WorldWideScience

Sample records for neutron radio activation

  1. Radio Pulsars: The Neutron Star Population & Fundamental Physics

    CERN Document Server

    Kaspi, Victoria M

    2016-01-01

    Radio pulsars are unique laboratories for a wide range of physics and astrophysics. Understanding how they are created, how they evolve and where we find them in the Galaxy, with or without binary companions, is highly constraining of theories of stellar and binary evolution. Pulsars' relationship with a recently discovered variety of apparently different classes of neutron stars is an interesting modern astrophysical puzzle which we consider in Part I of this review. Radio pulsars are also famous for allowing us to probe the laws of nature at a fundamental level. They act as precise cosmic clocks and, when in a binary system with a companion star, provide indispensable venues for precision tests of gravity. The different applications of radio pulsars for fundamental physics will be discussed in Part II. We finish by making mention of the newly discovered class of astrophysical objects, the Fast Radio Bursts, which may or may not be related to radio pulsars or neutron stars, but which were discovered in obser...

  2. Axion star collisions with neutron stars and fast radio bursts

    Science.gov (United States)

    Raby, Stuart

    2016-11-01

    Axions may make a significant contribution to the dark matter of the Universe. It has been suggested that these dark matter axions may condense into localized clumps, called "axion stars." In this paper we argue that collisions of dilute axion stars with neutron stars, of the type known as "magnetars," may be the origin of most of the observed fast radio bursts. This idea is a variation of an idea originally proposed by Iwazaki. However, instead of the surface effect of Iwazaki, we propose a perhaps stronger volume effect caused by the induced time dependent electric dipole moment of neutrons.

  3. Axion star collisions with Neutron stars and Fast Radio Bursts

    CERN Document Server

    Raby, Stuart

    2016-01-01

    Axions may make a significant contribution to the dark matter of the universe. It has been suggested that these dark matter axions may condense into localized clumps, called "axion stars." In this paper we argue that collisions of dilute axion stars with neutron stars may be the origin of most of the observed fast radio bursts. This idea is a variation of an idea originally proposed by Iwazaki. However, instead of the surface effect of Iwazaki, we propose a perhaps stronger volume effect caused by the induced time dependent electric dipole moment of neutrons.

  4. Neutron activation analysis: Modelling studies to improve the neutron flux of Americium-Beryllium source

    Energy Technology Data Exchange (ETDEWEB)

    Didi, Abdessamad; Dadouch, Ahmed; Tajmouati, Jaouad; Bekkouri, Hassane [Advanced Technology and Integration System, Dept. of Physics, Faculty of Science Dhar Mehraz, University Sidi Mohamed Ben Abdellah, Fez (Morocco); Jai, Otman [Laboratory of Radiation and Nuclear Systems, Dept. of Physics, Faculty of Sciences, Tetouan (Morocco)

    2017-06-15

    Americium–beryllium (Am-Be; n, γ) is a neutron emitting source used in various research fields such as chemistry, physics, geology, archaeology, medicine, and environmental monitoring, as well as in the forensic sciences. It is a mobile source of neutron activity (20 Ci), yielding a small thermal neutron flux that is water moderated. The aim of this study is to develop a model to increase the neutron thermal flux of a source such as Am-Be. This study achieved multiple advantageous results: primarily, it will help us perform neutron activation analysis. Next, it will give us the opportunity to produce radio-elements with short half-lives. Am-Be single and multisource (5 sources) experiments were performed within an irradiation facility with a paraffin moderator. The resulting models mainly increase the thermal neutron flux compared to the traditional method with water moderator.

  5. Fast Radio Bursts from the Inspiral of Double Neutron Stars

    CERN Document Server

    Wang, Jie-Shuang; Wu, Xue-Feng; Dai, Zi-Gao; Wang, Fa-Yin

    2016-01-01

    Recently, a fading radio transient after the fast radio burst (FRB) 150418 was discovered and its cosmological redshift was measured by Keane et al. (2016}. This afterglow lasting $\\sim 6$ days is largely in agreement with the radio afterglow of a short gamma-ray burst (SGRB), and thus the double neutron star (NS-NS) merger model for this FRB is favored. Here we suggest that an FRB could originate from the magnetic interaction between two NSs during their inspiral, within the framework of a unipolar inductor model. In this model, an electromotive force is induced on one NS to accelerate electrons. We show that coherent curvature radiation from these electrons in the magnetosphere of the other NS is responsible for the observed FRB signal, that is, the characteristic luminosity, duration, frequency and event rate of an FRB can be well understood. In addition, we discuss several implications of this model, including possible associations of FRBs with SGRB afterglows and gravitational wave events.

  6. Recurrent radio activity in active galactic nuclei

    Directory of Open Access Journals (Sweden)

    Jamrozy M.

    2012-12-01

    Full Text Available There has been a growing body of persuasive evidence to indicate that AGN activity, powered by mass accretion onto a supermassive black hole, can involve multiple episodes. Thus thinking of jet activity as occurring within a unique brief period in the life of a galaxy is no longer valid. The most striking examples of AGNs with recurrent jet activity are the double-double radio sources, which contain two or more pairs of distinct lobes on the opposite sides of a parent optical object. On the other hand, we have now conclusive arguments that galaxy mergers and interactions are principal triggers for AGNs. Quite a number of examples of powerful radio sources hosted by galaxies with peculiar optical morphologies (tails, shells, dust-lanes, etc. can be cited to support such a scenario. The structure and spectra of extended radio emission from radio galaxies, with sizes ranging up to a few Mpc, can provide a lot of information on the history of the central AGN activity, while the spectral and dynamical ages of these extended radio lobes could be used to constrain the time scales of recurrent AGN activity.

  7. Enhanced NIF neutron activation diagnostics.

    Science.gov (United States)

    Yeamans, C B; Bleuel, D L; Bernstein, L A

    2012-10-01

    The NIF neutron activation diagnostic suite relies on removable activation samples, leading to operational inefficiencies and a fundamental lower limit on the half-life of the activated product that can be observed. A neutron diagnostic system measuring activation of permanently installed samples could remove these limitations and significantly enhance overall neutron diagnostic capabilities. The physics and engineering aspects of two proposed systems are considered: one measuring the (89)Zr/(89 m)Zr isomer ratio in the existing Zr activation medium and the other using potassium zirconate as the activation medium. Both proposed systems could improve the signal-to-noise ratio of the current system by at least a factor of 5 and would allow independent measurement of fusion core velocity and fuel areal density.

  8. A review on radio based activity recognition

    Directory of Open Access Journals (Sweden)

    Shuangquan Wang

    2015-02-01

    Full Text Available Recognizing human activities in their daily living enables the development and widely usage of human-centric applications, such as health monitoring, assisted living, etc. Traditional activity recognition methods often rely on physical sensors (camera, accelerometer, gyroscope, etc. to continuously collect sensor readings, and utilize pattern recognition algorithms to identify user׳s activities at an aggregator. Though traditional activity recognition methods have been demonstrated to be effective in previous work, they raise some concerns such as privacy, energy consumption and deployment cost. In recent years, a new activity recognition approach, which takes advantage of body attenuation and/or channel fading of wireless radio, has been proposed. Compared with traditional activity recognition methods, radio based methods utilize wireless transceivers in environments as infrastructure, exploit radio communication characters to achieve high recognition accuracy, reduce energy cost and preserve user׳s privacy. In this paper, we divide radio based methods into four categories: ZigBee radio based activity recognition, WiFi radio based activity recognition, RFID radio based activity recognition, and other radio based activity recognition. Some existing work in each category is introduced and reviewed in detail. Then, we compare some representative methods to show their advantages and disadvantages. At last, we point out some future research directions of this new research topic.

  9. Neutron activation analysis: Modelling studies to improve the neutron flux of Americium–Beryllium source

    Directory of Open Access Journals (Sweden)

    Abdessamad Didi

    2017-06-01

    Full Text Available Americium–beryllium (Am-Be; n, γ is a neutron emitting source used in various research fields such as chemistry, physics, geology, archaeology, medicine, and environmental monitoring, as well as in the forensic sciences. It is a mobile source of neutron activity (20 Ci, yielding a small thermal neutron flux that is water moderated. The aim of this study is to develop a model to increase the neutron thermal flux of a source such as Am-Be. This study achieved multiple advantageous results: primarily, it will help us perform neutron activation analysis. Next, it will give us the opportunity to produce radio-elements with short half-lives. Am-Be single and multisource (5 sources experiments were performed within an irradiation facility with a paraffin moderator. The resulting models mainly increase the thermal neutron flux compared to the traditional method with water moderator.

  10. Magneto–Thermal Evolution of Neutron Stars with Emphasis to Radio Pulsars

    Indian Academy of Sciences (India)

    U. Geppert

    2017-09-01

    The magnetic and thermal evolution of neutron stars is a very complex process with many non-linear interactions. For a decent understanding of neutron star physics, these evolutions cannot be considered isolated. A brief overview is presented, which describes the main magneto–thermal interactions that determine the fate of both isolated neutron stars and accreting ones. Special attention is devoted to the interplay of thermal and magnetic evolution at the polar cap of radio pulsars. There, a strong meridional temperature gradient is maintained over the lifetime of radio pulsars. It may be strong enough to drive thermoelectric magnetic field creation which perpetuate a toroidal magnetic field around the polar cap rim. Such a local field component may amplify and curve the poloidal surface field at the cap, forming a strong and small scale magnetic field as required for the radio emission of pulsars.

  11. Neutron-activation revisited: the depletion and depletion-activation models.

    Science.gov (United States)

    Abdel-Rahman, Wamied; Podgorsak, Ervin B

    2005-02-01

    The growth of a radioactive daughter in neutron activation is commonly described with the saturation model that ignores the consumption of parent nuclei during the radio-activation process. This approach is not valid when radioactive sources with high specific activities are produced or when the particle fluence rates used are very high. Assuming a constant neutron fluence rate throughout the activation target, a neutron-activation model that accounts for the depletion in parent nuclei is introduced. This depletion model is governed by relationships similar to those describing the parent-daughter-granddaughter decay series, and, in contrast to the saturation model, correctly predicts the practical limit of the daughter specific activity, irrespective of the particle fluence rate. Also introduced is a neutron-activation model that in addition to parent depletion accounts for the neutron activation of daughter nuclei in situations where the cross section for this effect is high. The model is referred to as the depletion-activation model and it provides the most realistic description for the daughter specific activity in neutron activation. Three specific neutron activation examples of interest to medical physics are presented: activation of molybdenum-98 into molybdenum-99 described by the saturation model; activation of cobalt-59 into cobalt-60 described by the depletion model; and activation of iridium-191 into iridium-192 described by the depletion-activation model.

  12. Neutron Activation Analysis of Water - A Review

    Science.gov (United States)

    Buchanan, John D.

    1971-01-01

    Recent developments in this field are emphasized. After a brief review of basic principles, topics discussed include sources of neutrons, pre-irradiation physical and chemical treatment of samples, neutron capture and gamma-ray analysis, and selected applications. Applications of neutron activation analysis of water have increased rapidly within the last few years and may be expected to increase in the future.

  13. Testing the Young Neutron Star Scenario with Persistent Radio Emission Associated with FRB 121102

    Science.gov (United States)

    Kashiyama, Kazumi; Murase, Kohta

    2017-04-01

    Recently a repeating fast radio burst (FRB) 121102 has been confirmed to be an extragalactic event and a persistent radio counterpart has been identified. While other possibilities are not ruled out, the emission properties are broadly consistent with Murase et al. that theoretically proposed quasi-steady radio emission as a counterpart of both FRBs and pulsar-driven supernovae. Here, we constrain the model parameters of such a young neutron star scenario for FRB 121102. If the associated supernova has a conventional ejecta mass of M ej ≳ a few M ⊙, a neutron star with an age of t age ∼ 10–100 years, an initial spin period of P i ≲ a few ms, and a dipole magnetic field of B dip ≲ a few × 1013 G can be compatible with the observations. However, in this case, the magnetically powered scenario may be favored as an FRB energy source because of the efficiency problem in the rotation-powered scenario. On the other hand, if the associated supernova is an ultra-stripped one or the neutron star is born by the accretion-induced collapse with M ej ∼ 0.1 M ⊙, a younger neutron star with t age ∼ 1–10 years can be the persistent radio source and might produce FRBs with the spin-down power. These possibilities can be distinguished by the decline rate of the quasi-steady radio counterpart.

