectrum and from a system of three equations for the three unknowns namely C, N and O, the maximum counts from each of these elements were extracted. Unlike conventional spectral analysis techniques, the present method included the Compton continuum under a spectrum. For a neutron output of ∼2×10 7 ns −1 and using four 12.7 cm diameter×12.7 cm NaI(Tl) detectors, the C/N and C/O gamma-ray counts ratios of the explosive fillers were vastly different from that of an inert substance like sand. Conversion of the counts ratios to elemental ratios could further discriminate the different types of explosive fillers. The interrogation time was kept at ten minutes for each projectile.

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.

Neutron absorbers and detector types for spent fuel verification using the self-interrogation neutron resonance densitometry

International Nuclear Information System (INIS)

Rossa, Riccardo; Borella, Alessandro; Labeau, Pierre-Etienne; Pauly, Nicolas; Meer, Klaas van der

2015-01-01

The Self-Interrogation Neutron Resonance Densitometry (SINRD) is a passive non-destructive assay (NDA) technique that is proposed for the direct measurement of 239 Pu in a spent fuel assembly. The insertion of neutron detectors wrapped with different neutron absorbing materials, or neutron filters, in the central guide tube of a PWR fuel assembly is envisaged to measure the neutron flux in the energy region close to the 0.3 eV resonance of 239 Pu. In addition, the measurement of the fast neutron flux is foreseen. This paper is focused on the determination of the Gd and Cd neutron filters thickness to maximize the detection of neutrons within the resonance region. Moreover, several detector types are compared to identify the optimal condition and to assess the expected total neutron counts that can be obtained with the SINRD measurements. Results from Monte Carlo simulations showed that ranges between 0.1–0.3 mm and 0.5–1.0 mm ensure the optimal conditions for the Gd and Cd filters, respectively. Moreover, a 239 Pu fission chamber is better suited to measure neutrons close to the 0.3 eV resonance and it has the highest sensitivity to 239 Pu, in comparison with a 235 U fission chamber, with a 3 He proportional counter, and with a 10 B proportional counter. The use of a thin Gd filter and a thick Cd filter is suggested for the 239 Pu and 235 U fission chambers to increase the total counts achieved in a measurement, while a thick Gd filter and a thin Cd filter are envisaged for the 3 He and 10 B proportional counters to increase the sensitivity to 239 Pu. We concluded that an optimization process that takes into account measurement time, filters thickness, and detector size is needed to develop a SINRD detector that can meet the requirement for an efficient verification of spent fuel assemblies

Neutron absorbers and detector types for spent fuel verification using the self-interrogation neutron resonance densitometry

Energy Technology Data Exchange (ETDEWEB)

Rossa, Riccardo, E-mail: rrossa@sckcen.be [SCK-CEN, Belgian Nuclear Research Centre, Boeretang, 200, B2400 Mol (Belgium); Université libre de Bruxelles, Ecole polytechnique de Bruxelles, Service de Métrologie Nucléaire (CP 165/84), Avenue F.D. Roosevelt, 50, B1050 Brussels (Belgium); Borella, Alessandro, E-mail: aborella@sckcen.be [SCK-CEN, Belgian Nuclear Research Centre, Boeretang, 200, B2400 Mol (Belgium); Labeau, Pierre-Etienne, E-mail: pelabeau@ulb.ac.be [Université libre de Bruxelles, Ecole polytechnique de Bruxelles, Service de Métrologie Nucléaire (CP 165/84), Avenue F.D. Roosevelt, 50, B1050 Brussels (Belgium); Pauly, Nicolas, E-mail: nipauly@ulb.ac.be [Université libre de Bruxelles, Ecole polytechnique de Bruxelles, Service de Métrologie Nucléaire (CP 165/84), Avenue F.D. Roosevelt, 50, B1050 Brussels (Belgium); Meer, Klaas van der, E-mail: kvdmeer@sckcen.be [SCK-CEN, Belgian Nuclear Research Centre, Boeretang, 200, B2400 Mol (Belgium)

2015-08-11

The Self-Interrogation Neutron Resonance Densitometry (SINRD) is a passive non-destructive assay (NDA) technique that is proposed for the direct measurement of {sup 239}Pu in a spent fuel assembly. The insertion of neutron detectors wrapped with different neutron absorbing materials, or neutron filters, in the central guide tube of a PWR fuel assembly is envisaged to measure the neutron flux in the energy region close to the 0.3 eV resonance of {sup 239}Pu. In addition, the measurement of the fast neutron flux is foreseen. This paper is focused on the determination of the Gd and Cd neutron filters thickness to maximize the detection of neutrons within the resonance region. Moreover, several detector types are compared to identify the optimal condition and to assess the expected total neutron counts that can be obtained with the SINRD measurements. Results from Monte Carlo simulations showed that ranges between 0.1–0.3 mm and 0.5–1.0 mm ensure the optimal conditions for the Gd and Cd filters, respectively. Moreover, a {sup 239}Pu fission chamber is better suited to measure neutrons close to the 0.3 eV resonance and it has the highest sensitivity to {sup 239}Pu, in comparison with a {sup 235}U fission chamber, with a {sup 3}He proportional counter, and with a {sup 10}B proportional counter. The use of a thin Gd filter and a thick Cd filter is suggested for the {sup 239}Pu and {sup 235}U fission chambers to increase the total counts achieved in a measurement, while a thick Gd filter and a thin Cd filter are envisaged for the {sup 3}He and {sup 10}B proportional counters to increase the sensitivity to {sup 239}Pu. We concluded that an optimization process that takes into account measurement time, filters thickness, and detector size is needed to develop a SINRD detector that can meet the requirement for an efficient verification of spent fuel assemblies.

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

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.

Correcting the effects of the matrix using capture gamma-ray spectrometry: Application to measurement by Active Neutron Interrogation; Correction des effets de matrice par spectrometrie des rayonnements gamma de capture: Application a la mesure par Interrogation Neutronique Active (I.N.A.)

Energy Technology Data Exchange (ETDEWEB)

Baudry, G.

2003-11-15

In the field of the measurement of low masses of fissile material ({sup 235}U, {sup 239}Pu, {sup 241}Pu) in radioactive waste drums, the Active Neutron Interrogation is a non-destructive method achieving good results. It does however remain reliant upon uncertainties related to the matrix effects on interrogation and fission neutrons. The aim of this thesis is to develop a correction method able to take into account these matrix effects by quantifying the amount of absorbent materials (chlorine and hydrogen) in a 118- liter homogeneous matrix. The main idea is to use the gamma-ray spectrometry of gamma emitted by neutron captures to identify and quantify the composition of the matrix. An indicator from its chlorine content is then deduced in order to choose the calibration coefficient which best represents the real composition of the matrix. This document firstly presents the needs of control and characterization of radioactive objects, and the means used in the field of nuclear measurement. Emphases is put in particular on the Active Neutron Interrogation method. The matrices of interest are those made of light technological waste (density {<=} 0,4 g/cm{sup 3}) containing hydrogenated and chlorinated materials. The advantages of gamma-rays emitted by neutron captures for the determination of a chlorine content indicator of the matrices and the principles of the correction method are then explained. Measurements have been firstly realized with an existing Neutron Interrogation device (PROMETHEE 6). Such measurements have proven its inadequacy: no signal from the matrix hydrogen was detected, due to an intense signal from the polyethylene contained in some cell elements. Moreover, the matrix chlorine content appeared difficult to be measured. A new and specific device, named REGAIN and dedicated to active gamma-rays spectrometry, was defined with the Monte-Carlo N-Particle (MCNP) code. The experiments conducted with this new device made it possible to detect the

INL Active Interrogation Testing In Support of the GNEP Safeguards Campaign

International Nuclear Information System (INIS)

David L. Chichester

2008-01-01

Active interrogation, a measurement technique which uses a radiation source to probe materials and generate unique signatures useful for characterizing those materials, is a powerful tool for assaying special nuclear material. Work at Idaho National Laboratory (INL) in the area of active interrogation, using neutron and photon sources, has been under way for many years to develop methods for detecting and quantifying nuclear material for national and homeland security research areas. This research knowledge base is now being extended to address nuclear safeguards and process monitoring issues related to the Global Nuclear Energy Partnership (GNEP). As a first step in this area preliminary scoping studies have been performed to investigate the usefulness of using active neutron interrogation, with a low-power electronic neutron generator, to assay Department of Transportation 6M shipping drums containing uranium oxide fuel rodlets from INL's zero power physics reactor. Using the paired-counting technique during the die-away time period of interrogation, a lower detection limit of approximately 4.2 grams of enriched uranium (40% 235U) was calculated for a 40 minute measurement using a field portable 2.5 MeV neutron source and an array of 16 moderated helium-3 neutron tubes. Future work in this area, including the use of a more powerful neutron source and a better tailored detector array, would likely improve this limit to a much lower level. Further development work at INL will explore the applicability of active interrogation in association with the nuclear safeguards and process monitoring needs of the advanced GNEP facilities under consideration. This work, which will include both analyses and field demonstrations, will be performed in collaboration with colleagues at INL and elsewhere that have expertise in nuclear fuel reprocessing as well as active interrogation and its use for nuclear material analyses

Confirmatory measurements of UF6 using the neutron self-interrogation method

International Nuclear Information System (INIS)

Stewart, J.E.; Ensslin, N.; Menlove, H.O.; Cowder, L.R.; Polk, P.J.

1985-01-01

A passive neutron counting method has been developed for measurement of the 235 U mass in Model 5A cylinders of UF 6 . The unique neutronic properties of UF 6 containing highly enriched uranium (HEU) permit 235 U assay using only passive neutron counting. The sample effectively assays itself by self-interrogation. Shipped from enrichment plants and received at fuel fabrication and conversion facilities, 5A UF 6 cylinders hold up to approx.17 kg of 235 U each. Field measurements at the Portsmouth Gaseous Diffusion Plant (GDP) showed an average assay accuracy of 6.8% (1sigma) for 44 cylinders with enrichments from 6 to 98% and with a range of fill heights. Further measurements on 38 cylinders containing 97%-enriched material yielded an accuracy of 2.8% (1sigma). Typical counting times for these measurements were less than 5 min. An in-plant instrument for receipts confirmation measurements of 5A UF 6 cylinders has been developed for the Savannah River Plant. The Receipts Assay Monitor (RAM) is currently being tested and calibrated. It is designed to confirm declared fissile mass in all incoming 5A cylinders containing HEU in the form of UF 6 . One of the computer-controlled features is a removable cadmium liner for the sample cavity. The liner allows a sample fill-height correction, which significantly improves assay accuracy

Neutron interrogation systems using pyroelectric crystals and methods of preparation thereof

Science.gov (United States)

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.

Combined Photoneutron And X Ray Interrogation Of Containers For Nuclear Materials

Science.gov (United States)

Gozani, Tsahi; Shaw, Timothy; King, Michael J.; Stevenson, John; Elsalim, Mashal; Brown, Craig; Condron, Cathie

2011-06-01

Effective cargo inspection systems for nuclear material detection require good penetration by the interrogating radiation, generation of a sufficient number of fissions, and strong and penetrating detection signatures. Inspection systems need also to be sensitive over a wide range of cargo types and densities encountered in daily commerce. Thus they need to be effective with highly hydrogenous cargo, where neutron attenuation is a major limitation, as well as with dense metallic cargo, where x-ray penetration is low. A system that interrogates cargo with both neutrons and x-rays can, in principle, achieve high performance over the widest range of cargos. Moreover, utilizing strong prompt-neutron (˜3 per fission) and delayed-gamma ray (˜7 per fission) signatures further strengthens the detection sensitivity across all cargo types. The complementary nature of x-rays and neutrons, used as both probing radiation and detection signatures, alleviates the need to employ exceedingly strong sources, which would otherwise be required to achieve adequate performance across all cargo types, if only one type of radiation probe were employed. A system based on the above principles, employing a commercially-available 9 MV linac was developed and designed. Neutrons are produced simultaneously with x-rays by the photonuclear interaction of the x-ray beam with a suitable converter. A total neutron yield on the order of 1011 n/s is achieved with an average electron beam current of 100 μA. If fissionable material is present, fissions are produced both by the high-energy x-ray beam and by the photoneutrons. Photofission and neutron fission dominate in hydrogenous and metallic cargos, respectively. Neutron-capture gamma rays provide information on the cargo composition. The prompt neutrons resulting from fission are detected by two independent detector systems: by very efficient Differential Die Away Analysis (DDAA) detectors, and by direct detection of neutrons with energies higher

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

Active interrogation using energetic protons

International Nuclear Information System (INIS)

Morris, Christopher L.; Chung, Kiwhan; Greene, Steven J.; Hogan, Gary E.; Makela, Mark; Mariam, Fesseha; Milner, Edward C.; Murray, Matthew; Saunders, Alexander; Spaulding, Randy; Wang, Zhehui; Waters, Laurie; Wysocki, Frederick

2010-01-01

Energetic proton beams provide an attractive alternative when compared to electromagnetic and neutron beams for active interrogation of nuclear threats because they have large fission cross sections, long mean free paths and high penetration, and they can be manipulated with magnetic optics. We have measured time-dependent cross sections and neutron yields for delayed neutrons and gamma rays using 800 MeV and 4 GeV proton beams with a set of bare and shielded targets. The results show significant signals from both unshielded and shielded nuclear materials. Measurements of neutron energies yield suggest a signature unique to fissile material. Results are presented in this paper.

Performance assessment of self-interrogation neutron resonance densitometry for spent nuclear fuel assay

Energy Technology Data Exchange (ETDEWEB)

Hu, Jianwei, E-mail: huj1@ornl.gov [Reactor and Nuclear Systems Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, PO Box 2008, MS-6172, Oak Ridge, TN 37831-6172 (United States); Tobin, Stephen J.; LaFleur, Adrienne M.; Menlove, Howard O.; Swinhoe, Martyn T. [Nuclear Engineering and Nonproliferation Division, Los Alamos National Laboratory (United States)

2013-11-21

Self-Interrogation Neutron Resonance Densitometry (SINRD) is one of several nondestructive assay (NDA) techniques being integrated into systems to measure spent fuel as part of the Next Generation Safeguards Initiative (NGSI) Spent Fuel Project. The NGSI Spent Fuel Project is sponsored by the US Department of Energy's National Nuclear Security Administration to measure plutonium in, and detect diversion of fuel pins from, spent nuclear fuel assemblies. SINRD shows promising capability in determining the {sup 239}Pu and {sup 235}U content in spent fuel. SINRD is a relatively low-cost and lightweight instrument, and it is easy to implement in the field. The technique makes use of the passive neutron source existing in a spent fuel assembly, and it uses ratios between the count rates collected in fission chambers that are covered with different absorbing materials. These ratios are correlated to key attributes of the spent fuel assembly, such as the total mass of {sup 239}Pu and {sup 235}U. Using count rate ratios instead of absolute count rates makes SINRD less vulnerable to systematic uncertainties. Building upon the previous research, this work focuses on the underlying physics of the SINRD technique: quantifying the individual impacts on the count rate ratios of a few important nuclides using the perturbation method; examining new correlations between count rate ratio and mass quantities based on the results of the perturbation study; quantifying the impacts on the energy windows of the filtering materials that cover the fission chambers by tallying the neutron spectra before and after the neutrons go through the filters; and identifying the most important nuclides that cause cooling-time variations in the count rate ratios. The results of these studies show that {sup 235}U content has a major impact on the SINRD signal in addition to the {sup 239}Pu content. Plutonium-241 and {sup 241}Am are the two main nuclides responsible for the variation in the count

Development of a Liquid Scintillator-Based Active Interrogation System for LEU Fuel Assemblies

International Nuclear Information System (INIS)

Lavietes, Anthony D.; Plenteda, Romano; Mascahrenas, Nicholas; Cronholm, L. Marie; Aspinall, Michael; Joyce, Malcolm; Tomanin, Alice; Peerani, Paolo

2013-06-01

The IAEA, in collaboration with the Joint Research Center (Ispra, IT) and Hybrid Instruments (Lancaster, UK), has developed a full scale, liquid scintillator-based active interrogation system to determine uranium (U) mass in fresh fuel assemblies. The system implements an array of moderate volume (∼1000 ml) liquid scintillator detectors, a multichannel pulse shape discrimination (PSD) system, and a high-speed data acquisition and signal processing system to assess the U content of fresh fuel assemblies. Extensive MCNPX-PoliMi modelling has been carried out to refine the system design and optimize the detector performance. These measurements, traditionally performed with 3 He-based assay systems (e.g., Uranium Neutron Coincidence Collar [UNCL], Active Well Coincidence Collar [AWCC]), can now be performed with higher precision in a fraction of the acquisition time. The system uses a high-flash point, non-hazardous scintillating fluid (EJ309) enabling their use in commercial nuclear facilities and achieves significantly enhanced performance and capabilities through the combination of extremely short gate times, adjustable energy detection threshold, real-time PSD electronics, and high-speed, FPGA-based data acquisition. Given the possible applications, this technology is also an excellent candidate for the replacement of select 3 He-based systems. Comparisons to existing 3 He-based active interrogation systems are presented where possible to provide a baseline performance reference. This paper will describe the laboratory experiments and associated modelling activities undertaken to develop and initially test the prototype detection system. (authors)

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...

A novel method for active fissile mass estimation with a pulsed neutron source

International Nuclear Information System (INIS)

Dubi, C.; Ridnik, T.; Israelashvili, I.; Pedersen, B.

2013-01-01

Neutron interrogation facilities for mass evaluation of Special Nuclear Materials (SNM) samples are divided into two main categories: passive interrogation, where all neutron detections are due to spontaneous events, and active interrogation, where fissions are induced on the tested material by an external neutron source. While active methods are, in general, faster and more effective, their analysis is much harder to carry out. In the paper, we will introduce a new formalism for analyzing the detection signal generated by a pulsed source active interrogation facility. The analysis is aimed to distinct between fission neutrons from the main neutron source in the system, and the surrounding “neutron noise”. In particular, we derive analytic expressions for the first three central moments of the number of detections in a given time interval, in terms of the different neutron sources. While the method depends on exactly the same physical assumptions as known models, the simplicity of the suggested formalism allows us to take into account the variance of the external neutron source—an effect that was so far neglected

A novel method for active fissile mass estimation with a pulsed neutron source

Energy Technology Data Exchange (ETDEWEB)

Dubi, C., E-mail: chendb331@gmail.com [Physics Department, Nuclear Research Center of the Negev, POB 9001, Beer Sheva (Israel); Ridnik, T.; Israelashvili, I. [Physics Department, Nuclear Research Center of the Negev, POB 9001, Beer Sheva (Israel); Pedersen, B. [Nuclear Security Unit, Institute for Transuranium Elements, Via E. Fermi, 2749 JRC, Ispra (Italy)

2013-07-01

Neutron interrogation facilities for mass evaluation of Special Nuclear Materials (SNM) samples are divided into two main categories: passive interrogation, where all neutron detections are due to spontaneous events, and active interrogation, where fissions are induced on the tested material by an external neutron source. While active methods are, in general, faster and more effective, their analysis is much harder to carry out. In the paper, we will introduce a new formalism for analyzing the detection signal generated by a pulsed source active interrogation facility. The analysis is aimed to distinct between fission neutrons from the main neutron source in the system, and the surrounding “neutron noise”. In particular, we derive analytic expressions for the first three central moments of the number of detections in a given time interval, in terms of the different neutron sources. While the method depends on exactly the same physical assumptions as known models, the simplicity of the suggested formalism allows us to take into account the variance of the external neutron source—an effect that was so far neglected.

Expected total counts for the Self-Interrogation Neutron Resonance Densitometry measurements of spent nuclear fuel

Energy Technology Data Exchange (ETDEWEB)

Rossa, Riccardo [Belgian nuclear research centre SCK.CEN (Belgium); Universite Libre de Bruxelles (Belgium); Borella, Alessandro; Van der Meer, Klaas [Belgian nuclear research centre SCK.CEN. Boeretang 200, 2400 Mol (Belgium); Labeau, Pierre-Etienne; Pauly, Nicolas [Universite Libre de Bruxelles. Av. 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 spent 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 counts in the fast energy region and around the 0.3 eV resonance region. The SINRD measurement approach in this study consisted 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 were 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 total neutron counts 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 total neutron counts 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 total neutron counts by increasing the detector size. The study shows that the highest total neutron counts are 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 total neutron counts

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

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

International Nuclear Information System (INIS)

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

2009-01-01

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 252 Cf 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.

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.

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

Optimization of periodical interrogation of transducers of radioisotope measuring systems

International Nuclear Information System (INIS)

Ivashchenko, A.S.; Kaznakov, V.P.; Korolev, V.M.

1978-01-01

Certain methods are examined of optimizing periodic interrogation of sensors connected in a definite sequence to device for data processing in a system for controlling production processes. It is shown that in designing multiinput radioisotope measurement systems with a centralized data processing, the choice of the method of organizing periodic interrogation should be made with account for the conditions existing in each specific case

A 252Cf based nondestructive assay system for fissile material

International Nuclear Information System (INIS)

Menlove, H.O.; Crane, T.W.

1978-01-01

A modulated 252 Cf source assay system 'Shuffler' based on fast-or-thermal-neutron interrogation combined with delayed-neutron counting has been developed for the assay of fissile material. The 252 Cf neutron source is repetitively transferred from the interrogation position to a shielded position while the delayed neutrons are counted in a high efficiency 3 He neutron well-counter. For samples containing plutonium, this well-counter is also used in the passive coincidence mode to assay the effective 240 Pu content. The design of an optimized neutron tailoring assembly for fast-neutron interrogation using a Monte Carlo Neutron Computer Code is described. The Shuffler system has been applied to the assay of fuel pellets, inventory samples, irradiated fuel and plutonium mixed-oxide fuel. The system can assay samples with fissile contents from a few milligrams up to several kilograms using thermal-neutron interrogation for the low mass samples and fast-neutron interrogation for the high mass samples. Samples containing 235 U- 238 U, or 233 U-Th, or UO 2 -PuO 2 fuel mixtures have been assayed with the Shuffler system. (Auth.)

Simulation and preliminary experimental results for an active neutron counter using a neutron generator for a fissile material accounting

International Nuclear Information System (INIS)

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

2009-01-01

An active neutron coincidence counter using a neutron generator as an interrogation source has been suggested. Because of the high energy of the interrogation neutron source, 2.5 MeV, the induced fission rate is strongly affected by the moderator design. MCNPX simulation has been performed to evaluate the performance achieved with these moderators. The side- and bottom-moderator are significantly important to thermalize neutrons to induce fission. Based on the simulation results, the moderators are designed to be adapted to the experimental system. Their preliminary performance has been tested by using natural uranium oxide powder samples. For a sample of up to 3.5 kg, which contains 21.7 g of 235 U, 2.64 cps/g- 235 U coincidence events have been measured. Mean background error was 9.57 cps and the resultant coincidence error was 13.8 cps. The experimental result shows the current status of an active counting using a neutron generator which still has some challenges to overcome. However, the controllability of an interrogation source makes this system more applicable for a variety of combinations with other non-destructive methods like a passive coincidence counting especially under a harsh environment such as a hot cell. More precise experimental setup and tests with higher enriched samples will be followed to develop a system to apply it to an active measurement for the safeguards of a spent fuel treatment process.

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

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).

Neutron interrogation system using high gamma ray signature to detect contraband special nuclear materials in cargo

Science.gov (United States)

Slaughter, Dennis R [Oakland, CA; Pohl, Bertram A [Berkeley, CA; Dougan, Arden D [San Ramon, CA; Bernstein, Adam [Palo Alto, CA; Prussin, Stanley G [Kensington, CA; Norman, Eric B [Oakland, CA

2008-04-15

A system for inspecting cargo for the presence of special nuclear material. The cargo is irradiated with neutrons. The neutrons produce fission products in the special nuclear material which generate gamma rays. The gamma rays are detecting indicating the presence of the special nuclear material.

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

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.

Contraband detection with fast neutrons

Energy Technology Data Exchange (ETDEWEB)

Buffler, Andy E-mail: abuffler@science.uct.ac.za

2004-11-01

Recent terror events and the increase in the trade of illicit drugs have fuelled the exploration of the use of fast neutrons as probes for the detection of hidden contraband, especially explosives, in packages ranging in size from small mail items to cargo containers. The various approaches using fast neutrons for contraband detection, presently under development, are reviewed. The role that a neutron system might play in the non-intrusive interrogation of airline luggage is discussed.

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.

Observation of Neutron Skyshine from an Accelerator Based Neutron Source

Energy Technology Data Exchange (ETDEWEB)

Franklyn, C. B. [Radiation Science Department, Necsa, PO Box 582, Pretoria 0001 (South Africa)

2011-12-13

A key feature of neutron based interrogation systems is the need for adequate provision of shielding around the facility. Accelerator facilities adapted for fast neutron generation are not necessarily suitably equipped to ensure complete containment of the vast quantity of neutrons generated, typically >10{sup 11} n{center_dot}s{sup -1}. Simulating the neutron leakage from a facility is not a simple exercise since the energy and directional distribution can only be approximated. Although adequate horizontal, planar shielding provision is made for a neutron generator facility, it is sometimes the case that vertical shielding is minimized, due to structural and economic constraints. It is further justified by assuming the atmosphere above a facility functions as an adequate radiation shield. It has become apparent that multiple neutron scattering within the atmosphere can result in a measurable dose of neutrons reaching ground level some distance from a facility, an effect commonly known as skyshine. This paper describes a neutron detection system developed to monitor neutrons detected several hundred metres from a neutron source due to the effect of skyshine.

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

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.

Influence of fuel composition on the spent fuel verification by Self‑Interrogation Neutron Resonance Densitometry

International Nuclear Information System (INIS)

Rossa, Riccardo; Borella, Alessandro; Van der Meer, Klaas; Labeau, Pierre‑Etienne; Pauly, Nicolas

2015-01-01

The Self‑Interrogation Neutron Resonance Densitometry (SINRD) is a passive Non‑Destructive Assay (NDA) that is developed for the safeguards verification of spent nuclear fuel. The main goal of SINRD is the direct quantification of 239Pu by estimating the SINRD signature, which is the ratio between the neutron flux in the fast energy region and in the region close to the 0.3 eV resonance of 239 Pu. The resonance region was chosen because the reduction of the neutron flux within 0.2-0.4 eV is due mainly to neutron absorption from 239 Pu, and therefore the SINRD signature can be correlated to the 239Pu mass in the fuel assembly. This work provides an estimate of the influence of 239 Pu and other nuclides on the SINRD signature. This assessment is performed by Monte Carlo simulations by introducing several nuclides in the fuel material composition and by calculating the SINRD signature for each case. The reference spent fuel library developed by SCK CEN was used for the detailed fuel compositions of PWR 17x17 fuel assemblies with different initial enrichments, burnup, and cooling times. The results from the simulations show that the SINRD signature is mainly correlated to the 239 Pu mass, with significant influence by 235 U. Moreover, the SINRD technique is largely insensitive to the cooling time of the assembly, while it is affected by the burnup and initial enrichment of the fuel. Apart from 239 Pu and 235 U, many other nuclides give minor contributions to the SINRD signature, especially at burnup higher than 20 GWd/tHM.

Detection of SNM by Pulsed Neutron Interrogation

International Nuclear Information System (INIS)

Pedersen, Bent; Mayorov, Valeriy; Roesgen, Eric; Mosconi, Marita; Crochemore, Jean-Michel; Ocherashvili, Aharon; Beck, Arie; Ettedgui, Hanania

2014-01-01

A method for the detection of special nuclear materials (SNM) in shielded containers which is both sensitive and easily applicable under field conditions is presented. The method applies neutron induced fission in SNM by means of an external pulsed neutron source with subsequent detection of the fast prompt fission neutrons. Liquid scintillation detectors surrounding the container under investigation are able to discriminate gamma rays from fast neutrons by the so-called pulse shape discrimination technique (PSD)

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.

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

International Nuclear Information System (INIS)

Loche, F.

2006-10-01

In the framework of radioactive waste drums control, difficulties arise in the nondestructive measurement of fissile mass ( 235 U, 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,γ) 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 γ 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)

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

Science.gov (United States)

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.

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.

Californium interrogation prompt neutron (CIPN) instrument for non-destructive assay of spent nuclear fuel—Design concept and experimental demonstration

International Nuclear Information System (INIS)

Henzlova, D.; Menlove, H.O.; Rael, C.D.; Trellue, H.R.; Tobin, S.J.; Park, Se-Hwan; Oh, Jong-Myeong; Lee, Seung-Kyu; Ahn, Seong-Kyu; Kwon, In-Chan; Kim, Ho-Dong

2016-01-01

This paper presents results of the first experimental demonstration of the Californium Interrogation Prompt Neutron (CIPN) instrument developed within a multi-year effort launched by the Next Generation Safeguards Initiative Spent Fuel Project of the United States Department of Energy. The goals of this project focused on developing viable non-destructive assay techniques with capabilities to improve an independent verification of spent fuel assembly characteristics. For this purpose, the CIPN instrument combines active and passive neutron interrogation, along with passive gamma-ray measurements, to provide three independent observables. This paper describes the initial feasibility demonstration of the CIPN instrument, which involved measurements of four pressurized-water-reactor spent fuel assemblies with different levels of burnup and two initial enrichments. The measurements were performed at the Post-Irradiation Examination Facility at the Korea Atomic Energy Institute in the Republic of Korea. The key aim of the demonstration was to evaluate CIPN instrument performance under realistic deployment conditions, with the focus on a detailed assessment of systematic uncertainties that are best evaluated experimentally. The measurements revealed good positioning reproducibility, as well as a high degree of insensitivity of the CIPN instrument's response to irregularities in a radial burnup profile. Systematic uncertainty of individual CIPN instrument signals due to assembly rotation was found to be <4.5%, even for assemblies with fairly extreme gradients in the radial burnup profile. These features suggest that the CIPN instrument is capable of providing a good representation of assembly average characteristics, independent of assembly orientation in the instrument.

Californium interrogation prompt neutron (CIPN) instrument for non-destructive assay of spent nuclear fuel—Design concept and experimental demonstration

Energy Technology Data Exchange (ETDEWEB)

Henzlova, D., E-mail: henzlova@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Menlove, H.O.; Rael, C.D.; Trellue, H.R.; Tobin, S.J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Park, Se-Hwan; Oh, Jong-Myeong; Lee, Seung-Kyu; Ahn, Seong-Kyu; Kwon, In-Chan; Kim, Ho-Dong [Korea Atomic Energy Research Institute, Daejeong (Korea, Republic of)

2016-01-11

This paper presents results of the first experimental demonstration of the Californium Interrogation Prompt Neutron (CIPN) instrument developed within a multi-year effort launched by the Next Generation Safeguards Initiative Spent Fuel Project of the United States Department of Energy. The goals of this project focused on developing viable non-destructive assay techniques with capabilities to improve an independent verification of spent fuel assembly characteristics. For this purpose, the CIPN instrument combines active and passive neutron interrogation, along with passive gamma-ray measurements, to provide three independent observables. This paper describes the initial feasibility demonstration of the CIPN instrument, which involved measurements of four pressurized-water-reactor spent fuel assemblies with different levels of burnup and two initial enrichments. The measurements were performed at the Post-Irradiation Examination Facility at the Korea Atomic Energy Institute in the Republic of Korea. The key aim of the demonstration was to evaluate CIPN instrument performance under realistic deployment conditions, with the focus on a detailed assessment of systematic uncertainties that are best evaluated experimentally. The measurements revealed good positioning reproducibility, as well as a high degree of insensitivity of the CIPN instrument's response to irregularities in a radial burnup profile. Systematic uncertainty of individual CIPN instrument signals due to assembly rotation was found to be <4.5%, even for assemblies with fairly extreme gradients in the radial burnup profile. These features suggest that the CIPN instrument is capable of providing a good representation of assembly average characteristics, independent of assembly orientation in the instrument.

Dual Neutral Particle Beam Interrogation of Intermodal Shipping Containers for Special Nuclear Material

Science.gov (United States)

Keith, Rodney Lyman

Intermodal shipping containers entering the United States provide an avenue to smuggle unsecured or stolen special nuclear material (SNM). The only direct method fielded to indicate the presence of SNM is by passive photon/neutron radiation detection. Active interrogation using neutral particle beams to induce fission in SNM is a method under consideration. One by-product of fission is the creation of fragments that undergo radioactive decay over a time period on the order of tens of seconds after the initial event. The "delayed" gamma-rays emitted from these fragments over this period are considered a hallmark for the presence of SNM. A fundamental model is developed using homogenized cargos with a SNM target embedded at the center and computationally interrogated using simultaneous neutron and photon beams. Findings from analysis of the delayed gamma emissions from these experiments are intended to mitigate the effects of poor quality information about the composition and disposition of suspect cargo before examination in an active interrogation portal.

A programme for Euratom safeguards inspectors, used in the assay of high enriched (H.E.U.) and low enriched (L.E.U.) uranium fuel materials by active neutron interrogation

International Nuclear Information System (INIS)

Vocino, V.; Farese, N.; Maucq, T.; Nebuloni, M.

1991-01-01

The programme AECC (Active Euratom Coincidence Counters) has been developed at the Joint Research Center, Ispra by the Euratom Safeguards Directorate, Luxembourg and the Safety Technology Institute, Ispra for the acquisition, evaluation, management and storage of measurement data originating from active neutron interrogation of HEU and LEU fuel materials. The software accommodates the implementation of the NDA (Non Destructive Assay) procedures for the Active Well Coincidence Counters and Active Neutron Coincidence Counters deployed by the Euratom Safeguards Directorate, Luxembourg

Recent advances in fast neutron radiography for cargo inspection

International Nuclear Information System (INIS)

Sowerby, B.D.; Tickner, J.R.

2007-01-01

Fast neutron radiography techniques are attractive for screening cargo for contraband such as narcotics and explosives. Neutrons have the required penetration, they interact with matter in a manner complementary to X-rays and they can be used to determine elemental composition. Compared to neutron interrogation techniques that measure secondary radiation (neutron or gamma-rays), neutron radiography systems are much more efficient and rapid and they are much more amenable to imaging. However, for neutron techniques to be successfully applied to cargo screening, they must demonstrate significant advantages over well-established X-ray techniques. This paper reviews recent developments and applications of fast neutron radiography for cargo inspection. These developments include a fast neutron and gamma-ray radiography system that utilizes a 14 MeV neutron generator as well as fast neutron resonance radiography systems that use variable energy quasi-monoenergetic neutrons and pulsed broad energy neutron beams. These systems will be discussed and compared with particular emphasis on user requirements, sources, detector systems, imaging ability and performance

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

International Nuclear Information System (INIS)

Favalli, Andrea; Aymond, F.; Bridgewater, Jon S.; Croft, Stephen; Deppert, O.; Devlin, Matthew James; Falk, Katerina; Fernandez, Juan Carlos; Gautier, Donald Cort; Gonzales, Manuel A.; Goodsell, Alison Victoria; Guler, Nevzat; Hamilton, Christopher Eric; Hegelich, Bjorn Manuel; Henzlova, Daniela; Ianakiev, Kiril Dimitrov; Iliev, Metodi; Johnson, Randall Philip; Jung, Daniel; Kleinschmidt, Annika; Koehler, Katrina Elizabeth; Pomerantz, Ishay; Roth, Markus; Santi, Peter Angelo; Shimada, Tsutomu; Swinhoe, Martyn Thomas; Taddeucci, Terry Nicholas; Wurden, Glen Anthony; Palaniyappan, Sasikumar; McCary, E.

2015-01-01

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.

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

Analysis of experimental measurements of PWR fresh and spent fuel assemblies using Self-Interrogation Neutron Resonance Densitometry

Energy Technology Data Exchange (ETDEWEB)

LaFleur, Adrienne M., E-mail: alafleur@lanl.gov; Menlove, Howard O., E-mail: hmenlove@lanl.gov

2015-05-01

Self-Interrogation Neutron Resonance Densitometry (SINRD) is a new NDA technique that was developed at Los Alamos National Laboratory (LANL) to improve existing nuclear safeguards measurements for LWR fuel assemblies. The SINRD detector consists of four fission chambers (FCs) wrapped with different absorber filters to isolate different parts of the neutron energy spectrum and one ion chamber (IC) to measure the gross gamma rate. As a result, two different techniques can be utilized using the same SINRD detector unit and hardware. These techniques are the Passive Neutron Multiplication Counter (PNMC) method and the SINRD method. The focus of the work described in this paper is the analysis of experimental measurements of fresh and spent PWR fuel assemblies that were performed at LANL and the Korea Atomic Energy Research Institute (KAERI), respectively, using the SINRD detector. The purpose of these experiments was to assess the following capabilities of the SINRD detector: 1) reproducibility of measurements to quantify systematic errors, 2) sensitivity to water gap between detector and fuel assembly, 3) sensitivity and penetrability to the removal of fuel rods from the assembly, and 4) use of PNMC/SINRD ratios to quantify neutron multiplication and/or fissile content. The results from these simulations and measurements provide valuable experimental data that directly supports safeguards research and development (R&D) efforts on the viability of passive neutron NDA techniques and detector designs for partial defect verification of spent fuel assemblies. - Highlights: • Experimental measurements of PWR fresh and spent FAs were performed with SINRD. • Good agreement of MCNPX and measured results confirmed accuracy of SINRD model. • For fresh fuel, SINRD and PNMC ratios were not sensitive to water gaps of ≤5-mm. • Practical use of SINRD would be in Fork detector to reduce systematic uncertainties.

Nuclear materials identification by photon interrogation

International Nuclear Information System (INIS)

Pozzi, S.A.; Monville, M.; Padovani, E.

2005-01-01

We describe a preliminary modification to the Monte Carlo codes MCNP-X and MCNP-PoliMi that is aimed at simulating the neutron and photon field generated by interrogating fissile (and non-fissile) material with a high energy photon source. Photo-atomic and photo-nuclear collisions are modeled, with particular emphasis on the generation of secondary particles that are emitted as a result of these interactions. The simulations can be used to design and analyze measurements that are performed in a wide variety of scenarios. An application of the methodology to the interrogation of packages on a luggage belt conveyor is presented. Preliminary results show that it is possible to detect 5 Kg of highly enriched uranium in a package by measuring the correlation function between 2 detectors. This correlation function is based on the detection of prompt radiation from photonuclear events

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.

A dual neutron/gamma source for the Fissmat Inspection for Nuclear Detection (FIND) system.

Energy Technology Data Exchange (ETDEWEB)

Doyle, Barney Lee (Sandia National Laboratories, Albuquerque, NM); King, Michael; Rossi, Paolo (Sandia National Laboratories, Albuquerque, NM); McDaniel, Floyd Del (Sandia National Laboratories, Albuquerque, NM); Morse, Daniel Henry; Antolak, Arlyn J.; Provencio, Paula Polyak (Sandia National Laboratories, Albuquerque, NM); Raber, Thomas N.

2008-12-01

Shielded special nuclear material (SNM) is very difficult to detect and new technologies are needed to clear alarms and verify the presence of SNM. High-energy photons and neutrons can be used to actively interrogate for heavily shielded SNM, such as highly enriched uranium (HEU), since neutrons can penetrate gamma-ray shielding and gamma-rays can penetrate neutron shielding. Both source particles then induce unique detectable signals from fission. In this LDRD, we explored a new type of interrogation source that uses low-energy proton- or deuteron-induced nuclear reactions to generate high fluxes of mono-energetic gammas or neutrons. Accelerator-based experiments, computational studies, and prototype source tests were performed to obtain a better understanding of (1) the flux requirements, (2) fission-induced signals, background, and interferences, and (3) operational performance of the source. The results of this research led to the development and testing of an axial-type gamma tube source and the design/construction of a high power coaxial-type gamma generator based on the {sup 11}B(p,{gamma}){sup 12}C nuclear reaction.

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)

System for nondestructive assay of spent fuel subassemblies: comparison of calculations and measurements

International Nuclear Information System (INIS)

Ragan, G.L; Ricker, C.W.; Chiles, M.M.; Ingersoll, D.T.; Slaughter, G.G.; Williams, L.R.

1979-01-01

A nondestructive assay system was developed for determining the total fissile content of spent fuel subassemblies at the head end of a reprocessing plant. The system can perform an assay in 20 min with an uncertainty of <5%. Antimony-beryllium neutrons interrogate the subassemblies, and proton recoil counters detect the resulting fission neutrons. Pulse-height discrimination differentiates between the low-energy interrogation neutrons and the higher-energy fission neutrons. Calculated and measured results were compared for (1) interrogation-neutron penetrability, (2) fission-neutron detectability, (3) radial variation of assay sensitivity, (4) axial variation of assay sensitivity, and (5) the variation of detector count rate as a function of the number of fuel rods in a special 61-rod, LMFBR-type subassembly

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.

Detection of fission signatures induced by a low-energy neutron source

International Nuclear Information System (INIS)

Ocherashvili, A.; Becka, A.; Mayorovb, V.; Roesgen, E.; Crochemoreb, J.-M.; Mosconi, M.; Pedersen, B.; Heger, C.

2015-01-01

We present a method for the detection of special nuclear materials (SNM) in shielded containers which is both sensitive and applicable under field conditions. The method uses an external pulsed neutron source to induce fission in SNM and subsequent detection of the fast prompt fission neutrons. The detectors surrounding the container under investigation are liquid scintillation detectors able to distinguish gamma rays from fast neutrons by means of the pulse shape discrimination method (PSD). One advantage of these detectors, besides the ability for PSD analysis, is that the analogue signal from a detection event is of very short duration (typically few tens of nanoseconds). This allows the use of very short coincidence gates for the detection of the prompt fission neutrons in multiple detectors while benefiting from a low accidental (background) coincidence rate yielding a low detection limit. Another principle advantage of this method derives from the fact that the external neutron source is pulsed. By proper time gating the interrogation can be conducted by epithermal and thermal source neutrons only. These source neutrons do not appear in the fast neutron signal following the PSD analysis thus providing a fundamental method for separating the interrogating source neutrons from the sample response in form of fast fission neutrons. The paper describes laboratory tests with a configuration of eight detectors in the Pulsed Neutron Interrogation Test Assembly (PUNITA). The sensitivity of the coincidence signal to fissile mass is investigated for different sample configurations and interrogation regimes.

Performance of an optical identification and interrogation system

Science.gov (United States)

Venugopalan, A.; Ghosh, A. K.; Verma, P.; Cheng, S.

2008-04-01

A free space optics based identification and interrogation system has been designed. The applications of the proposed system lie primarily in areas which require a secure means of mutual identification and information exchange between optical readers and tags. Conventional RFIDs raise issues regarding security threats, electromagnetic interference and health safety. The security of RF-ID chips is low due to the wide spatial spread of radio waves. Malicious nodes can read data being transmitted on the network, if they are in the receiving range. The proposed system provides an alternative which utilizes the narrow paraxial beams of lasers and an RSA-based authentication scheme. These provide enhanced security to communication between a tag and the base station or reader. The optical reader can also perform remote identification and the tag can be read from a far off distance, given line of sight. The free space optical identification and interrogation system can be used for inventory management, security systems at airports, port security, communication with high security systems, etc. to name a few. The proposed system was implemented with low-cost, off-the-shelf components and its performance in terms of throughput and bit error rate has been measured and analyzed. The range of operation with a bit-error-rate lower than 10-9 was measured to be about 4.5 m. The security of the system is based on the strengths of the RSA encryption scheme implemented using more than 1024 bits.

Detection of actinides with an electron accelerator by active photoneutron interrogation measurements

International Nuclear Information System (INIS)

Sari, A.; Carrel, F.; Gmar, M.; Laine, F.; Normand, S.; Lyoussi, A.

2012-01-01

The solution for management of a nuclear waste package is chosen according to its radiological characteristics. One of the most important of these features is the α-activity which is due to actinides ( 235 U, 238 U, 239 Pu, etc.) If non-destructive passive methods are not sufficient to quantify the latter, non-destructive active methods based on the fission process represent a solution of interest. First, these methods consist in irradiating a package in order to induce fission reactions on the actinides, and then, to detect the prompt and delayed particles which are emitted following these reactions. Our aim is to conduct neutron interrogation measurements on nuclear waste packages using an electron accelerator as a photoneutron generator. One of the main interests of this approach is that the intensity of the neutron flux can be one or two orders of magnitude higher than the one delivered by a deuterium-tritium generator. With the objective of improving nuclear waste characterization, the development of this method could enable the integration of three complementary techniques on a single measurement cell (active neutron interrogation, active photon interrogation, and high-energy imaging). In this paper, simulation and experimental results are presented. A simulation study using MCNPX has been conducted in order to determine the characteristics of the photoneutron flux emitted by the electron accelerator of the SAPHIR facility owned by CEA LIST. Energy spectra, angular distribution and intensity of the photoneutron flux have been obtained. A photoneutron interrogation measurement cell based on this accelerator has been built and assessed by carrying out measurements on uranium samples. Delayed gamma-ray spectra have been acquired and enabled to confirm the experimental feasibility of our method. (authors)

Determination of alpha activity and fissile mass content in solid waste by systems using neutron interrogation

International Nuclear Information System (INIS)

Romeyer Dherbey, J.; Lacruche, G.; Berne, R.; Auge, J.; Martin Deidier, L.; Butez, M.

1990-01-01

The Quantitative control (determination of heavy nuclides and alpha activity) of alpha radioactive wastes is necessary, particularly to determine if the waste is in accordance with the surface storage limits. In order to reduce the uncertainty on the alpha activity resulting from unknown isotopic composition, inhomogeneity of heavy nuclides in the matrix, combination of several methods is necessary. In the paper we present the Cadarache development work in the NDA of solid waste using the Californium shuffler, 14 Mev neutron generator, and also passive techniques such as neutron emission measurement and gamma spectrometry. Experimental systems combining active and passive methods are presented (COSAC, BANCO, DANAIDE, PROMETHEE)

Fissile and fertile nuclear material measurements using a new differential die-away self-interrogation technique

International Nuclear Information System (INIS)

Menlove, H.O.; Menlove, S.H.; Tobin, S.J.

2009-01-01

This paper presents a new technique for the measurement of fissile and fertile nuclear materials in spent fuel and plutonium-laden materials such as mixed oxide (MOX) fuel. The technique, called differential die-away self-interrogation, is similar to traditional differential die-away analysis, but it does not require a pulsed neutron generator or pulsed beam accelerator, and it can measure the fertile mass in addition to the fissile mass. The new method uses the spontaneous fission neutrons from 244 Cm in spent fuel and 240 Pu effective neutrons in MOX as the 'pulsed' neutron source, with an average of ∼2.7 neutrons per pulse. The time-correlated neutrons from the spontaneous fission and the subsequent induced fissions are analyzed as a function of time to determine the spontaneous fission rate, the induced fast-neutron fissions, and the induced thermal-neutron fissions. The fissile mass is determined from the induced thermal-neutron fissions that are produced by reflected thermal neutrons that originated from the spontaneous fission reaction. The sensitivity of the fissile mass measurement is enhanced by the use of two measurements, with and without a cadmium liner between the sample and a hydrogenous moderator that surrounds the sample. The fertile mass is determined from the multiplicity analysis of the neutrons detected soon after the initial triggering neutron is detected. The method obtains good sensitivity by the optimal design of two different neutron die-away regions: a short die-away for the neutron detector region and a longer die-away for the sample interrogation region.

Accelerating fissile material detection with a neutron source

Science.gov (United States)

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.

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.

Detection of land mines using fast and thermal neutron analysis

International Nuclear Information System (INIS)

Bach, P.

1998-01-01

The detection of land mines is made possible by using nuclear sensor based on neutron interrogation. Neutron interrogation allows to detect the sensitive elements (C, H, O, N) of the explosives in land mines or in unexploded shells: the evaluation of characteristic ratio N/O and C/O in a volume element gives a signature of high explosives. Fast neutron interrogation has been qualified in our laboratories as a powerful close distance method for identifying the presence of a mine or explosive. This method could be implemented together with a multisensor detection system - for instance IR or microwave - to reduce the false alarm rate by addressing the suspected area. Principle of operation is based on the measurement of gamma rays induced by neutron interaction with irradiated nuclei from the soil and from a possible mine. Specific energy of these gamma rays allows to recognise the elements at the origin of neutron interaction. Several detection methods can be used, depending on nuclei to be identified. Analysis of physical data, computations by simulation codes, and experimentations performed in our laboratory have shown the interest of Fast Neutron Analysis (FNA) combined with Thermal Neutron Analysis (TNA) techniques, especially for detection of nitrogen 14 N, carbon 12 C and oxygen 16 O. The FNA technique can be implemented using a 14 MeV sealed neutron tube, and a set of detectors. The mines detection has been demonstrated from our investigations, using a low power neutron generator working in the 10 8 n/s range, which is reasonable when considering safety rules. A fieldable demonstrator would be made with a detection head including tube and detectors, and with remote electronics, power supplies and computer installed in a vehicle. (author)

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.

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)

Guidelines for calculating and enhancing detection efficiency of PIT tag interrogation systems

Science.gov (United States)

Connolly, Patrick J.

2010-01-01

With increasing use of passive integrated transponder (PIT) tags and reliance on stationary PIT tag interrogation systems to monitor fish populations, guidelines are offered to inform users how best to use limited funding and human resources to create functional systems that maximize a desired level of detection and precision. The estimators of detection efficiency and their variability as described by Connolly et al. (2008) are explored over a span of likely performance metrics. These estimators were developed to estimate detection efficiency without relying on a known number of fish passing the system. I present graphical displays of the results derived from these estimators to show the potential efficiency and precision to be gained by adding an array or by increasing the number of PIT-tagged fish expected to move past an interrogation system.

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

International Nuclear Information System (INIS)

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

2017-01-01

An extension of the point kinetics model is developed in this paper 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. Finally, the spatial dependence of multiplication is also suspected of introducing further systematic bias for high multiplication uranium objects.

Investigation of Active Interrogation Techniques to Detect Special Nuclear Material in Maritime Environments

International Nuclear Information System (INIS)

Miller, Thomas Martin; Patton, Bruce W.

2010-01-01

The detection and interdiction of special nuclear material (SNM) is still a high-priority focus area for many organizations around the world. One method that is commonly considered a leading candidate in the detection of SNM is active interrogation (AI). AI is different from its close relative, passive interrogation, in that an active source is used to enhance or create a detectable signal (usually fission) from SNM, particularly in shielded scenarios or scenarios where the SNM has a low activity. The use of AI thus makes the detection of SNM easier or, in some scenarios, even enables previously impossible detection. In this work the signal from prompt neutrons and photons as well as delayed neutrons and photons will be combined, as is typically done in AI. In previous work AI has been evaluated experimentally and computationally. However, for the purposes of this work, past scenarios are considered lightly shielded and tightly coupled spatially. At most, the previous work interrogated the contents of one standard cargo container (2.44 x 2.60 x 6.10 m) and the source and detector were both within a few meters of the object being interrogated. A few examples of this type of previous work can be found in references 1 and 2. Obviously, more heavily shielded AI scenarios will require larger source intensities, larger detector surface areas (larger detectors or more detectors), greater detector efficiencies, longer count times, or some combination of these.

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.

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.

Performance of a remote interrogation system for the in-hospital evaluation of cardiac implantable electronic devices.

Science.gov (United States)

Mittal, Suneet; Younge, Kevin; King-Ellison, Kelly; Hammill, Eric; Stein, Kenneth

2016-08-01

Patients with a cardiac implantable electronic device (CIED) often need device interrogation in an in-hospital environment. A diagnosis-only, remote interrogation device and process for CIED interrogation was developed to address this situation. Here, we describe our initial clinical experience with this system. The LATITUDE Consult Communicator is a stand-alone interrogation-only device used to read the patient's implanted CIED. Once retrieved, the data are securely transmitted via an analog phone line to a central server. The clinician can request a review of the transmitted data at any time. Following FDA approval, we determined the usage and performance of the system. Communicators (n = 53) were installed in 42 hospital facilities. The most common location was in the emergency department (n = 32, 60 %). There were 509 discreet transmissions, which were categorized as follows: no arrhythmia episodes in the past 72 h and no out of range measurements (n = 174, 34 %); arrhythmia episodes in past 72 h but no out of range measurements (n = 170, 33 %); and further review recommended (n = 130, 26 %). (In 35 [7 %] instances, interrogation without analysis was requested.) The further review interrogations were then sub-divided into those of a non-urgent and urgent nature. Overall, only 53 (10 %) of the 509 transmissions were classified as urgent. Clinicians had access to full technical consultation in ≤15 min in 89 % of instances. Our data demonstrate the feasibility of a new diagnosis-only, remote interrogation device and remote evaluation process for the interrogation of CIEDs in an in-hospital environment.

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.

The Nuclear Car Wash: Neutron interrogation of cargo containers to detect hidden SNM

Science.gov (United States)

Hall, J. M.; Asztalos, S.; Biltoft, P.; Church, J.; Descalle, M.-A.; Luu, T.; Manatt, D.; Mauger, G.; Norman, E.; Petersen, D.; Pruet, J.; Prussin, S.; Slaughter, D.

2007-08-01

LLNL is actively involved in the development of advanced technologies for use in detecting threats in sea-going cargo containers, particularly the presence of hidden special nuclear materials (SNM). The "Nuclear Car Wash" (NCW) project presented here uses a high-energy (En ≈ 3.5-7.0 MeV) neutron probe to scan a container and then takes high-energy (Eγ ⩾ 2.5 MeV), β-delayed γ-rays emitted during the subsequent decay of any short-lived, neutron-induced fission products as a signature of fissionable material. The components of the proposed system (e.g. neutron source, gamma detectors, etc.) will be discussed along with data processing schemes, possible threat detection metrics and potential interference signals. Results from recent laboratory experiments using a prototype system at LLNL will also be presented.

The Nuclear Car Wash: Neutron interrogation of cargo containers to detect hidden SNM

International Nuclear Information System (INIS)

Hall, J.M.; Asztalos, S.; Biltoft, P.; Church, J.; Descalle, M.-A.; Luu, T.; Manatt, D.; Mauger, G.; Norman, E.; Petersen, D.; Pruet, J.; Prussin, S.; Slaughter, D.

2007-01-01

LLNL is actively involved in the development of advanced technologies for use in detecting threats in sea-going cargo containers, particularly the presence of hidden special nuclear materials (SNM). The 'Nuclear Car Wash' (NCW) project presented here uses a high-energy (E n ∼ 3.5-7.0 MeV) neutron probe to scan a container and then takes high-energy (E γ ≥ 2.5 MeV), β-delayed γ-rays emitted during the subsequent decay of any short-lived, neutron-induced fission products as a signature of fissionable material. The components of the proposed system (e.g. neutron source, gamma detectors, etc.) will be discussed along with data processing schemes, possible threat detection metrics and potential interference signals. Results from recent laboratory experiments using a prototype system at LLNL will also be presented

A Fiber Bragg Grating Interrogation System with Self-Adaption Threshold Peak Detection Algorithm.

Science.gov (United States)

Zhang, Weifang; Li, Yingwu; Jin, Bo; Ren, Feifei; Wang, Hongxun; Dai, Wei

2018-04-08

A Fiber Bragg Grating (FBG) interrogation system with a self-adaption threshold peak detection algorithm is proposed and experimentally demonstrated in this study. This system is composed of a field programmable gate array (FPGA) and advanced RISC machine (ARM) platform, tunable Fabry-Perot (F-P) filter and optical switch. To improve system resolution, the F-P filter was employed. As this filter is non-linear, this causes the shifting of central wavelengths with the deviation compensated by the parts of the circuit. Time-division multiplexing (TDM) of FBG sensors is achieved by an optical switch, with the system able to realize the combination of 256 FBG sensors. The wavelength scanning speed of 800 Hz can be achieved by a FPGA+ARM platform. In addition, a peak detection algorithm based on a self-adaption threshold is designed and the peak recognition rate is 100%. Experiments with different temperatures were conducted to demonstrate the effectiveness of the system. Four FBG sensors were examined in the thermal chamber without stress. When the temperature changed from 0 °C to 100 °C, the degree of linearity between central wavelengths and temperature was about 0.999 with the temperature sensitivity being 10 pm/°C. The static interrogation precision was able to reach 0.5 pm. Through the comparison of different peak detection algorithms and interrogation approaches, the system was verified to have an optimum comprehensive performance in terms of precision, capacity and speed.

A Fiber Bragg Grating Interrogation System with Self-Adaption Threshold Peak Detection Algorithm

Directory of Open Access Journals (Sweden)

Weifang Zhang

2018-04-01

Full Text Available A Fiber Bragg Grating (FBG interrogation system with a self-adaption threshold peak detection algorithm is proposed and experimentally demonstrated in this study. This system is composed of a field programmable gate array (FPGA and advanced RISC machine (ARM platform, tunable Fabry–Perot (F–P filter and optical switch. To improve system resolution, the F–P filter was employed. As this filter is non-linear, this causes the shifting of central wavelengths with the deviation compensated by the parts of the circuit. Time-division multiplexing (TDM of FBG sensors is achieved by an optical switch, with the system able to realize the combination of 256 FBG sensors. The wavelength scanning speed of 800 Hz can be achieved by a FPGA+ARM platform. In addition, a peak detection algorithm based on a self-adaption threshold is designed and the peak recognition rate is 100%. Experiments with different temperatures were conducted to demonstrate the effectiveness of the system. Four FBG sensors were examined in the thermal chamber without stress. When the temperature changed from 0 °C to 100 °C, the degree of linearity between central wavelengths and temperature was about 0.999 with the temperature sensitivity being 10 pm/°C. The static interrogation precision was able to reach 0.5 pm. Through the comparison of different peak detection algorithms and interrogation approaches, the system was verified to have an optimum comprehensive performance in terms of precision, capacity and speed.

A Fiber Bragg Grating Sensor Interrogation System Based on a Linearly Wavelength-Swept Thermo-Optic Laser Chip

Science.gov (United States)

Lee, Hyung-Seok; Lee, Hwi Don; Kim, Hyo Jin; Cho, Jae Du; Jeong, Myung Yung; Kim, Chang-Seok

2014-01-01

A linearized wavelength-swept thermo-optic laser chip was applied to demonstrate a fiber Bragg grating (FBG) sensor interrogation system. A broad tuning range of 11.8 nm was periodically obtained from the laser chip for a sweep rate of 16 Hz. To measure the linear time response of the reflection signal from the FBG sensor, a programmed driving signal was directly applied to the wavelength-swept laser chip. The linear wavelength response of the applied strain was clearly extracted with an R-squared value of 0.99994. To test the feasibility of the system for dynamic measurements, the dynamic strain was successfully interrogated with a repetition rate of 0.2 Hz by using this FBG sensor interrogation system. PMID:25177803

Miniature fiber Bragg grating sensor interrogator (FBG-Transceiver) system

Science.gov (United States)

Mendoza, Edgar A.; Kempen, Cornelia; Lopatin, Craig

2007-04-01

This paper describes recent progress conducted towards the development of a miniature fiber Bragg grating sensor interrogator (FBG-Transceiver TM) system based on multi-channel integrated optic sensor (InOSense TM) microchip technology. The hybrid InOSense TM microchip technology enables the integration of all of the functionalities, both passive and active, of conventional bench top FBG sensor interrogator systems, packaged in a miniaturized, low power operation, 2-cm x 5-cm package suitable for the long-term structural health monitoring in applications where size, weight, and power are critical for operation. The FBG-Transceiver system uses active optoelectronic components monolithically integrated to the InOSense TM microchip, a microprocessor controlled signal processing electronics board capable of processing the FBG sensors signals related to stress-strain and temperature as well as vibration and acoustics. The FBG-Transceiver TM system represents a new, reliable, highly robust technology that can be used to accurately monitor the status of an array of distributed fiber optic Bragg grating sensors installed in critical infrastructures. Its miniature package, low power operation, and state-of-the-art data communications architecture, all at a very affordable price makes it a very attractive solution for a large number of SHM/NDI applications in aerospace, naval and maritime industry, civil structures like bridges, buildings and dams, the oil and chemical industry, and for homeland security applications. The miniature, cost-efficient FBG-Transceiver TM system is poised to revolutionize the field of structural health monitoring and nondestructive inspection market. The sponsor of this program is NAVAIR under a DOD SBIR contract.

Monitoring system including an electronic sensor platform and an interrogation transceiver

Science.gov (United States)

Kinzel, Robert L.; Sheets, Larry R.

2003-09-23

A wireless monitoring system suitable for a wide range of remote data collection applications. The system includes at least one Electronic Sensor Platform (ESP), an Interrogator Transceiver (IT) and a general purpose host computer. The ESP functions as a remote data collector from a number of digital and analog sensors located therein. The host computer provides for data logging, testing, demonstration, installation checkout, and troubleshooting of the system. The IT transmits signals from one or more ESP's to the host computer to the ESP's. The IT host computer may be powered by a common power supply, and each ESP is individually powered by a battery. This monitoring system has an extremely low power consumption which allows remote operation of the ESP for long periods; provides authenticated message traffic over a wireless network; utilizes state-of-health and tamper sensors to ensure that the ESP is secure and undamaged; has robust housing of the ESP suitable for use in radiation environments; and is low in cost. With one base station (host computer and interrogator transceiver), multiple ESP's may be controlled at a single monitoring site.

Investigations of active interrogation techniques to detect special nuclear material in maritime environments: Standoff interrogation of small- and medium-sized cargo ships

Energy Technology Data Exchange (ETDEWEB)

Miller, Thomas M., E-mail: millertm@ornl.gov; Patton, Bruce W.; Grogan, Brandon R.; Henkel, James J.; Murphy, Brian D.; Johnson, Jeffrey O.; Mihalczo, John T.

2013-12-01

In this work, several active interrogation (AI) sources are evaluated to determine their usefulness in detecting the presence of special nuclear material (SNM) in fishing trawlers, small cargo transport ships, and luxury yachts at large standoff distances from the AI source and detector. This evaluation is performed via computational analysis applying Monte Carlo methods with advanced variance reduction techniques. The goal is to determine the AI source strength required to detect the presence of SNM. The general conclusion of this study is that AI is not reliable when SNM is heavily shielded and not tightly coupled geometrically with the source and detector, to the point that AI should not be considered a via interrogation option in these scenarios. More specifically, when SNM is shielded by hydrogenous material large AI source strengths are required if detection is based on neutrons, which is not surprising. However, if the SNM is shielded by high-Z material the required AI source strengths are not significantly different if detection is based on neutrons or photons, which is somewhat surprising. Furthermore, some of the required AI source strengths that were calculated are very large. These results coupled with the realities of two ships moving independently at sea and other assumptions made during this analysis make the use of standoff AI in the maritime environment impractical.

Investigations of active interrogation techniques to detect special nuclear material in maritime environments: Standoff interrogation of small- and medium-sized cargo ships

International Nuclear Information System (INIS)

Miller, Thomas M.; Patton, Bruce W.; Grogan, Brandon R.; Henkel, James J.; Murphy, Brian D.; Johnson, Jeffrey O.; Mihalczo, John T.

2013-01-01

In this work, several active interrogation (AI) sources are evaluated to determine their usefulness in detecting the presence of special nuclear material (SNM) in fishing trawlers, small cargo transport ships, and luxury yachts at large standoff distances from the AI source and detector. This evaluation is performed via computational analysis applying Monte Carlo methods with advanced variance reduction techniques. The goal is to determine the AI source strength required to detect the presence of SNM. The general conclusion of this study is that AI is not reliable when SNM is heavily shielded and not tightly coupled geometrically with the source and detector, to the point that AI should not be considered a via interrogation option in these scenarios. More specifically, when SNM is shielded by hydrogenous material large AI source strengths are required if detection is based on neutrons, which is not surprising. However, if the SNM is shielded by high-Z material the required AI source strengths are not significantly different if detection is based on neutrons or photons, which is somewhat surprising. Furthermore, some of the required AI source strengths that were calculated are very large. These results coupled with the realities of two ships moving independently at sea and other assumptions made during this analysis make the use of standoff AI in the maritime environment impractical

PELAN - a transportable, neutron-based UXO identification technique

International Nuclear Information System (INIS)

Vourvopoulos, G.

1998-01-01

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

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.

Battery-less wireless interrogation of microstrip patch antenna for strain sensing

International Nuclear Information System (INIS)

Xu, X; Huang, H

2012-01-01

This paper presents a battery-less wireless interrogation system that can measure the resonant frequency of a microstrip patch antenna with a fine resolution. Since the antenna resonant frequency is sensitive to strain-induced deformations, wireless interrogation of the antenna sensor for strain measurement was demonstrated. By implementing a microwatt impedance switching circuit at the sensor node, the antenna backscattering is amplitude modulated at the sensor node so that it can be separated from the structural backscattering at the interrogator. The sensor node can be powered by a small photocell and thus achieve battery-less operation. The operating principle of the wireless interrogation system is first described, followed by the implementation and characterization of the wireless interrogation system. The antenna resonant frequency shifts were correlated to the applied strains through a static tensile experiment. An excellent agreement between the experimental results and the analytical prediction was obtained. A power transmission model was established and validated with experimental measurements. Based on this power transmission model, we estimated that the maximum interrogation distance of the wireless strain measurement system is 26 m. (paper)

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

Illicit substance detection using fast-neutron transmission spectroscopy

International Nuclear Information System (INIS)

Micklich, B.J.; Harper, M.K.; Novick, A.H.; Smith, D.L.