  14. Fast neutron activation dosimetry with TLDS

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, D.W.; Moran, P.R.

    1975-01-01

    Fast neutron activation using threshold reactions is the only neutron dosimetry method which offers complete discrimination against gamma-rays and preserves some information about the neutron energy. Conventional activation foil technique requires sensitive radiation detectors to count the decay of the neutron induced activity. For extensive measurements at low neutron fluences, vast outlays of counting equipment are required. TL dosimeters are inexpensive, extremely sensitive radiation detectors. The work of Mayhugh et al. (Proc. Third Int. Conf. on Luminescence Dosimetry, Riso Report 249, 1040, (1971)) showed that CaSO/sub 4/: DyTLDs could be used to measure the integrated dose from the decay of the radioactivity produced in the dosimeters by exposure to thermal neutrons. This neatly combines the activation detector and counter functions in one solid state device. This work has been expanded to fast neutron exposures and other TL phosphors. The reactions /sup 19/F(n, 2n)/sup 18/F, /sup 32/S(n,p)/sup 32/P, /sup 24/Mg(n,p)/sup 24/, and /sup 64/Zn(n,p)/sup 64/Cu were found useful for fast neutron activation in commercial TLDs. As each TLD is its own integrating decay particle counter, many activation measurements can be made at the same time. The subsequent readings of the TL signals can be done serially after the induced radioactivity has decayed, using only one TL reader. The neutron detection sensitivity is limited mainly by the number statistics of the neutron activations. The precision of the neutron measurement is within a factor of two of conventional foil activation for comparable mass detectors. Commercially available TLDs can measure neutron fluences of 10/sup 9/n/cm/sup 2/ with 10 percent precision.

  15. The synchronous active neutron detection assay system

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-08-01

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

  16. Radio Detection of A Candidate Neutron Star Associated with Galactic Center Supernova Remnant Sagittarius A East

    CERN Document Server

    Zhao, Jun-Hui; Goss, W M

    2013-01-01

    We report the VLA detection of the radio counterpart of the X-ray object referred to as the "Cannonball", which has been proposed to be the remnant neutron star resulting from the creation of the Galactic Center supernova remnant, Sagittarius A East. The radio object was detected both in our new VLA image from observations in 2012 at 5.5 GHz and in archival VLA images from observations in 1987 at 4.75 GHz and in the period from 1990 to 2002 at 8.31 GHz. The radio morphology of this object is characterized as a compact, partially resolved point source located at the northern tip of a radio "tongue" similar to the X-ray structure observed by Chandra. Behind the Cannonball, a radio counterpart to the X-ray plume is observed. This object consists of a broad radio plume with a size of 30\\arcsec$\\times$15\\arcsec, followed by a linear tail having a length of 30\\arcsec. The compact head and broad plume sources appear to have relatively flat spectra ($\\propto\

  17. Neutron counter based on beryllium activation

    Energy Technology Data Exchange (ETDEWEB)

    Bienkowska, B.; Prokopowicz, R.; Kaczmarczyk, J.; Paducha, M. [Institute of Plasma Physics and Laser Microfusion (IPPLM), Hery 23, 01-497 Warsaw (Poland); Scholz, M.; Igielski, A. [Institute of Nuclear Physics PAS (IFJPAN), Radzikowskiego 152, 31-342 Krakow (Poland); Karpinski, L. [Faculty of Electrical Engineering, Rzeszow University of Technology, Pola 2, 35-959 Rzeszow (Poland); Pytel, K. [National Centre for Nuclear Research (NCBJ), Soltana 7, 05-400 Otwock - Swierk (Poland)

    2014-08-21

    The fusion reaction occurring in DD plasma is followed by emission of 2.45 MeV neutrons, which carry out information about fusion reaction rate and plasma parameters and properties as well. Neutron activation of beryllium has been chosen for detection of DD fusion neutrons. The cross-section for reaction {sup 9}Be(n, α){sup 6}He has a useful threshold near 1 MeV, which means that undesirable multiple-scattered neutrons do not undergo that reaction and therefore are not recorded. The product of the reaction, {sup 6}He, decays with half-life T{sub 1/2} = 0.807 s emitting β{sup −} particles which are easy to detect. Large area gas sealed proportional detector has been chosen as a counter of β–particles leaving activated beryllium plate. The plate with optimized dimensions adjoins the proportional counter entrance window. Such set-up is also equipped with appropriate electronic components and forms beryllium neutron activation counter. The neutron flux density on beryllium plate can be determined from the number of counts. The proper calibration procedure needs to be performed, therefore, to establish such relation. The measurements with the use of known β–source have been done. In order to determine the detector response function such experiment have been modeled by means of MCNP5–the Monte Carlo transport code. It allowed proper application of the results of transport calculations of β{sup −} particles emitted from radioactive {sup 6}He and reaching proportional detector active volume. In order to test the counter system and measuring procedure a number of experiments have been performed on PF devices. The experimental conditions have been simulated by means of MCNP5. The correctness of simulation outcome have been proved by measurements with known radioactive neutron source. The results of the DD fusion neutron measurements have been compared with other neutron diagnostics.

  18. Neutron counter based on beryllium activation

    Science.gov (United States)

    Bienkowska, B.; Prokopowicz, R.; Scholz, M.; Kaczmarczyk, J.; Igielski, A.; Karpinski, L.; Paducha, M.; Pytel, K.

    2014-08-01

    The fusion reaction occurring in DD plasma is followed by emission of 2.45 MeV neutrons, which carry out information about fusion reaction rate and plasma parameters and properties as well. Neutron activation of beryllium has been chosen for detection of DD fusion neutrons. The cross-section for reaction 9Be(n, α)6He has a useful threshold near 1 MeV, which means that undesirable multiple-scattered neutrons do not undergo that reaction and therefore are not recorded. The product of the reaction, 6He, decays with half-life T1/2 = 0.807 s emitting β- particles which are easy to detect. Large area gas sealed proportional detector has been chosen as a counter of β-particles leaving activated beryllium plate. The plate with optimized dimensions adjoins the proportional counter entrance window. Such set-up is also equipped with appropriate electronic components and forms beryllium neutron activation counter. The neutron flux density on beryllium plate can be determined from the number of counts. The proper calibration procedure needs to be performed, therefore, to establish such relation. The measurements with the use of known β-source have been done. In order to determine the detector response function such experiment have been modeled by means of MCNP5-the Monte Carlo transport code. It allowed proper application of the results of transport calculations of β- particles emitted from radioactive 6He and reaching proportional detector active volume. In order to test the counter system and measuring procedure a number of experiments have been performed on PF devices. The experimental conditions have been simulated by means of MCNP5. The correctness of simulation outcome have been proved by measurements with known radioactive neutron source. The results of the DD fusion neutron measurements have been compared with other neutron diagnostics.

  19. Overview of Ignitor Neutronics and Activation

    Science.gov (United States)

    Rollet, S.; Batistoni, P.; Forrest, R.

    1999-11-01

    The Ignitor experiment is designed to produce D-T plasmas where ignition can take place and the physics of α-particles can be studied. After a first period of operation without significant neutron production, a second phase in deuterium with 2.5 MeV neutron production rate up to 10^17 n/s is planned. This will be followed by operations at increasing percentages of tritium, leading to short, but intense 14 MeV neutron production, up to ≈ 3 × 10^19 n/s. To calculate the neutron fluxes in all the machine components, including the streaming through the ports, a detailed description of the actual Ignitor machine is implemented in the MCNP-4B Monte Carlo code. These fluxes are then used as input for the FISPACT-97 code for the analysis of the activation at the end of life (EOL) and at intermediate times for safety assessment purposes. The estimated neutron emission pulse results in rather modest neutron fluences (≈ 10^18 n/cm^2 on the first wall at EOL). Therefore, radiation damage in the device components is not a concern, with the possible exception of the toroidal magnet insulator. On the other hand, the neutron flux on the first wall can be as high as that of a demonstration reactor (≈ 10^14 n/s/cm^2), inducing, in the absence of a blanket, considerable activation. The shielding strategy and possible solutions to prevent/reduce the activation of the cryostat are presented.

  20. High space velocities of single radio pulsars versus low orbital eccentricities and masses of double neutron stars: Evidence for two different neutron star formation mechanisms

    NARCIS (Netherlands)

    van den Heuvel, E.P.J.

    2010-01-01

    Radio pulsars tend to be high-velocity objects, which implies that the majority of them received a velocity kick of several hundreds of km s(-1) at birth. However, six of the eight known double neutron stars in the galactic disk have quite low orbital eccentricities (0.085-0.27), indicating - taking

  1. High space velocities of single radio pulsars versus low orbital eccentricities and masses of double neutron stars: Evidence for two different neutron star formation mechanisms

    NARCIS (Netherlands)

    van den Heuvel, E.P.J.

    2010-01-01

    Radio pulsars tend to be high-velocity objects, which implies that the majority of them received a velocity kick of several hundreds of km s(-1) at birth. However, six of the eight known double neutron stars in the galactic disk have quite low orbital eccentricities (0.085-0.27), indicating - taking

  2. Correlation between radio luminosity and X-ray timing frequencies in neutron star and black hole X-ray binaries

    NARCIS (Netherlands)

    Migliari, S.; Fender, R.P.; van der Klis, M.

    2005-01-01

    We report on correlations between radio luminosity and X-ray timing features in X-ray binary systems containing low magnetic field neutron stars and black holes. The sample of neutron star systems consists of 4U 1728-34, 4U 1820-34, Ser X-1, MXB 1730-335, GX 13+1, the millisecond X-ray pulsars SAX J

  3. Passive neutron dosemeter with activation detector

    Energy Technology Data Exchange (ETDEWEB)

    Valero L, C.; Banuelos F, A.; Guzman G, K. A.; Borja H, C. G.; Hernandez D, V. M.; Vega C, H. R., E-mail: fermineutron@yahoo.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2011-10-15

    A passive neutron dosemeter with {sup 197}Au activation detector has been developed. The area dosemeter was made as a 20.5 {phi} x 20.5 cm{sup 2} polyethylene moderator, with a polyethylene pug where a {sup 197}Au foil can be located either parallel or perpendicular to moderator axis. Using Monte Carlo methods, with the MCNP5 code. With the fluence response and the fluence-to-equivalent dose conversion coefficients from ICRP-74, responses to H*(10) were also calculated, these were compared against responses of commercially available neutron area monitors and dosemeters. (Author)

  4. Opportunities for innovation in neutron activation analysis

    NARCIS (Netherlands)

    Bode, P.

    2011-01-01

    Neutron activation laboratories worldwide are at a turning point at which new staff has to be found for the retiring pioneers from the 1960s–1970s. A scientific career in a well-understood technique, often characterized as ‘mature’ may only be attractive to young scientists if still challenges for f

  5. Observational Constraints on Radio Transient Emissions from Binary Neutron Star Mergers

    Science.gov (United States)

    Papadopoulos, Joanna; Dispoto, D.; Cardena, B.; Kavic, M.; Ellingson, S.; Simonetti, J.; Cutchin, S.; Patterson, C.

    2012-01-01

    The merger of a binary neutron star pair is expected to generate a strong transient radio signal. This emission will be strongest at low-frequency and will disperse as it transverses the interstellar medium arriving at Earth after coincidentally emitted gravitational or (higher frequency) electromagnetic signals. The rate of compact object merger events is poorly constrained by observations. The Eight-meter-wavelength Transient Array (ETA) telescope is a low-frequency radio telescope initially located at the Pisgah Astronomical Research Institute (PARI), which is sensitive to a frequency range of 29-47 MHz. It is being upgraded and relocated to western Virginia where it will continue to conduct low frequency observations. This instrument is an all-sky instrument designed to detect astronomical sources of radio transients. Using a series of observations taken during the ETA's first science run, we were able to constrain the rate of such merger events to <1.3 x 10-5 Mpc-3/yr.