1994-01-01

Fast-neutron interrogation techniques are of interest for detecting illicit substances such as explosives and drugs because of their ability to identify light elements such as carbon, nitrogen, and oxygen. Fast-Neutron Transmission Spectroscopy (FNTS) uses standard time-of-flight techniques to measure the energy spectrum of neutrons emitted from a collimated continuum source before and after transmission through the interrogated sample. The Monte Carlo transport code MCNP is used to model fast-neutron transmission experiments using a 9 Be(d, n) source (E d =5 MeV). The areal densities (number of atoms per cm 2 ), and the uncertainties, of various elements present in the sample are determined by an unfolding algorithm which includes the effects of cross-section errors and correlations. Results are displayed in the form of normalized densities, including their errors and correlations, which are then compared to the values for explosives and benign substances. Probabilistic interpretations of the results are discussed in terms of substance detection and identification. ((orig.))

Illicit substance detection using Fast-Neutron Transmission Spectroscopy

International Nuclear Information System (INIS)

Micklich, B.J.; Harper, M.K.; Novick, A.H.; Smith, D.L.

1994-01-01

Fast-neutron interrogation techniques are of interest for detecting illicit substances such as explosives and drugs because of their ability to identify light elements such as carbon, nitrogen, and oxygen. Fast-Neutron Transmission Spectroscopy (FNTS) uses standard time-of-flight techniques to measure the energy spectrum of neutrons emitted from a collimated continuum source before and after transmission through the interrogated sample. The Monte Carlo transport code MCNP is used to model fast-neutron transmission experiments using a 9 Be(d,n) source [E d = 5 MeV]. The areal densities (number of atoms per cm 2 ), and the uncertainties, of various elements present in the sample are determined by an unfolding algorithm which includes the effects of cross-section errors and correlations. Results are displayed in the form of normalized densities, including their errors and correlations, which are then compared to the values for explosives and benign substances. Probabilistic interpretations of the results are discussed in terms of substance detection and identification

Development of fiber optic sensing interrogators for launchers

Science.gov (United States)

Plattner, M. P.; Buck, T. C.; Eder, B.; Reutlinger, A.; McKenzie, I.

2017-11-01

We present our work about the development of two complementary interrogation schemes based on fiber optic sensing for the use of structural and thermal monitoring of Ariane launchers. The advantages of fiber optic sensing in particular light-weight, immunity to electromagnetic interferences and the possibility of sensor distribution along optical fibers are driving factors for utilization of this technology in space crafts [1]. The edge-filter (EF) and scanning-laser (SL) interrogators for determination of the mean wavelength of fiber Bragg grating (FBG) sensors have been implemented as two separate demonstrators. Within this paper we describe the functional principles of both interrogators. Furthermore we present test results where the developed systems have been used for readout of FBG sensors which are implemented in an Ariane structural demonstrator during thermal, thermal-vacuum and vibration tests. Functionality of both systems is demonstrated and their potential for further development towards space qualified systems is shown. Since the performance characteristics of the two systems are different from each other, they are dedicated for different sensing applications on a launcher. The EF sensor interrogator provides a sample rate of 20 kHz at a number of 4 connected sensors and supports parallel readout and aliasing free operation. Therefore it is best suited for high priority measurement. Structural monitoring which requires the acquisition of real time sensor information in order to support control of the launcher is one operation area for a future EF system. The SL interrogator provides an overall measurement rate of 1 kHz at a number of 24 connected sensors distributed on three sensor channels. It can be adapted to any sensors that have design wavelengths lying within the output spectrum of the laser diode. Furthermore the number of overall sensors to be read out with this system can be adapted easily. Thermal mapping of satellite panels is one possible

Detection and identification of unexploded ordnance (UXO) by neutron interrogation

International Nuclear Information System (INIS)

Caffrey, A.J.; Hartwell, J.K.; Krebs, K.M.; McLaughlin, G.D.

1998-01-01

This document reviews the principle of operation and unexploded ordnance (UXO) signatures of the PINS Chemical Assay System, a prompt-gamma-ray neutron activation analysis (PGNAA) for the identification of recovered UXO. Two related low cost methods for buried landmine detection are also suggested. Nuclear methods may compliment existing search techniques to improve the overall probability of detection and to reduce the false positive rate of other technologies. In addition, nuclear methods are a proven method for identification of UXO such as landmines

Psychological Perspectives on Interrogation.

Science.gov (United States)

Vrij, Aldert; Meissner, Christian A; Fisher, Ronald P; Kassin, Saul M; Morgan, Charles A; Kleinman, Steven M

2017-11-01

Proponents of "enhanced interrogation techniques" in the United States have claimed that such methods are necessary for obtaining information from uncooperative terrorism subjects. In the present article, we offer an informed, academic perspective on such claims. Psychological theory and research shows that harsh interrogation methods are ineffective. First, they are likely to increase resistance by the subject rather than facilitate cooperation. Second, the threatening and adversarial nature of harsh interrogation is often inimical to the goal of facilitating the retrieval of information from memory and therefore reduces the likelihood that a subject will provide reports that are extensive, detailed, and accurate. Third, harsh interrogation methods make lie detection difficult. Analyzing speech content and eliciting verifiable details are the most reliable cues to assessing credibility; however, to elicit such cues subjects must be encouraged to provide extensive narratives, something that does not occur in harsh interrogations. Evidence is accumulating for the effectiveness of rapport-based information-gathering approaches as an alternative to harsh interrogations. Such approaches promote cooperation, enhance recall of relevant and reliable information, and facilitate assessments of credibility. Given the available evidence that torture is ineffective, why might some laypersons, policymakers, and interrogation personnel support the use of torture? We conclude our review by offering a psychological perspective on this important question.

Police practices and perceptions regarding juvenile interrogation and interrogative suggestibility.

Science.gov (United States)

Meyer, Jessica R; Reppucci, N Dickon

2007-01-01

Recent media coverage has highlighted cases in which young suspects were wrongly convicted because they provided interrogation-induced false confessions. Although youth may be more highly suggestible and easily influenced by authority than adults, police are trained to use the same psychologically coercive and deceptive tactics with youth as with adults. This investigation is the first standard documentation of the reported interrogation practices of law enforcement and police beliefs about the reliability of these techniques and their knowledge of child development. Participants were 332 law enforcement officers who completed surveys about interrogation procedures and developmental issues pertaining to youth. Results indicated that, while police acknowledge some developmental differences between youth and adults, there were indications that (1) how police perceive youth in general and how they perceive and treat them in the interrogation context may be contradictory and (2) their general view is that youth can be dealt with in the same manner as adults. Copyright (c) 2007 John Wiley & Sons, Ltd.

Development and characterization of a high yield transportable pulsed neutron source with efficient and compact pulsed power system

Energy Technology Data Exchange (ETDEWEB)

Verma, Rishi, E-mail: rishiv9@gmail.com, E-mail: rishiv@barc.gov.in; Mishra, Ekansh; Dhang, Prosenjit; Sagar, Karuna; Meena, Manraj; Shyam, Anurag [Energetics and Electromagnetics Division, Bhabha Atomic Research Centre Autonagar, Vishakapatnam 530012 (India)

2016-09-15

The results of characterization experiments carried out on a newly developed dense plasma focus device based intense pulsed neutron source with efficient and compact pulsed power system are reported. Its high current sealed pseudospark switch based low inductance capacitor bank with maximum stored energy of ∼10 kJ is segregated into four modules of ∼2.5 kJ each and it cumulatively delivers peak current in the range of 400 kA–600 kA (corresponding to charging voltage range of 14 kV–18 kV) in a quarter time period of ∼2 μs. The neutron yield performance of this device has been optimized by discretely varying deuterium filling gas pressure in the range of 6 mbar–11 mbar at ∼17 kV/550 kA discharge. At ∼7 kJ/8.5 mbar operation, the average neutron yield has been measured to be in the order of ∼4 × 10{sup 9} neutrons/pulse which is the highest ever reported neutron yield from a plasma focus device with the same stored energy. The average forward to radial anisotropy in neutron yield is found to be ∼2. The entire system is contained on a moveable trolley having dimensions 1.5 m × 1 m × 0.7 m and its operation and control (up to the distance of 25 m) are facilitated through optically isolated handheld remote console. The overall compactness of this system provides minimum proximity to small as well as large samples for irradiation. The major intended application objective of this high neutron yield dense plasma focus device development is to explore the feasibility of active neutron interrogation experiments by utilization of intense pulsed neutron sources.

Dual reference point temperature interrogating method for distributed temperature sensor

International Nuclear Information System (INIS)

Ma, Xin; Ju, Fang; Chang, Jun; Wang, Weijie; Wang, Zongliang

2013-01-01

A novel method based on dual temperature reference points is presented to interrogate the temperature in a distributed temperature sensing (DTS) system. This new method is suitable to overcome deficiencies due to the impact of DC offsets and the gain difference in the two signal channels of the sensing system during temperature interrogation. Moreover, this method can in most cases avoid the need to calibrate the gain and DC offsets in the receiver, data acquisition and conversion. An improved temperature interrogation formula is presented and the experimental results show that this method can efficiently estimate the channel amplification and system DC offset, thus improving the system accuracy. (letter)

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...... analyze and investigate errors and drawbacks, which are typical for spectrometer-based interrogators: undersampling, grating internal reflection, photo response nonuniformity, pixel crosstalk and temperature and long term drift. We propose a novel type of multichannel Digital Micromirror Device (DMD......) 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...

On-line analysis of bulk materials using pulsed neutron interrogation

International Nuclear Information System (INIS)

Lebrun, P.; Tourneur, P. Le; Poumarede, B.; Bach, P.; Moeller, H.

1999-01-01

On the basis of our joint experience in neutronics for SODERN and in cement plant engineering for KRUPP POLYSIUS, we have developed a new on-line bulk materials analyser for the cement industry. This equipment includes a pulsed neutron generator GENIE 16, some gamma ray and neutron detectors, specially designed electronics with high counting rate, software delivering the mean elemental composition of raw material, and adequate shielding. This material is transported through the equipment on a conveyor belt, the size of which is adapted to the requirements. This paper briefly describes the equipment and some results, as obtained in dynamic test from a demonstrator installed in Germany

On-line analysis of bulk materials using pulsed neutron interrogation

Science.gov (United States)

Lebrun, P.; Tourneur, P. Le; Poumarede, B.; Möller, H.; Bach, P.

1999-06-01

On the basis of our joint experience in neutronics for SODERN and in cement plant engineering for KRUPP POLYSIUS, we have developed a new on-line bulk materials analyser for the cement industry. This equipment includes a pulsed neutron generator GENIE 16, some gamma ray and neutron detectors, specially designed electronics with high counting rate, software delivering the mean elemental composition of raw material, and adequate shielding. This material is transported through the equipment on a conveyor belt, the size of which is adapted to the requirements. This paper briefly describes the equipment and some results, as obtained in dynamic test from a demonstrator installed in Germany.

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)

Detection of special nuclear material from delayed neutron emission induced by a dual-particle monoenergetic source

Energy Technology Data Exchange (ETDEWEB)

Mayer, M. [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Nattress, J.; Jovanovic, I., E-mail: ijov@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2016-06-27

Detection of unique signatures of special nuclear materials is critical for their interdiction in a variety of nuclear security and nonproliferation scenarios. We report on the observation of delayed neutrons from fission of uranium induced in dual-particle active interrogation based on the {sup 11}B(d,n γ){sup 12}C nuclear reaction. Majority of the fissions are attributed to fast fission induced by the incident quasi-monoenergetic neutrons. A Li-doped glass–polymer composite scintillation neutron detector, which displays excellent neutron/γ discrimination at low energies, was used in the measurements, along with a recoil-based liquid scintillation detector. Time-dependent buildup and decay of delayed neutron emission from {sup 238}U were measured between the interrogating beam pulses and after the interrogating beam was turned off, respectively. Characteristic buildup and decay time profiles were compared to the common parametrization into six delayed neutron groups, finding a good agreement between the measurement and nuclear data. This method is promising for detecting fissile and fissionable materials in cargo scanning applications and can be readily integrated with transmission radiography using low-energy nuclear reaction sources.

System to detect contraband in cargo containers using fast and slow neutron irradiation and collimated gamma detectors

International Nuclear Information System (INIS)

Smith, R.C.; Hurwitz, M.J.; Tran, K.C.

1995-01-01

We have produced a product design concept for an automatic, shipping-container inspection system to be used for detection of contraband, including illicit drugs, and for trade regulation enforcement via shipping manifest confirmation. Using nondestructive nuclear techniques the system can see deeply into the cargo and generate a 3-D spatial image of an entire container's contents automatically and in real time. A pulsed, sealed-tube, neutron generator is employed. The approach divides a container into numerous, small, volume elements that are individually interrogated using concurrent fast and slow neutron activation and gamma detection by collimated scintillators. We have designed, built, and operated a laboratory apparatus which has demonstrated the attractiveness of this approach. Experimental data were found to agree with design expectations derived from computer modeling. By combining selected element signatures and phenomenological measures, together with discrimination algorithms, we have demonstrated that a full-scale inspection system would need from less than 5 min to 30 min (depending on cargo type) to process an 8 ftx8 ftx40 ft container in order to detect hidden contraband. (orig.)

Wide range neutron detection system

International Nuclear Information System (INIS)

Todt, W.H. Sr.

1978-01-01

A neutron detection system for reactor control is described which is operable over a wide range of neutron flux levels. The system includes a fission type ionization chamber neutron detector, means for gamma and alpha signal compensation, and means for operating the neutron detector in the pulse counting mode for low neutron flux levels, and in the direct current mode for high neutron flux levels

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.

Optimization of combined delayed neutron and differential die-away prompt neutron signal detection for characterization of spent nuclear fuel assemblies

International Nuclear Information System (INIS)

Blanc, Pauline; Tobin, Stephen J.; Croft, Stephen; Menlove, Howard O.; Swinhoe, M.; Lee, T.

2010-01-01

The Next Generation Safeguards Initiative (NGSI) of the U.S. Department of Energy (DOE) has funded multiple laboratories and universities to develop a means to accurately quantify the Plutonium (Pu) mass in spent nuclear fuel assemblies and ways to also detect potential diversion of fuel pins. Delayed Neutron (DN) counting provides a signature somewhat more sensitive to 235 U than Pu while Differential Die-Away (DDA) is complementary in that it has greater sensitivity to Pu. The two methods can, with care, be combined into a single instrument which also provides passive neutron information. Individually the techniques cannot robustly quantify the Pu content but coupled together the information content in the signatures enables Pu quantification separate to the total fissile content. The challenge of merging DN and DDA, prompt neutron (PN) signal, capabilities in the same design is the focus of this paper. Other possibilities also suggest themselves, such as a direct measurement of the reactivity (multiplication) by either the boost in signal obtained during the active interrogation itself or by the extension of the die-away profile. In an early study, conceptual designs have been modeled using a neutron detector comprising fission chambers or 3He proportional counters and a ∼14 MeV neutron Deuterium-Tritium (DT) generator as the interrogation source. Modeling was performed using the radiation transport code Monte Carlo N-Particles eXtended (MCNPX). Building on this foundation, the present paper quantifies the capability of a new design using an array of 3 He detectors together with fission chambers to optimize both DN and PN detections and active characterization, respectively. This new design was created in order to minimize fission in 238 U (a nuisance DN emitter), to use a realistic neutron generator, to reduce the cost and to achieve near spatial interrogation and detection of the DN and PN, important for detection of diversion, all within the constraints of

The stationary neutron radiography system

International Nuclear Information System (INIS)

Weeks, A.A.; Newell, D.L.; Heidel, C.C.

1990-01-01

To provide the high intensity neutron beam and support systems necessary for radiography, the Stationary Neutron Radiography System was constructed at McClellan Air Force Base. The Stationary Neutron Radiography System utilizes a one megawatt TRIGA reactor contained in an Aluminium tank surrounded by eight foot thick concrete walls. There are four neutron beam tubes at inclined angles from the reactor core to separate radiography bays. In three of the bays, robotic systems manipulate aircraft components in the neutron beam, while real-time imaging systems provide images concurrent with the irradiation. Film radiography of smaller components is performed in the remaining bay

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...... the interrogation regions, and we show typical interrogation regions of the proposed ITER CTS system. The backscattering system with receivers on the low-field side is sensitive to fast ions with pitch |p| = |v/v| ... scattering system with receivers on the high-field side would be sensitive to co- and counter-passing fast ions in narrow interrogation regions with pitch |p| > 0.6–0.8. Additionally, we use weight functions to reconstruct 2D fast-ion distribution functions, given two projected 1D velocity distribution...

Guidelines to indirectly measure and enhance detection efficiency of stationary PIT tag interrogation systems in streams

Science.gov (United States)

Connolly, Patrick J.; Wolf, Keith; O'Neal, Jennifer S.

2010-01-01

With increasing use of passive integrated transponder (PIT) tags and reliance on stationary PIT tag interrogation systems to monitor fish populations, guidelines are offered to inform users how best to use limited funding and human resources to create functional systems that maximize a desired level of detection and precision. The estimators of detection efficiency and their variability as described by Connolly et al. (2008) are explored over a span of likely performance metrics. These estimators were developed to estimate detection efficiency without relying on a known number of fish passing the system. I present graphical displays of the results derived from these estimators to show the potential efficiency and precision to be gained by adding an array or by increasing the number of PIT-tagged fish expected to move past an interrogation system.

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.

A neutron well logging system

International Nuclear Information System (INIS)

1980-01-01

A pulsed neutron well logging system using a sealed off neutron generator tube is provided with a programmable digital neutron output control system. The control system monitors the target beam current and compares a function of this current with a pre-programmed control function to develop a control signal for the neutron generator. The control signal is used in a series regulator to control the average replenisher current of the neutron generator tube. The programmable digital control system of the invention also provides digital control signals as a function of time to provide ion source voltages. This arrangement may be utilized to control neutron pulses durations and repetition rates or to produce other modulated wave forms for intensity modulating the output of the neutron generator as a function of time. (Auth.)

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.

Research opportunities with compact accelerator-driven neutron sources

International Nuclear Information System (INIS)

Anderson, I.S.; Andreani, C.; Carpenter, J.M.; Festa, G.; Gorini, G.; Loong, C.-K.; Senesi, R.

2016-01-01

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.

Research opportunities with compact accelerator-driven neutron sources

Science.gov (United States)

Anderson, I. S.; Andreani, C.; Carpenter, J. M.; Festa, G.; Gorini, G.; Loong, C.-K.; Senesi, R.

2016-10-01

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.

Repetitive Interrogation of 2-Level Quantum Systems

Science.gov (United States)

Prestage, John D.; Chung, Sang K.

2010-01-01

Trapped ion clocks derive information from a reference atomic transition by repetitive interrogations of the same quantum system, either a single ion or ionized gas of many millions of ions. Atomic beam frequency standards, by contrast, measure reference atomic transitions in a continuously replenished "flow through" configuration where initial ensemble atomic coherence is zero. We will describe some issues and problems that can arise when atomic state selection and preparation of the quantum atomic system is not completed, that is, optical pumping has not fully relaxed the coherence and also not fully transferred atoms to the initial state. We present a simple two-level density matrix analysis showing how frequency shifts during the state-selection process can cause frequency shifts of the measured clock transition. Such considerations are very important when a low intensity lamp light source is used for state selection, where there is relatively weak relaxation and re-pumping of ions to an initial state and much weaker 'environmental' relaxation of the atomic coherence set-up in the atomic sample.

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

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

Associated-particle sealed-tube neutron generators and hodoscopes for NDA applications

International Nuclear Information System (INIS)

Rhodes, E.; Peters, C.W.

1991-01-01

With radioisotope sources, gamma-ray transmission hodoscopes can inspect canisters and railcars to monitor rocket motors, can detect nuclear warheads by their characteristic strong gamma-ray absorption, or can count nuclear warheads inside a missile by low-resolution tomography. Intrinsic gamma-ray radiation from warheads can also be detected in a passive mode. Neutron hodoscopes can use neutron transmission, intrinsic neutron emission, or reactions stimulated by a neutron source, in treaty verification roles. Gamma-ray and neutron hodoscopes can be combined with a recently developed neutron diagnostic probe system, based on a unique associated-particle sealed-tube neutron generator (APSTNG) that interrogates the object of interest with a low-intensity beam of 14-MeV neutrons, and that uses flight-time to electronically collimate transmitted neutrons and to tomographically image nuclides identified by reaction gamma-rays. Gamma-ray spectra of resulting neutron reactions identify nuclides associated with all major chemicals in chemical warfare agents, explosives, and drugs, as well as many pollutants and fissile and fertile special nuclear material. 5 refs., 12 figs

Conceptual Design of a 14-MeV D-T Neutron Source for Material Inspection

International Nuclear Information System (INIS)

Kim, Jin-Choon; Oh, Byung-Hoon

2007-01-01

There is a worldwide need for the efficient inspection of cargo containers at airports, seaports and border crossings. And there is also a growing need for nondestructive inspection of metal objects such as airplane parts. The limitations of X-ray systems for the detection of explosives, drugs, and thick metal structures have stimulated interest in neutron radiograph or tomography. The weak link in such applications is the neutron source. The ideal neutron source should provide a high intensity, high-energy for sufficient penetration and activation, a reliable long-term operation, and a monoenergetic neutron beam. In this paper, we describe a conceptual design of a DT fusion neutron source (monoenergetic 14 MeV neutron generator) which satisfies the fore-mentioned requirements. The current design is based upon the actually proven system using the drive-in target principle. The design is versatile enough to accommodate various applications, ranging from material inspection and explosive interrogation to medical probing and cancer treatment

The dynamic nature of interrogation.

Science.gov (United States)

Kelly, Christopher E; Miller, Jeaneé C; Redlich, Allison D

2016-06-01

Building on a substantial body of literature examining interrogation methods employed by police investigators and their relationship to suspect behaviors, we analyzed a sample of audio and video interrogation recordings of individuals suspected of serious violent crimes. Existing survey research has focused on the tactics reportedly used, at what rate, and under what conditions; observational studies detail which methods are actually employed. With a few notable exceptions, these foundational studies were static examinations of interrogation methods that documented the absence or presence of various approaches. In the present study, we cast interrogation as a dynamic phenomenon and code the recordings in 5-min intervals to examine how interrogation methods and suspect cooperation change over time. Employing the interrogation taxonomy framework, particularly 4 discrete domains-rapport and relationship building, emotion provocation, presentation of evidence, and confrontation/competition-we found that the emphasis of the domains varied across interrogations and were significantly different when suspects confessed versus when they denied involvement. In regression models, suspect cooperation was positively influenced by the rapport and relationship building domain, though it was negatively impacted by presentation of evidence and confrontation/competition. Moreover, we found that the negative effects of confrontation/competition on suspect cooperation lasted for up to 15 min. The implications of the findings for practice and future research include the benefits of a rapport-based approach, the deleterious effects of accusatorial methods, and the importance of studying when, not just if, certain interrogation techniques are employed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Neutronic measurements of radioactive waste; Les mesures neutroniques des dechets radioactifs

Energy Technology Data Exchange (ETDEWEB)

Perot, B

1997-12-31

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).

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.

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.)

A simple neutron-gamma discriminating system

International Nuclear Information System (INIS)

Liu Zhongming; Xing Shilin; Wang Zhongmin

1986-01-01

A simple neutron-gamma discriminating system is described. A detector and a pulse shape discriminator are suitable for the neutron-gamma discriminating system. The influence of the constant fraction discriminator threshold energy on the neutron-gamma resolution properties is shown. The neutron-gamma timing distributions from an 241 Am-Be source, 2.5 MeV neutron beam and 14 MeV neutron beam are presented

Fiber-MZI-based FBG sensor interrogation: comparative study with a CCD spectrometer.

Science.gov (United States)

Das, Bhargab; Chandra, Vikash

2016-10-10

We present an experimental comparative study of the two most commonly used fiber Bragg grating (FBG) sensor interrogation techniques: a charge-coupled device (CCD) spectrometer and a fiber Mach-Zehnder interferometer (F-MZI). Although the interferometric interrogation technique is historically known to offer the highest sensitivity measurements, very little information exists regarding how it compares with the current commercially available spectral-characteristics-based interrogation systems. It is experimentally established here that the performance of a modern-day CCD spectrometer interrogator is very close to a F-MZI interrogator with the capability of measuring Bragg wavelength shifts with sub-picometer-level accuracy. The results presented in this research study can further be used as a guideline for choosing between the two FBG sensor interrogator types for small-amplitude dynamic perturbation measurements down to nano-level strain.

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.

Real time interrogation technique for fiber Bragg grating enhanced fiber loop ringdown sensors array.

Science.gov (United States)

Zhang, Yunlong; Li, Ruoming; Shi, Yuechun; Zhang, Jintao; Chen, Xiangfei; Liu, Shengchun

2015-06-01

A novel fiber Bragg grating aided fiber loop ringdown (FLRD) sensor array and the wavelength-time multiplexing based interrogation technique for the FLRD sensors array are proposed. The interrogation frequency of the system is formulated and the interrelationships among the parameters of the system are analyzed. To validate the performance of the proposed system, a five elements array is experimentally demonstrated, and the system shows the capability of real time monitoring every FLRD element with interrogation frequency of 125.5 Hz.

Pulsed neutron porosity logging system

International Nuclear Information System (INIS)

Smith, H.D. Jr.; Smith, M.P.; Schultz, W.E.

1978-01-01

An improved pulsed neutron porosity logging system is provided in the present invention. A logging tool provided with a 14 MeV pulsed neutron source, an epithermal neutron detector, and a fast neutron detector is moved through a borehole. Repetitive bursts of neutrons irradiate the earth formations and, during the bursts, the fast neutron population is sampled. During the interval between bursts the epithermal neutron population is sampled along with background gamma radiation due to lingering thermal neutrons. The fast and epithermal neutron population measurements are combined to provide a measurement of formation porosity

Development of fast neutron radiography system based on portable neutron generator

Energy Technology Data Exchange (ETDEWEB)

Yi, Chia Jia, E-mail: gei-i-kani@hotmail.com; Nilsuwankosit, Sunchai, E-mail: sunchai.n@chula.ac.th [Department of Nuclear Engineering, Faculty of Engineering, Chulalongkorn University, Phayathai Rd., Patumwan, Bangkok, THAILAND 10330 (Thailand)

2016-01-22

Due to the high installation cost, the safety concern and the immobility of the research reactors, the neutron radiography system based on portable neutron generator is proposed. Since the neutrons generated from a portable neutron generator are mostly the fast neutrons, the system is emphasized on using the fast neutrons for the purpose of conducting the radiography. In order to suppress the influence of X-ray produced by the neutron generator, a combination of a shielding material sandwiched between two identical imaging plates is used. A binary XOR operation is then applied for combining the information from the imaging plates. The raw images obtained confirm that the X-ray really has a large effect and that XOR operation can help enhance the effect of the neutrons.

Innocence and resisting confession during interrogation: effects on physiologic activity.

Science.gov (United States)

Guyll, Max; Madon, Stephanie; Yang, Yueran; Lannin, Daniel G; Scherr, Kyle; Greathouse, Sarah

2013-10-01

Innocent suspects may not adequately protect themselves during interrogation because they fail to fully appreciate the danger of the situation. This experiment tested whether innocent suspects experience less stress during interrogation than guilty suspects, and whether refusing to confess expends physiologic resources. After experimentally manipulating innocence and guilt, 132 participants were accused and interrogated for misconduct, and then pressured to confess. Systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), respiratory sinus arrhythmia (RSA), and preejection period (PEP) responses quantified stress reactions. As hypothesized, the innocent evidenced smaller stress responses to interrogation for SBP, DBP, HR, and RSA than did the guilty. Furthermore, innocents who refused to confess exhibited greater sympathetic nervous system activation, as evidenced by shorter PEPs, than did innocent or guilty confessors. These findings suggest that innocent suspects underestimate the threat of interrogation and that resisting pressures to confess can diminish suspects' physiologic resources and lead to false confessions. PsycINFO Database Record (c) 2013 APA, all rights reserved

Neutron instrumentation system

International Nuclear Information System (INIS)

Akiyama, Takao; Arita, Setsuo; Yuchi, Hiroyuki

1989-01-01

The neutron instrumentation system of this invention can greatly reduce the possibility that the shutdown flux is increased greater than a predetermiend value to cause scram due to vibrations caused by earthquakes or shocks in the neutron instrumentation system without injuring the reactor safety. That is, a sensor having a zero sensitivity to a neutron flux which is an object to be detected by the sensor (dummy sensor) is used together with a conventional sensor (a sensor having predetermined sensitivity to a neutron flux as an object to be measured ----- true sensor). Further, identical signal transmission cables, connector and the signal processing circuits are used for both of true sensor and the dummy sensor. The signal from the dummy sensor is subtracted from the signal from the true sensor at the output of the signal processing circuit. Since the output of the dummy sensor is zero during normal operation, the subtracted value is the same as the value from the true sensor. If the true sensor causes an output with the reason other than the neutron flux, this is outputted also from the dummy sensor but does not appear in the subtracted value. (I.S.)

Progress in miniaturization of a multichannel optical fiber Bragg grating sensor interrogator

Science.gov (United States)

Lopatin, Craig M.; Mahmood, Shah; Mendoza, Edgar; Moslehi, Behzad; Black, Richard; Chau, Kelvin; Oblea, Levy

2007-07-01

An effort to develop a miniaturized multichannel optical fiber Bragg grating sensor interrogator was initiated in 2006 under the Small Business Innovative Research (SBIR) program. The goal was to develop an interrogator that would be sufficiently small and light to be incorporated into a health monitoring system for use on tactical missiles. Two companies, Intelligent Fiber Optic Systems Corporation (IFOS) and Redondo Optics, were funded in Phase I, and this paper describes the prototype interrogators that were developed. The two companies took very different approaches: IFOS focused on developing a unit that would have a high channel count and high resolution, using off-the-shelf components, while Redondo Optics chose to develop a unit that would be very small and lightweight, using custom designed integrated optical chips. It is believed that both approaches will result in interrogators that will be significantly small, lighter, and possibly even more precise than what is currently commercially available. This paper will also briefly describe some of the sensing concepts that may be used to interrogate the health of the solid rocket motors used in many missile systems. The sponsor of this program was NAVAIR PMA 280.

Neutron activation system for spectral measurements of pulsed ion diode neutron production

International Nuclear Information System (INIS)

Hanson, D.L.; Kruse, L.W.

1980-02-01

A neutron energy spectrometer has been developed to study intense ion beam-target interactions in the harsh radiation environment of a relativistic electron beam source. The main component is a neutron threshold activation system employing two multiplexed high efficiency Ge(Li) detectors, an annihilation gamma coincidence system, and a pneumatic sample transport. Additional constraints on the neutron spectrum are provided by total neutron yield and time-of-flight measurements. A practical lower limit on the total neutron yield into 4π required for a spectral measurement with this system is approx. 10 10 n where the neutron yield is predominantly below 4 MeV and approx. 10 8 n when a significant fraction of the yield is above 4 MeV. Applications of this system to pulsed ion diode neutron production experiments on Hermes II are described

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)

Compact multichannel high-resolution micro-electro-mechanical systems-based interrogator for Fiber Bragg grating sensing

DEFF Research Database (Denmark)

Ganziy, Denis; Rose, Bjarke; Bang, Ole

2017-01-01

We propose a novel type of compact high-resolution multichannel micro-electro-mechanical systems (MEMS)-based interrogator, where we replace the linear detector with a digital micromirror device (DMD). The DMD is typically cheaper and has better pixel sampling than an InGaAs detector used...

Development of an integrated assay facility

International Nuclear Information System (INIS)

Molesworth, T.V.; Bailey, M.; Findlay, D.J.S.; Sene, M.R.; Swinhoe, M.T.

1990-01-01

Initial results of active neutron and active gamma-ray interrogation of a 500 liter cemented simulated CAGR intermediate level radioactive waste drum are described. The basis of the interrogation systems was the Harwell electron linear accelerator HELIOS, which was used to produce the interrogating neutrons and gamma-rays. Several sets of neutron detectors were located around the drum to count signature neutrons. The responses of the system were measured by placing known samples at many different locations within the drum. In general, measured responses confirmed calculated responses. Good agreement was obtained for the azimuthal angle dependences. The absolute responses agreed well for gamma-ray interrogation, but the calculations were apparently over-estimates for neutron interrogation. Those aspects requiring consideration in the practical application of assay techniques are identified. 8 refs., 6 figs

8 CFR 343b.3 - Interrogation.

Science.gov (United States)

2010-01-01

... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Interrogation. 343b.3 Section 343b.3 Aliens... NATURALIZATION FOR RECOGNITION BY A FOREIGN STATE § 343b.3 Interrogation. When Form N-565 presents a prima facie... issuance of the certificate. Interrogation of the applicant shall be conducted before the application is...

Radioisotopes produced by neutron irradiation of food

International Nuclear Information System (INIS)

Albright, S.; Seviour, R.

2016-01-01

The use of neutrons for cargo interrogation has the potential to drastically improve threat detection. Previous research has focussed on the production of "2"4Na, 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 "2"4Na 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. - Highlights: • We show that neutron interrogation of food can produce many radioisotopes. • We show a strong dependance between food and certain radioisotopes. • Some isotopes are shown to have an energy dependence. • Previous claims that 24Na is the main threat is shown to only apply in special cases.