  6. A New Perspective on the Radio Active Zone at The Galactic Center - Feedback from Nuclear Activities

    CERN Document Server

    Zhao, Jun-Hui; Goss, W M

    2013-01-01

    Based on our deep image of Sgr A using broadband data observed with the Jansky VLA at 6 cm, we present a new perspective of the radio bright zone at the Galactic center. We further show the radio detection of the X-ray Cannonball, a candidate neutron star associated with the Galactic center SNR Sgr A East. The radio image is compared with the Chandra X-ray image to show the detailed structure of the radio counterparts of the bipolar X-ray lobes. The bipolar lobes are likely produced by the winds from the activities within Sgr A West, which could be collimated by the inertia of gas in the CND, or by the momentum driving of Sgr A*; and the poloidal magnetic fields likely play an important role in the collimation. The less-collimated SE lobe, in comparison to the NW one, is perhaps due to the fact that the Sgr A East SN might have locally reconfigured the magnetic field toward negative galactic latitudes. In agreement with the X-ray observations, the time-scale of ~ $1\\times10^4$ yr estimated for the outermost r...

  7. A neutron activation spectrometer and neutronic experimental platform for the National Ignition Facility (invited)

    Science.gov (United States)

    Yeamans, C. B.; Gharibyan, N.

    2016-11-01

    At the National Ignition Facility, the diagnostic instrument manipulator-based neutron activation spectrometer is used as a diagnostic of implosion performance for inertial confinement fusion experiments. Additionally, it serves as a platform for independent neutronic experiments and may be connected to fast recording systems for neutron effect tests on active electronics. As an implosion diagnostic, the neutron activation spectrometers are used to quantify fluence of primary DT neutrons, downscattered neutrons, and neutrons above the primary DT neutron energy created by reactions of upscattered D and T in flight. At a primary neutron yield of 1015 and a downscattered fraction of neutrons in the 10-12 MeV energy range of 0.04, the downscattered neutron fraction can be measured to a relative uncertainty of 8%. Significant asymmetries in downscattered neutrons have been observed. Spectrometers have been designed and fielded to measure the tritium-tritium and deuterium-tritium neutron outputs simultaneously in experiments using DT/TT fusion ratio as a direct measure of mix of ablator into the gas.

  8. Fast neutron activation analysis by means of low voltage neutron generator

    Science.gov (United States)

    Medhat, M. E.

    A description of D-T neutron generator (NG) is presented. This machine can be used for fast neutron activation analysis applied to determine some selected elements, especially light elements, in different materials. Procedure of neutron flux determination and efficiency calculation is described. Examples of testing some Egyptian natural cosmetics are given.

  9. A new neutron monitor with silver activation

    CERN Document Server

    Luszik-Bhadra, M; Hohmann, E

    2010-01-01

    A moderator-type neutron monitor has been developed, which registers delayed beta rays from neutron-induced silver activation and which is able to measure dose equivalent in pulsed fields with peak dose rates of several thousand Sv h(-1). The monitor uses four silicon diodes in the centre of a polyethylene moderator, 30 cm in diameter. Two of the diodes are covered by natural silver foils and two of them by tin foils. The latter are used to subtract photon-induced pulses. For registering signals, a pulse height threshold is set at 662 key, which minimizes the effect of Cs-137 and lower energy radiation and - in addition - enhances the detection of beta rays from the shorter half-life silver isotope Ag-110 (25 s) as compared to the longer half-life isotope Ag-108 (144 s). The results of measurements in neutron and photon calibration fields, of MCNPX neutron response calculations and of first measurements in a high-intensity pulsed field at the PSI accelerator are shown. (c) 2010 Elsevier Ltd. All rights reserv...

  10. Radio Bursts in the Active Period January 2005

    CERN Document Server

    Bouratzis, K; Hillaris, A; Moussas, X; Caroubalos, C; Petoussis, V; Tsitsipis, P; Kontogeorgos, A; 10.1063/1.2347980

    2010-01-01

    We present complex radio bursts recorded by the radiospectrograph ARTEMIS-IV in the active period of January 2005. The wide spectral coverage of this recorder, in the 650-20 MHz range, permits an analysis of the radio bursts from the base of the Solar Corona to 2 Solar Radii; it thus facilitates the association of radio activity with other types of solar energetic phenomena. Furthermore the ARTEMIS-IV1, high time resolution (1/100 sec) in the 450-270 MHz range, makes possible the detection and analysis of the fine structure which most of the major radio events exhibit.

  11. Introduction of Prompt Gamma Thermal Neutron Activation Analysis at CARR

    Institute of Scientific and Technical Information of China (English)

    WANG; Xing-hua; XIAO; Cai-jin; ZHANG; Gui-ying; YAO; Yong-gang; JIN; Xiang-chun; WANG; Ping-sheng; HUA; Long; NI; Bang-fa

    2013-01-01

    CARR will provide with maximal neutron flux in Asia,the third of the world.By using the high quality neutron beam and the advanced international experience,Prompt Gamma Neutron Activation Analysis(PGNAA)facility will be setup at high level.PGNAA on CARR will promote the development of nuclear analysis technology and improve Chinese status in the nuclear analysis field.

  12. The Radio Activity-Rotation Relation of Ultracool Dwarfs

    CERN Document Server

    McLean, M; Reiners, A

    2011-01-01

    [Abridged] We present a new radio survey of about 100 late-M and L dwarfs undertaken with the VLA. The sample was chosen to explore the role of rotation in the radio activity of ultracool dwarfs. Combining the new sample with results from our previous studies and from the literature, we compile the largest sample to date of ultracool dwarfs with radio observations and measured rotation velocities (167 objects). In the spectral type range M0-M6 we find a radio activity-rotation relation, with saturation at log(L_rad/L_bol) 10^(-7.5) above vsini~5 km/s, similar to the relation in H-alpha and X-rays. However, at spectral types >M7 the ratio of radio to bolometric luminosity increases regardless of rotation velocity, and the scatter in radio luminosity increases. In particular, while the most rapid rotators (vsini>20 km/s) exhibit "super-saturation" in X-rays and H-alpha, this effect is not seen in the radio. We also find that ultracool dwarfs with vsini>20 km/s have a higher radio detection fraction by about a f...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-11-06

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

  14. Controlling the Dissolution of Realgar by Neutron Activation

    Directory of Open Access Journals (Sweden)

    Pujić, Z.

    2009-03-01

    Full Text Available Radioanalytical method for monitoring of separation of arsenic from realgar ore through As-76 was described. The procedure follows the distribution of radioactive components between a liquid and a solid phase in any kind of chemical treatment.The method is applicable in examination of metallurgical procedures with natural materials that are characterized with a high cross section for neutron capture. The method can be applied in examination of samples containing mercury (II sulphide HgS, which are not suitable for conventional chemical treatments concerning ecological risks.The samples examined were from Vareš mine zone - a sample of realgar ore and a sample of dolomite. The realgar seam has not been treated separately, but the sample has been collected by flotation in a concentrate which is a mixture of different ores in Vares mine area. We assumed that such seams should be treated separately, and not as a part of an ore concentrate, because arsenic is only a trace element in a concentrate collected (0.2 % – 0.4 %, and its separation is therefore difficult. A sample of realgar ore has been irradiated with a neutron source americium – 241/beryllium with neutron flux 2.6×107 n s-1. The radio analytical procedure proposed consists of three main phases:– The investigated sample is irradiated in a neutron source and gamma-spectrometrically charecterised.– An identical sample is exposed to any kind of chemical treatment. A part of the sample that isnot dissolved is then separated and the remainder is gamma-spectrometrically characterized aswell.– When the obtained gamma spectra are compared, the information on distribution of radionuclides is gained, and the yield of dissolving process is defined.Reliability of the neutron activation method depends on the neutron source used, but also on the quality of gamma-spectrometer. A typical gamma spectrum of a realgar sample (0.5 g, after it has been irradiated in a neutron source, was recorded on

  15. A Neutron Star-White Dwarf Binary Model for Repeating Fast Radio Burst 121102

    CERN Document Server

    Gu, Wei-Min; Liu, Tong; Ma, Renyi; Wang, Junfeng

    2016-01-01

    We propose a compact binary model for the fast radio burst (FRB) repeaters, where the system consists of a magnetic white dwarf (WD) and a neutron star (NS) with strong bipolar magnetic fields. When the WD fills its Roche lobe, mass transfer will occur from the WD to the NS through the inner Lagrange point. The accreted magnetized materials may trigger magnetic reconnection when they approach the NS surface, and therefore the electrons can be accelerated to an ultra-relativistic speed. In this scenario, the curvature radiation of the electrons moving along the NS magnetic field lines can account for the characteristic frequency and the timescale of an FRB. Owing to the conservation of angular momentum, the WD may be kicked away after a burst, and the next burst may appear when the system becomes semi-detached again through the gravitational radiation. By comparing our analyses with the observations, we show that such an intermittent Roche lobe overflow mechanism can be responsible for the observed repeating b...

  16. Apparatus for the measurement of total body nitrogen using prompt neutron activation analysis with californium-252.

    Science.gov (United States)

    Mackie, A; Hannan, W J; Smith, M A; Tothill, P

    1988-01-01

    Details of clinical apparatus designed for the measurement of total body nitrogen (as an indicator of body protein), suitable for the critically ill, intensive-care patient are presented. Californium-252 radio-isotopic neutron sources are used, enabling a nitrogen measurement by prompt neutron activation analysis to be made in 40 min with a precision of +/- 3.2% for a whole body dose equivalent of 0.145 mSv. The advantages of Californium-252 over alternative neutron sources are discussed. A comparison between two irradiation/detection geometries is made, leading to an explanation of the geometry adopted for the apparatus. The choice of construction and shielding materials to reduce the count rate at the detectors and consequently to reduce the pile-up contribution to the nitrogen background is discussed. Salient features of the gamma ray spectroscopy system to reduce spectral distortion from pulse pile-up are presented.

  17. Chemical weapons detection by fast neutron activation analysis techniques

    Science.gov (United States)

    Bach, P.; Ma, J. L.; Froment, D.; Jaureguy, J. C.

    1993-06-01

    A neutron diagnostic experimental apparatus has been tested for nondestructive verification of sealed munitions. Designed to potentially satisfy a significant number of van-mobile requirements, this equipment is based on an easy to use industrial sealed tube neutron generator that interrogates the munitions of interest with 14 MeV neutrons. Gamma ray spectra are detected with a high purity germanium detector, especially shielded from neutrons and gamma ray background. A mobile shell holder has been used. Possible configurations allow the detection, in continuous or in pulsed modes, of gamma rays from neutron inelastic scattering, from thermal neutron capture, and from fast or thermal neutron activation. Tests on full scale sealed munitions with chemical simulants show that those with chlorine (old generation materials) are detectable in a few minutes, and those including phosphorus (new generation materials) in nearly the same time.

  18. Radio pulsar activity and the crustal Hall drift

    CERN Document Server

    Geppert, U; Melikidze, G

    2013-01-01

    Models of pulsar radio emission that are based on an inner accelerating region require the existence of very strong and small scale surface magnetic field structures at or near the canonical polar cap. The aim of this paper is to identify a mechanism that creates such field structures and maintains them over a pulsar's lifetime. The likely physical process that can create the required 'magnetic spots' is the Hall drift occurring in the crust of a neutron star. It is demonstrated, that the Hall drift can produce small scale strong surface magnetic field anomalies (spots) on timescales of $10^4$ years by means of non-linear interaction between poloidal and toroidal components of the subsurface magnetic field. These anomalies are characterized by strengths of about $10^{14}$ G and curvature radii of field lines of about $10^6$ cm, both of which are fundamental for generation of observable radio emission.

  19. Measurements of fusion neutron yields by neutron activation technique: Uncertainty due to the uncertainty on activation cross-sections

    Energy Technology Data Exchange (ETDEWEB)

    Stankunas, Gediminas, E-mail: gediminas.stankunas@lei.lt [Lithuanian Energy Institute, Laboratory of Nuclear Installation Safety, Breslaujos str. 3, LT-44403 Kaunas (Lithuania); EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Batistoni, Paola [ENEA, Via E. Fermi, 45, 00044 Frascati, Rome (Italy); EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Sjöstrand, Henrik; Conroy, Sean [Department of Physics and Astronomy, Uppsala University, PO Box 516, SE-75120 Uppsala (Sweden); EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2015-07-11

    The neutron activation technique is routinely used in fusion experiments to measure the neutron yields. This paper investigates the uncertainty on these measurements as due to the uncertainties on dosimetry and activation reactions. For this purpose, activation cross-sections were taken from the International Reactor Dosimetry and Fusion File (IRDFF-v1.05) in 640 groups ENDF-6 format for several reactions of interest for both 2.5 and 14 MeV neutrons. Activation coefficients (reaction rates) have been calculated using the neutron flux spectra at JET vacuum vessel, both for DD and DT plasmas, calculated by MCNP in the required 640-energy group format. The related uncertainties for the JET neutron spectra are evaluated as well using the covariance data available in the library. These uncertainties are in general small, but not negligible when high accuracy is required in the determination of the fusion neutron yields.

  20. Neutron Activation Analysis of Inhomogeneous Large Samples; An Explorative Study

    NARCIS (Netherlands)

    Baas, H.W.

    2004-01-01

    Neutron activation analysis is a powerful technique for the determination of trace-element concentrations. Since both neutrons that are used for activation and gamma rays that are detected have a high penetrating power, the technique can be applied for relatively large samples (up to 13 L), as demon

  1. Development of educational program for neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Yong Sam; Moon, Jong Hwa; Kim, Sun Ha; Ryel, Sung; Kang, Young Hwan; Lee, Kil Yong; Yeon, Yeon Yel; Cho, Seung Yeon

    2000-08-01

    This technical report is developed to apply an educational and training program for graduate student and analyst utilizing neutron activation analysis. The contents of guide book consists of five parts as follows; introduction, gamma-ray spectrometry and measurement statistics, its applications, to understand of comprehensive methodology and to utilize a relevant knowledge and information on neutron activation analysis.

  2. Activity report on neutron scattering research

    Energy Technology Data Exchange (ETDEWEB)

    Nagao, M.; Tawata, N.; Fujii, Y. [eds.] [Tokyo Univ. (Japan). Inst. for Solid State Physics

    1998-12-31

    The experiments performed on the thirteen university-owned spectrometers installed at JRR-3M of JAERI in the fiscal year of 1997 were described in this report. The latest ``Neutron News`` (vol. 9, issue 3, 1998) has featured highlights of the activities based on the JRR-3M and its cover displays a graph showing an endless increase of the number of proposals to the users program in the fiscal 1997. The university-owned spectrometers are available for general users all over Japan. The users` requirement for a higher flux beam reactor became larger and larger with time. Thus, JAERI has refurbished JRR-3 to satisfy these demands. In 1997, a joint project between Chiba University and Institute for Solid State Physics (ISSP) started to build a new 4-cycle diffractometer for crystal physics/chemistry at T{sub 2-2} beam port on a thermal guide. (M.N.)

  3. Evidence for Infrared-faint Radio Sources as z > 1 Radio-loud Active Galactic Nuclei

    Science.gov (United States)

    Huynh, Minh T.; Norris, Ray P.; Siana, Brian; Middelberg, Enno

    2010-02-01

    Infrared-Faint Radio Sources (IFRSs) are a class of radio objects found in the Australia Telescope Large Area Survey which have no observable mid-infrared counterpart in the Spitzer Wide-area Infrared Extragalactic (SWIRE) survey. The extended Chandra Deep Field South now has even deeper Spitzer imaging (3.6-70 μm) from a number of Legacy surveys. We report the detections of two IFRS sources in IRAC images. The non-detection of two other IFRSs allows us to constrain the source type. Detailed modeling of the spectral energy distribution of these objects shows that they are consistent with high-redshift (z >~ 1) active galactic nuclei.

  4. A dosimetry study of deuterium-deuterium neutron generator-based in vivo neutron activation analysis

    Science.gov (United States)

    Sowers, Daniel A.

    A neutron irradiation cavity for in vivo Neutron Activation Analysis (IVNAA) to detect manganese, aluminum, and other potentially toxic elements in human hand bone has been designed and its dosimetric specifications measured. The neutron source is a customized deuterium-deuterium neutron generator which produces neutrons at 2.45 MeV by the fusion reaction 2H(d, n)3He at a calculated flux of 7 x 108 +/-30% s-1. A moderator/reflector/shielding (5 cm high density polyethylene (HDPE), 5.3 cm graphite & 5.7 cm borated HDPE) assembly has been designed and built to maximize the thermal neutron flux inside the hand irradiation cavity and to reduce the extremity dose and effective dose to the human subject. Lead sheets are used to attenuate bremsstrahlung x rays and activation gammas. A Monte Carlo simulation (MCNP6) was used to model the system and calculate extremity dose. The extremity dose was measured with neutron and photon sensitive film badges and Fuji electronic pocket dosimeter (EPD). The neutron ambient dose outside the shielding was measured by Fuji NSN3, and photon dose by a Bicron MicroREM scintillator. Neutron extremity dose was calculated to be 32.3 mSv using MCNP6 simulations given a 10 min IVNAA measurement of manganese. Measurements by EPD and film badge indicate hand dose to be 31.7 +/- 0.8 mSv for neutron and 4.2 +/- 0.2 mSv for photon for 10 mins; whole body effective dose was calculated conservatively to be 0.052 mSv. Experimental values closely match values obtained from MCNP6 simulations. These are acceptable doses to apply the technology for a manganese toxicity study in a human population.

  5. Neutron activation analysis (NAA), radioisotope production via neutron activation (PNA) and fission product gas-jet (GJA)

    Energy Technology Data Exchange (ETDEWEB)

    Gaeggeler, H.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-11-01

    Three different non-diffractive applications of neutrons are outlined, neutron activation analysis, production of radionuclides, mostly for medical applications, and production of short-lived fission nuclides with a so-called gas-jet. It is shown that all three devices may be incorporated into one single insert at SINQ due to their different requests with respect to thermal neutron flux. Some applications of these three facilities are summarized. (author) 3 figs., 1 tab., 8 refs.

  6. Self-shielding effects in neutron spectra measurements for neutron capture therapy by means of activation foils.

    Science.gov (United States)

    Pytel, Krzysztof; Józefowicz, Krystyna; Pytel, Beatrycze; Koziel, Alina

    2004-01-01

    The design and optimisation of a neutron beam for neutron capture therapy (NCT) is accompanied by the neutron spectra measurements at the target position. The method of activation detectors was applied for the neutron spectra measurements. Epithermal neutron energy region imposes the resonance structure of activation cross sections resulting in strong self-shielding effects. The neutron self-shielding correction factor was calculated using a simple analytical model of a single absorption event. Such a procedure has been applied to individual cross sections from pointwise ENDF/B-VI library and new corrected activation cross sections were introduced to a spectra unfolding algorithm. The method has been verified experimentally both for isotropic and for parallel neutron beams. Two sets of diluted and non-diluted activation foils covered with cadmium were irradiated in the neutron field. The comparison of activation rates of diluted and non-diluted foils has demonstrated the correctness of the applied self-shielding model.

  7. Activities on Nuclear Data Measurements at Pohang Neutron Facility

    Science.gov (United States)

    Kim, Guinyun

    2009-03-01

    We report the activities of the Pohang Neutron Facility which consists of an electron linear accelerator, a water-cooled Ta target, and a 12-m time-of-flight path. It has been equipped with a four-position sample changer controlled remotely by a CAMAC data acquisition system, which allows simultaneous accumulation of the neutron time of flight spectra from 4 different detectors. It can be possible to measure the neutron total cross-sections in the neutron energy range from 0.1 eV to few hundreds eV by using the neutron time-of-flight method. A 6LiZnS(Ag) glass scintillator was used as a neutron detector. The neutron flight path from the water-cooled Ta target to the neutron detector was 12.1 m. The background level was determined by using notch-filters of Co, In, Ta, and Cd sheets. In order to reduce the gamma rays from bremsstrahlung and those from neutron capture, we employed a neutron-gamma separation system based on their different pulse shapes. The present measurements of several samples (Ta, Mo) are in general agreement with the evaluated data in ENDF/B-VI. We measured the thermal neutron capture cross-sections and the resonance integrals of the 186W(n,γ)187W reaction and the 98Mo(n,γ)99Mo reaction by the activation method using the 197Au(n,γ)198Au monitor reaction as a single comparator. We also report the isomeric yield ratios for the 44 m, gSc isomeric pairs produced from four different photonuclear reactions 45Sc(γ,n)44m,gSc, natTi(γ,xn1p)44m,gSc, natFe(γ,xn5p)52m,gMn, and 103Rh(γ,4n)99m,gRh by using the activation method.

  8. Optical-radio positional offsets for active galactic nuclei

    CERN Document Server

    Orosz, G

    2013-01-01

    Context. It will soon become possible to directly link the most accurate radio reference frame with the Gaia optical reference frame using many common extragalactic objects. It is important to know the level of coincidence between the radio and optical positions of compact active galactic nuclei (AGN). Aims. Using the best catalogues available at present, we investigate how many AGN with significantly large optical-radio positional offsets exist as well as the possible causes of these offsets. Methods. We performed a case study by finding optical counterparts to the International Celestial Reference Frame (ICRF2) radio sources in the Sloan Digital Sky Survey (SDSS) Data Release 9 (DR9). The ICRF2 catalogue was used as a reference because the radio positions determined by Very Long Baseline Interferometry (VLBI) observations are about two orders of magnitude more accurate than the optical positions. Results. We find 1297 objects in common for ICRF2 and SDSS DR9. Statistical analysis of the optical-radio differ...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-10-01

    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-in{close_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.

  10. Dark Matter-induced Collapse of Neutron Stars: A Possible Link Between Fast Radio Bursts and the Missing Pulsar Problem

    CERN Document Server

    Fuller, Jim

    2014-01-01

    Fast radio bursts (FRBs) are an emerging class of short and bright radio transients whose sources remain enigmatic. Within the galactic center, the non-detection of pulsars within the inner $\\sim \\!10\\,{\\rm pc}$ has created a missing pulsar problem that has intensified with time. With all reserve, we advance the notion that the two problems could be linked by a common solution: the collapse of neutron stars (NS) due to capture and sedimentation of dark matter (DM) within their cores. Bramante \\& Linden (2014), Phys.\\ Rev.\\ Lett.~19, 191301 showed that certain DM properties allow for rapid NS collapse within the high DM density environments near galactic centers while permitting NS survival elsewhere. Each DM-induced collapse could generate an FRB as the NS magnetosphere is suddenly expelled. This scenario could explain several features of FRBs: their short time scales, large energies, locally produced scattering tails, and high event rates. Our scenario predicts that FRBs are localized to galactic centers...

  11. The jet-disc connection: evidence for a reinterpretation in radio loud and radio quiet active galactic nuclei

    CERN Document Server

    Garofalo, David

    2013-01-01

    To constrain models of the jet-disc connection, we explore Eddington ratios reported in Foschini (2011) and interpret them in relation to the values in Sikora et al. across the active galactic nuclei population from radio loud quasars, their flat spectrum radio quasar subclass, the recently discovered gamma-ray loud narrow-line type 1 Seyfert galaxies, Fanaroff-Riley type I (FRI) radio galaxies and radio quiet quasars of the Palomar Green survey. While appeal to disc truncation in radiatively inefficient flow appears to explain the observed inverse relation between radio loudness and Eddington ratio in radio loud and radio quiet quasars, FR I objects, scale invariance and recent data on powerful jets in narrow-line Seyfert 1 galaxies offer compelling arguments in favour of a reinterpretaion of the jet-disc connection.