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

Interrogation of an object for dimensional and topographical information

Science.gov (United States)

McMakin, Doug L [Richland, WA; Severtsen, Ronald H [Richland, WA; Hall, Thomas E [Richland, WA; Sheen, David M [Richland, WA

2003-01-14

Disclosed are systems, methods, devices, and apparatus to interrogate a clothed individual with electromagnetic radiation to determine one or more body measurements at least partially covered by the individual's clothing. The invention further includes techniques to interrogate an object with electromagnetic radiation in the millimeter and/or microwave range to provide a volumetric representation of the object. This representation can be used to display images and/or determine dimensional information concerning the object.

Language style matching and police interrogation outcomes

NARCIS (Netherlands)

Richardson, Beth H.; Taylor, Paul J; Snook, Brent; Conchie, Stacey M.; Bennell, Craig

2014-01-01

This research examined the coordination of interrogator and suspects’ verbal behavior in interrogations. Sixty-four police interrogations were examined at the aggregate and utterance level using a measure of verbal mimicry known as Language Style Matching. Analyses revealed an interaction between

Manually controlled neutron-activation system

International Nuclear Information System (INIS)

Johns, R.A.; Carothers, G.A.

1982-01-01

A manually controlled neutron activation system, the Manual Reactor Activation System, was designed and built and has been operating at one of the Savannah River Plant's production reactors. With this system, samples can be irradiated for up to 24 hours and pneumatically transferred to a shielded repository for decay until their activity is low enough for them to be handled at a radiobench. The Manual Reactor Activation System was built to provide neutron activation of solid waste forms for the Alternative Waste Forms Leach Testing Program. Neutron activation of the bulk sample prior to leaching permits sensitive multielement radiometric analyses of the leachates

Comparison of neutron and high-energy X-ray dual-beam radiography for air cargo inspection

International Nuclear Information System (INIS)

Liu, Y.; Sowerby, B.D.; Tickner, J.R.

2008-01-01

Dual-beam radiography techniques utilising various combinations of high-energy X-rays and neutrons are attractive for screening bulk cargo for contraband such as narcotics and explosives. Dual-beam radiography is an important enhancement to conventional single-beam X-ray radiography systems in that it provides additional information on the composition of the object being imaged. By comparing the attenuations of transmitted dual high-energy beams, it is possible to build a 2D image, colour coded to indicate material. Only high-energy X-rays, gamma-rays and neutrons have the required penetration to screen cargo containers. This paper reviews recent developments and applications of dual-beam radiography for air cargo inspection. These developments include dual high-energy X-ray techniques as well as fast neutron and gamma-ray (or X-ray) radiography systems. High-energy X-ray systems have the advantage of generally better penetration than neutron systems, depending on the material being interrogated. However, neutron systems have the advantage of much better sensitivity to material composition compared to dual high-energy X-ray techniques. In particular, fast neutron radiography offers the potential to discriminate between various classes of organic material, unlike dual energy X-ray techniques that realistically only offer the ability to discriminate between organic and metal objects

Wireless interrogation of passive antenna sensors

International Nuclear Information System (INIS)

Deshmukh, S; Huang, H

2010-01-01

Recently, we discovered that the resonant frequency of a microstrip patch antenna is sensitive to mechanical strains or crack presence in the ground plane. Based on this principle, antenna sensors have been demonstrated to measure strain and detect crack in metallic structures. This paper presents a wireless method to remotely interrogate a dual-frequency antenna sensor. An interrogation horn antenna was used to irradiate the antenna sensor with a linear chirp microwave signal. By implementing a light-activated switch at the sensor node and performing signal processing of the backscattered signals, the resonant frequencies of the antenna sensor along both polarizations can be measured remotely. Since the antenna sensor does not need a local power source and can be interrogated wirelessly, electric wiring can be eliminated. The sensor implementation, the signal processing and the experimental setup that validate the remote interrogation of the antenna sensor are presented. A power budget model has also been established to estimate the maximum interrogation range

Coherent pulse interrogation system for fiber Bragg grating sensing of strain and pressure in dynamic extremes of materials.

Science.gov (United States)

Rodriguez, George; Jaime, Marcelo; Balakirev, Fedor; Mielke, Chuck H; Azad, Abul; Marshall, Bruce; La Lone, Brandon M; Henson, Bryan; Smilowitz, Laura

2015-06-01

A 100 MHz fiber Bragg grating (FBG) interrogation system is described and applied to strain and pressure sensing. The approach relies on coherent pulse illumination of the FBG sensor with a broadband short pulse from a femtosecond modelocked erbium fiber laser. After interrogation of the FBG sensor, a long multi-kilometer run of single mode fiber is used for chromatic dispersion to temporally stretch the spectral components of the reflected pulse from the FBG sensor. Dynamic strain or pressure induced spectral shifts in the FBG sensor are detected as a pulsed time domain waveform shift after encoding by the chromatic dispersive line. Signals are recorded using a single 35 GHz photodetector and a 50 G Samples per second, 25 GHz bandwidth, digitizing oscilloscope. Application of this approach to high-speed strain sensing in magnetic materials in pulsed magnetic fields to ~150 T is demonstrated. The FBG wavelength shifts are used to study magnetic field driven magnetostriction effects in LaCoO3. A sub-microsecond temporal shift in the FBG sensor wavelength attached to the sample under first order phase change appears as a fractional length change (strain: ΔL/L-4) in the material. A second application used FBG sensing of pressure dynamics to nearly 2 GPa in the thermal ignition of the high explosive PBX-9501 is also demonstrated. Both applications demonstrate the use of this FBG interrogation system in dynamical extreme conditions that would otherwise not be possible using traditional FBG interrogation approaches that are deemed too slow to resolve such events.

Differential die-away analysis system response modeling and detector design

International Nuclear Information System (INIS)

Jordan, K.A.; Gozani, T.; Vujic, J.

2008-01-01

Differential die-away-analysis (DDAA) is a sensitive technique to detect presence of fissile materials such as 235 U and 239 Pu. DDAA uses a high-energy (14 MeV) pulsed neutron generator to interrogate a shipping container. The signature is a fast neutron signal hundreds of microseconds after the cessation of the neutron pulse. This fast neutron signal has decay time identical to the thermal neutron diffusion decay time of the inspected cargo. The theoretical aspects of a cargo inspection system based on the differential die-away technique are explored. A detailed mathematical model of the system is developed, and experimental results validating this model are presented

Low-Cost Interrogation Technique for Dynamic Measurements with FBG-Based Devices.

Science.gov (United States)

Díaz, Camilo A R; Leitão, Cátia; Marques, Carlos A; Domingues, M Fátima; Alberto, Nélia; Pontes, Maria José; Frizera, Anselmo; Ribeiro, Moisés R N; André, Paulo S B; Antunes, Paulo F C

2017-10-23

Fiber Bragg gratings are widely used optical fiber sensors for measuring temperature and/or mechanical strain. Nevertheless, the high cost of the interrogation systems is the most important drawback for their large commercial application. In this work, an in-line Fabry-Perot interferometer based edge filter is explored in the interrogation of fiber Bragg grating dynamic measurements up to 5 kHz. Two devices an accelerometer and an arterial pulse wave probe were interrogated with the developed approach and the results were compared with a commercial interrogation monitor. The data obtained with the edge filter are in agreement with the commercial device, with a maximum RMSE of 0.05 being able to meet the requirements of the measurements. Resolutions of 3.6 pm and 2.4 pm were obtained, using the optical accelerometer and the arterial pulse wave probe, respectively.

Effects of neutron spectrum and external neutron source on neutron multiplication parameters in accelerator-driven system

International Nuclear Information System (INIS)

Shahbunder, Hesham; Pyeon, Cheol Ho; Misawa, Tsuyoshi; Lim, Jae-Yong; Shiroya, Seiji

2010-01-01

The neutron multiplication parameters: neutron multiplication M, subcritical multiplication factor k s , external source efficiency φ*, play an important role for numerical assessment and reactor power evaluation of an accelerator-driven system (ADS). Those parameters can be evaluated by using the measured reaction rate distribution in the subcritical system. In this study, the experimental verification of this methodology is performed in various ADS cores; with high-energy (100 MeV) proton-tungsten source in hard and soft neutron spectra cores and 14 MeV D-T neutron source in soft spectrum core. The comparison between measured and calculated multiplication parameters reveals a maximum relative difference in the range of 6.6-13.7% that is attributed to the calculation nuclear libraries uncertainty and accuracy for energies higher than 20 MeV and also dependent on the reaction rate distribution position and count rates. The effects of different core neutron spectra and external neutron sources on the neutron multiplication parameters are discussed.

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.

CVD polycrystalline diamond. A novel neutron detector and applications

International Nuclear Information System (INIS)

Mongkolnavin, R.

1998-01-01

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 spectrometer 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. Also other neutron related applications have been suggested. (author)

The help of simulation codes in designing waste assay systems using neutron measurement methods: Application to the alpha low level waste assay system PROMETHEE 6

Energy Technology Data Exchange (ETDEWEB)

Mariani, A.; Passard, C.; Jallu, F. E-mail: fanny.jallu@cea.fr; Toubon, H

2003-11-01

The design of a specific nuclear assay system for a dedicated application begins with a phase of development, which relies on information from the literature or on knowledge resulting from experience, and on specific experimental verifications. The latter ones may require experimental devices which can be restricting in terms of deadline, cost and safety. One way generally chosen to bypass these difficulties is to use simulation codes to study particular aspects. This paper deals with the potentialities offered by the simulation in the case of a passive-active neutron (PAN) assay system for alpha low level waste characterization; this system has been carried out at the Nuclear Measurements Development Laboratory of the French Atomic Energy Commission. Due to the high number of parameters to be taken into account for its development, this is a particularly sophisticated example. Since the PAN assay system, called PROMETHEE (prompt epithermal and thermal interrogation experiment), must have a detection efficiency of more than 20% and preserve a high level of modularity for various applications, an improved version has been studied using the MCNP4 (Monte Carlo N-Particle) transport code. Parameters such as the dimensions of the assay system, of the cavity and of the detection blocks, and the thicknesses of the nuclear materials of neutronic interest have been optimised. Therefore, the number of necessary experiments was reduced.

The help of simulation codes in designing waste assay systems using neutron measurement methods: Application to the alpha low level waste assay system PROMETHEE 6

International Nuclear Information System (INIS)

Mariani, A.; Passard, C.; Jallu, F.; Toubon, H.

2003-01-01

The design of a specific nuclear assay system for a dedicated application begins with a phase of development, which relies on information from the literature or on knowledge resulting from experience, and on specific experimental verifications. The latter ones may require experimental devices which can be restricting in terms of deadline, cost and safety. One way generally chosen to bypass these difficulties is to use simulation codes to study particular aspects. This paper deals with the potentialities offered by the simulation in the case of a passive-active neutron (PAN) assay system for alpha low level waste characterization; this system has been carried out at the Nuclear Measurements Development Laboratory of the French Atomic Energy Commission. Due to the high number of parameters to be taken into account for its development, this is a particularly sophisticated example. Since the PAN assay system, called PROMETHEE (prompt epithermal and thermal interrogation experiment), must have a detection efficiency of more than 20% and preserve a high level of modularity for various applications, an improved version has been studied using the MCNP4 (Monte Carlo N-Particle) transport code. Parameters such as the dimensions of the assay system, of the cavity and of the detection blocks, and the thicknesses of the nuclear materials of neutronic interest have been optimised. Therefore, the number of necessary experiments was reduced

Interrogative suggestibility in opiate users.

Science.gov (United States)

Murakami, A; Edelmann, R J; Davis, P E

1996-09-01

The present study investigated interrogative suggestibility in opiate users. A group of patients undergoing a methadone detoxification programme in an in-patient drug treatment unit (Detox group, n = 21), and a group of residents who had come off drugs and were no longer suffering from withdrawal syndrome (Rehab group, n = 19) were compared on interrogative suggestibility and various other psychological factors. Significant differences were found between the two groups, with the Detox group having more physical and psychological problems, and a higher total suggestibility score in comparison with the Rehab group. These findings are discussed in relation to the context of police interrogations and the reliability of confessions made by suspects and witnesses dependent on opiates.

Elemental analysis using temporal gating of a pulsed neutron generator

Energy Technology Data Exchange (ETDEWEB)

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.

Design of a fiber-optic interrogator module for telecommunication satellites

Science.gov (United States)

Putzer, Philipp; Koch, Alexander W.; Plattner, Markus; Hurni, Andreas; Manhart, Markus

2017-11-01

In this paper we present the results of the radiation tests performed on the optical components of the fiber-optic interrogator module as a part of the Hybrid Sensor Bus (HSB) system. The HSB-system is developed in the frame of an ESAARTES program and will be verified as flight demonstrator onboard the German Heinrich Hertz satellite in 2016. The HSB system is based on a modular concept which includes sensor interrogation modules based on I2C electrical and fiber Bragg grating (FBG) fiber-optical sensor elements. Onboard fiber-optic sensing allows the implementation of novel control and monitoring methods. For read-out of multiple FBG sensors, a design based on a tunable laser diode as well as a design based on a spectrometer is considered. The expected and tested total ionizing dose (TID) applicable to the HSB system is in the range between 100 krad and 300 krad inside the satellite in the geostationary orbit over a life time of 15 years. We present radiation test results carried out on critical optical components to be used in the fiber-optic interrogation module. These components are a modulated grating Y-branch (MGY) tunable laser diode acting as light source for the tuning laser approach, the line detector of a spectrometer, photodetectors and the FBG sensors acting as sensor elements. A detailed literature inquiry of radiation effects on optical fibers and FBG sensors, is also included in the paper. The fiber-optic interrogator module implemented in the HSB system is based on the most suitable technology, which sustains the harsh environment in the geostationary orbit.

Fast digitization and discrimination of prompt neutron and photon signals using a novel silicon carbide detector

International Nuclear Information System (INIS)

Brandon W. Blackburn; James T. Johnson; Scott M. Watson; David L. Chichester; James L. Jones; Frank H. Ruddy; John G. Seidel; Robert W. Flammang

2007-01-01

Current requirements of some Homeland Security active interrogation projects for the detection of Special Nuclear Material (SNM) necessitate the development of faster inspection and acquisition capabilities. In order to do so, fast detectors which can operate during and shortly after intense interrogation radiation flashes are being developed. Novel silicon carbide (SiC) semiconductor Schottky diodes have been utilized as robust neutron and photon detectors in both pulsed photon and pulsed neutron fields and are being integrated into active inspection environments to allow exploitation of both prompt and delayed emissions. These detectors have demonstrated the capability of detecting both photon and neutron events during intense photon flashes typical of an active inspection environment. Beyond the inherent insensitivity of SiC to gamma radiation, fast digitization and processing has demonstrated that pulse shape discrimination (PSD) in combination with amplitude discrimination can further suppress unwanted gamma signals and extract fast neutron signatures. Usable neutron signals have been extracted from mixed radiation fields where the background has exceeded the signals of interest by >1000:1

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)

Modeling the tagged-neutron UXO identification technique using the Geant4 toolkit

International Nuclear Information System (INIS)

Zhou, Y.; Zhu, X.; Wang, Y.; Mitra, S.

2012-01-01

It is proposed to use 14 MeV neutrons tagged by the associated particle neutron time-of-flight technique (APnTOF) to identify the fillers of unexploded ordnances (UXO) by characterizing their carbon, nitrogen and oxygen contents. To facilitate the design and construction of a prototype system, a preliminary simulation model was developed, using the Geant4 toolkit. This work established the toolkit environment for (a) generating tagged neutrons, (b) their transport and interactions within a sample to induce emission and detection of characteristic gamma-rays, and (c) 2D and 3D-image reconstruction of the interrogated object using the neutron and gamma-ray time-of-flight information. Using the modeling, this article demonstrates the novelty of the tagged-neutron approach for extracting useful signals with high signal-to-background discrimination of an object-of-interest from that of its environment. Simulations indicated that an UXO filled with the RDX explosive, hexogen (C 3 H 6 O 6 N 6 ), can be identified to a depth of 20 cm when buried in soil. (author)

Application of probability generating function to the essentials of nondestructive nuclear materials assay system using neutron correlation

International Nuclear Information System (INIS)

Hosoma, Takashi

2017-01-01

In the previous research (JAEA-Research 2015-009), essentials of neutron multiplicity counting mathematics were reconsidered where experiences obtained at the Plutonium Conversion Development Facility were taken into, and formulae of multiplicity distribution were algebraically derived up to septuplet using a probability generating function to make a strategic move in the future. Its principle was reported by K. Böhnel in 1985, but such a high-order expansion was the first case due to its increasing complexity. In this research, characteristics of the high-order correlation were investigated. It was found that higher-order correlation increases rapidly in response to the increase of leakage multiplication, crosses and leaves lower-order correlations behind, when leakage multiplication is > 1.3 that depends on detector efficiency and counter setting. In addition, fission rates and doubles count rates by fast neutron and by thermal neutron in their coexisting system were algebraically derived using a probability generating function again. Its principle was reported by I. Pázsit and L. Pál in 2012, but such a physical interpretation, i.e. associating their stochastic variables with fission rate, doubles count rate and leakage multiplication, is the first case. From Rossi-alpha combined distribution and measured ratio of each area obtained by Differential Die-Away Self-Interrogation (DDSI) and conventional assay data, it is possible to estimate: the number of induced fissions per unit time by fast neutron and by thermal neutron; the number of induced fissions (< 1) by one source neutron; and individual doubles count rates. During the research, a hypothesis introduced in their report was proved to be true. Provisional calculations were done for UO_2 of 1∼10 kgU containing ∼ 0.009 wt% "2"4"4Cm. (author)

A system for fast neutron radiography

International Nuclear Information System (INIS)

Klann, R.T.

1996-01-01

A system has been designed and a neutron generator installed to perform fast neutron radiography. With this sytem, objects as small as a coin or as large as a waste drum can be radiographed. The neutron source is an MF Physics A-711 neutron generator which produces 3x10 10 neutrons/second with an average energy of 14.5 MeV. The radiography system uses x-ray scintillation screens and film in commercially available cassettes. The cassettes have been modified to include a thin sheet of plastic to convert neutrons to protons through elastic scattering from hydrogen and other low Z materials in the plastic. For film densities from 1.8 to 3.0, exposures range from 1.9x10 7 to 3.8x10 8 n/cm 2 depending on the type of screen and film

Resolution-improved in situ DNA hybridization detection based on microwave photonic interrogation.

Science.gov (United States)

Cao, Yuan; Guo, Tuan; Wang, Xudong; Sun, Dandan; Ran, Yang; Feng, Xinhuan; Guan, Bai-ou

2015-10-19

In situ bio-sensing system based on microwave photonics filter (MPF) interrogation method with improved resolution is proposed and experimentally demonstrated. A microfiber Bragg grating (mFBG) is used as sensing probe for DNA hybridization detection. Different from the traditional wavelength monitoring technique, we use the frequency interrogation scheme for resolution-improved bio-sensing detection. Experimental results show that the frequency shift of MPF notch presents a linear response to the surrounding refractive index (SRI) change over the range of 1.33 to 1.38, with a SRI resolution up to 2.6 × 10(-5) RIU, which has been increased for almost two orders of magnitude compared with the traditional fundamental mode monitoring technique (~3.6 × 10(-3) RIU). Due to the high Q value (about 27), the whole process of DNA hybridization can be in situ monitored. The proposed MPF-based bio-sensing system provides a new interrogation method over the frequency domain with improved sensing resolution and rapid interrogation rate for biochemical and environmental measurement.

Ultrafast Fiber Bragg Grating Interrogation for Sensing in Detonation and Shock Wave Experiments.

Science.gov (United States)

Rodriguez, George; Gilbertson, Steve M

2017-01-27

Chirped fiber Bragg grating (CFBG) sensors coupled to high speed interrogation systems are described as robust diagnostic approaches to monitoring shock wave and detonation front propagation tracking events for use in high energy density shock physics applications. Taking advantage of the linear distributed spatial encoding of the spectral band in single-mode CFBGs, embedded fiber systems and associated photonic interrogation methodologies are shown as an effective approach to sensing shock and detonation-driven loading processes along the CFBG length. Two approaches, one that detects spectral changes in the integrated spectrum of the CFBG and another coherent pulse interrogation approach that fully resolves its spectral response, shows that 100-MHz-1-GHz interrogation rates are possible with spatial resolution along the CFBG in the 50 µm to sub-millimeter range depending on the combination of CFBG parameters (i.e., length, chirp rate, spectrum) and interrogator design specifics. Results from several dynamic tests are used to demonstrate the performance of these high speed systems for shock and detonation propagation tracking under strong and weak shock pressure loading: (1) linear detonation front tracking in the plastic bonded explosive (PBX) PBX-9501; (2) tracking of radial decaying shock with crossover to non-destructive CFBG response; (3) shock wave tracking along an aluminum cylinder wall under weak loading accompanied by dynamic strain effects in the CFBG sensor.

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.

Incorporation of Photon Analysis into an Active Interrogation System for Shielded Uranium Characterization

Energy Technology Data Exchange (ETDEWEB)

Canion, Bonnie E. [Univ. of Texas, Austin, TX (United States)

2016-02-01

The main goal of this project is to investigate how photon and neutron signatures from an Associated Particle Imaging (API) Deuterium-Tritium (DT) neutron generator detector system can be used to non-destructively predict the enrichment of uranium in an unknown configuration of shielded uranium.

Detection of explosives and other illicit materials by a single nanosecond neutron pulses - Monte-Carlo simulations of the detection process

International Nuclear Information System (INIS)

Miklaszewski, R.; Drozdowicz, K.; Wiacek, U.; Dworak, D.; Gribkov, V.

2011-01-01

Recent progress in the development of a single-pulse Nanosecond Impulse Neutron Investigation System (NINIS) intended for interrogation of hidden objects (explosives and other illicit materials) by means of measuring elastically scattered neutrons is presented in this paper. The method is based on the well know fact that nuclide-specific information is present in the scattered neutron field. The method uses very bright neutron pulses having duration of the order of few nanoseconds, generated by a dense plasma focus (DPF) devices filled with a pure deuterium or deuterium-tritium mixture as a working gas. Very short duration of the neutron pulse, its high brightness and mono-chromaticity allow to use the time-of-flight method with bases of about few meters to distinguish signals from neutrons scattered by different elements. Results of the Monte Carlo simulations of the scattered neutron field from several compounds (explosives and everyday use materials) are presented in the paper. The MCNP5 code has been used to get information on the angular and energy distributions of the neutrons scattered by the above mentioned compounds assuming the initial neutron energy equal to 2.45 MeV (D-D). A new input has been elaborated that allows the modelling of not only a spectrum of the neutrons scattered at different angles but also their time history from the moment of generation up to detection. Such an approach allows getting approximate signals as registered by scintillator + photomultiplier probes placed at various distances from the scattering object, demonstrating a principal capability of the method to identify an elemental content of the inspected objects. Preliminary results of the MCNP modelling of the interrogation process of the airport luggage containing several illicit objects are presented as well. (authors)

Experimental system using an active method for the measurement of low alpha emitter grades

International Nuclear Information System (INIS)

Bernard, P.; Cance, M.

1986-06-01

The diversity of waste produced in France, the limitations of passive neutron measurements, the new safety requirements in the field of low level waste disposal have induced us to develop active neutron techniques. Two experimental pulsed neutron interrogation systems are described giving a sensitivity lower than 10 mg Pu 239 in 200 l drums. This project is the result of a close cooperation between the CEA, SGN and SODERN

Spallation source neutron target systems

International Nuclear Information System (INIS)

Russell, G.; Brown, R.; Collier, M.; Donahue, J.

1996-01-01

This is the final report for a two-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project sought to design a next-generation spallation source neutron target system for the Manuel Lujan, Jr., Neutron Scattering Center (LANSCE) at Los Alamos. It has been recognized for some time that new advanced neutron sources are needed in the US if the country is to maintain a competitive position in several important scientific and technological areas. A recent DOE panel concluded that the proposed Advanced Neutron Source (a nuclear reactor at Oak Ridge National Laboratory) and a high-power pulsed spallation source are both needed in the near future. One of the most technically challenging designs for a spallation source is the target station itself and, more specifically, the target-moderator-reflector arrangement. Los Alamos has demonstrated capabilities in designing, building, and operating high-power spallation-neutron-source target stations. Most of the new design ideas proposed worldwide for target system design for the next generation pulsed spallation source have either been conceived and implemented at LANSCE or proposed by LANSCE target system designers. These concepts include split targets, flux-trap moderators, back scattering and composite moderators, and composite reflectors

The Sociocultural Psychology as a Postformal Theory of Academic Achievement: Interrogating Formal Education

Science.gov (United States)

Sinha, Chetan

2013-01-01

The present paper interrogates the dominance of formal education. As formal education system relies on ability based academic achievement as a goal, exploring post-formal approaches, such as sociocultural notion of academic achievement is the hallmark of present paper. An attempt is made to interrogate the existing cultural dominance in formal…

The stationary neutron radiography system: a TRIGA-based production neutron radiography facility

International Nuclear Information System (INIS)

Chesworth, Robert H.; Hagmann, Dean B.

1988-01-01

General Atomics (GA) is under contract to construct a Stationary Neutron Radiography System (SNRS) - on a turnkey basis - at McClellan Air Force Base in Sacramento, California. The SNRS is a custom designed neutron radiography system which will utilize a 1000 KW TRIGA reactor as the neutron source. The partially below-ground reactor will be equipped with four inclined beam tubes originating near the top of the reactor graphite reflector and installed tangential to the reactor core to provide a strong current of thermal neutrons with minimum gamma ray contamination. The inclined beam tubes will terminate in four large bays and will interface with rugged component positioning systems designed to handle intact aircraft wings, other honeycomb aircraft structures, and pyrotechnics. The SNRS will be equipped with real-time, near real-time, and film radiographic imaging systems to provide a broad spectrum of capability for detection of entrained moisture or corrosion in large aircraft panels. GA is prime contractor to the Air Force for the SNRS and is specifically responsible for the TRIGA reactor system and a portion of the neutron beam system design. Science Applications International Corporation and the Lionakis-Beaumont Design Group are principal subcontractors to GA on the project. (author)

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

Portable fluorescence lifetime spectroscopy system for in-situ interrogation of biological tissues

Science.gov (United States)

Saito Nogueira, Marcelo; Cosci, Alessandro; Teixeira Rosa, Ramon Gabriel; Salvio, Ana Gabriela; Pratavieira, Sebastião; Kurachi, Cristina

2017-12-01

Fluorescence spectroscopy and lifetime techniques are potential methods for optical diagnosis and characterization of biological tissues with an in-situ, fast, and noninvasive interrogation. Several diseases may be diagnosed due to differences in the fluorescence spectra of targeted fluorophores, when, these spectra are similar, considering steady-state fluorescence, others may be detected by monitoring their fluorescence lifetime. Despite this complementarity, most of the current fluorescence lifetime systems are not robust and portable, and not being feasible for clinical applications. We describe the assembly of a fluorescence lifetime spectroscopy system in a suitcase, its characterization, and validation with clinical measurements of skin lesions. The assembled system is all encased and robust, maintaining its mechanical, electrical, and optical stability during transportation, and is feasible for clinical measurements. The instrument response function measured was about 300 ps, and the system is properly calibrated. At the clinical study, the system showed to be reliable, and the achieved spectroscopy results support its potential use as an auxiliary tool for skin diagnostics.

High performance multi-spectral interrogation for surface plasmon resonance imaging sensors.

Science.gov (United States)

Sereda, A; Moreau, J; Canva, M; Maillart, E

2014-04-15

Surface plasmon resonance (SPR) sensing has proven to be a valuable tool in the field of surface interactions characterization, especially for biomedical applications where label-free techniques are of particular interest. In order to approach the theoretical resolution limit, most SPR-based systems have turned to either angular or spectral interrogation modes, which both offer very accurate real-time measurements, but at the expense of the 2-dimensional imaging capability, therefore decreasing the data throughput. In this article, we show numerically and experimentally how to combine the multi-spectral interrogation technique with 2D-imaging, while finding an optimum in terms of resolution, accuracy, acquisition speed and reduction in data dispersion with respect to the classical reflectivity interrogation mode. This multi-spectral interrogation methodology is based on a robust five parameter fitting of the spectral reflectivity curve which enables monitoring of the reflectivity spectral shift with a resolution of the order of ten picometers, and using only five wavelength measurements per point. In fine, such multi-spectral based plasmonic imaging system allows biomolecular interaction monitoring in a linear regime independently of variations of buffer optical index, which is illustrated on a DNA-DNA model case. © 2013 Elsevier B.V. All rights reserved.

Neutron excess generation by fusion neutron source for self-consistency of nuclear energy system

International Nuclear Information System (INIS)

Saito, Masaki; Artisyuk, V.; Chmelev, A.

1999-01-01

The present day fission energy technology faces with the problem of transmutation of dangerous radionuclides that requires neutron excess generation. Nuclear energy system based on fission reactors needs fuel breeding and, therefore, suffers from lack of neutron excess to apply large-scale transmutation option including elimination of fission products. Fusion neutron source (FNS) was proposed to improve neutron balance in the nuclear energy system. Energy associated with the performance of FNS should be small enough to keep the position of neutron excess generator, thus, leaving the role of dominant energy producers to fission reactors. The present paper deals with development of general methodology to estimate the effect of neutron excess generation by FNS on the performance of nuclear energy system as a whole. Multiplication of fusion neutrons in both non-fissionable and fissionable multipliers was considered. Based on the present methodology it was concluded that neutron self-consistency with respect to fuel breeding and transmutation of fission products can be attained with small fraction of energy associated with innovated fusion facilities. (author)

Experimental verification of a method to create a variable energy neutron beam from a monoenergetic, isotropic source using neutron elastic scatter and time of flight

Energy Technology Data Exchange (ETDEWEB)

Whetstone, Zachary D., E-mail: zacwhets@umich.edu; Flaska, Marek, E-mail: mflaska@umich.edu; Kearfott, Kimberlee J., E-mail: kearfott@umich.edu

2016-08-11

An experiment was performed to determine the neutron energy of near-monoergetic deuterium–deuterium (D–D) neutrons that elastically scatter in a hydrogenous target. The experiment used two liquid scintillators to perform time of flight (TOF) measurements to determine neutron energy, with the start detector also serving as the scatter target. The stop detector was placed 1.0 m away and at scatter angles of π/6, π/4, and π/3 rad, and 1.5 m at a scatter angle of π/4 rad. When discrete 1 ns increments were implemented, the TOF peaks had estimated errors between −21.2 and 3.6% relative to their expected locations. Full widths at half-maximum (FWHM) ranged between 9.6 and 20.9 ns, or approximately 0.56–0.66 MeV. Monte Carlo simulations were also conducted that approximated the experimental setup and had both D–D and deuterium–tritium (DT) neutrons. The simulated results had errors between −17.2 and 0.0% relative to their expected TOF peaks when 1 ns increments were applied. The largest D–D and D–T FWHMs were 26.7 and 13.7 ns, or approximately 0.85 and 4.98 MeV, respectively. These values, however, can be reduced through manipulation of the dimensions of the system components. The results encourage further study of the neutron elastic scatter TOF system with particular interest in application to active neutron interrogation to search for conventional explosives.

In-plant test and evaluation of the neutron collar for verification of PWR fuel assemblies at Resende, Brazil

International Nuclear Information System (INIS)

Menlove, H.O.; Marzo, M.A.S.; de Almeida, S.G.; de Almeida, M.C.; Moitta, L.P.M.; Conti, L.F.; de Paiva, J.R.T.

1985-11-01

The neutron-coincidence collar has been evaluated for the measurement of pressurized-water reactor (PWR) fuel assemblies at the Fabrica de Elementos Combustiveis plant in Resende, Brazil. This evaluation was part of the cooperative-bilateral-safeguards technical-exchange program between the United States and Brazil. The neutron collar measures the 235 U content per unit length of full fuel assemblies using neutron interrogation and coincidence counting. The 238 U content is measured in the passive mode without the AmLi neutron-interrogation source. The extended evaluation took place over a period of 6 months with both scanning and single-zone measurements. The results of the tests gave a coincidence-response standard deviation of 0.7% (sigma = 1.49% for mass) for the active case and 2.5% for the passive case in 1000-s measurement times. The length measurement in the scanning mode was accurate to 0.77%. The accuracies of different calibration methods were evaluated and compared

Wavelength interrogation of fiber Bragg grating sensors using tapered hollow Bragg waveguides.