  12. PKS 0347+05: a radio-loud/radio-quiet double active galactic nucleus system triggered in a major galaxy merger

    NARCIS (Netherlands)

    Tadhunter, C. N.; Ramos Almeida, C.; Morganti, R.; Holt, J.; Rose, M.; Dicken, D.; Inskip, K.

    2012-01-01

    We present optical, infrared (IR) and radio observations of the powerful Fanaroff-Riley type II (FR II) radio source PKS 0347+05 (z = 0.3390), and demonstrate that it is a rare example of a radio-loud/radio-quiet double active galactic nucleus (AGN) system, comprising a weak-line radio galaxy (WLRG)

  13. PKS 0347+05: a radio-loud/radio-quiet double active galactic nucleus system triggered in a major galaxy merger

    NARCIS (Netherlands)

    Tadhunter, C. N.; Ramos Almeida, C.; Morganti, R.; Holt, J.; Rose, M.; Dicken, D.; Inskip, K.

    2012-01-01

    We present optical, infrared (IR) and radio observations of the powerful Fanaroff-Riley type II (FR II) radio source PKS 0347+05 (z = 0.3390), and demonstrate that it is a rare example of a radio-loud/radio-quiet double active galactic nucleus (AGN) system, comprising a weak-line radio galaxy (WLRG)

  14. Radio Imaging Observations of Solar Activity Cycle and Its Anomaly

    Science.gov (United States)

    Shibasaki, K.

    2011-12-01

    The 24th solar activity cycle has started and relative sunspot numbers are increasing. However, their rate of increase is rather slow compared to previous cycles. Active region sizes are small, lifetime is short, and big (X-class) flares are rare so far. We study this anomalous situation using data from Nobeyama Radioheliograph (NoRH). Radio imaging observations have been done by NoRH since 1992. Nearly 20 years of daily radio images of the Sun at 17 GHz are used to synthesize a radio butterfly diagram. Due to stable operation of the instrument and a robust calibration method, uniform datasets are available covering the whole period of observation. The radio butterfly diagram shows bright features corresponding to active region belts and their migration toward low latitude as the solar cycle progresses. In the present solar activity cycle (24), increase of radio brightness is delayed and slow. There are also bright features around both poles (polar brightening). Their brightness show solar cycle dependence but peaks around solar minimum. Comparison between the last minimum and the previous one shows decrease of its brightness. This corresponds to weakening of polar magnetic field activity between them. In the northern pole, polar brightening is already weakened in 2011, which means it is close to solar maximum in the northern hemisphere. Southern pole does not show such feature yet. Slow rise of activity in active region belt, weakening of polar activity during the minimum, and large north-south asymmetry in polar activity imply that global solar activity and its synchronization are weakening.

  15. Progress in neutron activation analysis for uranium

    Institute of Scientific and Technical Information of China (English)

    杜鸿善; 李贵群; 董桂芝; 李俊兰; K.H.Chiu; C.M.Wai

    1996-01-01

    A new type of extractant, sym-dibenzo-16-crown-5-oxyhydroxamic acid (HL) is introduced. The extractions of UO22+, Na+, K+, Sr2+, Ba2+ and Br- were studied with HL in chloroform. The results obtained show that UO22+ can be quantitatively extracted at pH values above 5, whereas the extractions of K+, Na+, Sr2+, Ba2+ and Br- are negligible in the pH range of 2 - 7. The dependence of the distribution ratio of U(VI) on both the concentration of the HL and pH are linear, and they have the same slope of 2. This suggests that U(VI) appears to form a 1:2 complex with ligand. Uranium(VI) can be selectively separated and concentrated from interfering elements such as Na, K, Sr and Br by solvent extraction with HL under specific conditions. The recovery of uranium is nearly 100% and the radionudear purity of uranium is greater than 99.99%. Therefore, neutron activation analysis has greatly improved the sensitivity and accuracy for the detection of trace uranium from seawater.

  16. Measurements of DT and DD neutron yields by neutron activation on TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, C.W.; Larson, A.R. [Los Alamos National Lab., NM (United States); LeMunyan, G. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Loughlin, M.J. [JET Joint Undertaking, Abingdon (United Kingdom)

    1995-03-01

    A variety of elemental foils have been activated by neutron fluence from TFTR under conditions with the DT neutron yield per shot ranging from 10{sup 12} to over 10{sup 18}, and with the DT/(DD+DT) neutron ratio varying from 0.5% (from triton burnup) to unity. Linear response over this large dynamic range is obtained by reducing the mass of the foils and increasing the cooling time, all while accepting greatly improved counting statistics. Effects on background gamma-ray lines from foil-capsule-material contaminants, and the resulting lower limits on activation foil mass, have been determined. DT neutron yields from dosimetry standard reactions on aluminum, chromium, iron, nickel, zirconium, and indium are in agreement within the {+-}9% (one-sigma) accuracy of the measurements; also agreeing are yields from silicon foils using the ACTL library cross-section, while the ENDF/B-V library has too low a cross-section. Preliminary results from a variety of other threshold reactions are presented. Use of the {sup 115}In(n.n{prime}) {sup 115m}In reaction (0.42 times as sensitive to DT neutrons as DD neutrons) in conjunction with pure-DT reactions allows a determination of the DT/(DD+DT) ratio in trace tritium or low-power tritium beam experiments.

  17. Planetary Geochemistry Using Active Neutron and Gamma Ray Instrumentation

    Science.gov (United States)

    Parsons, A.; Bodnarik, J.; Evans, L.; Floyd, S.; Lim, L.; McClanahan, T.; Namkung, M.; Schweitzer, J.; Starr, R.; Trombka, J.

    2010-01-01

    The Pulsed Neutron Generator-Gamma Ray And Neutron Detector (PNG-GRAND) experiment is an innovative application of the active neutron-gamma ray technology so successfully used in oil field well logging and mineral exploration on Earth, The objective of our active neutron-gamma ray technology program at NASA Goddard Space Flight Center (NASA/GSFC) is to bring the PNG-GRAND instrument to the point where it can be flown on a variety of surface lander or rover missions to the Moon, Mars, Venus, asterOIds, comets and the satellites of the outer planets, Gamma-Ray Spectrometers have been incorporated into numerous orbital planetary science missions and, especially in the case of Mars Odyssey, have contributed detailed maps of the elemental composition over the entire surface of Mars, Neutron detectors have also been placed onboard orbital missions such as the Lunar Reconnaissance Orbiter and Lunar Prospector to measure the hydrogen content of the surface of the moon, The DAN in situ experiment on the Mars Science Laboratory not only includes neutron detectors, but also has its own neutron generator, However, no one has ever combined the three into one instrument PNG-GRAND combines a pulsed neutron generator (PNG) with gamma ray and neutron detectors to produce a landed instrument that can determine subsurface elemental composition without drilling. We are testing PNG-GRAND at a unique outdoor neutron instrumentation test facility recently constructed at NASA/GSFC that consists of a 2 m x 2 m x 1 m granite structure in an empty field, We will present data from the operation of PNG-GRAND in various experimental configurations on a known sample in a geometry that is identical to that which can be achieved on a planetary surface. We will also compare the material composition results inferred from our experiments to both an independent laboratory elemental composition analysis and MCNPX computer modeling results,

  18. Neutron threshold activation detectors (TAD) for the detection of fissions

    Science.gov (United States)

    Gozani, Tsahi; Stevenson, John; King, Michael J.

    2011-10-01

    Prompt fission neutrons are one of the strongest signatures of the fission process. Depending on the fission inducing radiation, their average number ranges from 2.5 to 4 neutrons per fission. They are more energetic and abundant, by about 2 orders of magnitude, than the delayed neutrons (≈3 vs. ≈0.01) that are commonly used as indicators for the presence of fissionable materials. The detection of fission prompt neutrons, however, has to be done in the presence of extremely intense probing radiation that stimulated them. During irradiation, the fission stimulation radiation, X-rays or neutrons, overwhelms the neutron detectors and temporarily incapacitate them. Consequently, by the time the detectors recover from the source radiation, fission prompt neutrons are no longer emitted. In order to measure the prompt fission signatures under these circumstances, special measures are usually taken with the detectors such as heavy shielding with collimation, use of inefficient geometries, high pulse height bias and gamma-neutron separation via pulse-shape discrimination with an appropriate organic scintillator. These attempts to shield the detector from the flash of radiation result in a major loss of sensitivity. It can lead to a complete inability to detect the fission prompt neutrons. In order to overcome the blinding induced background from the source radiation, the detection of prompt fission neutrons needs to occur long after the fission event and after the detector has fully recovered from the source overload. A new approach to achieve this is to detect the delayed activation induced by the fission neutrons. The approach demonstrates a good sensitivity in adverse overload situations (gamma and neutron "flash") where fission prompt neutrons could normally not be detected. The new approach achieves the required temporal separation between the detection of prompt neutrons and the detector overload by the neutron activation of the detector material. The technique

  19. In vivo neutron activation facility at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-11-01

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

  20. Contribution to the determination of Sb-Ag-Cu-Ga-Mo-Zn using 14 MeV neutron activation; Contribution au dosage de Sb-Ag-Cu-Ga-Mo-Zn par activation aux neutrons de 14 MeV

    Energy Technology Data Exchange (ETDEWEB)

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

    1966-04-01

    By using, 14 MeV, neutron irradiation it is possible to extend the field of application of neutron radio-activation analysis, in particular to the case of light elements. For, many other elements it can replace in-pile irradiation thereby making it possible, thanks to portable 14 MeV neutron generators, to carry out radio-activation analyses away from nuclear-research c e n t r e s. With a view to applying this analytical technique to routine work, we have developed some rapid chemical separation methods in order to make possible the determination of several elements which after exposure to fast neutrons, produce {beta} emitting nuclides which cannot be differentiated by a simple instrumental study, the emitted radiation being of the same type and of similar half-life the two cases. (author) [French] L'irradiation au moyen de neutrons de 14 MeV permet d'etendre le domaine d'application de l'analyse par radioactivation neutronique, en particulier aux elements legers. Cependant pour de nombreux autres elements elle peut remplacer l'irradiation en reacteur nucleaire permettant ainsi grace aux ensembles portables producteurs de neutrons de 14 MeV, l'extension de l'analyse par radioactivation a l'exterieur des centres d'etudes nucleaires. Dans le but d'appliquer cette methode d'analyse a des travaux de routine, nous avons mis au point des separations chimiques rapides, afin de permettre le dosage de quelques elements qui par irradiation aux neutrons rapides, engendrent des nucleides emetteurs {beta} qu'une simple etude instrumentale ne peut differencier en raison de l'identite de leur rayonnement et de leurs periodes radioactives trop proches. (auteur)

  1. Active miniature radio frequency field probe

    Directory of Open Access Journals (Sweden)

    A. Glasmachers

    2003-01-01

    Full Text Available For the measuring of the electromagnetic interference (e.g. on men of RF fields produced by mobile communication equipment field probes are required with high spatial resolution and high sensitivity. Available passive probes show good results with respect to bandwidth and low field distortion, but do not provide the required sensitivity and dynamic range. A significant limitation for active miniature probes is the power supply problem, because batteries cannot be used. Therefore the effect of high impedance connection lines is examined by a numerical field simulation. Different approaches for the design of an active probe are discussed, a favourable solution with a logarithmic demodulator is implemented and measuring results are presented.

  2. Control of active reflector system for radio telescope

    Science.gov (United States)

    Zhou, Guo-hua; Li, Guo-ping; Zhang, Yong; Zhang, Zhen-chao

    2016-10-01

    According to the control requirements of the active reflector surface in the 110 m radio telescope at QiTai(QTT) Xinjiang, a new displacement actuator and a new displacement control system were designed and manufactured and then their characteristics were tested by a dual-frequency laser interferometer in the micro-displacement laboratory. The displacement actuator was designed by a scheme of high precision worm and roller screw structures, and the displacement control system was based on a ARM micro-processor. Finally, the S curve acceleration control methods were used to design the hardware platform and software algorithm for the active reflection surface of the control system. The test experiments were performed based on the laser metrology system on an active reflector close-loop antenna prototype for large radio telescope. Experimental results indicate that it achieves a 30 mm working stroke and 5 μm RMS motion resolution. The accuracy (standard deviation) is 3.67 mm, and the error between the determined and theoretical values is 0.04% when the rated load is 300 kg, the step is 2 mm and the stroke is 30mm. Furthermore, the active reflector integrated system was tested by the laser sensors with the accuracy of 0.25 μm RMS on 4-panel radio telescope prototype, the measurement results show that the integrated precision of the active reflector closed-loop control system is less than 5 μm RMS, and well satisfies the technical requirements of active reflector control system of the QTT radio telescope in 3 mm wavelength.

  3. 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

  4. Background by neutron activation in GERDA

    Energy Technology Data Exchange (ETDEWEB)

    Meierhofer, Georg; Dietrich, Dennis; Freund, Kai; Grabmayr, Peter; Hegai, Alexander; Jochum, Josef; Knapp, Markus; Ritter, Florian [Kepler Center for Astro and Particle Physics, Universitaet Tuebingen (Germany); Canella, Lea [Institut fuer Radiochemie, Technische Universitaet Muenchen (Germany); Jolie, Jan [Institut fuer Kernphysik, Universitaet zu Koeln (Germany); Kudejova, Petra [FRM II, Technische Universitaet Muenchen (Germany)

    2010-07-01

    The observation of the neutrinoless double beta decay is a proof of the Majorana nature of the neutrino. The long half-life of this decay requires experiments of very low background rates in the region of interest at Q{sub {beta}}{sub {beta}}. Prompt {gamma}-rays after neutron capture on germanium and the {beta}-decay of {sup 77}Ge contribute to the background in experiments using {sup 76}Ge for the search of the neutrinoless double beta decay. The poorly known prompt {gamma}-ray spectra and the neutron capture cross sections for the (n,{gamma}) reactions of {sup 74}Ge and {sup 76}Ge were measured at the research reactor FRM II (Munich). The obtained data are needed in MC simulations for qualitative and quantitative background prediction in the Gerda experiment. The data and their implication on the background in Gerda are presented.

  5. Analysis of natural neutron flux in a seismically active zone

    Directory of Open Access Journals (Sweden)

    V. F. Ostapenko

    2003-01-01

    Full Text Available In a seismically active zone in the near Almaty area (Kazakhstan since 1996 observations of variations of a natural neutron flux have been conducted. Sometimes the neutron flux rises sharply within the one-hour interval in comparison with the background. It occurs on the eve of activation of seismic processes. Increase of the neutron flux level had taken place from 1 h to 10 days prior to earthquakes. It is also indicated a tendency of growth of the anomaly level in accordance with the growth of energetic class of the subsequent earthquake. A character of connection between the neutron flux and earthquakes is still not clear. It is proposed that the neutron flux anomalies caused by variations of cosmic radiation intensity under action of fluxes of solar material, which is burst into interplanetary space (solar wind during solar flares. Energy of the solar wind transferred to Earth puts into action a trigger mechanism of the process of initiation of earthquakes at those places where conditions have already been prepared for them. The neutron flux anomalies can be used as substantial additional information for classical geophysical methods of short-term earthquake prediction.

  6. Quantitative neutron capture resonance analysis verified with instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Blaauw, M. E-mail: blaauw@iri.tudelft.nl; Postma, H.; Mutti, P

    2003-06-01

    The newly developed elemental analysis technique Neutron Resonance Capture Analysis (NRCA) was verified by analyzing a prehistoric bronze arrowhead with both NRCA and Instrumental Activation Analysis (INAA). In NRCA, elements are identified through their neutron resonance capture energies as determined through detection of prompt capture gamma-rays as a function of time of flight. The quantification is obtained from the resonance peak areas. Corrections are required for neutron-energy-dependent dead time and self-shielding, the latter also depending on Doppler broadening. The analysis program REFIT, of which the intended use is the determination of the resonance parameters, was used to this end. The agreement observed between INAA and NRCA results indicates that the NRCA results obtained are accurate.

  7. Ultrafast outflows in radio-loud active galactic nuclei

    Science.gov (United States)

    Tombesi, F.; Tazaki, F.; Mushotzky, R. F.; Ueda, Y.; Cappi, M.; Gofford, J.; Reeves, J. N.; Guainazzi, M.

    2014-09-01

    Recent X-ray observations show absorbing winds with velocities up to mildly relativistic values of the order of ˜0.1c in a limited sample of six broad-line radio galaxies. They are observed as blueshifted Fe XXV-XXVI K-shell absorption lines, similarly to the ultrafast outflows (UFOs) reported in Seyferts and quasars. In this work we extend the search for such Fe K absorption lines to a larger sample of 26 radio-loud active galactic nuclei (AGN) observed with XMM-Newton and Suzaku. The sample is drawn from the Swift Burst Alert Telescope 58-month catalogue and blazars are excluded. X-ray bright Fanaroff-Riley Class II radio galaxies constitute the majority of the sources. Combining the results of this analysis with those in the literature we find that UFOs are detected in >27 per cent of the sources. However, correcting for the number of spectra with insufficient signal-to-noise ratio, we can estimate that the incidence of UFOs is this sample of radio-loud AGN is likely in the range f ≃ (50 ± 20) per cent. A photoionization modelling of the absorption lines with XSTAR allows us to estimate the distribution of their main parameters. The observed outflow velocities are broadly distributed between vout ≲ 1000 km s-1 and vout ≃ 0.4c, with mean and median values of vout ≃ 0.133c and vout ≃ 0.117c, respectively. The material is highly ionized, with an average ionization parameter of logξ ≃ 4.5 erg s-1 cm, and the column densities are larger than NH > 1022 cm-2. Overall, these characteristics are consistent with the presence of complex accretion disc winds in a significant fraction of radio-loud AGN and demonstrate that the presence of relativistic jets does not preclude the existence of winds, in accordance with several theoretical models.

  8. Long duration radio transients lacking optical counterparts are possibly Galactic Neutron Stars

    CERN Document Server

    Ofek, E O; Gal-Yam, A; Frail, D; Kasliwal, M M; Kulkarni, S R; Waxman, E

    2009-01-01

    (abridged) Recently, a new class of radio transients in the 5-GHz band was detected by Bower et al. We present new deep near-Infrared (IR) observations of the field containing these transients, and find no counterparts down to a limiting magnitude of K=20.4 mag. We argue that the bright (>1 Jy) radio transients recently reported by Kida et al. are consistent with being additional examples of the Bower et al. transients. We refer to these groups of events as "long-duration radio transients". The main characteristics of this population are: time scales longer than 30 minute but shorter than several days; rate, ~10^3 deg^-2 yr^-1; progenitors sky surface density of >60 deg^-2 (95% C.L.) at Galactic latitude ~40 deg; 1.4-5 GHz spectral slopes, f_\

  9. The Energetics and Lifetimes of Local Radio Active Galactic Nuclei

    CERN Document Server

    Turner, Ross J

    2015-01-01

    We present a model describing the evolution of Fanaroff-Riley type I and II radio AGN, and the transition between these classes. We quantify galaxy environments using a semi-analytic galaxy formation model, and apply our model to a volume-limited low redshift ($0.03 \\leqslant z \\leqslant 0.1$) sample of observed AGN to determine the distribution of jet powers and active lifetimes at the present epoch. Radio sources in massive galaxies are found to remain active for longer, spend less time in the quiescent phase, and inject more energy into their hosts than their less massive counterparts. The jet power is independent of the host stellar mass within uncertainties, consistent with maintenance-mode AGN feedback paradigm. The environments of these AGN are in or close to long-term heating-cooling balance. We also examine the properties of high- and low-excitation radio galaxy sub-populations. The HERGs are younger than LERGs by an order of magnitude, whilst their jet powers are greater by a factor of four. The Edd...

  10. Neutron orbital radii in {sup 13} C; Radios orbitales neutronicos en {sup 13} C

    Energy Technology Data Exchange (ETDEWEB)

    Aguilera R, E.F.; Murillo, G.; Ramirez, J.J.; Avila, O.L. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1988-01-15

    In this work its were carried out experimental measurements of the reaction {sup 12}C(d,p) {sup 13}C at low energy. Preliminary results of a DWBA analysis of the data are presented, and the possibility of using this reaction to obtain the orbital radius of the transferred neutron is investigated. (Author)

  11. Active detection of small quantities of shielded highly-enriched uranium using low-dose 60-kev neutron interrogation

    Science.gov (United States)

    Kerr, Phil; Rowland, Mark; Dietrich, Dan; Stoeffl, Wolfgang; Wheeler, Boyd; Nakae, Les; Howard, Doug; Hagmann, Chris; Newby, Jason; Porter, Robert

    2007-08-01

    Active interrogation with low-energy neutrons provides a search technique for highly-enriched uranium concealed in cargo. We describe the technique and show initial results using a low-dose 60-keV neutron beam. This technique produces a clear induced fission signal in the presence of small quantities of 235U. The technique has been validated with low-Z and high-Z cargo materials. The technique uses a forward-directed beam of 60-keV neutrons to induce fission in 235U. Detection of the fast fission neutrons with pulse-shape discriminating scintillators is then the signature for 235U. The beam of neutrons is generated with a 1.93 MeV proton beam impinging on a natural lithium target. The proton beam is produced by a radio-frequency quadrupole LINAC. The 60 keV neutron beam is forward-directed because the 7Li(p, n) reaction is just above threshold for a proton energy of 1.93 MeV.

  12. Intercomparison of Neutron Beam Guides for Cold Neutron Activation Station at HANARO using McStas/VITESS/RESTRAX Codes

    Energy Technology Data Exchange (ETDEWEB)

    Tuan, Hoang Sy Minh; Sun, Gwang Min [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-05-15

    The HANARO (KAERI) research reactor has been developed a neutron guide system for cold neutron (CN) research facilities since July, 2003. The neutron guide system plays an important role in transporting cold neutrons from the CN source to the neutron facilities as CN-NDP, CN-PGAA, SANS, etc. The CN activation station is being installed in the HANARO cold-neutron research project. The CN-NDP and CN-PGAA were selected as two facilities using at this station. At the end position of CG1 and CG2B beam guides, the CN-NDP and CN-PGAA will be installed in the CN guide hall. In order to predict the neutron flux and intensity values at the CG1 and CG2B beam guides, the simulation results of neutron flux at the CG1 and CG2B beam guides are presented by using several Monte Carlo (MC) neutron ray-tracing simulation codes. The intercomparison of neutron flux values between McStas, VITESS and RESTRAX are performed for getting fairly correct results at two neutron beam guides

  13. Triton burnup measurements in KSTAR using a neutron activation system

    Science.gov (United States)

    Jo, Jungmin; Cheon, MunSeong; Kim, Jun Young; Rhee, T.; Kim, Junghee; Shi, Yue-Jiang; Isobe, M.; Ogawa, K.; Chung, Kyoung-Jae; Hwang, Y. S.