Science.gov (United States)

Potts, C; Allen, T W; Azar, A; Melnyk, A; Dennison, C R; DeCorby, R G

2014-10-15

We describe an integrated system for wavelength interrogation, which uses tapered hollow Bragg waveguides coupled to an image sensor. Spectral shifts are extracted from the wavelength dependence of the light radiated at mode cutoff. Wavelength shifts as small as ~10  pm were resolved by employing a simple peak detection algorithm. Si/SiO₂-based cladding mirrors enable a potential operational range of several hundred nanometers in the 1550 nm wavelength region for a taper length of ~1  mm. Interrogation of a strain-tuned grating was accomplished using a broadband amplified spontaneous emission (ASE) source, and potential for single-chip interrogation of multiplexed sensor arrays is demonstrated.

High-Speed Interrogation for Large-Scale Fiber Bragg Grating Sensing.

Science.gov (United States)

Hu, Chenyuan; Bai, Wei

2018-02-24

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.

Interrogative suggestibility in patients with conversion disorders.

Science.gov (United States)

Foong, J; Lucas, P A; Ron, M A

1997-09-01

We tested the hypothesis that increased interrogative suggestibility may contribute to the shaping and maintaining of conversions symptoms. Interrogative suggestibility was measured in 12 patients with conversion disorder and 10 control patients with confirmed neurological disease matched for age, premorbid intelligence, and as closely as possible in terms of their neurological symptoms to the patients with conversion disorder. Our observations do not support the contention that individual differences in interrogative suggestibility are of importance in the etiology of conversion disorders.

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

International Nuclear Information System (INIS)

D’Amico, N. M. B; Mayer, R.E; Tartaglione, A.

2013-01-01

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

A SYSTEMATIC APPROACH TO THE PSYCHOLOGICAL IMPACT OF THE INVESTIGATOR ON A PERSON BEING INTERROGATED

Directory of Open Access Journals (Sweden)

Ivan Cherevko

2017-03-01

Full Text Available The subject of the research is an interaction with a person being interrogated organized by an investigator with the use of his interests, needs and other individual-mental features, his reinforcement, which must be done through secretive, invisible influence in an organized situation encouraging to do deeds desirable for investigation. The object of the research is interrogation as the most psychologized investigative action. The methodological basis of the research is made by the systematic and logical approach aimed at neutralization of watchfulness of the interrogated, penetration into his inner world influencing both rational and irrational spheres of mental make-up, actualization of the unity of understanding and experience. In this research general scientific and specific scientific methods of cognition are used. General scientific methods of the research are represented by systemic structural, comparative, formal and legal, statistical methods. The approach to the psychological impact on a person being interrogated as a systemic phenomenon has enabled to develop a conceptual model presented in the form of a diagram made up of four blocks reflecting emotional background sources of interrogation procedures, the interrogated case, interaction and basic methods of psychological influence, the leading of which is persuasion. Suggestion is purposeful influence on feelings and volitional pressure acts as pressure maintenance, complementary, used depending on the situational behaviour of the interrogated. Methods of implementation of each of these methods of psychological influence are also considered in this article.

A system for fast neutron radiography

International Nuclear Information System (INIS)

Klann, R.T.

1997-01-01

A system has been designed and a neutron generator installed to perform fast neutron radiography. With this system, objects as small as a coin and as large as a 19 liter container have been radiographed. The neutron source is an MF Physics A-711 neutron generator which produces 3 x 10[sup 10] neutrons/second with an average energy of 14. 5 MeV. The radiography system uses x-ray scintillation screens and film in commercially available light-tight cassettes. The cassettes have been modified to include a thin sheet of plastic to produce protons from the neutron beam through elastic scattering from hydrogen and other low Z materials in the plastic. For film densities from 1.8 to 3.0, exposures range from 1.9 x 10[sup 7] n/cm[sup 2] to 3.8 x 10[sup 8] n/cm[sup 2] depending on the type of screen and film. The optimum source-to-film distance was found to be 150 cm. At this distance, the geometric unsharpness was determined to be approximately 2.2-2.3 mm and the smallest hole that could be resolved in a 1.25 cm thick sample had a diameter of 0.079 cm

A Neutron Radiography System for Field Use

Science.gov (United States)

1989-06-01

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

Fast-neutron detecting system with n, γ discrimination

International Nuclear Information System (INIS)

Ouyang Xiaoping; Huang Bao; Cao Jinyun

1997-11-01

In the present work, a new type neutron detecting system is reported, which can absolutely measure neutron parameters in n + γ mixed fields and has a long continuance of static high vacuum of 10 -4 Pa. The detecting system, with middle neutron-detecting sensitivity, short time response and big linear current output, has applied successfully in pulsed neutron beam measurement

Project and construction of counting system for neutron probe

International Nuclear Information System (INIS)

Monteiro, W.P.

1985-01-01

A counting system was developed for coupling neutron probe aiming to register pulses produced by slow neutron interaction in the detector. The neutron probe consists of fast neutron source, thermal neutron detector, amplifier circuit and pulse counting circuit. The counting system is composed by counting circuit, timer and signal circuit. (M.C.K.)

Compact deuterium-tritium neutron generator using a novel field ionization source

Energy Technology Data Exchange (ETDEWEB)

Ellsworth, J. L., E-mail: ellsworth7@llnl.gov; Falabella, S.; Sanchez, J.; Tang, V. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States); Wang, H. [Department of Computer Science, Stanford University, Stanford, California 94305 (United States)

2014-11-21

Active interrogation using neutrons is an effective method for detecting shielded nuclear material. A lightweight, lunch-box-sized, battery-operated neutron source would enable new concepts of operation in the field. We have developed at-scale components for a highly portable, completely self-contained, pulsed Deuterium-Tritium (DT) neutron source producing 14 MeV neutrons with average yields of 10{sup 7} n/s. A gated, field ionization ion source using etched electrodes has been developed that produces pulsed ion currents up to 500 nA. A compact Cockcroft-Walton high voltage source is used to accelerate deuterons into a metal hydride target for neutron production. The results of full scale DT tests using the field ionization source are presented.

Development of a new electronic neutron imaging system

Energy Technology Data Exchange (ETDEWEB)

Brenizer, J.S. [Department of Mechanical, Aerospace and Nuclear Engineering, Thornton Hall, University of Virginia, Charlottesville, VA 22903-2442 (United States); Berger, H. [Industrial Quality, Inc., Gaithersburg, MD (United States); Gibbs, K.M. [Industrial Quality, Inc., Gaithersburg, MD (United States); Mengers, P. [Paultek Systems, Inc., Nevada City, CA (United States); Stebbings, C.T. [Department of Mechanical, Aerospace and Nuclear Engineering, Thornton Hall, University of Virginia, Charlottesville, VA 22903-2442 (United States); Polansky, D. [Industrial Quality, Inc., Gaithersburg, MD (United States); Rogerson, D.J. [Naval Air Warfare Center, China Lake, CA (United States)

1999-11-03

An electronic neutron imaging camera system was developed for use with thermal, epithermal, and fast neutrons in applications that include nondestructive inspection of explosives, corrosion, turbine blades, electronics, low Z components, etc. The neutron images are expected to provide information to supplement that available from X-ray tests. The primary camera image area was a 30x30 cm field-of-view with a spatial resolution approaching 1.6 line pairs/mm (lp/mm). The camera had a remotely changeable second lens to limit the field-of-view to 7.6x7.6 cm for high spatial resolution (at least 4 lp/mm) thermal neutron imaging, but neutron and light scatter will limit resolution for fast neutrons to about 0.5 lp/mm. Remote focus capability enhanced camera set-up for optimum operation. The 75 dB dynamic range camera system included {sup 6}Li-based screens for imaging of thermal and epithermal neutrons and ZnS(Ag)-based screens for fast neutron imaging. The fast optics was input to a Super S-25 Gen II image intensifier, fiber optically coupled to a 1134 (h)x486 (v) frame transfer CCD camera. The camera system was designed to be compatible with a Navy-sponsored accelerator neutron source. The planned neutron source is an RF quadrupole accelerator that will provide a fast neutron flux of 10{sup 7} n/cm{sup 2}-s (at a source distance of 1 m) at an energy of about 2.2 MeV and a thermal neutron flux of 10{sup 6} n/cm{sup 2}-s at a source L/D ratio of 30. The electronic camera produced good quality real-time images at these neutron levels. On-chip integration could be used to improve image quality for low flux situations. The camera and accelerator combination provided a useful non-reactor neutron inspection system.

Performance Test of BF3 Neutron Detection System

Energy Technology Data Exchange (ETDEWEB)

Choi, Yu Sun; Shin, Ho Cheol [KHNP-CRI, Daejeon (Korea, Republic of); Cho, Jin Bok; Oh, Sae Hyun; Ryou, Seok Jean [USERS, Daejeon (Korea, Republic of)

2015-10-15

The neutron detecting system of First-of-a-kind plant such an APR1400 at Shin Kori should have been verified in the condition of low operating temperature and pressure of the primary coolant system before receiving the operation license. Auxiliary Ex-core Neutron Flux Monitoring System (AENFMS) is supposed to be installed using BF3 neutron detector in Shin Kori plant. The performance test of AENFMS was conducted to measure neutron sensitivity, moderation ratio and count rate in the same condition with Ex-core Neutron Flux Monitoring System (ENFMS) of APR1400 to verify its detection characteristics in compliance with the functional requirement. Performance test has been conducted for AENFMS of APR1400 to verify BF3 neutron sensitivity, moderation ration of PE, expecting neutron signal count rate from AENFMS, possible extending cable length from detector to pre-amplifier. As a result of measurement, the neutron sensitivity of 34.246±0.168(95%CI)cps/nv, moderation ratio of 11.343±0.039(95%CI) and AENFMS expecting count rate related to ENFMS of 17.8 times are acceptable in compliance with functional requirement, respectively.

TRU assay system and measurements

International Nuclear Information System (INIS)

Brodzinski, R.L.

1984-02-01

The measurement of the transuranic content of nuclear products or process residues has become increasingly important for the recovery of fissionable material from spent fuel elements, the identification of commercial fuel elements which have not yet reached full burnup, the measurement and recovery of transuranics from discarded or stored waste materials, the determination of the transuranic content in high gamma activity waste material scheduled for disposal, compliance with 10CFR61 by land burial operators/shippers, and the satisfaction of accountability requirements. Active neutron interrogation techniques measure either the prompt neutrons or the beta delayed neutrons from fission products following induced fission. These techniques normally only measure fissile transuranics ( 235 U, 239 Pu, and 241 Pu) and are commonly applied only to contact handleable waste. Passive neutron interrogation techniques, on the other hand, are capable of measuring all transuranics except 235 U with adequate sensitivity and will work on both contact handleable and high gamma activity wastes. Since the passive techniques are senstitive to a wider spectrum of transuranic isotopes than the active techniques, substantially less complex and less expensive than the active systems, and they have proven techniques for measuring small quantities of TRU in high gamma activity packages, the passive neutron TRU assay technology was chosen for development into the instruments discussed in this paper

A wireless interrogation system exploiting narrowband acoustic resonator for remote physical quantity measurement

Energy Technology Data Exchange (ETDEWEB)

Friedt, J.-M [SENSeOR, 32 Avenue de l' Observatoire, 25044 Besancon (France); Droit, C.; Martin, G.; Ballandras, S. [Department of Time and Frequency, FEMTO-ST, 32 Avenue de l' Observatoire, 25044 Besancon (France)

2010-01-15

Monitoring physical quantities using acoustic wave devices can be advantageously achieved using the wave characteristic dependence to various parametric perturbations (temperature, stress, and pressure). Surface acoustic wave (SAW) resonators are particularly well suited to such applications as their resonance frequency is directly influenced by these perturbations, modifying both the phase velocity and resonance conditions. Moreover, the intrinsic radio frequency (rf) nature of these devices makes them ideal for wireless applications, mainly exploiting antennas reciprocity and piezoelectric reversibility. In this paper, we present a wireless SAW sensor interrogation unit operating in the 434 MHz centered ISM band--selected as a tradeoff between antenna dimensions and electromagnetic wave penetration in dielectric media--based on the principles of a frequency sweep network analyzer. We particularly focus on the compliance with the ISM standard which reveals complicated by the need for switching from emission to reception modes similarly to radar operation. In this matter, we propose a fully digital rf synthesis chain to develop various interrogation strategies to overcome the corresponding difficulties and comply with the above-mentioned standard. We finally assess the reader interrogation range, accuracy, and dynamics.

A wireless interrogation system exploiting narrowband acoustic resonator for remote physical quantity measurement

International Nuclear Information System (INIS)

Friedt, J.-M; Droit, C.; Martin, G.; Ballandras, S.

2010-01-01

Monitoring physical quantities using acoustic wave devices can be advantageously achieved using the wave characteristic dependence to various parametric perturbations (temperature, stress, and pressure). Surface acoustic wave (SAW) resonators are particularly well suited to such applications as their resonance frequency is directly influenced by these perturbations, modifying both the phase velocity and resonance conditions. Moreover, the intrinsic radio frequency (rf) nature of these devices makes them ideal for wireless applications, mainly exploiting antennas reciprocity and piezoelectric reversibility. In this paper, we present a wireless SAW sensor interrogation unit operating in the 434 MHz centered ISM band--selected as a tradeoff between antenna dimensions and electromagnetic wave penetration in dielectric media--based on the principles of a frequency sweep network analyzer. We particularly focus on the compliance with the ISM standard which reveals complicated by the need for switching from emission to reception modes similarly to radar operation. In this matter, we propose a fully digital rf synthesis chain to develop various interrogation strategies to overcome the corresponding difficulties and comply with the above-mentioned standard. We finally assess the reader interrogation range, accuracy, and dynamics.

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

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

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.

Assessment of effectiveness of geologic isolation systems: the feasibility of computer interrogation of experts for WISAP

Energy Technology Data Exchange (ETDEWEB)

Wight, L.H.

1980-05-01

Simulation of the response of a waste repository to events that could initiate a fault tree to breach and failure is currently a keystone to the Battelle Waste Isolation Safety Assessment Program (WISAP). The repository simulation, which is part of the Disruptive Event Analysis Task, models the repository for its entire design life, one million years. This is clearly a challenging calculation, requiring input unlike any other response analysis by virtue of the long design life of the facility. What technology will provide design criteria for a million year design life. Answers to questions like this can, to some extent, be based on data, but always require some subjective judgments. The subjectivity, which is sometimes driven by inadequate or incomplete data or by a lack of understanding of the physical process, is therefore a crucial ingredient in an analysis of initiating events. Because of the variety of possible initiating events (glaciation, man-caused disruption, volcanism, etc.), many expert opinions will be solicited as input. The complexity of the simulation, the variety of experts involved, and the volume of applicable data all suggest that there may be a more direct, economical method to solicit the expert opinion. This report addresses the feasibility of such a system. Background information is presented that demonstrates the advantages of a computer interrogation system over conventional interrogation and assessment techniques. In the subsequent three sections the three elements - structure and decomposition, scaling, and synthesis - that are basic to any interrogation and assessment technique are reviewed. The interrelationship are schematically illustrated between these three fundamental elements and, therefore, serves as a useful guide to these three sections. Each of these three sections begins with a recommended approach to the particular element and ends with an illustration of representative dialogue.

Assessment of effectiveness of geologic isolation systems: the feasibility of computer interrogation of experts for WISAP

International Nuclear Information System (INIS)

Wight, L.H.

1980-05-01

Simulation of the response of a waste repository to events that could initiate a fault tree to breach and failure is currently a keystone to the Battelle Waste Isolation Safety Assessment Program (WISAP). The repository simulation, which is part of the Disruptive Event Analysis Task, models the repository for its entire design life, one million years. This is clearly a challenging calculation, requiring input unlike any other response analysis by virtue of the long design life of the facility. What technology will provide design criteria for a million year design life. Answers to questions like this can, to some extent, be based on data, but always require some subjective judgments. The subjectivity, which is sometimes driven by inadequate or incomplete data or by a lack of understanding of the physical process, is therefore a crucial ingredient in an analysis of initiating events. Because of the variety of possible initiating events (glaciation, man-caused disruption, volcanism, etc.), many expert opinions will be solicited as input. The complexity of the simulation, the variety of experts involved, and the volume of applicable data all suggest that there may be a more direct, economical method to solicit the expert opinion. This report addresses the feasibility of such a system. Background information is presented that demonstrates the advantages of a computer interrogation system over conventional interrogation and assessment techniques. In the subsequent three sections the three elements - structure and decomposition, scaling, and synthesis - that are basic to any interrogation and assessment technique are reviewed. The interrelationship are schematically illustrated between these three fundamental elements and, therefore, serves as a useful guide to these three sections. Each of these three sections begins with a recommended approach to the particular element and ends with an illustration of representative dialogue

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)

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

International Nuclear Information System (INIS)

Robinson, G.S.

1984-03-01

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

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

A Portable System for Nuclear, Chemical Agent and Explosives Identification

International Nuclear Information System (INIS)

Parker, W.E.; Buckley, W.M.; Kreek, S.A.; Caffrey, A.J.; Mauger, G.J.; Lavietes, A.D.; Dougan, A.D.

2000-01-01

The FRIS/PINS hybrid integrates the LLNL-developed Field Radionuclide Identification System (FRIS) with the INEEL-developed Portable Isotopic Neutron Spectroscopy (PINS) chemical assay system to yield a combined general radioisotope, special nuclear material, and chemical weapons/explosives detection and identification system. The PINS system uses a neutron source and a high-purity germanium γ-ray detector. The FRIS system uses an electrochemically cooled germanium detector and its own analysis software to detect and identify special nuclear material and other radioisotopes. The FRIS/PINS combined system also uses the electromechanically-cooled germanium detector. There is no other currently available integrated technology that can combine an active neutron interrogation and analysis capability for CWE with a passive radioisotope measurement and identification capability for special nuclear material

A gamma/neutron-discriminating, Cooled, Optically Stimulated Luminescence (COSL) dosemeter

International Nuclear Information System (INIS)

Eschbach, P.A.; Miller, S.D.

1992-07-01

The Cooled Optically Stimulated Luminescence (COSL) of CaF 2 :Mn (grain sizes from 0.1 to 100 microns) powder embedded in a hydrogenous matrix is reported as a function of fast-neutron dose. When all the CaF 2 :Mn grains are interrogated at once, the COSL plastic dosemeters have a minimum detectable limit of 1 cSv fast neutrons; the gamma component from the bare 252 cf exposure was determined with a separate dosemeter. We report here on a proton-recoil-based dosemeter that generates pulse height spectra, much like the scintillator of Hornyak, (2) to provide information on both the neutron and gamma dose

A proposed neutron spectrometer system for JET

International Nuclear Information System (INIS)

Elevant, T.; Hellbom, G.; Scheffel, J.; Malmskog, S.

1979-12-01

A neutron spectrometer system is proposed primarily for measurements of ion temperature and density and ion beam energy distribution in extended fusion plasmas like e.g. in JET. Three different spectrometers are involved: time of flight, proton recoil and 3 He. Energy resolutions of a few percent both for DD and DT neutrons are provided. Six order of magnitudes in flux ranges will be covered by the system when employing multi-target systems. A neutron collimator and shielding system will be desirable in order to obtain relevant information. Due to the entire differences in energy and fluxes for DD and DT plasmas a flexible collimator-shielding system is recommended

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...

Improvement of non-destructive fissile mass assays in α low-level waste drums: A matrix correction method based on neutron capture gamma-rays and a neutron generator

Science.gov (United States)

Jallu, F.; Loche, F.

2008-08-01

Within the framework of radioactive waste control, non-destructive assay (NDA) methods may be employed. The active neutron interrogation (ANI) method is now well-known and effective in quantifying low α-activity fissile masses (mainly 235U, 239Pu, 241Pu) with low densities, i.e. less than about 0.4, in radioactive waste drums of volumes up to 200 l. The PROMpt Epithermal and THErmal interrogation Experiment (PROMETHEE [F. Jallu, A. Mariani, C. Passard, A.-C. Raoux, H. Toubon, Alpha low level waste control: improvement of the PROMETHEE 6 assay system performances. Nucl. Technol. 153 (January) (2006); C. Passard, A. Mariani, F. Jallu, J. Romeyer-Dherber, H. Recroix, M. Rodriguez, J. Loridon, C. Denis, PROMETHEE: an alpha low level waste assay system using passive and active neutron measurement methods. Nucl. Technol. 140 (December) (2002) 303-314]) based on ANI has been under development since 1996 to reach the incinerating α low level waste (LLW) criterion of about 50 Bq[α] per gram of crude waste (≈50 μg Pu) in 118 l drums on the date the drums are conditioned. Difficulties arise when dealing with matrices containing neutron energy moderators such as H and neutron absorbents such as Cl. These components may have a great influence on the fissile mass deduced from the neutron signal measured by ANI. For example, the calibration coefficient measured in a 118 l drum containing a cellulose matrix (density d = 0.144 g cm -3) may be 50 times higher than that obtained in a poly-vinyl-chloride matrix ( d = 0.253 g cm -3). Without any information on the matrix, the fissile mass is often overestimated due to safety procedures and by considering the most disadvantageous calibration coefficient corresponding to the most absorbing and moderating calibration matrix. The work discussed in this paper was performed at the CEA Nuclear Measurement Laboratory in France. It concerns the development of a matrix effect correction method, which consists in identifying and quantifying

Improvement of non-destructive fissile mass assays in α low-level waste drums: A matrix correction method based on neutron capture gamma-rays and a neutron generator

International Nuclear Information System (INIS)

Jallu, F.; Loche, F.

2008-01-01

Within the framework of radioactive waste control, non-destructive assay (NDA) methods may be employed. The active neutron interrogation (ANI) method is now well-known and effective in quantifying low α-activity fissile masses (mainly 235 U, 239 Pu, 241 Pu) with low densities, i.e. less than about 0.4, in radioactive waste drums of volumes up to 200 l. The PROMpt Epithermal and THErmal interrogation Experiment (PROMETHEE [F. Jallu, A. Mariani, C. Passard, A.-C. Raoux, H. Toubon, Alpha low level waste control: improvement of the PROMETHEE 6 assay system performances. Nucl. Technol. 153 (January) (2006); C. Passard, A. Mariani, F. Jallu, J. Romeyer-Dherber, H. Recroix, M. Rodriguez, J. Loridon, C. Denis, PROMETHEE: an alpha low level waste assay system using passive and active neutron measurement methods. Nucl. Technol. 140 (December) (2002) 303-314]) based on ANI has been under development since 1996 to reach the incinerating α low level waste (LLW) criterion of about 50 Bq[α] per gram of crude waste (∼50 μg Pu) in 118 l drums on the date the drums are conditioned. Difficulties arise when dealing with matrices containing neutron energy moderators such as H and neutron absorbents such as Cl. These components may have a great influence on the fissile mass deduced from the neutron signal measured by ANI. For example, the calibration coefficient measured in a 118 l drum containing a cellulose matrix (density d = 0.144 g cm -3 ) may be 50 times higher than that obtained in a poly-vinyl-chloride matrix (d = 0.253 g cm -3 ). Without any information on the matrix, the fissile mass is often overestimated due to safety procedures and by considering the most disadvantageous calibration coefficient corresponding to the most absorbing and moderating calibration matrix. The work discussed in this paper was performed at the CEA Nuclear Measurement Laboratory in France. It concerns the development of a matrix effect correction method, which consists in identifying and

Improvement of non-destructive fissile mass assays in {alpha} low-level waste drums: A matrix correction method based on neutron capture gamma-rays and a neutron generator

Energy Technology Data Exchange (ETDEWEB)

Jallu, F. [Commissariat a l' Energie Atomique, CEA, DEN, Nuclear Measurement Laboratory, Bat. 224, 13108 Saint Paul lez Durance (France)], E-mail: fanny.jallu@cea.fr; Loche, F. [Commissariat a l' Energie Atomique, CEA, DEN, Nuclear Measurement Laboratory, Bat. 224, 13108 Saint Paul lez Durance (France)

2008-08-15

Within the framework of radioactive waste control, non-destructive assay (NDA) methods may be employed. The active neutron interrogation (ANI) method is now well-known and effective in quantifying low {alpha}-activity fissile masses (mainly {sup 235}U, {sup 239}Pu, {sup 241}Pu) with low densities, i.e. less than about 0.4, in radioactive waste drums of volumes up to 200 l. The PROMpt Epithermal and THErmal interrogation Experiment (PROMETHEE [F. Jallu, A. Mariani, C. Passard, A.-C. Raoux, H. Toubon, Alpha low level waste control: improvement of the PROMETHEE 6 assay system performances. Nucl. Technol. 153 (January) (2006); C. Passard, A. Mariani, F. Jallu, J. Romeyer-Dherber, H. Recroix, M. Rodriguez, J. Loridon, C. Denis, PROMETHEE: an alpha low level waste assay system using passive and active neutron measurement methods. Nucl. Technol. 140 (December) (2002) 303-314]) based on ANI has been under development since 1996 to reach the incinerating {alpha} low level waste (LLW) criterion of about 50 Bq[{alpha}] per gram of crude waste ({approx}50 {mu}g Pu) in 118 l drums on the date the drums are conditioned. Difficulties arise when dealing with matrices containing neutron energy moderators such as H and neutron absorbents such as Cl. These components may have a great influence on the fissile mass deduced from the neutron signal measured by ANI. For example, the calibration coefficient measured in a 118 l drum containing a cellulose matrix (density d = 0.144 g cm{sup -3}) may be 50 times higher than that obtained in a poly-vinyl-chloride matrix (d = 0.253 g cm{sup -3}). Without any information on the matrix, the fissile mass is often overestimated due to safety procedures and by considering the most disadvantageous calibration coefficient corresponding to the most absorbing and moderating calibration matrix. The work discussed in this paper was performed at the CEA Nuclear Measurement Laboratory in France. It concerns the development of a matrix effect correction

Photon interrogation annual report for FY 1979

International Nuclear Information System (INIS)

Nieschmidt, E.B.; Johnson, L.O.; Lawrence, R.S.; Vegors, S.H. Jr.

1980-03-01

Summaries of experimental information and information from vendors is presented to show the adequacy of the photon interrogation technique for transuranic waste assay. An instrument system is described which has high immunity to gamma flash and has good high count rate capabilities. Comparison of the progress of the program with a schedule presented at its inception is presented

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.

Portable fluorescence lifetime spectroscopy system for in-situ interrogation of biological tissues.

Science.gov (United States)

Saito Nogueira, Marcelo; Cosci, Alessandro; Teixeira Rosa, Ramon Gabriel; Salvio, Ana Gabriela; Pratavieira, Sebastião; Kurachi, Cristina

2017-10-01

Fluorescence spectroscopy and lifetime techniques are potential methods for optical diagnosis and characterization of biological tissues with an in-situ, fast, and noninvasive interrogation. Several diseases may be diagnosed due to differences in the fluorescence spectra of targeted fluorophores, when, these spectra are similar, considering steady-state fluorescence, others may be detected by monitoring their fluorescence lifetime. Despite this complementarity, most of the current fluorescence lifetime systems are not robust and portable, and not being feasible for clinical applications. We describe the assembly of a fluorescence lifetime spectroscopy system in a suitcase, its characterization, and validation with clinical measurements of skin lesions. The assembled system is all encased and robust, maintaining its mechanical, electrical, and optical stability during transportation, and is feasible for clinical measurements. The instrument response function measured was about 300 ps, and the system is properly calibrated. At the clinical study, the system showed to be reliable, and the achieved spectroscopy results support its potential use as an auxiliary tool for skin diagnostics. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

The Neutron Spectrometry System Using 3He Counter

International Nuclear Information System (INIS)

Dang Lanh; Pham Ngoc Tuan; Tuong Thi Thu Huong; Nguyen Nhi Dien; Nguyen Van Hung

2011-01-01

A spectrometry system was designed for neutron counting at the horizontal channels of Dalat nuclear reactor. The system is able to interface to PC via EZ-USB with full speed. The designed system can be installed for operation not only at the channel No. 4 of the reactor, but also operated with the neutron Howitzer system installed at the Training Center of Nuclear Research Institute for training purposes. Almost results can be achieved effectively while choosing the shaping time of 2 μs of amplifier unit; and an appropriate preamplifier is used to measure neutron spectra. In this work, the multi-channel spectrometer for measuring neutron was designed and tested. (author)

Design of Interrogation Protocols for Radiation Dose Measurements Using Optically-Stimulated Luminescent Dosimeters.

Science.gov (United States)

Abraham, Sara A; Kearfott, Kimberlee J; Jawad, Ali H; Boria, Andrew J; Buth, Tobias J; Dawson, Alexander S; Eng, Sheldon C; Frank, Samuel J; Green, Crystal A; Jacobs, Mitchell L; Liu, Kevin; Miklos, Joseph A; Nguyen, Hien; Rafique, Muhammad; Rucinski, Blake D; Smith, Travis; Tan, Yanliang

2017-03-01

Optically-stimulated luminescent dosimeters are capable of being interrogated multiple times post-irradiation. Each interrogation removes a fraction of the signal stored within the optically-stimulated luminescent dosimeter. This signal loss must be corrected to avoid systematic errors in estimating the average signal of a series of optically-stimulated luminescent dosimeter interrogations and requires a minimum number of consecutive readings to determine an average signal that is within a desired accuracy of the true signal with a desired statistical confidence. This paper establishes a technical basis for determining the required number of readings for a particular application of these dosimeters when using certain OSL dosimetry systems.

Interrogative constructions in Danish Sign Language (DSL)

DEFF Research Database (Denmark)

Hansen, Julie

This study investigates the primary types of interrogative constructions: Polar and content questions. The aim is to identify how and in which types of interrogative constructions the non-manual patterns described by Engberg-Pedersen (1993, 1998)are used. Furthermore, the aim is to identify...

The National Ignition Facility Neutron Imaging System

International Nuclear Information System (INIS)

Wilke, Mark D.; Batha, Steven H.; Bradley, Paul A.; Day, Robert D.; Clark, David D.; Fatherley, Valerie E.; Finch, Joshua P.; Gallegos, Robert A.; Garcia, Felix P.; Grim, Gary P.; Jaramillo, Steven A.; Montoya, Andrew J.; Morgan, George L.; Oertel, John A.; Ortiz, Thomas A.; Payton, Jeremy R.; Pazuchanics, Peter; Schmidt, Derek W.; Valdez, Adelaida C.; Wilde, Carl H.

2008-01-01

The National Ignition Facility (NIF) is scheduled to begin deuterium-tritium (DT) shots possibly in the next several years. One of the important diagnostics in understanding capsule behavior and to guide changes in Hohlraum illumination, capsule design, and geometry will be neutron imaging of both the primary 14 MeV neutrons and the lower-energy downscattered neutrons in the 6-13 MeV range. The neutron imaging system (NIS) described here, which we are currently building for use on NIF, uses a precisely aligned set of apertures near the target to form the neutron images on a segmented scintillator. The images are recorded on a gated, intensified charge coupled device. Although the aperture set may be as close as 20 cm to the target, the imaging camera system will be located at a distance of 28 m from the target. At 28 m the camera system is outside the NIF building. Because of the distance and shielding, the imager will be able to obtain images with little background noise. The imager will be capable of imaging downscattered neutrons from failed capsules with yields Y n >10 14 neutrons. The shielding will also permit the NIS to function at neutron yields >10 18 , which is in contrast to most other diagnostics that may not work at high neutron yields. The following describes the current NIF NIS design and compares the predicted performance with the NIF specifications that must be satisfied to generate images that can be interpreted to understand results of a particular shot. The current design, including the aperture, scintillator, camera system, and reconstruction methods, is briefly described. System modeling of the existing Omega NIS and comparison with the Omega data that guided the NIF design based on our Omega results is described. We will show NIS model calculations of the expected NIF images based on component evaluations at Omega. We will also compare the calculated NIF input images with those unfolded from the NIS images generated from our NIS numerical

Measurement 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, making use of the change in the fission cross section of a nuclide with the neutron energy. The active interrogation method was used by irradiating the samples with pulsed 14 MeV neutrons and further detection of delayed fission neutrons. In order to discriminate 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 Student distribution was estimated to be 0.33%. The minimal detectable mass was estimated to be 4.4 g. (author) [pt

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

System to detect nuclear materials by active neutron method

International Nuclear Information System (INIS)

Koroev, M.; Korolev, Yu.; Lopatin, Yu.; Filonov, V.