    2016-11-01

    Measurements of the time-integrated triton burnup for deuterium plasma in Korea Superconducting Tokamak Advanced Research (KSTAR) have been performed following the simultaneous detection of the d-d and d-t neutrons. The d-d neutrons were measured using a 3He proportional counter, fission chamber, and activated indium sample, whereas the d-t neutrons were detected using activated silicon and copper samples. The triton burnup ratio from KSTAR discharges is found to be in the range 0.01%-0.50% depending on the plasma conditions. The measured burnup ratio is compared with the prompt loss fraction of tritons calculated with the Lorentz orbit code and the classical slowing-down time. The burnup ratio is found to increase as plasma current and classical slowing-down time increase.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-01

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

  15. Current status of neutron activation analysis in HANARO Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Yong Sam; Moon, Jong Hwa; Sohn, Jae Min [Korea Atomic Energy Research Institute, Daejeon (Korea)

    2003-03-01

    The facilities for neutron activation analysis in the HANARO (Hi-flux Advanced Neutron Application Research Reactor) are described and the main applications of NAA (Neutron Activation Analysis) are reviewed. The sample irradiation tube, automatic and manual pneumatic transfer system were installed at three irradiation holes of HANARO at the end of 1995. The performance of the NAA facility was examined to identify the characteristics of the tube transfer system, irradiation sites and custom-made polyethylene irradiation capsule. The available thermal neutron fluxes at irradiation sites are in the range of 3 x 10{sup 13} - 1 x 10{sup 14} n/cm{sup 2}{center_dot}s and cadmium ratios are in 15 - 250. For an automatic sample changer for gamma-ray counting, a domestic product was designed and manufactured. An integrated computer program (Labview) to analyse the content was developed. In 2001, PGNAA (Prompt Gamma Neutron Activation Analysis) facility has been installed using a diffracted neutron beam of ST1. NAA has been applied in the trace component analysis of nuclear, geological, biological, environmental and high purity materials, and various polymers for research and development. The improvement of analytical procedures and establishment of an analytical quality control and assurance system were studied. Applied research and development for the environment, industry and human health by NAA and its standardization were carried out. For the application of the KOLAS (Korea Laboratory Accreditation Scheme), evaluation of measurement uncertainty and proficiency testing of reference materials were performed. Also to verify the reliability and to validate analytical results, intercomparison studies between laboratories were carried out. (author)

  16. Discovery of ultra-steep spectrum giant radio galaxy with recurrent radio jet activity in Abell 449

    CERN Document Server

    Hunik, D

    2016-01-01

    We report a discovery of a 1.3 Mpc diffuse radio source with extremely steep spectrum fading radio structures in the vicinity of the Abell 449 cluster of galaxies. Its extended diffuse lobes are bright only at low radio frequencies and their synchrotron age is about 160 Myr. The parent galaxy of the extended relic structure, which is the dominant galaxy within the cluster, is starting a new jet activity. There are three weak X-rays sources in the vicinity of the cluster as found in the ROSAT survey, however it is not known if they are connected with this cluster of galaxies. Just a few radio galaxy relics are currently known in the literature, as finding them requires sensitive and high angular resolution low-frequency radio observations. Objects of this kind, which also are starting a new jet activity, are important for understanding the life cycle and evolution of active galactic nuclei. A new 613 MHz map as well as the archival radio data pertaining to this object are presented and analyzed.

  17. DISCOVERY OF ULTRA-STEEP SPECTRUM GIANT RADIO GALAXY WITH RECURRENT RADIO JET ACTIVITY IN ABELL 449

    Energy Technology Data Exchange (ETDEWEB)

    Hunik, Dominika; Jamrozy, Marek, E-mail: dominika.hunik@uj.edu.pl [Obserwatorium Astronomiczne, Uniwersytet Jagielloński, ul. Orla 171, 30-244 Kraków (Poland)

    2016-01-20

    We report a discovery of a 1.3 Mpc diffuse radio source with extremely steep spectrum fading radio structures in the vicinity of the Abell 449 cluster of galaxies. Its extended diffuse lobes are bright only at low radio frequencies and their synchrotron age is about 160 Myr. The parent galaxy of the extended relic structure, which is the dominant galaxy within the cluster, is starting a new jet activity. There are three weak X-rays sources in the vicinity of the cluster as found in the ROSAT survey, however it is not known if they are connected with this cluster of galaxies. Just a few radio galaxy relics are currently known in the literature, as finding them requires sensitive and high angular resolution low-frequency radio observations. Objects of this kind, which also are starting a new jet activity, are important for understanding the life cycle and evolution of active galactic nuclei. A new 613 MHz map as well as the archival radio data pertaining to this object are presented and analyzed.

  18. Neutron Field Measurements in Phantom with Foil Activation Methods.

    Science.gov (United States)

    1986-11-29

    jI25 Ii III uumu ullli~ S....- - Lb - w * .qJ’ AD-A 192 122 ulJ. IL (pj DNA-TR-87- 10 N EUTRON FIELD MEASUREMENTS IN PHANTOM WITH FOIL ACTIVATION...SAND II Measurements in Phantom 6 4 The 5-Foil Neutron Dosimetry Method 29 5 Comparison of SAND II and Simple 5-Foil Dosimetry Method 34 6 Thermal ...quite reasonable. The monkey phantom spectrum differs from the NBS U-235 fission spectrum in that the former has a I/E tail plus thermal -neutron peak

  19. Status report of CPHS and neutron activities at Tsinghua University

    Science.gov (United States)

    Wang, X.; Xing, Q.; Zheng, S.; Yang, Y.; Gong, H.; Xiao, Y.; Wu, H.; Guan, X.; Du, T.

    2016-11-01

    The Compact Pulsed Hadron Source (CPHS) project that was launched in September 2009 at Tsinghua University has reached a first commissioning stage in conjunction with ongoing activities to fulfill the eventual design goal of a ˜ 1013 n/s epithermal-to-cold neutron yield for education, instrumentation development, and industrial applications. Here, we report the latest progress on the commissioning and applications of 3MeV proton and neutron beam lines in the last one and half years, and the design, fabrication, engineering of the 13MeV/16kW proton accelerator system.

  20. Active helium target: Neutron scalar polarizability extraction via Compton scattering

    Energy Technology Data Exchange (ETDEWEB)

    Morris, Meg, E-mail: mmorris@mta.ca; Hornidge, David [Mount Allison University, Sackville, New Brunswick (Canada); Annand, John; Strandberg, Bruno [University of Glasgow, Scotland (United Kingdom)

    2015-12-31

    Precise measurement of the neutron scalar polarizabilities has been a lasting challenge because of the lack of a free-neutron target. Led by the University of Glasgow and the Mount Allison University groups of the A2 collaboration in Mainz, Germany, preparations have begun to test a recent theoretical model with an active helium target with the hope of determining these elusive quantities with small statistical, systematic, and model-dependent errors. Apparatus testing and background-event simulations have been carried out, with the full experiment projected to run in 2015. Once determined, these values can be applied to help understand quantum chromodynamics in the nonperturbative region.

  1. Progress in small angle neutron scattering activities in Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Abdul Aziz Bin Mohamed; Azali Bin Muhamad; Shukri Bin Mohd [Malaysian Institute for Nuclear Technology Research (MINT), Bangi, Kajang (Malaysia)

    1999-10-01

    The current status of SANS (Small Angle Neutron Scattering facility) activities in Malaysia has been presented. Many works need to be done for system improvement before the system can be confidently used as one of effective quality control tools in materials production and engineering sectors. (author)

  2. Applied research of environmental monitoring using instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Young Sam; Moon, Jong Hwa; Chung, Young Ju

    1997-08-01

    This technical report is written as a guide book for applied research of environmental monitoring using Instrumental Neutron Activation Analysis. The contents are as followings; sampling and sample preparation as a airborne particulate matter, analytical methodologies, data evaluation and interpretation, basic statistical methods of data analysis applied in environmental pollution studies. (author). 23 refs., 7 tabs., 9 figs.

  3. Instrumental Neutron Activation Analysis Technique using Subsecond Radionuclides

    DEFF Research Database (Denmark)

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

    1987-01-01

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

  4. Instrumental neutron activation analysis of some ayurvedic medicines: Pt. 1

    Energy Technology Data Exchange (ETDEWEB)

    Rajurkar, N.S.; Vinchurkar, M.S. (Poona Univ., Pune (India). Dept. of Chemistry)

    1992-12-01

    Several medicines have been manufactured and prescribed to overcome mineral deficiencies in the human body. Such medicines are mixtures of several components. The present work is undertaken to analyze various Ayurvedic medicines, mainly of herbal origin and used for different purposes, for their elemental contents, by neutron activation analysis. (author).

  5. BNL ACTIVITIES IN ADVANCED NEUTRON SOURCE DEVELOPMENT: PAST AND PRESENT

    Energy Technology Data Exchange (ETDEWEB)

    HASTINGS,J.B.; LUDEWIG,H.; MONTANEZ,P.; TODOSOW,M.; SMITH,G.C.; LARESE,J.Z.

    1998-06-14

    Brookhaven National Laboratory has been involved in advanced neutron sources almost from its inception in 1947. These efforts have mainly focused on steady state reactors beginning with the construction of the first research reactor for neutron beams, the Brookhaven Graphite Research Reactor. This was followed by the High Flux Beam Reactor that has served as the design standard for all the subsequent high flux reactors constructed worldwide. In parallel with the reactor developments BNL has focused on the construction and use of high energy proton accelerators. The first machine to operate over 1 GeV in the world was the Cosmotron. The machine that followed this, the AGS, is still operating and is the highest intensity proton machine in the world and has nucleated an international collaboration investigating liquid metal targets for next generation pulsed spallation sources. Early work using the Cosmotron focused on spallation product studies for both light and heavy elements into the several GeV proton energy region. These original studies are still important today. In the sections below the authors discuss the facilities and activities at BNL focused on advanced neutron sources. BNL is involved in the proton source for the Spallation Neutron source, spectrometer development at LANSCE, target studies using the AGS and state-of-the-art neutron detector development.

  6. BNL Activities in Advanced Neutron Source Development: Past and Present

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, J.B.; Ludewig, H.; Montanez, P.; Todosow, M.; Smith, G.C.; Larese, J.Z.

    1998-06-14

    Brookhaven National Laboratory has been involved in advanced neutron sources almost from its inception in 1947. These efforts have mainly focused on steady state reactors beginning with the construction of the first research reactor for neutron beams, the Brookhaven Graphite Research Reactor. This was followed by the High Flux Beam Reactor that has served as the design standard for all the subsequent high flux reactors constructed worldwide. In parallel with the reactor developments BNL has focused on the construction and use of high energy proton accelerators. The first machine to operate over 1 GeV in the world was the Cosmotron. The machine that followed this, the AGS, is still operating and is the highest intensity proton machine in the world and has nucleated an international collaboration investigating liquid metal targets for next generation pulsed spallation sources. Early work using the Cosmotron focused on spallation product studies for both light and heavy elements into the several GeV proton energy region. These original studies are still important today. In this report we discuss the facilities and activities at BNL focused on advanced neutron sources. BNL is involved in the proton source for the Spallation Neutron source, spectrometer development at LANSCE, target studies using the AGS and state-of-the-art neutron detector development.

  7. Active neutron spectrometry with superheated drop (bubble) detectors

    Energy Technology Data Exchange (ETDEWEB)

    d`Errico, F.; Curzio, G. [Pisa Univ. (Italy). Dipt. di Costruzioni Meccaniche e Nucleari]|[Istituto Nazionale di Fisica Nucleare, Pisa (Italy); Alberts, W.G.; Guldbakke, S.; Kluge, H.; Matzke, M. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

    1995-12-31

    A new approach to neutron spectrometry has been developed in a joint project by DCMN Pisa and PTB Braunschweig. The system relies on the use of superheated drop (bubble) detectors and the thermodynamic control of their detection thresholds. This is the result of investigations into the physics of these detectors combined with extensive experimental work on their response to neutrons. These studies indicate that the higher the degree of superheat of a detector, the lower the minimum energy that secondary charged particles, and therefore primary neutrons, must impart to the droplets in order to nucleate their evaporation. Therefore, by controlling the temperature of the detectors, accurately defined detection thresholds, virtually any desired one, can be generated in the 0.01-10 MeV neutron energy range. An active prototype instrument has been developed: bubbles are counted acoustically and temperature regulation is achieved by means of thin heating strips. Tests with reference neutron spectra show that the system is suitable for few-channel spectrometry and may be useful for radiation protection dosimetry. Appropriate unfolding algorithms are currently investigated, to be ultimately implemented in an automatic device. (author).