1999-01-01

The report presents the results of the development of the system to detect nuclear materials by active neutron method measuring delayed neutrons. As the neutron source the neutron generator was used. The neutron generator was controlled by the system. The detectors were developed on the base of the helium-3 counters. Each detector consist of 6 counters. Using a number of such detectors it is possible to verify materials stored in different geometry. There is an spectrometric scintillator detector in the system which gives an additional functional ability to the system. The system could be used to estimate the nuclear materials in waste, to detect the unauthorized transfer of the nuclear materials, to estimate the material in tubes [ru

Feasibility study of a neutron activation system for EU test blanket systems

Energy Technology Data Exchange (ETDEWEB)

Tian, Kuo, E-mail: kuo.tian@kit.edu [Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Calderoni, Pattrick [Fusion for Energy(F4E), Barcelona (Spain); Ghidersa, Bradut-Eugen; Klix, Axel [Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany)

2016-11-01

Highlights: • This paper summarizes the technical baseline and preliminary design of EU TBM Neutron Activation System, briefly describes the key components, and outlines the major integration challenges. - Abstract: The Neutron Activation System (NAS) for the EU Helium Cooled Lithium Lead (HCLL) and Helium Cooled Pebble Bed (HCPB) Test Blanket Systems (TBSs) is an instrument that is proposed to determine the absolute neutron fluence and absolute neutron flux with information on the neutron spectrum in selected positions of the corresponding Test Blanket Modules (TBMs). In the NAS activation probes are exposed to the ITER neutron flux for periods ranging from several tens of seconds up to a full plasma pulse length, and the induced gamma activities are subsequently measured. The NAS is composed of a pneumatic transfer system and a counting station. The pneumatic transfer system includes irradiation ends in TBMs, transfer pipes, return gas pipes, a transfer station with a distributor (carousel), and a pressurized gas driving system, while the counting station consists of gamma ray detectors, signal processing electronic devices, and data analyzing software for neutron source strength evaluation. In this paper, a brief description on the proposed TBM NAS as well as the key components is presented, and the integration challenges of TBM NAS are outlined.

Methods and systems for Raman and optical cross-interrogation in flow-through silicon membranes

Science.gov (United States)

Bond, Tiziana C.; Letant, Sonia E.

2014-09-09

Cross-interrogating photonic detection systems and methods are shown. A flow through photonic crystal membrane with a surface enhanced Raman scattering (SERS) substrate is provided with pores which are distributed along multiple regions. The pores of one region have walls to which a first type of target specific anchor can be attached, while pores of another region have walls to which a second type of target specific anchor can be attached. An optical arrangement out-of-plane to the SERS substrate is also provided for enhanced sensitivity and identification of target organisms.

Neutron tomography of axially symmetric objects using 14 MeV neutrons from a portable neutron generator

Energy Technology Data Exchange (ETDEWEB)

Andersson, P., E-mail: peter.andersson@physics.uu.se; Andersson-Sunden, E.; Sjöstrand, H.; Jacobsson-Svärd, S. [Department of Physics and Astronomy, Division of Applied Nuclear Physics, Uppsala University, Lägerhyddsgatan 1, 751 20 Uppsala (Sweden)

2014-08-01

In nuclear boiling water reactor cores, the distribution of water and steam (void) is essential for both safety and efficiency reasons. In order to enhance predictive capabilities, void distribution assessment is performed in two-phase test-loops under reactor-relevant conditions. This article proposes the novel technique of fast-neutron tomography using a portable deuterium-tritium neutron generator to determine the time-averaged void distribution in these loops. Fast neutrons have the advantage of high transmission through the metallic structures and pipes typically concealing a thermal-hydraulic test loop, while still being fairly sensitive to the water/void content. However, commercially available fast-neutron generators also have the disadvantage of a relatively low yield and fast-neutron detection also suffers from relatively low detection efficiency. Fortunately, some loops are axially symmetric, a property which can be exploited to reduce the amount of data needed for tomographic measurement, thus limiting the interrogation time needed. In this article, three axially symmetric test objects depicting a thermal-hydraulic test loop have been examined; steel pipes with outer diameter 24 mm, thickness 1.5 mm, and with three different distributions of the plastic material POM inside the pipes. Data recorded with the FANTOM fast-neutron tomography instrument have been used to perform tomographic reconstructions to assess their radial material distribution. Here, a dedicated tomographic algorithm that exploits the symmetry of these objects has been applied, which is described in the paper. Results are demonstrated in 20 rixel (radial pixel) reconstructions of the interior constitution and 2D visualization of the pipe interior is demonstrated. The local POM attenuation coefficients in the rixels were measured with errors (RMS) of 0.025, 0.020, and 0.022 cm{sup −1}, solid POM attenuation coefficient. The accuracy and precision is high enough to provide a useful

Neutron tomography of axially symmetric objects using 14 MeV neutrons from a portable neutron generator.

Science.gov (United States)

Andersson, P; Andersson-Sunden, E; Sjöstrand, H; Jacobsson-Svärd, S

2014-08-01

In nuclear boiling water reactor cores, the distribution of water and steam (void) is essential for both safety and efficiency reasons. In order to enhance predictive capabilities, void distribution assessment is performed in two-phase test-loops under reactor-relevant conditions. This article proposes the novel technique of fast-neutron tomography using a portable deuterium-tritium neutron generator to determine the time-averaged void distribution in these loops. Fast neutrons have the advantage of high transmission through the metallic structures and pipes typically concealing a thermal-hydraulic test loop, while still being fairly sensitive to the water/void content. However, commercially available fast-neutron generators also have the disadvantage of a relatively low yield and fast-neutron detection also suffers from relatively low detection efficiency. Fortunately, some loops are axially symmetric, a property which can be exploited to reduce the amount of data needed for tomographic measurement, thus limiting the interrogation time needed. In this article, three axially symmetric test objects depicting a thermal-hydraulic test loop have been examined; steel pipes with outer diameter 24 mm, thickness 1.5 mm, and with three different distributions of the plastic material POM inside the pipes. Data recorded with the FANTOM fast-neutron tomography instrument have been used to perform tomographic reconstructions to assess their radial material distribution. Here, a dedicated tomographic algorithm that exploits the symmetry of these objects has been applied, which is described in the paper. Results are demonstrated in 20 rixel (radial pixel) reconstructions of the interior constitution and 2D visualization of the pipe interior is demonstrated. The local POM attenuation coefficients in the rixels were measured with errors (RMS) of 0.025, 0.020, and 0.022 cm(-1), solid POM attenuation coefficient. The accuracy and precision is high enough to provide a useful

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

Development of beryllium-based neutron target system with three-layer structure for accelerator-based neutron source for boron neutron capture therapy.

Science.gov (United States)

Kumada, Hiroaki; Kurihara, Toshikazu; Yoshioka, Masakazu; Kobayashi, Hitoshi; Matsumoto, Hiroshi; Sugano, Tomei; Sakurai, Hideyuki; Sakae, Takeji; Matsumura, Akira

2015-12-01

The iBNCT project team with University of Tsukuba is developing an accelerator-based neutron source. Regarding neutron target material, our project has applied beryllium. To deal with large heat load and blistering of the target system, we developed a three-layer structure for the target system that includes a blistering mitigation material between the beryllium used as the neutron generator and the copper heat sink. The three materials were bonded through diffusion bonding using a hot isostatic pressing method. Based on several verifications, our project chose palladium as the intermediate layer. A prototype of the neutron target system was produced. We will verify that sufficient neutrons for BNCT treatment are generated by the device in the near future. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modeling the National Ignition Facility neutron imaging system.

Science.gov (United States)

Wilson, D C; Grim, G P; Tregillis, I L; Wilke, M D; Patel, M V; Sepke, S M; Morgan, G L; Hatarik, R; Loomis, E N; Wilde, C H; Oertel, J A; Fatherley, V E; Clark, D D; Fittinghoff, D N; Bower, D E; Schmitt, M J; Marinak, M M; Munro, D H; Merrill, F E; Moran, M J; Wang, T-S F; Danly, C R; Hilko, R A; Batha, S H; Frank, M; Buckles, R

2010-10-01

Numerical modeling of the neutron imaging system for the National Ignition Facility (NIF), forward from calculated target neutron emission to a camera image, will guide both the reduction of data and the future development of the system. Located 28 m from target chamber center, the system can produce two images at different neutron energies by gating on neutron arrival time. The brighter image, using neutrons near 14 MeV, reflects the size and symmetry of the implosion "hot spot." A second image in scattered neutrons, 10-12 MeV, reflects the size and symmetry of colder, denser fuel, but with only ∼1%-7% of the neutrons. A misalignment of the pinhole assembly up to ±175 μm is covered by a set of 37 subapertures with different pointings. The model includes the variability of the pinhole point spread function across the field of view. Omega experiments provided absolute calibration, scintillator spatial broadening, and the level of residual light in the down-scattered image from the primary neutrons. Application of the model to light decay measurements of EJ399, BC422, BCF99-55, Xylene, DPAC-30, and Liquid A suggests that DPAC-30 and Liquid A would be preferred over the BCF99-55 scintillator chosen for the first NIF system, if they could be fabricated into detectors with sufficient resolution.

Development of Cold Neutron Depth Profiling System at HANARO

International Nuclear Information System (INIS)

Park, B. G.; Choi, H. D.; Sun, G. M.

2012-01-01

The depth profiles of intentional or intrinsic constituents of a sample provide valuable information for the characterization of materials. A number of analytical techniques for depth profiling have been developed. Neutron Depth Profiling (NDP) system which was developed by Ziegler et al. is one of the leading analytical techniques. In NDP, a thermal or cold neutron beam passes through a material and interacts with certain isotopes that are known to emit monoenergetic-charged particle remaining a recoil nucleus after neutron absorption. The depth is obtained from the energy loss of those charged particles escaping surface of substrate material. For various applications of NDP technique, the Cold Neutron Depth Profiling System (CN-NDP) was developed at a neutron guide CG1 installed at the HANARO cold neutron source. In this study the design features of the cold neutron beam and target chamber for the CN-NDP system are given. Also, some experiments for the performance tests of the CN-NDP system are described

The neutron imaging system fielded at the National Ignition Facility

Directory of Open Access Journals (Sweden)

Fittinghoff D.N.

2013-11-01

Full Text Available We have fielded a neutron imaging system at the National Ignition Facility to collect images of fusion neutrons produced in the implosion of inertial confinement fusion experiments and scattered neutrons from (n, n′ reactions of the source neutrons in the surrounding dense material. A description of the neutron imaging system is presented, including the pinhole array aperture, the line-of-sight collimation, the scintillator-based detection system and the alignment systems and methods. Discussion of the alignment and resolution of the system is presented. We also discuss future improvements to the system hardware.

Non-destructive assay of mechanical components using gamma-rays and thermal neutrons

Energy Technology Data Exchange (ETDEWEB)

Souza, Erica Silvani; Avelino, Mila R. [PPG-EM/UERJ, R. Sao Francisco Xavier, 524, Maracana - Rio de Janeiro - RJ (Brazil); Almeida, Gevaldo L. de; Souza, Maria Ines S. [IEN/CNEN, Rua Helio de Almeida, 75, Ilha do Fundao, Rio de Janeiro - RJ (Brazil)

2013-05-06

This work presents the results obtained in the inspection of several mechanical components through neutron and gamma-ray transmission radiography. The 4.46 Multiplication-Sign 10{sup 5} n.cm{sup -2}.s{sup -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 {gamma}-ray emitted by {sup 198}Au, 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.

Interrogating Planar Cyclooctatetraenes

DEFF Research Database (Denmark)

Hensel, Thomas

]circulenes were established. The antiaromaticity of the formal COT core of the hetero[8]circulenes was interrogated by comparison of the respective 13C-NMR carbon shifts with those of 3,6-dimethoxycarbazole (the starting material), tetrahydroxy intermediate and literature values. No uniform paratropic...

Real-time thermal neutron radiographic detection systems

International Nuclear Information System (INIS)

Berger, H.; Bracher, D.A.

1976-01-01

Systems for real-time detection of thermal neutron images are reviewed. Characteristics of one system are presented; the data include contrast, resolution and speed of response over the thermal neutron intensity range 2.5 10 3 n/cm 2 -sec to 10 7 n/cm 2 -sec

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

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

AN/UPX-41(C) IFF Interrogator Compatibility with the National Airspace System : Top-Level Test Plan Chesapeake Fixed-Base Experiment

Science.gov (United States)

2015-08-04

In 2012, the Navy requested spectrum certification for the shipboard AN/UPX-41(C) Digital Interrogator System, Software Version 5.5 with Mode 5. : Current operating conditions for the Navys AN/UPX-41(C) are the same as restrictions imposed on the ...

29 CFR 18.614 - Calling and interrogation of witnesses by judge.

Science.gov (United States)

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Calling and interrogation of witnesses by judge. 18.614... interrogation of witnesses by judge. (a) Calling by the judge. The judge may, on the judge's own motion or at... thus called. (b) Interrogation by the judge. The judge may interrogate witnesses, whether called by the...

Bright Lights and Questions: Using Mutual Interrogation

Science.gov (United States)

Adam, Aishikin; Alangui, Willy; Barton, Bill

2010-01-01

Mutual Interrogation is a research methodology for ethnomathematics proposed by Alangui in 2006 in an attempt to avoid the potential inequality set up when a restricted cultural practice is viewed through the lens of the near-universal and highly developed research domain of mathematics. Using three significant examples of mutual interrogation in…

Safety and efficiency of emergency department interrogation of cardiac devices.

Science.gov (United States)

Neuenschwander, James F; Peacock, W Frank; Migeed, Madgy; Hunter, Sara A; Daughtery, John C; McCleese, Ian C; Hiestand, Brian C

2016-12-01

Patients with implanted cardiac devices may wait extended periods for interrogation in emergency departments (EDs). Our purpose was to determine if device interrogation could be done safely and faster by ED staff. Prospective randomized, standard therapy controlled, trial of ED staff device interrogation vs. standard process (SP), with 30-day follow-up. Eligibility criteria: ED presentation with a self-report of a potential device related complaint, with signed informed consent. SP interrogation was by company representative or hospital employee. Of 60 patients, 42 (70%) were male, all were white, with a median (interquartile range) age of 71 (64 to 82) years. No patient was lost to follow up. Of all patients, 32 (53%) were enrolled during business hours. The overall median (interquartile range) ED vs. SP time to interrogation was 98.5 (40 to 260) vs. 166.5 (64 to 412) minutes (P=0.013). While ED and SP interrogation times were similar during business hours, 102 (59 to 138) vs. 105 (64 to 172) minutes (P=0.62), ED interrogation times were shorter vs. SP during non-business hours; 97 (60 to 126) vs. 225 (144 to 412) minutes, P=0.002, respectively. There was no difference in ED length of stay between the ED and SP interrogation, 249 (153 to 390) vs. 246 (143 to 333) minutes (P=0.71), regardless of time of presentation. No patient in any cohort suffered an unplanned medical contact or post-discharge adverse device related event. ED staff cardiac device interrogations are faster, and with similar 30-day outcomes, as compared to SP.

Neutron flux control systems validation

International Nuclear Information System (INIS)

Hascik, R.

2003-01-01

In nuclear installations main requirement is to obtain corresponding nuclear safety in all operation conditions. From the nuclear safety point of view is commissioning and start-up after reactor refuelling appropriate period for safety systems verification. In this paper, methodology, performance and results of neutron flux measurements systems validation is presented. Standard neutron flux measuring chains incorporated into the reactor protection and control system are used. Standard neutron flux measuring chain contains detector, preamplifier, wiring to data acquisition unit, data acquisition unit, wiring to display at control room and display at control room. During reactor outage only data acquisition unit and wiring and displaying at reactor control room is verified. It is impossible to verify detector, preamplifier and wiring to data acquisition recording unit during reactor refuelling according to low power. Adjustment and accurate functionality of these chains is confirmed by start-up rate (SUR) measurement during start-up tests after refuelling of the reactors. This measurement has direct impact to nuclear safety and increase operational nuclear safety level. Briefly description of each measuring system is given. Results are illustrated on measurements performed at Bohunice NPP during reactor start-up tests. Main failures and their elimination are described (Authors)

Characterization of FBG sensor interrogation based on a FDML wavelength swept laser

Science.gov (United States)

Jung, Eun Joo; Kim, Chang-Seok; Jeong, Myung Yung; Kim, Moon Ki; Jeon, Min Yong; Jung, Woonggyu; Chen, Zhongping

2012-01-01

In this study, we develop an ultra-fast fiber Bragg grating sensor system that is based on the Fourier domain mode-locked (FDML) swept laser. A FDML wavelength swept laser has many advantages compared to the conventional wavelength swept laser source, such as high-speed interrogation, narrow spectral sensitivity, and high phase stability. The newly developed FDML wavelength swept laser shows a superior performance of a high scan rate of 31.3 kHz and a broad scan range of over 70 nm simultaneously. The performance of the grating sensor interrogating system using a FDML wavelength swept laser is characterized in both static and dynamic strain responses. PMID:18852764

IEC-based neutron generator for security inspection system

International Nuclear Information System (INIS)

Miley, G.H.; Wu, L.; Kim, H.J.

2005-01-01

Use of a combined X-ray and neutron source for security inspections based on Inertial Electrostatic Confinement (IEC) fusion is discussed. Current inspection systems typically use X-ray techniques, but thermal neutron analysis (TNA) and fast neutron analysis (FNA), allow expanded detection of certain types of explosives. The integrated unit proposed here uses three separate IEC sources producing 14 and 2.45 MeV neutrons plus soft X-rays. This combination allows multiple detection methods with the composite signal analysis being done by a fuzzy logic system, significantly reducing false signals. (author)

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

OpenAIRE

Halpern, Abraham L; Halpern, John H; Doherty, Sean B

2008-01-01

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 agg...

Importance of delayed neutron data in transmutation system

International Nuclear Information System (INIS)

Tsujimoto, Kazufumi

1999-01-01

The accelerator-driven transmutation system has been studied at the Japan Atomic Energy Research Institute. This system is a hybrid system which consists of a high intensity accelerator, a spallation target and a subcritical core region. The subcritical core is driven by neutrons generated by spallation reaction in the target region. There is no control rod in this system, so the power is controlled only by proton beam current. The beam current to keep constant power change with effective multiplication factor of subcritical core. So, the evaluation of delayed neutron fraction which is strongly connected to the measurement of subcritical level is important factor in operation of accelerator-driven system. In this paper, important nuclides for the delayed neutron fraction of ADS will be discussed, moreover, present state of delayed neutron data in evaluated nuclear data library is presented. (author)

Development of high sensitivity eight-element multiplexed fiber laser acoustic pressure hydrophone array and interrogation system

Science.gov (United States)

Li, Ming; Sun, Zhihui; Zhang, Xiaolei; Li, Shujuan; Song, Zhiqiang; Wang, Meng; Guo, Jian; Ni, Jiasheng; Wang, Chang; Peng, Gangding; Xu, Xiangang

2017-09-01

Fiber laser hydrophones have got widespread concerns due to the unique advantages and broad application prospects. In this paper, the research results of the eight-element multiplexed fiber laser acoustic pressure array and the interrogation system are introduced, containing low-noise distributed feedback fiber laser (DFB-FL) fabrication, sensitivity enhancement packaging, and interferometric signal demodulation. The frequency response range of the system is 10Hz-10kHz, the laser frequency acoustic pressure sensitivity reaches 115 dB re Hz/Pa, and the equivalent noise acoustic pressure is less than 60μPa/Hz1/2. The dynamic range of the system is greater than 120 dB.

Development of a new electronic neutron imaging system

CERN Document Server

Brenizer, J S; Gibbs, K M; Mengers, P; Stebbings, C T; Polansky, D; Rogerson, D J

1999-01-01

An electronic neutron imaging camera system was developed for use with thermal, epithermal, and fast neutrons in applications that include nondestructive inspection of explosives, corrosion, turbine blades, electronics, low Z components, etc. The neutron images are expected to provide information to supplement that available from X-ray tests. The primary camera image area was a 30x30 cm field-of-view with a spatial resolution approaching 1.6 line pairs/mm (lp/mm). The camera had a remotely changeable second lens to limit the field-of-view to 7.6x7.6 cm for high spatial resolution (at least 4 lp/mm) thermal neutron imaging, but neutron and light scatter will limit resolution for fast neutrons to about 0.5 lp/mm. Remote focus capability enhanced camera set-up for optimum operation. The 75 dB dynamic range camera system included sup 6 Li-based screens for imaging of thermal and epithermal neutrons and ZnS(Ag)-based screens for fast neutron imaging. The fast optics was input to a Super S-25 Gen II image intensifi...

High-Resolution Fast-Neutron Spectrometry for Arms Control and Treaty Verification

Energy Technology Data Exchange (ETDEWEB)

David L. Chichester; James T. Johnson; Edward H. Seabury

2012-07-01

Many nondestructive nuclear analysis techniques have been developed to support the measurement needs of arms control and treaty verification, including gross photon and neutron counting, low- and high-resolution gamma spectrometry, time-correlated neutron measurements, and photon and neutron imaging. One notable measurement technique that has not been extensively studied to date for these applications is high-resolution fast-neutron spectrometry (HRFNS). Applied for arms control and treaty verification, HRFNS has the potential to serve as a complimentary measurement approach to these other techniques by providing a means to either qualitatively or quantitatively determine the composition and thickness of non-nuclear materials surrounding neutron-emitting materials. The technique uses the normally-occurring neutrons present in arms control and treaty verification objects of interest as an internal source of neutrons for performing active-interrogation transmission measurements. Most low-Z nuclei of interest for arms control and treaty verification, including 9Be, 12C, 14N, and 16O, possess fast-neutron resonance features in their absorption cross sections in the 0.5- to 5-MeV energy range. Measuring the selective removal of source neutrons over this energy range, assuming for example a fission-spectrum starting distribution, may be used to estimate the stoichiometric composition of intervening materials between the neutron source and detector. At a simpler level, determination of the emitted fast-neutron spectrum may be used for fingerprinting 'known' assemblies for later use in template-matching tests. As with photon spectrometry, automated analysis of fast-neutron spectra may be performed to support decision making and reporting systems protected behind information barriers. This paper will report recent work at Idaho National Laboratory to explore the feasibility of using HRFNS for arms control and treaty verification applications, including simulations

A study of television imaging system for fast neutron radiography

International Nuclear Information System (INIS)

Yoshii, Koji

1992-01-01

The neutron radiography with fast neutron beam is a very useful imaging technique for thicker objects, especially those composed of hydrogen-rich materials which are sometimes difficult to image by thermal neutron radiography. The fast neutron radiography has not been studied so much as the thermal neutron radiography. The fast neutron radiography has been studied at the fast neutron source reactor 'Yayoi' of the University of Tokyo built in Tokai-mura. The average neutron energy of the Yayoi is about 1 MeV, and the peak neutron flux at the core center is 0.8 x 10 12 at the maximum operating power of 2 kW. In the experiment on fast neutron radiography, a CR39 nuclear track detector has been used successfully. But in the Yayoi radiography procedure, about 24 hours were required for obtaining an imaging result. To get a prompt imaging result and a real-time imaging result, it is necessary to develop a fast neutron television system, and in this paper, a new fast neutron TV system is proposed. The main difference is the converter material sensitive to fast neutrons. The study on the fast neutron TV system was carried out by using the Baby Cyclotron of Japan Steel Works, and the good images were realized. (K.I.)

Data processing system for neutron experiments

Energy Technology Data Exchange (ETDEWEB)

Emoto, T; Yamamuro, N [Tokyo Inst. of Tech. (Japan). Research Lab. of Nuclear Reactor

1979-03-01

A data processing system for neutron experiments has been equipped at the Pelletron Laboratory of the Research Laboratory for Nuclear Reactors. The system comprises a Hewlett Packard 21 MX computer and a CAMAC standard. It can control two ADCs and some CAMAC modules. CAMAC control programs as well as data acquisition programs with high-level language can be readily developed. Terminals are well designed for man-machine interactions and program developments. To demonstrate the usefulness of the system, it was applied for the on-line data processing of neutron spectrum measurement.

SRAC2006: A comprehensive neutronics calculation code system

International Nuclear Information System (INIS)

Okumura, Keisuke; Kugo, Teruhiko; Kaneko, Kunio; Tsuchihashi, Keichiro

2007-02-01

The SRAC is a code system applicable to neutronics analysis of a variety of reactor types. Since the publication of the second version of the users manual (JAERI-1302) in 1986 for the SRAC system, a number of additions and modifications to the functions and the library data have been made to establish a comprehensive neutronics code system. The current system includes major neutron data libraries (JENDL-3.3, JENDL-3.2, ENDF/B-VII, ENDF/B-VI.8, JEFF-3.1, JEF-2.2, etc.), and integrates five elementary codes for neutron transport and diffusion calculation; PIJ based on the collision probability method applicable to 16 kind of lattice models, S N transport codes ANISN(1D) and TWOTRN(2D), diffusion codes TUD(1D) and CITATION(multi-D). The system also includes an auxiliary code COREBN for multi-dimensional core burn-up calculation. (author)

Reflection of neutrons from a helicoidal system

International Nuclear Information System (INIS)

Aksenov, V.L.; Ignatovich, V.K.; Nikitenko, Yu.V.

2006-01-01

Analytical solution for neutron reflection and transmission of magnetic mirrors with helicoidal magnetization is found. The dependence of neutron speed of reflection and transmission curves is shown. Resonant properties of helicoidal systems are found

Gamma–neutron imaging system utilizing pulse shape discrimination with CLYC

International Nuclear Information System (INIS)

Whitney, Chad M.; Soundara-Pandian, Lakshmi; Johnson, Erik B.; Vogel, Sam; Vinci, Bob; Squillante, Michael; Glodo, Jarek; Christian, James F.

2015-01-01

Recently, RMD has investigated the use of CLYC (Cs 2 LiYCl 6 :Ce), a new and emerging scintillation material, in a gamma–neutron coded aperture imaging system based on RMD's commercial RadCam TM instrument. CLYC offers efficient thermal neutron detection, fast neutron detection capabilities, excellent pulse shape discrimination (PSD), and gamma-ray energy resolution as good as 4% at 662 keV. PSD improves the isolation of higher energy gammas from thermal neutron interactions (>3 MeV electron equivalent peak), compared to conventional pulse height techniques. The scintillation emission time in CLYC provides the basis for PSD; where neutron interactions result in a slower emission rise and decay components while gamma interactions result in a faster emission components. By creating a population plot based on the ratio of the decay tail compared to the total integral amplitude (PSD ratio), discrimination of gammas, thermal neutrons, and fast neutrons is possible. Previously, we characterized the CLYC-based RadCam system for imaging gammas and neutrons using a layered W-Cd coded aperture mask and employing only pulse height discrimination. In this paper, we present the latest results which investigate gamma-neutron imaging capabilities using PSD. An FPGA system is used to acquire the CLYC–PSPMT last dynode signals, determine a PSD ratio for each event, and compare it to a calibrated PSD cutoff. Each event is assigned either a gamma (low) or neutron (high) flag signal which is then correlated with the imaging information for each event. - Highlights: • The latest results are presented for our CLYC RadCam-2 system which investigate gamma–neutron imaging using pulse shape discrimination. • CLYC RadCam-2 system successfully discriminates gammas, thermal neutrons, and fast neutrons by employing a fully integrated, FPGA-based PSD system. • Imaging of our 252 Cf source was possible using both pulse height and pulse shape discrimination with CLYC. • Imaging

Quantum prisoners' dilemma under enhanced interrogation

Science.gov (United States)

Siopsis, George; Balu, Radhakrishnan; Solmeyer, Neal

2018-06-01

In the quantum version of prisoners' dilemma, each prisoner is equipped with a single qubit that the interrogator can entangle. We enlarge the available Hilbert space by introducing a third qubit that the interrogator can entangle with the other two. We discuss an enhanced interrogation technique based on tripartite entanglement and analyze Nash equilibria. We show that for tripartite entanglement approaching a W-state, we calculate the Nash equilibria numerically and show that they coincide with the Pareto-optimal choice where both prisoners cooperate. Upon continuous variation between a W-state and a pure bipartite entangled state, the game is shown to have a surprisingly rich structure. The role of bipartite and tripartite entanglement is explored to explain that structure. As an application, we consider an evolutionary game based on our quantum game with a network of agents on a square lattice with periodic boundary conditions and show that the strategy corresponding to Nash equilibrium completely dominates without placing any restrictions on the initial set of strategies.

DD fusion neutron production at UW-Madison using IEC devices

Science.gov (United States)

Fancher, Aaron; Michalak, Matt; Kulcinski, Gerald; Santarius, John; Bonomo, Richard

2017-10-01

An inertial electrostatic confinement (IEC) device using spherical, gridded electrodes at high voltage accelerates deuterium ions, allowing for neutrons to be produced within the device from DD fusion reactions. The effects of the device cathode voltage (30-170 kV), current (30-100 mA), and pressure (0.15-1.25 mTorr) on the neutron production rate have been measured. New high voltage capabilities have resulted in the achievement of a steady state neutron production rate of 3.3x108 n/s at 175 kV, 100 mA, and 1.0 mTorr of deuterium. Applications of IEC devices include the production of DD neutrons to detect chemical explosives and special nuclear materials using active interrogation methods. Research supported by US Dept. of Homeland Security Grant 2015-DN-077-AR1095 and the Grainger Foundation.

The role of abusive states of being in interrogation.

Science.gov (United States)

Putnam, Frank W

2013-01-01

Interrogation, the questioning of persons detained by police, military, or intelligence organizations, is designed to extract information that a subject may resist disclosing. Interrogation techniques are frequently predicated on inducing mental states of despair, dread, dependency, and debility that weaken an individual's resistance. Descriptions of techniques from 2 Central Intelligence Agency training manuals are illustrated by examples from interviews of and writings by Murat Kurnaz, who was held at Guantánamo Bay Detention Camp for 5 years. Interrogation techniques are designed to create a destabilizing sense of shock; undermine an individual's grasp on reality; and provoke internal psychological division, self-conflict, and confusion. The long-term effects of interrogation often include posttraumatic stress disorder as well as states of anxiety, depression, and depersonalization.

MCNPX simulations of fast neutron diagnostics for accelerator-driven systems

Energy Technology Data Exchange (ETDEWEB)

Habob, Moinul

2005-12-15

In accelerator-driven systems, the neutron spectrum will extend all the way up to the incident beam energy, i.e., several hundred MeV or even up to GeV energies. The high neutron energy allows novel diagnostics with a set of measurement techniques that can be used in a sub-critical reactor environment. Such measurements are primarily connected to system safety and validation. This report shows that in-core fast-neutron diagnostics can be employed to monitor changes in the position of incidence of the primary proton beam onto the neutron production target. It has also been shown that fast neutrons can be used to detect temperature-dependent density changes in a liquid lead-bismuth target. Fast neutrons can escape the system via the beam pipe for the incident proton beam. Out-of-core monitoring of these so called back-streaming neutrons could potentially be used to monitor beam changes if the target has a suitable shape. Moreover, diagnostics of back-streaming neutrons might be used for validation of the system design.

MCNPX simulations of fast neutron diagnostics for accelerator-driven systems

International Nuclear Information System (INIS)

Habib, Moinul

2005-12-01

In accelerator-driven systems, the neutron spectrum will extend all the way up to the incident beam energy, i.e., several hundred MeV or even up to GeV energies. The high neutron energy allows novel diagnostics with a set of measurement techniques that can be used in a sub-critical reactor environment. Such measurements are primarily connected to system safety and validation. This report shows that in-core fast-neutron diagnostics can be employed to monitor changes in the position of incidence of the primary proton beam onto the neutron production target. It has also been shown that fast neutrons can be used to detect temperature-dependent density changes in a liquid lead-bismuth target. Fast neutrons can escape the system via the beam pipe for the incident proton beam. Out-of-core monitoring of these so called back-streaming neutrons could potentially be used to monitor beam changes if the target has a suitable shape. Moreover, diagnostics of back-streaming neutrons might be used for validation of the system design

A control and recording system for a neutron diffractometer

International Nuclear Information System (INIS)

Czech, Z.; Turek, L.; Wierzewski, K.

1982-01-01

A digital system for automatic control and data recording being a part of a neutron diffractometer designed for measurement of the angular distribution of monochromatic neutrons is described. The system is built using digital TTL integrated circuits. Particular attention is drawn to the interesting design of the optimized cross-matrix which selects the elements subjected to recording. The system successfully works with the neutron diffractometer at the EWA reactor. (author)

Increasing dynamic range of a fibre Bragg grating edge-filtering interrogator with a proportional control loop

International Nuclear Information System (INIS)

Stan, Nikola; Bailey, D C; Chadderdon, S L; Selfridge, R H; Schultz, S M; Webb, S; Zikry, M; Peters, K J

2014-01-01

We present a fibre Bragg grating (FBG) interrogator that uses a microcontroller board and a tunable optical filter in a proportional control loop to increase dynamic range and achieve high strain sensitivity. It is an edge-filtering interrogator with added proportional control loop that locks the operating wavelength to the mid-reflection point on the FBG spectrum. The interrogator separates low-frequency (LF) components of strain and measures them with extended dynamic range, while at the same time measuring high-frequency (HF) strain without loss in strain sensitivity. In this paper, we describe the implementation of the interrogator and analyse the characteristics of individual components, such as the speed and voltage resolution of the microcontroller and the tunable optical filter. We measure the performance of the proportional control loop at frequencies up to 1 kHz and characterize the system using control theory. We illustrate the limitation of the conventional interrogator to measure strains greater than 40 μϵ and demonstrate successful application of the proposed interrogator for simultaneous measurement of 450 μϵ LF strain at 50 Hz superimposed with 32 kHz HF strain. (paper)

Neutronic calculations for a subcritical system with external source

International Nuclear Information System (INIS)

Cintas, A; Lopasso, E.M; Marquez Damian, J. I

2006-01-01

We present a neutronic study on an A D S, systems capable of transmute minor actinides and fission products in order to reduce their radiotoxicity and mean-life.We compare neutronic parameters obtained with Scale/Tort and M C N P modelling a sub-critical system with source from a N E A Benchmark.Due to lack of nuclear data at the temperature of the system, we perform calculations at available temperature of libraries (300 K); to compensate the reactivity insertion due to the temperature change we reduce the size of the fuel zone in order to get a sub-critical system that allow u s to evaluate neutronic parameters of the system with source.We have found that the numerical results (neutron spectrum, neutron flux distributions and other neutronic parameters) are in agreement with the M C N P and with those of the benchmark participants even though the geometric models used are not exactly the same. We conclude that with the real temperature cross sections, the calculation scheme developed (Scale/Tort and M C N P) will give reliable results in A D S evaluations [es

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

Unique furnace system for high-energy-neutron experiments

International Nuclear Information System (INIS)

Panayotou, N.F.; Green, D.R.; Price, L.S.

1982-03-01

The low flux of high energy neutron sources requires optimum utilization of the available neutron field. A furnace system has been developed in support of the US DOE fusion materials program which meets this challenge. Specimens positioned in two temperature zones just 1 mm away from the outside surface of a neutron window in the furnace enclosure can be irradiated simultaneously at two independent, isothermal (+- 1 0 C) temperatures. The temperature difference between these closely spaced isothermal zones is controllable from 0 to 320 0 C and the maximum temperature is 400 0 C. The design of the system also provides a controlled specimen environment, rapid heating and cooling and easy access to heaters and thermocouples. This furnace system is in use at the Rotating Target Neutron Source-II of Lawrence Livermore National Laboratory

Development of SiC Neutron Detector Assembly to Measure the Neutron Flux of the Reactor Core

Energy Technology Data Exchange (ETDEWEB)

Park, Se Hwan; Park, June Sic; Shin, Hee Sung; Kim, Ho Dong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Yong Kyun [Hanyang University, Seoul (Korea, Republic of)

2012-05-15

At present, the conventional detector to measure the neutron at harsh environment is a Self Powered Neutron Detector (SPND). Rhodium(Rh)-103 is in the SPND. When neutron is incident on the Rhodium, the neutron capture reaction occurs, and the Rh-103 is converted to Rh-104. The Rh-104 is decayed to Pd-104 by {beta}-decay, and electrons are generated as the decay products. Because of the half life of Rh-104, approximately 5 minutes are required for the SPND output to reach the equilibrium condition. Therefore the on-line monitoring of the nuclear reactor state is limited if the neutron flux in the reactor core is monitored with the SPND. Silicon carbide (SiC) has the possibility to be developed as neutron detector at harsh environment, because the SiC can be operative at high temperature and high neutron flux conditions. Previously, the basic operation properties of the SiC detector were studied. Also, the radiation response of the SiC detector was studied at high neutron and gamma dose rate. The measurement results for an ex-core neutron flux monitor or a neutron flux monitor of the spent fuel were published. The SiC detector was also developed as neutron detector to measure the fissile material with active interrogation method. However, the studies about the development of SiC detector are still limited. In the present work, the radiation damage effect of the SiC detector was studied. The detector structure was determined based on the study, and a neutron detector assembly was made with the SiC detectors. The neutron and gamma-ray response of the detector assembly is presented in this paper. The detector assembly was positioned in the HANARO research reactor core, the performance test was done. The preliminary results are also included in this paper

Commissioning of accelerator based boron neutron capture therapy system

International Nuclear Information System (INIS)

Nakamura, S.; Wakita, A.; Okamoto, H.; Igaki, H.; Itami, J.; Ito, M.; Abe, Y.; Imahori, Y.

2017-01-01

Boron neutron capture therapy (BNCT) is a treatment method using a nuclear reaction of 10 B(n, α) 7 Li. BNCT can be deposited the energy to a tumor since the 10 B which has a higher cross-section to a neutron is high is concentrated on the tumor. It is different from conventional radiation therapies that BNCT expects higher treatment effect to radiation resistant tumors since the generated alpha and lithium particles have higher radiological biological effectiveness. In general, BNCT has been performed in research nuclear reactor. Thus, BNCT is not widely applied in a clinical use. According to recent development of accelerator-based boron neutron capture therapy system, the system has an adequate flux of neutrons. Therefore, National Cancer Canter Hospital, Tokyo, Japan is planning to install accelerator based BNCT system. Protons with 2.5 MeV are irradiated to a lithium target system to generate neutrons. As a result, thermal load of the target is 50 kW since current of the protons is 20.0 mA. Additionally, when the accelerator-based BNCT system is installed in a hospital, the facility size is disadvantage in term of neutron measurements. Therefore, the commissioning of the BNCT system is being performed carefully. In this article, we report about the commissioning. (author)

Neutron density fluctuations in point reactor systems with dichotomic reactivity noise

International Nuclear Information System (INIS)

Sako, Okitsugu

1984-01-01

The exactly solvable stochastic point reactor model systems are analyzed through the stochastic Liouville equation. Three kinds of model systems are treated: (1) linear system without delayed neutrons, (2) linear system with one-group of delayed neutrons, and (3) nonlinear system with direct power feedback. The exact expressions for the fluctuations of neutron density, such as the moments, autocorrelation function and power spectral density, are derived in the case where the colored reactivity noise is described by the dichotomic, or two state, Markov process with arbitrary correlation time and intensity, and the effects of the finite correlation time and intensity of the noise on the neutron density fluctuations are investigated. The influence of presence of delayed neutrons and the effect of nonlinearity of system on the neutron density fluctuations are also elucidated. When the reactivity correlation time is very short, the correlation time has almost no effect on the power spectral density, and the relative fluctuation of neutron density in the stationary state is not affected very much by the presence of delayed neutrons and also by the nonlinearity of system. On the other hand, if the reactivity correlation time is very long, the effect of the reactivity noise on the power spectral density appears at very low frequency, and the presence of delayed neutrons has an effect of reducing the neutron density fluctuations. (author)

Development of Neutron Imaging System for Neutron Tomography at Thai Research Reactor TRR-1/M1

Science.gov (United States)

Wonglee, S.; Khaweerat, S.; Channuie, J.; Picha, R.; Liamsuwan, T.; Ratanatongchai, W.

2017-09-01

The neutron imaging is a powerful non-destructive technique to investigate the internal structure and provides the information which is different from the conventional X-ray/Gamma radiography. By reconstruction of the obtained 2-dimentional (2D) images from the taken different angle around the specimen, the tomographic image can be obtained and it can provide the information in more detail. The neutron imaging system at Thai Research Reactor TRR-1/M1 of Thailand Institute of Nuclear Technology (Public Organization) has been developed to conduct the neutron tomography since 2014. The primary goal of this work is to serve the investigation of archeological samples, however, this technique can also be applied to various fields, such as investigation of industrial specimen and others. This research paper presents the performance study of a compact neutron camera manufactured by Neutron Optics such as speed and sensitivity. Furthermore, the 3-dimentional (3D) neutron image was successfully reconstructed at the developed neutron imaging system of TRR-1/M1.

Notes on SAW Tag Interrogation Techniques

Science.gov (United States)

Barton, Richard J.

2010-01-01

We consider the problem of interrogating a single SAW RFID tag with a known ID and known range in the presence of multiple interfering tags under the following assumptions: (1) The RF propagation environment is well approximated as a simple delay channel with geometric power-decay constant alpha >/= 2. (2) The interfering tag IDs are unknown but well approximated as independent, identically distributed random samples from a probability distribution of tag ID waveforms with known second-order properties, and the tag of interest is drawn independently from the same distribution. (3) The ranges of the interfering tags are unknown but well approximated as independent, identically distributed realizations of a random variable rho with a known probability distribution f(sub rho) , and the tag ranges are independent of the tag ID waveforms. In particular, we model the tag waveforms as random impulse responses from a wide-sense-stationary, uncorrelated-scattering (WSSUS) fading channel with known bandwidth and scattering function. A brief discussion of the properties of such channels and the notation used to describe them in this document is given in the Appendix. Under these assumptions, we derive the expression for the output signal-to-noise ratio (SNR) for an arbitrary combination of transmitted interrogation signal and linear receiver filter. Based on this expression, we derive the optimal interrogator configuration (i.e., transmitted signal/receiver filter combination) in the two extreme noise/interference regimes, i.e., noise-limited and interference-limited, under the additional assumption that the coherence bandwidth of the tags is much smaller than the total tag bandwidth. Finally, we evaluate the performance of both optimal interrogators over a broad range of operating scenarios using both numerical simulation based on the assumed model and Monte Carlo simulation based on a small sample of measured tag waveforms. The performance evaluation results not only

A remotely triggered fast neutron detection instrument based on a plastic organic scintillator

Science.gov (United States)

Jones, A. R.; Aspinall, M. D.; Joyce, M. J.

2018-02-01

A detector system for the characterization of radiation fields of both fast neutrons and γ rays is described comprising of a gated photomultiplier tube (PMT), an EJ299-33 solid organic scintillator detector, and an external trigger circuit. The objective of this development was to conceive a means by which the PMT in such a system can be actuated remotely during the high-intensity bursts of pulsed γ-ray contamination that can arise during active interrogation procedures. The system is used to detect neutrons and γ rays using established pulse-shape discrimination (PSD) techniques. The gating circuit enables the PMT to be switched off remotely. This is compatible with use during intense radiation transients to avoid saturation and the disruption of the operation of the PMT during the burst. Data are presented in the form of pulse-height spectra and PSD scatter plots for the system triggered with a strobed light source. These confirm that the gain of the system and the throughput for both triggered and un-triggered scenarios are as expected, given the duty cycle of the stimulating radiation. This demonstrates that the triggering function does not perturb the system response of the detector.

Automatic readout system for superheated emulsion based neutron detector

International Nuclear Information System (INIS)

Meena, J.P.; Parihar, A.; Vaijapurkar, S.G.; Mohan, Anand

2011-01-01

The paper presents a microcontroller based automatic reader system for neutron measurement using indigenously developed superheated emulsion detector. The system is designed for real time counting of bubbles formed in superheated emulsion detector. A piezoelectric transducer is used for sensing bubble acoustic during the nucleation. The front end of system is mainly consisting of specially designed signal conditioning unit, piezoelectric transducer, an amplifier, a high-pass filter, a differentiator, a comparator and monostable multivibrator. The system is based on PlC 18F6520 microcontroller having large internal SRAM, 10-bit internal ADC, I 2 C interface, UART/USART modules. The paper also describes the design of following microcontroller peripheral units viz temperature monitoring, battery monitoring, LCD display, keypad and a serial communication. The reader system measures and displays neutron dose and dose rate, number of bubble and elapsed time. The developed system can be used for detecting very low neutron leakage in the accelerators, nuclear reactors and nuclear submarines. The important features of system are compact, light weight, cost effective and high neutron sensitivity. The prototype was tested and evaluated by exposing to 241 Am-Be neutron source and results have been reported. (author)

Automatic read out system for superheated emulsion based neutron detector

International Nuclear Information System (INIS)

Meena, J.P.; Parihar, A.; Vaijapurkar, S.G.; Mohan, Anand

2010-01-01

Full text: Defence Laboratory, Jodhpur (DLJ) has developed superheated emulsion technology for neutron and gamma measurements. The laboratory has attempted to develop reader system to display neutron dose and dose rate based on acoustic technique. The paper presents a microcontroller based automatic reader system for neutron measurements using indigenously developed superheated emulsion detector. The system is designed for real time counting of bubbles formed in superheated emulsion detector. A piezoelectric transducer is used for sensing bubble acoustic. The front end of system is mainly consisting of specially designed signal conditioning unit consisted of piezoelectric transducer, an amplifier, a high-pass filter, a differentiator, a comparator and monostable multivibrator. The system is based on PIC 18F6520 microcontroller having large internal SRAM, 10-bit internal ADC, I 2 C interface, UART/USART modules. The paper also describes the design of following peripheral units interfaced to microcontroller temperature and battery monitoring, display, keypad and a serial communication. The reader system measures and displays neutron dose and dose rate, number of bubble and elapsed time. The developed system can be used for detecting very low neutron leakage in the accelerators, nuclear reactors and nuclear submarines. The important features of system are compact, light weight, cost effective and high neutron sensitivity. The prototype was tested and evaluated by exposing to 241 Am-Be neutron source and results have been reported

Earth formation pulsed neutron porosity logging system utilizing epithermal neutron and inelastic scattering gamma ray detectors

International Nuclear Information System (INIS)

Smith, H.D. Jr.; Smith, M.P.; Schultz, W.E.

1978-01-01

An improved pulsed neutron porosity logging system is provided in the present invention. A logging tool provided with a 14 MeV pulsed neutron source, an epithermal neutron detector and an inelastic scattering gamma ray detector is moved through a borehole. The detection of inelastic gamma rays provides a measure of the fast neutron population in the vicinity of the detector. repetitive bursts of neutrons irradiate the earth formation and, during the busts, inelastic gamma rays representative of the fast neutron population is sampled. During the interval between bursts the epithermal neutron population is sampled along with background gamma radiation due to lingering thermal neutrons. the fast and epithermal neutron population measurements are combined to provide a measurement of formation porosity

Design of a system for neutrons dosimetry

International Nuclear Information System (INIS)

Ceron, P.; Rivera, T.; Paredes G, L.; Azorin, J.; Sanchez, A.; Vega C, H. R.

2014-08-01

At the present time diverse systems of detection of neutrons exist, as proportional counters based on BF 3 , He 3 and spectrometers of Bonner spheres. However, the cost and the complexity of the implementation of these systems put them far from the reach for dosimetric purposes. For these reasons a system of neutrons detection composed by a medium paraffin moderator that forms a 4π (spheres) arrangement and of several couples of thermoluminescent dosimeters TLD 600/TLD 700. The response of the system presents a minor repeatability to 5% in several assays when being irradiated with a 239 PuBe source and a deviation of 13.8% in the Tl readings of four different spheres. The calibration factor of the system with regard to the neutrons source which was of 56.2 p Sv/nc also was calculated. These detectors will be used as passive monitors of photoneutrons in a radiotherapy room with lineal accelerator of high energy. (Author)

Results from the coded aperture neutron imaging system

International Nuclear Information System (INIS)

Brubaker, Erik; Steele, John T.; Brennan, James S.; Marleau, Peter

2010-01-01

Because of their penetrating power, energetic neutrons and gamma rays (∼1 MeV) offer the best possibility of detecting highly shielded or distant special nuclear material (SNM). Of these, fast neutrons offer the greatest advantage due to their very low and well understood natural background. We are investigating a new approach to fast-neutron imaging - a coded aperture neutron imaging system (CANIS). Coded aperture neutron imaging should offer a highly efficient solution for improved detection speed, range, and sensitivity. We have demonstrated fast neutron and gamma ray imaging with several different configurations of coded masks patterns and detectors including an 'active' mask that is composed of neutron detectors. Here we describe our prototype detector and present some initial results from laboratory tests and demonstrations.

Police interviewing and interrogation of juvenile suspects: a descriptive examination of actual cases.

Science.gov (United States)

Cleary, Hayley M D

2014-06-01

Although empirical attention to police interrogation has gained traction in recent years, comparatively few studies have examined interrogation of juvenile suspects, and virtually none have examined actual interrogations. Despite a growing literature on youths' interrogation-related capacities, we still know very little about what actually transpires when police question youth. The present study examines electronically recorded police interviews with juveniles to describe the characteristics, processes, and outcomes that occur in actual juvenile interrogations, including interview duration, individuals present, and confessions. Fifty-seven electronic recordings from 17 police departments were analyzed using observational research software. The median juvenile interrogation lasted 46 min, though the range was extensive (6 min to nearly 5 hr). Youth frequently submitted to questioning without a parent or advocate present, and disruptions to the interview process were common. Interrogation outcomes varied and included full confessions, partially incriminating admissions, and denials of guilt. Results from this study provide context for interrogation research using other methods and suggest that youth may frequently consent to interrogation in the absence of important legal protections.

Demonstration of an ultrasensitive refractive-index plasmonic sensor by enabling its quadrupole resonance in phase interrogation.

Science.gov (United States)

Lee, Hsin-Cheng; Li, Chung-Tien; Chen, How-Foo; Yen, Ta-Jen

2015-11-15

We present an ultrasensitive plasmonic sensing system by introducing a nanostructured X-shaped plasmonic sensor (XPS) and measuring its localized optical properties in phase interrogation. Our tailored XPS exhibits two major resonant modes of a low-order dipole and a high-order quadrupole, between which the quadrupole resonance allows an ultrahigh sensitivity, due to its higher quality factor. Furthermore, we design an in-house common-path phase-interrogation system, in contrast to conventional wavelength-interrogation methods, to achieve greater sensing capability. The experimental measurement shows that the sensing resolution of the XPS reaches 1.15×10(-6) RIU, not only two orders of magnitude greater than the result of the controlled extinction measurement (i.e., 9.90×10(-5) RIU), but also superior than current reported plasmonic sensors.

Problems in the neutron dynamics of source-driven systems

International Nuclear Information System (INIS)

Ravetto, P.

2001-01-01

The present paper presents some neutronic features of source-driven neutron multiplying systems, with special regards to dynamics, discussing the validity and limitations of classical methods, developed for systems in the vicinity of criticality. Specific characteristics, such as source dominance and the role of delayed neutron emissions are illustrated. Some dynamic peculiarities of innovative concepts proposed for accelerator-driven systems, such as fluid-fuel, are also discussed. The second portion of the work formulates the quasi-static methods for source-driven systems, evidencing its novel features and presenting some numerical results. (author)

25 CFR 11.303 - Notification of rights prior to custodial interrogation.

Science.gov (United States)

2010-04-01

... 25 Indians 1 2010-04-01 2010-04-01 false Notification of rights prior to custodial interrogation. 11.303 Section 11.303 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAW AND ORDER... to custodial interrogation. Prior to custodial interrogation, the suspect shall be advised of the...

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

Science.gov (United States)

2010-07-01

... 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... interrogation and presentation effective for the ascertainment of the truth, (2) Avoid needless consumption of...

Fiber optic neutron imaging system: calibration

International Nuclear Information System (INIS)

Malone, R.M.; Gow, C.E.; Thayer, D.R.

1981-01-01

Two neutron imaging experiments using fiber optics have been performed at the Nevada Test Site. In each experiment, an array of scintillator fluor tubes is exposed to neutrons. Light is coupled out through radiation resistant PCS fibers (8-m long) into high-bandwidth, graded index fibers. For image reconstruction to be accurate, common timing differences and transmission variations between fiber optic channels are needed. The calibration system featured a scanning pulsed dye laser, a specially designed fiber optic star coupler, a tektronix 7912AD transient digitizer, and a DEC PDP 11/34 computing system

Simultaneous thermal neutron decay time and porosity logging system

International Nuclear Information System (INIS)

Smith, H.D. Jr.; Smith, M.P.; Schultz, W.E.

1979-01-01

A simultaneous pulsed neutron porosity and thermal neutron capture cross section logging system is provided for radiological well logging of subsurface earth formations. A logging tool provided with a 14 MeV pulsed neutron source, an epithermal neutron detector, and a combination gamma ray and fast neutron detector is moved through a borehole. Repetitive bursts of neutrons irradiate the earth formations; and, during the bursts, the fast neutron and epithermal neutron populations are sampled. During the interval between bursts the thermal neutron capture gamma ray population is sampled in two or more time intervals. The fast and epithermal neutron population measurements are combined to provide a measurement of formation porosity phi. The capture gamma ray measurements are combined to provide a simultaneous determination of the thermal neutron capture cross section Σ

A pilot study of implantable cardiac device interrogation by emergency department personnel.

Science.gov (United States)

Neuenschwander, James F; Hiestand, Brian C; Peacock, W Frank; Billings, John M; Sondrup, Cole; Hummel, John D; Abraham, William T

2014-03-01

Implanted devices (eg, pacemakers and defibrillators) provide valuable information and may be interrogated to obtain diagnostic information and to direct management. During admission to an emergency department (ED), significant time and cost are spent waiting for device manufacturer representatives or cardiologists to access the data. If ED personnel could safely interrogate implanted devices, more rapid disposition could occur, thus leading to potentially better outcomes at a reduced cost. This was a pilot study examining the feasibility of ED device interrogation. This was a prospective convenience sample study of patients presenting to the ED with any chief complaint and who had an implantable device capable of being interrogated by a Medtronic reader. After obtaining informed consent, study patients underwent device interrogation by ED research personnel. After reviewing the device data, the physician documented their opinions of the value of data in aiding care. Patients were followed up at intervals ranging from 30 days out to 1 year to determine adverse events relating to interrogation. Forty-four patients underwent device interrogation. Their mean age was 56 ± 14.7 years (range, 28-83), 75% (33/44) were male and 75% (33/44) were hospitalized from the ED. The interrogations took less than 10 minutes 89% of the time. In 60% of the cases, ED physicians reported the data-assisted patient care. No adverse events were reported relating to the ED interrogations. In this pilot study, we found that ED personnel can safely and quickly interrogate implantable devices to obtain potentially useful clinical data.

Development of the EURITRACK tagged neutron inspection system

International Nuclear Information System (INIS)

Perot, B.; Carasco, C.; Bernard, S.

2007-01-01

The EURopean Illicit TRAfficing Countermeasures Kit (EURITRACK) project is part of the 6th European Union Framework Program. It aims at developing a Tagged Neutron Inspection System (TNIS) to detect illicit materials, such as explosives and narcotics, in cargo containers. Fast neutron induced reactions produce specific gamma-rays used to determine the chemical composition of the inspected material. The associated particle technique is employed to precisely locate the interaction points of the neutrons. A new deuterium-tritium neutron generator has been developed, including a pixelized alpha particle detector. The TNIS also comprises high-efficiency fast neutron and gamma-ray detectors, a dedicated front-end electronics and an integrated software to entirely drive the system and automatically process the data. Most components have been integrated during last months at Institute Ruder Boskovic, in Zagreb, Croatia. An overview of the TNIS and of its preliminary performances is presented

Review of current neutron detection systems for emergency response

Science.gov (United States)

Mukhopadhyay, Sanjoy; Maurer, Richard; Guss, Paul; Kruschwitz, Craig

2014-09-01

Neutron detectors are used in a myriad of applications—from safeguarding special nuclear materials (SNM) to determining lattice spacing in soft materials. The transformational changes taking place in neutron detection and imaging techniques in the last few years are largely being driven by the global shortage of helium-3 (3He). This article reviews the status of neutron sensors used specifically for SNM detection in radiological emergency response. These neutron detectors must be highly efficient, be rugged, have fast electronics to measure neutron multiplicity, and be capable of measuring direction of the neutron sources and possibly image them with high spatial resolution. Neutron detection is an indirect physical process: neutrons react with nuclei in materials to initiate the release of one or more charged particles that produce electric signals that can be processed by the detection system. Therefore, neutron detection requires conversion materials as active elements of the detection system; these materials may include boron-10 (10B), lithium-6 (6Li), and gadollinium-157 (157Gd), to name a few, but the number of materials available for neutron detection is limited. However, in recent years, pulse-shape-discriminating plastic scintillators, scintillators made of helium-4 (4He) under high pressure, pillar and trench semiconductor diodes, and exotic semiconductor neutron detectors made from uranium oxide and other materials have widely expanded the parameter space in neutron detection methodology. In this article we will pay special attention to semiconductor-based neutron sensors. Modern microfabricated nanotubes covered inside with neutron converter materials and with very high aspect ratios for better charge transport will be discussed.

TDM interrogation of intensity-modulated USFBGs network based on multichannel lasers.

Science.gov (United States)

Rohollahnejad, Jalal; Xia, Li; Cheng, Rui; Ran, Yanli; Rahubadde, Udaya; Zhou, Jiaao; Zhu, Lin

2017-01-23

We report a large-scale multi-channel fiber sensing network, where ultra-short FBGs (USFBGs) instead of conventional narrow-band ultra-weak FBGs are used as the sensors. In the time division multiplexing scheme of the network, each grating response is resolved as three adjacent discrete peaks. The central wavelengths of USFBGs are tracked with the differential detection, which is achieved by calculating the peak-to-peak ratio of two maximum peaks. Compared with previous large-scale hybrid multiplexing sensing networks (e.g., WDM/TDM) which typically have relatively low interrogation speed and very high complexity, the proposed system can achieve interrogation of all channel sensors through very fast and simple intensity measurements with a broad dynamic range. A proof-of-concept experiment with twenty USFBGs, at two wavelength channels, was performed and a fast static strain measurements were demonstrated, with a high average sensitivity of ~0.54dB/µƐ and wide dynamic range of over ~3000µƐ. The channel to channel switching time was 10ms and total network interrogation time was 50ms.

Fissile interrogation using gamma rays from oxygen

Science.gov (United States)

Smith, Donald; Micklich, Bradley J.; Fessler, Andreas

2004-04-20

The subject apparatus provides a means to identify the presence of fissionable material or other nuclear material contained within an item to be tested. The system employs a portable accelerator to accelerate and direct protons to a fluorine-compound target. The interaction of the protons with the fluorine-compound target produces gamma rays which are directed at the item to be tested. If the item to be tested contains either a fissionable material or other nuclear material the interaction of the gamma rays with the material contained within the test item with result in the production of neutrons. A system of neutron detectors is positioned to intercept any neutrons generated by the test item. The results from the neutron detectors are analyzed to determine the presence of a fissionable material or other nuclear material.

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

International Nuclear Information System (INIS)

Lou, Tak Pui

2003-01-01

production could not be provided with a single D-T neutron generator. Therefore, a subcritical fission multiplier was designed to increase the neutron yield. The neutron flux was increased by a factor of 25. A D-D driven fission multiplier was also studied for BNCT and a gain of 17 was obtained. The fission multiplier system gain was shown to be limited by the neutron absorption in the fuel and the reduction of source brightness. A brief discussion was also given regarding the neutron generator applications for fast neutron brachytherapy and neutron interrogation systems. It was concluded that new designs of compact D-D/D-T neutron generators are feasible and that superior quality neutron beams could be produced and used for various applications

Conceptual design of neutron diagnostic systems for fusion experimental reactor

International Nuclear Information System (INIS)

Iguchi, T.; Kaneko, J.; Nakazawa, M.

1994-01-01

Neutron measurement in fusion experimental reactors is very important for burning plasma diagnostics and control, monitoring of irradiation effects on device components, neutron source characterization for in-situ engineering tests, etc. A conceptual design of neutron diagnostic systems for an ITER-like fusion experimental reactor has been made, which consists of a neutron yield monitor, a neutron emission profile monitor and a 14-MeV spectrometer. Each of them is based on a unique idea to meet the required performances for full power conditions assumed at ITER operation. Micro-fission chambers of 235 U (and 238 U) placed at several poloidal angles near the first wall are adopted as a promising neutron yield monitor. A collimated long counter system using a 235 U fission chamber and graphite neutron moderators is also proposed to improve the calibration accuracy of absolute neutron yield determination

Fluence-compensated down-scattered neutron imaging using the neutron imaging system at the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

Casey, D. T., E-mail: casey21@llnl.gov; Munro, D. H.; Grim, G. P.; Landen, O. L.; Spears, B. K.; Fittinghoff, D. N.; Field, J. E.; Smalyuk, V. A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Volegov, P. L.; Merrill, F. E. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2016-11-15

The Neutron Imaging System at the National Ignition Facility is used to observe the primary ∼14 MeV neutrons from the hotspot and down-scattered neutrons (6-12 MeV) from the assembled shell. Due to the strong spatial dependence of the primary neutron fluence through the dense shell, the down-scattered image is convolved with the primary-neutron fluence much like a backlighter profile. Using a characteristic scattering angle assumption, we estimate the primary neutron fluence and compensate the down-scattered image, which reveals information about asymmetry that is otherwise difficult to extract without invoking complicated models.

21 CFR 892.5300 - Medical neutron radiation therapy system.

Science.gov (United States)

2010-04-01

... therapy system. (a) Identification. A medical neutron radiation therapy system is a device intended to... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical neutron radiation therapy system. 892.5300... analysis and display equipment, patient and equipment support, treatment planning computer programs...

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.

What do potential jurors know about police interrogation techniques and false confessions?

Science.gov (United States)

Leo, Richard A; Liu, Brittany

2009-01-01

Psychological police interrogation methods in America inevitably involve some level of pressure and persuasion to achieve their goal of eliciting confessions of guilt from custodial suspects. In this article, we surveyed potential jurors about their perceptions of a range of psychological interrogation techniques, the likelihood that such techniques would elicit a true confession from guilty suspects, and the likelihood that such techniques could elicit a false confession from innocent suspects. Participants recognized that these interrogation techniques may be psychologically coercive and may elicit true confessions, but believed that psychologically coercive interrogation techniques are not likely to elicit false confessions. The findings from this survey study indicate that potential jurors believe that false confessions are both counter- intuitive and unlikely, even in response to psychologically coercive interrogation techniques that have been shown to lead to false confessions from the innocent. This study provides empirical support for the idea that expert witnesses may helpfully inform jurors about the social science research on psychologically coercive interrogation methods and how and why such interrogation techniques can lead to false confessions. (c) 2009 John Wiley & Sons, Ltd.

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…

Evaluation of fiber Bragg grating sensor interrogation using InGaAs linear detector arrays and Gaussian approximation on embedded hardware

Science.gov (United States)

Kumar, Saurabh; Amrutur, Bharadwaj; Asokan, Sundarrajan

2018-02-01

Fiber Bragg Grating (FBG) sensors have become popular for applications related to structural health monitoring, biomedical engineering, and robotics. However, for successful large scale adoption, FBG interrogation systems are as important as sensor characteristics. Apart from accuracy, the required number of FBG sensors per fiber and the distance between the device in which the sensors are used and the interrogation system also influence the selection of the interrogation technique. For several measurement devices developed for applications in biomedical engineering and robotics, only a few sensors per fiber are required and the device is close to the interrogation system. For these applications, interrogation systems based on InGaAs linear detector arrays provide a good choice. However, their resolution is dependent on the algorithms used for curve fitting. In this work, a detailed analysis of the choice of algorithm using the Gaussian approximation for the FBG spectrum and the number of pixels used for curve fitting on the errors is provided. The points where the maximum errors occur have been identified. All comparisons for wavelength shift detection have been made against another interrogation system based on the tunable swept laser. It has been shown that maximum errors occur when the wavelength shift is such that one new pixel is included for curve fitting. It has also been shown that an algorithm with lower computation cost compared to the more popular methods using iterative non-linear least squares estimation can be used without leading to the loss of accuracy. The algorithm has been implemented on embedded hardware, and a speed-up of approximately six times has been observed.

Design of the Mechanical Parts for the Neutron Guide System at HANARO

International Nuclear Information System (INIS)

Shin, J. W.; Cho, Y. G.; Cho, S. J.; Ryu, J. S.

2008-01-01

The research reactor HANARO (High-flux Advanced Neutron Application ReactOr) in Korea will be equipped with a neutron guide system, in order to transport cold neutrons from the neutron source to the neutron scattering instruments in the neutron guide hall near the reactor building. The neutron guide system of HANARO consists of the in-pile plug assembly with in-pile guides, the primary shutter with in-shutter guides, the neutron guides in the guide shielding room with dedicated secondary shutters, and the neutron guides connected to the instruments in the neutron guide hall. Functions of the in-pile plug assembly are to shield the reactor environment from nuclear radiation and to support the neutron guides and maintain them precisely oriented. The primary shutter is a mechanical structure to be installed just after the in-pile plug assembly, which stops neutron flux on demand. This paper describes the design of the in-pile assembly and the primary shutter for the neutron guide system at HANARO. The design of the guide shielding assembly for the primary shutter and the neutron guides is also presented

Asymptotic time dependent neutron transport in multidimensional systems

International Nuclear Information System (INIS)

Nagy, M.E.; Sawan, M.E.; Wassef, W.A.; El-Gueraly, L.A.

1983-01-01

A model which predicts the asymptotic time behavior of the neutron distribution in multi-dimensional systems is presented. The model is based on the kernel factorization method used for stationary neutron transport in a rectangular parallelepiped. The accuracy of diffusion theory in predicting the asymptotic time dependence is assessed. The use of neutron pulse experiments for predicting the diffusion parameters is also investigated

Upgrade of the neutron guide system at the OPAL Neutron Source

International Nuclear Information System (INIS)

Rodriguez, D Martin; Kennedy, S J; Klose, F

2010-01-01

The new research reactor at ANSTO (OPAL) is operating with seven neutron beam instruments in the user programme and three more under construction. The reactor design provides for expansion of the facility to eighteen instruments, and much of the basic infrastructure is already in place. However, an expansion of the neutron guide system is needed for further beam instruments. For this purpose, several possibilities are under consideration, such as insertion of multi-channel neutron benders in the existing cold guides or the construction of a new elliptic cold guide. In this work Monte Carlo (MC) simulations have been used to evaluate performance of these guide configurations. Results show that these configurations can be competitive with the best instruments in the world.

Analysis for In-situ Fission Rate Measurements using 4He Gas Scintillation Detectors

International Nuclear Information System (INIS)

Lewis, Jason M.; Raetz, Dominik; Jordan, Kelly A.; Murer, David

2013-06-01

Active neutron interrogation is a powerful NDA technique that relies on detecting and analyzing fission neutrons produced in a fuel sample by an interrogating high neutron flux. 4 He scintillation gas fast neutron detectors are investigated in this paper for use in a novel fission rate measurement technique The He-4 detectors have excellent gamma rejection, a fast response time, and give significant information on incident neutron energy allowing for energy cuts to be applied to the detected signal. These features are shown in this work to allow for the detection of prompt fission neutrons in-situ during active neutron interrogation of a 238 U sample. The energy spectrum from three different neutrons sources ( 252 Cf, AmBe, AmLi) is measured using the 4 He detection system and analyzed. An initial response matrix for the detector is determined using these measurements and the kinematic interaction properties of the elastic scattering with the 4 He. (authors)

Practical experience with a local verification system for containment and surveillance sensors

International Nuclear Information System (INIS)

Lauppe, W.D.; Richter, B.; Stein, G.

1984-01-01

With the growing number of nuclear facilities and a number of large commercial bulk handling facilities steadily coming into operation the International Atomic Energy Agency is faced with increasing requirements as to reducing its inspection efforts. One means of meeting these requirements will be to deploy facility based remote interrogation methods for its containment and surveillance instrumentation. Such a technical concept of remote interrogation was realized through the so-called LOVER system development, a local verification system for electronic safeguards seal systems. In the present investigations the application was extended to radiation monitoring by introducing an electronic interface between the electronic safeguards seal and the neutron detector electronics of a waste monitoring system. The paper discusses the safeguards motivation and background, the experimental setup of the safeguards system and the performance characteristics of this LOVER system. First conclusions can be drawn from the performance results with respect to the applicability in international safeguards. This comprises in particular the definition of design specifications for an integrated remote interrogation system for various types of containment and surveillance instruments and the specifications of safeguards applications employing such a system

Simultaneous thermal neutron decay time and porosity logging system

International Nuclear Information System (INIS)

Schultz, W.E.; Smith, H.D.; Smith, M.P.

1980-01-01

An improved method and apparatus are described for simultaneously measuring the porosity and thermal neutron capture cross section of earth formations in situ in the vicinity of a well borehole using pulsed neutron well logging techniques. The logging tool which is moved through the borehole consists of a 14 MeV pulsed neutron source, an epithermal neutron detector and a combination gamma ray and fast neutron detector. The associated gating systems, counters and combined digital computer are sited above ground. (U.K.)

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.

Interrogation: General vs. Local.

Science.gov (United States)

Johnson, Jeannette

This paper proposes a set of hypotheses on the nature of interrogration as a possible language universal. Examples and phrase structure rules and diagrams are given. Examining Tamazight and English, genetically unrelated languages with almost no contact, the author distinguishes two types of interrogation: (1) general, querying acceptability to…

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

2018-04-01

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.

An automated neutron monitor maintenance system

International Nuclear Information System (INIS)

Moore, F.S.; Griffin, J.C.; Odell, D.M.C.

1996-01-01

Neutron detectors are commonly used by the nuclear materials processing industry to monitor fissile materials in process vessels and tanks. The proper functioning of these neutron monitors must be periodically evaluated. We have developed and placed in routine use a PC-based multichannel analyzer (MCA) system for on-line BF3 and He-3 gas-filled detector function testing. The automated system: 1) acquires spectral data from the monitor system, 2) analyzes the spectrum to determine the detector's functionality, 3) makes suggestions for maintenance or repair, as required, and 4) saves the spectrum and results to disk for review. The operator interface has been designed to be user-friendly and to minimize the training requirements of the user. The system may also be easily customized for various applications

A quasi-distributed temperature sensor interrogated by a wavelength-sensitive optical time-domain reflectometer

International Nuclear Information System (INIS)

Crunelle, C; Wuilpart, M; Caucheteur, C; Mégret, P

2009-01-01

In this note, we present a quasi-distributed temperature monitoring system based on the concatenation of identical low-reflective fiber Bragg gratings (FBGs) and interrogated by means of an optical time-domain reflectometer (OTDR). An original wavelength-sensitive system placed before the OTDR detector is used to analyze the reflected signal. This system allows the height of the FBG reflection peaks in the OTDR trace to depend on their resonance wavelength, and therefore to the local temperature. In addition, a simple but original reference method is proposed. The configuration of the whole interrogating device is kept very basic, as a standard OTDR and some passive components are used. The cost of the overall system is therefore very limited. In this note, the wavelength-sensitive system is studied in details, as well as the reference method. Experimental results are reported. (technical design note)

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…

Interrogation of weak Bragg grating sensors based on dual-wavelength differential detection.

Science.gov (United States)

Cheng, Rui; Xia, Li

2016-11-15

It is shown that for weak Bragg gratings the logarithmic ratio of reflected intensities at any two wavelengths within the spectrum follows a linear relationship with the Bragg wavelength shift, with a slope proportional to their wavelength spacing. This finding is exploited to develop a flexible, efficient, and cheap interrogation solution of weak fiber Bragg grating (FBGs), especially ultra-short FBGs, in distributed sensing based on dual-wavelength differential detection. The concept is experimentally studied in both single and distributed sensing systems with ultra-short FBG sensors. The work may form the basis of new and promising FBG interrogation techniques based on detecting discrete rather than continuous spectra.

In-Pile Qualification of the Fast-Neutron-Detection-System

Science.gov (United States)

Fourmentel, D.; Villard, J.-F.; Destouches, C.; Geslot, B.; Vermeeren, L.; Schyns, M.

2018-01-01

In order to improve measurement techniques for neutron flux assessment, a unique system for online measurement of fast neutron flux has been developed and recently qualified in-pile by the French Alternative Energies and Atomic Energy Commission (CEA) in cooperation with the Belgian Nuclear Research Centre (SCK•ECEN). The Fast-Neutron-Detection-System (FNDS) has been designed to monitor accurately high-energy neutrons flux (E > 1 MeV) in typical Material Testing Reactor conditions, where overall neutron flux level can be as high as 1015 n.cm-2.s-1 and is generally dominated by thermal neutrons. Moreover, the neutron flux is coupled with a high gamma flux of typically a few 1015 γ.cm-2.s-1, which can be highly disturbing for the online measurement of neutron fluxes. The patented FNDS system is based on two detectors, including a miniature fission chamber with a special fissile material presenting an energy threshold near 1 MeV, which can be 242Pu for MTR conditions. Fission chambers are operated in Campbelling mode for an efficient gamma rejection. FNDS also includes a specific software that processes measurements to compensate online the fissile material depletion and to adjust the sensitivity of the detectors, in order to produce a precise evaluation of both thermal and fast neutron flux even after long term irradiation. FNDS has been validated through a two-step experimental program. A first set of tests was performed at BR2 reactor operated by SCK•CEN in Belgium. Then a second test was recently completed at ISIS reactor operated by CEA in France. FNDS proved its ability to measure online the fast neutron flux with an overall accuracy better than 5%.

Modeling and Interrogative Strategies.

Science.gov (United States)

Denney, Douglas R.

Three studies to determine the effects of adult models on interrogative strategies of children (ages 6-11) are reviewed. Two issues are analyzed: (1) the comparative effectiveness of various types of modeling procedures for changing rule-governed behaviors, and (2) the interaction between observational learning and the developmental level of the…

Boson representations of fermion systems: Proton-neutron systems

International Nuclear Information System (INIS)

Sambataro, M.

1988-01-01

Applications of a procedure recently proposed to construct boson images of fermion Hamiltonians are shown for proton-neutron systems. First the mapping from SD fermion onto sd boson spaces is discussed and a Q/sub π/xQ/sub ν/ interaction investigated. A Hermitian one-body Q boson operator is derived and analytical expressions for its coefficients are obtained. A (Q/sub π/+Q/sub ν/)x(Q/sub π/+Q/sub ν/) interaction is, then, studied for particle-hole systems and the connections with the SU/sup */(3) dynamical symmetry of the neutron-proton interacting boson model are discussed. Finally, an example of mapping from SDG onto sdg spaces is analyzed. Fermion spectra and E2 matrix elements are well reproduced in the boson spaces

Long fiber Bragg grating sensor interrogation using discrete-time microwave photonic filtering techniques.

Science.gov (United States)

Ricchiuti, Amelia Lavinia; Barrera, David; Sales, Salvador; Thevenaz, Luc; Capmany, José

2013-11-18

A novel technique for interrogating photonic sensors based on long fiber Bragg gratings (FBGs) is presented and experimentally demonstrated, dedicated to detect the presence and the precise location of several spot events. The principle of operation is based on a technique used to analyze microwave photonics (MWP) filters. The long FBGs are used as quasi-distributed sensors. Several hot-spots can be detected along the FBG with a spatial accuracy under 0.5 mm using a modulator and a photo-detector (PD) with a modest bandwidth of less than 1 GHz. The proposed interrogation system is intrinsically robust against environmental changes.

Miniature and low cost fiber Bragg grating interrogator for structural monitoring in nano-satellites

Science.gov (United States)

Toet, P. M.; Hagen, R. A. J.; Hakkesteegt, H. C.; Lugtenburg, J.; Maniscalco, M. P.

2017-11-01

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 beginning of 2013 and is financed by the Seventh Framework Program (FP7) of the European Commission. Within the PEASSS project, a Nano-Satellite is being designed and manufactured to be equipped with new technology that will help keep Europe on the cutting edge of space research, potentially reducing the cost and development time for more accurate future sensor platforms including synthetic aperture optics, moving target detection and identification, and compact radars. After on ground testing the satellite is planned to be launched at the end of 2015. Within the satellite, different technologies will be demonstrated on orbit to show their capabilities for different in-space applications. For our application the FBG interrogator monitors the structural and thermal behaviour of a so called "smart panel". These panels will enable fine angle control and thermal and vibration compensation in order to improve all types of future Earth observations, such as environmental and planetary mapping, border and regional imaging. The Fiber Optic (FO) system in PEASSS includes four FBG strain sensors and two FBG temperature sensors. The 3 channel interrogator has to have a small footprint (110x50x40mm), is low cost, low in mass and has a low power consumption. In order to meet all these requirements, an interrogator has been designed based on a tunable Vertical-Cavity Surface-Emitting Laser (VCSEL) enabling a wavelength sweep of around 7 nm. To guarantee the absolute and relative performance, two reference methods are included internally in the interrogator. First, stabilized reference FBG sensors are used to obtain absolute wavelength calibrations. This method is used for the temperature

[Research on symmetrical optical waveguide based surface plasmon resonance sensing with spectral interrogation].

Science.gov (United States)

Zhang, Yi-long; Liu, Le; Guo, Jun; Zhang, Peng-fei; Guo, Ji-hua; Ma, Hui; He, Yong-hong

2015-02-01

Surface plasmon resonance (SPR) sensors with spectral interrogation can adopt fiber to transmit light signals, thus leaving the sensing part separated, which is very convenient for miniaturization, remote-sensing and on-site analysis. Symmetrical optical waveguide (SOW) SPR has the same refractive index of the-two buffer media layers adjacent to the metal film, resulting in longer propagation distance, deeper penetration depth and better performance compared to conventional SPR In the present paper, we developed a symmetrical optical, waveguide (SOW) SPR sensor with wavelength interrogation. In the system, MgF2-Au-MgF2 film was used as SOW module for glucose sensing, and a fiber based light source and detection was used in the spectral interrogation. In the experiment, a refractive index resolution of 2.8 x 10(-7) RIU in fluid protocol was acquired. This technique provides advantages of high resolution and could have potential use in compact design, on-site analysis and remote sensing.

Apparatus and method for quantitatively evaluating total fissile and total fertile nuclide content in samples

International Nuclear Information System (INIS)

Caldwell, J.T.; Cates, M.R.; Franks, L.A.; Kunz, W.E.

1985-01-01

Simultaneous photon and neutron interrogation of samples for the quantitative determination of total fissile nuclide and total fertile nuclide material present is made possible by the use of an electron accelerator. Prompt and delayed neutrons produced from resulting induced fissions are counted using a single detection system and allow the resolution of the contributions from each interrogating flux leading in turn to the quantitative determination sought. Detection limits for 239 Pu are estimated to be about 3 mg using prompt fission neutrons and about 6 mg using delayed delayed neutrons

Performance of a thermal neutron radiographic system using imaging plates

International Nuclear Information System (INIS)

Silvani, Maria Ines; Almeida, Gevaldo L. de; Furieri, Rosanne; Lopes, Ricardo T.

2009-01-01

A performance evaluation of a neutron radiographic system equipped with a thermal neutron sensitive imaging plate has been undertaken. It includes the assessment of spatial resolution, linearity, dynamic range and the response to exposure time, as well as a comparison of these parameters with the equivalent ones for neutron radiography employing conventional films and a gadolinium foil as converter. The evaluation and comparison between the radiographic systems have been performed at the Instituto de Engenharia Nuclear - CNEN, using the Argonauta Reactor as source of thermal neutrons and a commercially available imaging plate reader. (author)

Results from the Coded Aperture Neutron Imaging System (CANIS)

International Nuclear Information System (INIS)

Brubaker, Erik; Steele, John T.; Brennan, James S.; Hilton, Nathan R.; Marleau, Peter

2010-01-01

Because of their penetrating power, energetic neutrons and gamma rays (∼1 MeV) offer the best possibility of detecting highly shielded or distant special nuclear material (SNM). Of these, fast neutrons offer the greatest advantage due to their very low and well understood natural background. We are investigating a new approach to fast-neutron imaging- a coded aperture neutron imaging system (CANIS). Coded aperture neutron imaging should offer a highly efficient solution for improved detection speed, range, and sensitivity. We have demonstrated fast neutron and gamma ray imaging with several different configurations of coded masks patterns and detectors including an 'active' mask that is composed of neutron detectors. Here we describe our prototype detector and present some initial results from laboratory tests and demonstrations.

Design of a system for neutrons dosimetry; Diseno de un sistema para dosimetria de neutrones

Energy Technology Data Exchange (ETDEWEB)

Ceron, P.; Rivera, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Legaria No. 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Paredes G, L. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Azorin, J. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Sanchez, A. [IPN, Escuela Superior de Fisica y Matematicas, Av. Instituto Politecnico Nacional s/n, Col. San Pedro Zacatenco, 07738 Mexico D. F. (Mexico); Vega C, H. R., E-mail: victceronr@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

2014-08-15

At the present time diverse systems of detection of neutrons exist, as proportional counters based on BF{sub 3}, He{sub 3} and spectrometers of Bonner spheres. However, the cost and the complexity of the implementation of these systems put them far from the reach for dosimetric purposes. For these reasons a system of neutrons detection composed by a medium paraffin moderator that forms a 4π (spheres) arrangement and of several couples of thermoluminescent dosimeters TLD 600/TLD 700. The response of the system presents a minor repeatability to 5% in several assays when being irradiated with a {sup 239}PuBe source and a deviation of 13.8% in the Tl readings of four different spheres. The calibration factor of the system with regard to the neutrons source which was of 56.2 p Sv/nc also was calculated. These detectors will be used as passive monitors of photoneutrons in a radiotherapy room with lineal accelerator of high energy. (Author)

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

Boron Neutron Capture Therapy (BNCT). The neutron flux required for positron production could not be provided with a single D-T neutron generator. Therefore, a subcritical fission multiplier was designed to increase the neutron yield. The neutron flux was increased by a factor of 25. A D-D driven fission multiplier was also studied for BNCT and a gain of 17 was obtained. The fission multiplier system gain was shown to be limited by the neutron absorption in the fuel and the reduction of source brightness. A brief discussion was also given regarding the neutron generator applications for fast neutron brachytherapy and neutron interrogation systems. It was concluded that new designs of compact D-D/D-T neutron generators are feasible and that superior quality neutron beams could be produced and used for various applications.

A newly developed technique of wireless remote controlled visual inspection system for neutron guides of cold neutron research facilities at HANARO

International Nuclear Information System (INIS)

Huh, Hyung; Cho, Yeong Garp; Kim, Jong In

2012-01-01

KAERI developed a neutron guide system for cold neutron research facilities at HANARO from 2003 to 2010. In 2008, the old plug shutter and instruments were removed, and a new plug and primary shutter were installed as the first cold neutron delivery system at HANARO. At the beginning of 2010, all the neutron guides and accessories had been successfully installed as well. The neutron guide system of HANARO consists of the in pile plug assembly with in pile guides, the primary shutter with in shutter guides, the neutron guides in the guide shielding room with secondary shutter, and the neutron guides in the neutron guide hall. Three kinds of glass materials were selected with optimum lengths by considering their lifetime, shielding, maintainability and cost as well. Radiation damage of the guides can occur on the coating and glass by neutron capturing in the glass. It is a big challenge to inspect a guide failure because of the difficult surrounding environment, such as high level radiation, limited working space, and massive hard work for removing and reinstalling the shielding blocks as shown in Fig 1. Therefore, KAERI has developed a wireless remote controlled visual inspection system for neutron guides using an infrared light camera mounted on the vehicle moving in the guide

A spin-transport system for a longitudinally polarized epithermal neutron beam

International Nuclear Information System (INIS)

Crawford, B.E.; Bowman, J.D.; Penttilae, S.I.; Roberson, N.R.

2001-01-01

The TRIPLE (Time Reversal and Parity at Low Energies) collaboration uses a polarized epithermal neutron beam and a capture γ-ray detector to study parity violation in neutron-nucleus reactions. In order to preserve the spin polarization of the neutrons as they travel the 60-m path to the target, the beam pipes are wrapped with wire to produce a solenoidal magnetic field of about 10 G along the beam direction. The flanges and bellows between sections of the beam pipe cause gaps in the windings which in turn produce radial fields that can depolarize the neutron spins. A computer code has been developed that numerically evaluates the effect of these gaps on the polarization. A measurement of the neutron depolarization for neutrons in the actual spin-transport system agrees with a calculation of the neutron depolarization for the TRIPLE system. Features that will aid in designing similar spin-transport systems are discussed

Performance Test for Neutron Detector and Associated System using Research Reactor

Energy Technology Data Exchange (ETDEWEB)

Yang, Seongwoo; Park, Sung Jae; Cho, Man Soon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Oh, Se Hyun [USERS, Daejeon (Korea, Republic of); Shin, Ho Cheol [KHNP CRI, Daejeon (Korea, Republic of)

2016-10-15

SPND (Self-Powered Neutron Detector) has been developed to extend its lifespan. ENFMS (Ex-Core Flux Monitoring System) of pressurized water reactor has been also improved. After the development and improvement, their performance must be verified under the neutron irradiation environment. We used a research reactor for the performance verification of neutron detector and associated system because the research reactor can meet the neutron flux level of commercial nuclear reactor. In this paper, we report the performance verification method and result for the SPND and ENFMS using the research reactor. The performance tests for the SPND and ENFMS were conducted using UCI TRIGA reactor. The test environment of commercial reactor’s neutron flux level must be required. However, it is difficult to perform the test in the commercial rector due to the constraint of time and space. The research reactor can be good alternative neutron source for the test of neutron detectors and associated system.

Design challenges of a tunable laser interrogator for geo-stationary communication satellites

Science.gov (United States)

Ibrahim, Selwan K.; Honniball, Arthur; McCue, Raymond; Todd, Michael; O'Dowd, John A.; Sheils, David; Voudouris, Liberis; Farnan, Martin; Hurni, Andreas; Putzer, Philipp; Lemke, Norbert; Roner, Markus

2017-09-01

Recently optical sensing solutions based on fiber Bragg grating (FBG) technology have been proposed for temperature monitoring in telecommunication satellite platforms with an operational life time beyond 15 years in geo-stationary orbit. Developing radiation hardened optical interrogators designed to be used with FBG sensors inscribed in radiation tolerant fibers offer the capabilities of multiplexing multiple sensors on the same fiber and reducing the overall weight by removing the copper wiring harnesses associated with electrical sensors. Here we propose the use of a tunable laser based optical interrogator that uses a semiconductor MG-Y type laser that has no moving parts and sweeps across the C-band wavelength range providing optical power to FBG sensors and optical wavelength references such as athermal Etalons and Gas Cells to guarantee stable operation of the interrogator over its targeted life time in radiation exposed environments. The MG-Y laser was calibrated so it remains in a stable operation mode which ensures that no mode hops occur due to aging of the laser, and/or thermal or radiation effects. The key optical components including tunable laser, references and FBGs were tested for radiation tolerances by emulating the conditions on a geo-stationary satellite including a Total Ionizing Dose (TID) radiation level of up to 100 krad for interrogator components and 25 Mrad for FBGs. Different tunable laser control, and signal processing algorithms have been designed and developed to fit within specific available radiation hardened FPGAs to guarantee operation of a single interrogator module providing at least 1 sample per second measurement capability across engineering model system developed in the frame of an ESA-ARTES program and is planned to be deployed as a flight demonstrator on-board the German Heinrich Hertz geo-stationary satellite.

Modeling delayed neutron monitoring systems for fast breeder reactors

International Nuclear Information System (INIS)

Bunch, W.L.; Tang, E.L.

1983-10-01

The purpose of the present work was to develop a general expression relating the count rate of a delayed neutron monitoring system to the introduction rate of fission fragments into the sodium coolant of a fast breeder reactor. Most fast breeder reactors include a system for detecting the presence of breached fuel that permits contact between the sodium coolant and the mixed oxide fuel. These systems monitor for the presence of fission fragments in the sodium that emit delayed neutrons. For operational reasons, the goal is to relate the count rate of the delayed neutron monitor to the condition of the breach in order that appropriate action might be taken

Interrogative suggestibility, confabulation, and acquiescence in people with mild learning disabilities (mental handicap): implications for reliability during police interrogations.

Science.gov (United States)

Clare, I C; Gudjonsson, G H

1993-09-01

In order to assess a criminal suspect's ability to make a reliable statement, performance on three measures--interrogative suggestibility, confabulation and acquiescence--may be used. This paper presents preliminary data on these measures for people with mild learning disabilities (Full Scale IQ [FSIQ]: 57-75). It was found that they were more suggestible than their average ability counterparts (FSIQ: 83-111) because they were much more susceptible to 'leading questions'. They also confabulated more and were more acquiescent. Overall, the data emphasized their potential vulnerability to giving erroneous testimony during interrogations.

Catching the Cyber Spy: ARL's Interrogator

National Research Council Canada - National Science Library

Long, Kerry S

2004-01-01

The U.S. Army Research Laboratory has designed a network-based intrusion detection framework, Interrogator, which addresses the constantly changing threat environment that Department of Defense networks...

Embedded data acquisition system for neutron monitors

International Nuclear Information System (INIS)

Población, Ó G; Tejedor, I G; Sánchez, S; Blanco, J J; Gómez-Herrero, R; Medina, J; Steigies, C T

2014-01-01

This article presents the design and implementation of a new data acquisition system to be used as replacement for the old ones that have been in use with neutron monitors for the last decades and, which are eventually becoming obsolete. This new system is also intended to be used in new installations, enabling these scientific instruments to use today's communication networks to send data and receive commands from the operators. This system is currently running in two stations: KIEL2, in the Christian-Albrechts-Universität zu Kiel, Kiel, Germany, and CALMA, in the Castilla-La Mancha Neutron Monitor, Guadalajara, Spain

Fusion Power Measurement Using a Combined Neutron Spectrometer-Camera System at ITER

International Nuclear Information System (INIS)

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

2008-01-01

A central task for fusion plasma diagnostics is to measure the 2.5 and 14 MeV neutron emission rate in order to determine the fusion power. A new method for determining the neutron yield has been developed at JET. It makes use of the magnetic proton recoil neutron spectrometer and a neutron camera and provides the neutron yield with small systematic errors. At ITER a similar system could operate if a high-resolution, high-performance neutron spectrometer similar to the MPR was installed. In this paper, we present how such system could be implemented and how well it would perform under different assumption of plasma scenarios and diagnostic capabilities. It is found that the systematic uncertainty for using such a system as an absolute calibration reference is as low as 3% and hence it would be an excellent candidate for the calibration of neutron monitors such as fission chambers. It is also shown that the system could provide a 1 ms time resolved estimation of the neutron rate with a total uncertainty of 5%

The real-time neutron radiography system at Texas A and M University

International Nuclear Information System (INIS)

Reuscher, Jon A.

1990-01-01

This paper reports on the development and fabrication of a real-time system at Texas A and M University using commercially available and relatively inexpensive components. The real-time neutron radiography system consists of two major components: a camera and image processing equipment. The neutron beam provides a thermal neutron flux of 10 neutrons/cm -sec (cadmium ratio of 4.0) with the TRIGA reactor operating at a power of 1 MW. A remotely operated turntable is used to position the sample in the neutron beam for optimum viewing and ease of changing position. The front surface mirror at 45 deg. to the neutron beam reflects the scintillation image to the lens. The IRO and CCD camera are placed behind shielding out of the neutron. Results using the imaging system for a cadmium plate (0.032 inch thick) with several holes of different diameters are presented. Applications of this neutron radiography system include sensitivity indicators for the spatial resolution of bubbles in water-filled tubes, moisture content of zeolite samples, operating heat pipes and the freezing and thawing of metallic samples

Neutronics investigation of advanced self-cooled liquid blanket systems in helical reactor

International Nuclear Information System (INIS)

Tanaka, T.; Sagara, A.; Muroga, T.; Youssef, M.Z.

2006-10-01

Neutronics performances of advanced self-cooled liquid blanket systems have been investigated in design activity of the helical-type reactor FFHR2. In the present study, a new three-dimensional (3-D) neutronics calculation system has been developed for the helical-type reactor to enhance quick feedback between neutronics evaluation and design modification. Using this new calculation system, advanced Flibe-cooled and Li-cooled liquid blanket systems proposed for FFHR2 have been evaluated to make clear design issues to enhance neutronics performance. Based on calculated results, modification of the blanket dimensions and configuration have been attempted to achieve the adequate tritium breeding ability and neutron shielding performance in the helical reactor. The total tritium breeding ratios (TBRs) obtained after modifying the blanket dimensions indicated that all the advanced blanket systems proposed for FFHR2 would achieve adequate tritium self-sufficiency by dimension adjustment and optimization of structures in the breeder layers. Issues in neutron shielding performance have been investigated quantitatively using 3-D geometry of the helical blanket system, support structures, poloidal coils etc. Shielding performance of the helical coils against direct neutrons from core plasma would achieve design target by further optimization of shielding materials. However, suppression of the neutron streaming and reflection through the divertor pumping areas in the original design is important issue to protect the poloidal coils and helical coils, respectively. Investigation of the neutron wall loading indicated that the peaking factor of the neutron wall load distribution would be moderated by the toroidal and helical effect of the plasma distribution in the helical reactor. (author)

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.

Neutron diffusion in spheroidal, bispherical, and toroidal systems

International Nuclear Information System (INIS)

Williams, M.M.R.

1986-01-01

The neutron flux has been studied around absorbing bodies of spheroidal, bispherical, and toroidal shapes in an infinite nonabsorbing medium. Exact solutions have been obtained by using effective boundary conditions at the surfaces of the absorbing bodies. The problems considered are as follows: 1. Neutron flux and current distributions around prolate and oblate spheroids. It is shown that an equivalent sphere approximation can lead to accurate values for the rate of absorption. 2. Neutron flux and current in a bispherical system of unequal spheres. Three separate situations arise here: (a) two absorbing spheres, (b) two spherical sources, and (c) one spherical source and one absorbing sphere. It is shown how the absorption rate in the two spheres depends on their separation. 3. Neutron flux and current in a toroidal system: (a) an absorbing toroid and (b) a toroidal source. The latter case simulates the flux distribution from a thermonuclear reactor vessel. Finally, a brief description of how these techniques can be extended to multiregion problems is given

Quantitative density measurements from a real-time neutron radiography system

International Nuclear Information System (INIS)

McRae, D.D.; Jenkins, R.W. Jr.; Brenizer, J.S.; Tobin, K.W.; Hosticka, B.; Sulcoski, M.F.

1986-01-01

An advanced video system has been assembled from commercially available equipment to support the real-time neutron radiography facility established jointly by the University of Virginia Department of Nuclear Engineering and Engineering Physics, and the Philip Morris Research Center. A schematic diagram of the equipment used for real-time neutron radiography is presented. To obtain quantitative density measurements with this system, several modifications of both hardware and image processing software were required. After implementation of these changes, the system was capable of determining material densities by measuring the degree of neutron attenuation

Improving Reasoning and Recall: The Differential Effects of Elaborative Interrogation and Mnemonic Elaboration.

Science.gov (United States)

Scruggs, Thomas E.; And Others

1993-01-01

Fifty-three adolescents with learning disabilities or mild mental retardation were taught reasons for dinosaur extinction. Those taught in a mnemonic elaborative interrogation condition recalled more reasons than did students who received direct teaching. Students in elaborative interrogation and mnemonic elaborative interrogation groups recalled…

Television imaging system for fast neutron radiography using baby cyclotron

International Nuclear Information System (INIS)

Yoshii, Koji; Miya, Kenzo; Katoh, Norihiko.

1993-01-01

A television imaging system for fast neutron radiography (FNR-TV) developed using the fast neutron source reactor YAYOI was applied to the baby-cyclotron based fast neutron source to get images of thick objects quickly. In the system the same technique as a current television imaging system of thermal neutron radiography was applied, while the luminescent converter was used to detect fast neutrons. Using the CR39 track etch method it took about 7 h to get an image, while the FNR-TV only 20 s enough for taking the same object. However the FNR-TV imaging result of the simulation model of a large explosive device for the space launch vehicle of H-2 type was not so good as the image taken with the CR39 track etch method. The reason was that the luminescence intensity of the FNR-TV converter was a quarter of that in the YAYOI. (author)

Optically powered and interrogated rotary position sensor for aircraft engine control applications

Science.gov (United States)

Spillman, W. B.; Crowne, D. H.; Woodward, D. W.

A throttle level angle (TLA) sensing system is described that utilizes a capacitance based rotary position transducer that is powered and interrogated via light from a single multimode optical fiber. The system incorporates a unique GaAs device that serves as both a power converter and optical data transmitter. Design considerations are discussed, and the fabrication and performance of the sensor system are detailed.

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

Design features of HANARO Neutron Flux Monitoring System and its operating experiences

International Nuclear Information System (INIS)

Kim, Young-Ki; Ahn, Guk-Hoon

1999-01-01

The Neutron Flux Monitoring System for HANARO provides reliable neutron flux measurement from reactor shutdown to reactor full power level ranging 10 decades from 10 0 nv to 10 10 nv. The neutron flux monitoring system consists of a guarded fission chamber, amplifier and signal processor. The neutron flux as the measure of reactor power is continuously monitored by six(6) fission chambers mounted on the courtside wall of the reflector tank in the pool. Three(3) of the fission chambers are used for reactor power control, while the other three(3) are used for tripping the reactor in case of power excursion. Only the wide range fission chamber-based neutron monitoring system is employed for neutron power measurement thereby source range and intermediate range detectors are not necessary and the number of neutron monitoring channels are minimized at HANARO. (author)

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)

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

Science.gov (United States)

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 as, “However well intended, were APA’s interrogation policies ethically sound?”; “Were they valid, realistic, and able to achieve their purpose?”; “Were other approaches available that would address interrogation issues more directly, comprehensively, and actively, that were more ethically and scientifically based, and that would have had a greater likelihood of success?”; and “Should APA continue to endorse its post-9–11 detainee interrogation policies?” PMID:22096660

System and plastic scintillator for discrimination of thermal neutron, fast neutron, and gamma radiation

Science.gov (United States)

Zaitseva, Natalia P.; Carman, M. Leslie; Faust, Michelle A.; Glenn, Andrew M.; Martinez, H. Paul; Pawelczak, Iwona A.; Payne, Stephen A.

2017-05-16

A scintillator material according to one embodiment includes a polymer matrix; a primary dye in the polymer matrix, the primary dye being a fluorescent dye, the primary dye being present in an amount of 3 wt % or more; and at least one component in the polymer matrix, the component being selected from a group consisting of B, Li, Gd, a B-containing compound, a Li-containing compound and a Gd-containing compound, wherein the scintillator material exhibits an optical response signature for thermal neutrons that is different than an optical response signature for fast neutrons and gamma rays. A system according to one embodiment includes a scintillator material as disclosed herein and a photodetector for detecting the response of the material to fast neutron, thermal neutron and gamma ray irradiation.