  8. Prototyping an Active Neutron Veto for SuperCDMS

    Energy Technology Data Exchange (ETDEWEB)

    Calkins, Robert [Southern Methodist U.; Loer, Ben [Fermilab

    2015-08-17

    Neutrons, originating cosmogenically or from radioactive decays, can produce signals in dark matter detectors that are indistinguishable from Weakly Interacting Massive Particles (WIMPs). To combat this background for the SuperCDMS SNOLAB experiment, we are investigating designs for an active neutron veto within the constrained space of the compact SuperCDMS passive shielding. The current design employs an organic liquid scintillator mixed with an agent to enhance thermal neutron captures, with the scintillation light collected using wavelength-shifting fibers and read out by silicon photo-multipliers. We will describe the proposed veto and its predicted efficiency in detail and give some recent results from our R&D and prototyping efforts.

  9. Prototyping an active neutron veto for SuperCDMS

    Science.gov (United States)

    Calkins, Robert; Loer, Ben

    2015-08-01

    Neutrons, originating cosmogenically or from radioactive decays, can produce signals in dark matter detectors that are indistinguishable from Weakly Interacting Massive Particles (WIMPs). To combat this background for the SuperCDMS SNOLAB experiment, we are investigating designs for an active neutron veto within the constrained space of the compact SuperCDMS passive shielding. The current design employs an organic liquid scintillator mixed with an agent to enhance thermal neutron captures, with the scintillation light collected using wavelength-shifting fibers and read out by silicon photo-multipliers. We will describe the proposed veto and its predicted efficiency in detail and give some recent results from our R&D and prototyping efforts.

  10. Prototyping an Active Neutron Veto for SuperCDMS

    CERN Document Server

    Calkins, Robert

    2015-01-01

    Neutrons, originating cosmogenically or from radioactive decays, can produce signals in dark matter detectors that are indistinguishable from Weakly Interacting Massive Particles (WIMPs). To combat this background for the SuperCDMS SNOLAB experiment, we are investigating designs for an active neutron veto within the constrained space of the compact SuperCDMS passive shielding. The current design employs an organic liquid scintillator mixed with an agent to enhance thermal neutron captures, with the scintillation light collected using wavelength-shifting fibers and read out by silicon photo-multipliers. We will describe the proposed veto and its predicted efficiency in detail and give some recent results from our R&D and prototyping efforts.

  11. Active Interrogation Using Electronic Neutron Generators for Nuclear Safeguards Applications

    Energy Technology Data Exchange (ETDEWEB)

    David L. Chichester; Edward H. Seabury

    2008-08-01

    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. The most commonly used technique for performing active interrogation is to use an electronic neutron generator as the probe radiation source. Exploiting the unique operating characteristics of these devices, including their monoenergetic neutron emissions and their ability to operate in pulsed modes, presents a number of options for performing prompt and delayed signature analyses using both photon and neutron sensors. A review of literature in this area shows multiple applications of the active neutron interrogation technique for performing nuclear nonproliferation measurements. Some examples include measuring the plutonium content of spent fuel, assaying plutonium residue in spent fuel hull claddings, assaying plutonium in aqueous fuel reprocessing process streams, and assaying nuclear fuel reprocessing facility waste streams to detect and quantify fissile material. This paper discusses the historical use of this technique and examines its context within the scope and challenges of next-generation nuclear fuel cycles and advanced concept nuclear fuel cycle facilities.

  12. On the Radio Dichotomy of Active Galactic Nuclei

    Science.gov (United States)

    Cao, Xinwu

    2016-12-01

    It is still a mystery why only a small fraction of active galactic nuclei (AGNs) contain relativistic jets. A strong magnetic field is a necessary ingredient for jet formation, however, the advection of the external field in a geometrically thin disk is inefficient. Gas with a small angular velocity may fall from the Bondi radius {R}{{B}} nearly freely to the circularization radius {R}{{c}}, and a thin accretion disk is formed within {R}{{c}}. We suggest that the external magnetic field is substantially enhanced in this region, and the magnetic field at {R}{{c}} can be sufficiently strong to drive outflows from the disk if the angular velocity of the gas is low at {R}{{B}}. The magnetic field is efficiently dragged in the disk, because most angular momentum of the disk is removed by the outflows that lead to a significantly high radial velocity. The strong magnetic field formed in this way may accelerate jets in the region near the black hole, either by the Blandford-Payne or/and Blandford-Znajek mechanisms. We suggest that the radio dichotomy of AGNs predominantly originates from the angular velocity of the circumnuclear gas. An AGN will appear as a radio-loud (RL) one if the angular velocity of the circumnuclear gas is lower than a critical value at the Bondi radius, otherwise, it will appear as a radio-quiet (RQ) AGN. This is supported by the observations that RL nuclei are invariably hosted by core galaxies. Our model suggests that the mass growth of the black holes in RL quasars is much faster than that in RQ quasars with the same luminosity, which is consistent with the fact that the massive black holes in RL quasars are systematically a few times heavier than those in their RQ counterparts.

  13. An improved prompt gamma neutron activation analysis facility using a focused diffracted neutron beam

    Science.gov (United States)

    Riley, Kent J.; Harling, Otto K.

    1998-09-01

    The performance of the prompt gamma neutron activation analysis (PGNAA) facility at the MIT Research Reactor has been improved by a series of modifications. These modifications have increased the flux by a factor of three at the sample position to 1.7 × 10 7 n/cm 2 s, and have increased the sensitivity, on average, by a factor of 2.5. The background for many samples of interest is dominated by unavoidable neutron interactions that occur in or near the sample. Other background components comprise only 20% of the total background count rate. The implementation of fast electronics has helped to keep dead time reasonable, in spite of the increased count rates. The PGNAA facility at the MIT Research Reactor continues to serve as a major analytical tool for quantifying 10B in biological samples for Boron Neutron Capture Therapy (BNCT) research. The sensitivity for boron-10 in water is 18 750 cps/mg. The sensitivity for pure elements suitable for PGNAA analysis is reported. Possible further improvements are discussed.

  14. Some Applications of Fast Neutron Activation Analysis of Oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Owrang, Farshid

    2003-07-01

    In this thesis we focus on applications of neutron activation of oxygen for several purposes: A) measuring the water level in a laboratory tank, B) measuring the water flow in a pipe system set-up, C) analysing the oxygen in combustion products formed in a modern gasoline SI engine, and D) measuring on-line the amount of oxygen in bulk liquids. A) Water level measurements. The purpose of this work was to perform radiation based water level measurements, aimed at nuclear reactor vessels, on a laboratory scale. A laboratory water tank was irradiated by fast neutrons from a neutron generator. The water was activated at different water levels and the water level was decreased. The produced gamma radiation was measured using two detectors at different heights. The results showed that the method is suitable for measurement of water level and that a relatively small experimental set-up can be used for developing methods for water level measurements in real boiling water reactors based on activated oxygen in the water. B) Water flows in pipe. The goal in this work was to investigate the asymmetric distribution of activity in flow measurements with pulsed neutron activation (PNA) in a laboratory piping system. Earlier investigations had shown a discrepancy between the measured velocity of the activated water by PNA and the true mean velocity in the pipe. This discrepancy decreased with larger distances from the activation point. It was speculated that the induced activity in the pipe did not distribute homogeneously. With inhomogeneous radial distribution of activity in combination with a velocity profile in the pipe, the activated water may not have the same velocity as the mean velocity of water in the pipe. To study this phenomenon, a water-soluble colour was injected into a transparent pipe for simulation of the transport of the activated water. The radial concentration of the colour, at different distances from the activation point, was determined. The result

  15. Neutron activation analysis applied to nutritional and foodstuff studies

    Energy Technology Data Exchange (ETDEWEB)

    Maihara, Vera A.; Santos, Paola S.; Moura, Patricia L.C.; Castro, Lilian P. de, E-mail: vmaihara@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Avegliano, Roseane P., E-mail: pagliaro@usp.b [Universidade de Sao Paulo (USP), SP (Brazil). Coordenadoria de Assistencia Social. Div. de Alimentacao

    2009-07-01

    Neutron Activation Analysis, NAA, has been successfully used on a regularly basis in several areas of nutrition and foodstuffs. NAA has become an important and useful research tool due to the methodology's advantages. These include high accuracy, small quantities of samples and no chemical treatment. This technique allows the determination of important elements directly related to human health. NAA also provides data concerning essential and toxic concentrations in foodstuffs and specific diets. In this paper some studies in the area of nutrition which have been carried out at the Neutron Activation Laboratory of IPEN/CNEN-SP will be presented: a Brazilian total diet study: nutritional element dietary intakes of Sao Paulo state population; a study of trace element in maternal milk and the determination of essential trace elements in some edible mushrooms. (author)

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

    Institute of Scientific and Technical Information of China (English)

    YinYi; ZhongWei-Ni; 等

    1997-01-01

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

  17. Characterization of Phoenician pottery from Mothia by neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Cesana, A.; Terrani, M. (Politecnico di Milano (Italy). Centro Studi Nucleari E. Fermi); Ciasca, A. (Rome Univ. (Italy)); Cuomo di Caprio, N. (Venice Univ. (Italy)); Tusa, V. (Soprintendenza Archeologica della Sicilia Occidentale, Palermo (Italy))

    1983-01-01

    The concentration of 7 elements (Na, Al, Mg, Ti, Ca, V, Mn) was determined by neutron activation analysis in 35 samples of pottery and 14 samples of clay. The samples were collected in ancient Mothia (Sicily) and in its neighbourhoods. Cluster analysis of the data showed that most of the samples are homogeneous and confirmed the archaeological evidence that they are mostly local ware. The detailed results of the analyses are reported and the technique used for cluster analysis is described.

  18. Diagnostic Application of Absolute Neutron Activation Analysis in Hematology

    Energy Technology Data Exchange (ETDEWEB)

    Zamboni, C.B.; Oliveira, L.C.; Dalaqua, L. Jr.

    2004-10-03

    The Absolute Neutron Activation Analysis (ANAA) technique was used to determine element concentrations of Cl and Na in blood of healthy group (male and female blood donators), select from Blood Banks at Sao Paulo city, to provide information which can help in diagnosis of patients. This study permitted to perform a discussion about the advantages and limitations of using this nuclear methodology in hematological examinations.

  19. Obsidian sources characterized by neutron-activation analysis.

    Science.gov (United States)

    Gordus, A A; Wright, G A; Griffin, J B

    1968-07-26

    Concentrations of elements such as manganese, scandium, lanthanum, rubidium, samarium, barium, and zirconium in obsidian samples from different flows show ranges of 1000 percent or more, whereas the variation in element content in obsidian samples from a single flow appears to be less than 40 percent. Neutron-activation analysis of these elements, as well as of sodium and iron, provides a means of identifying the geologic source of an archeological artifact of obsidian.

  20. NEUTRON ACTIVATION ANALYSIS APPLICATIONS AT THE SAVANNAH RIVER SITE USING AN ISOTOPIC NEUTRON SOURCE

    Energy Technology Data Exchange (ETDEWEB)

    Diprete, D; C Diprete, C; Raymond Sigg, R

    2006-08-14

    NAA using {sup 252}Cf is used to address important areas of applied interest at SRS. Sensitivity needs for many of the applications are not severe; analyses are accomplished using a 21 mg {sup 252}Cf NAA facility. Because NAA allows analysis of bulk samples, it offers strong advantages for samples in difficult-to-digest matrices when its sensitivity is sufficient. Following radiochemical separation with stable carrier addition, chemical yields for a number methods are determined by neutron activation of the stable carrier. In some of the cases where no suitable stable carriers exist, the source has been used to generate radioactive tracers to yield separations.

  1. Diagnosis of mucoviscidosis by neutron activation analysis. Part 1; Diagnostico da mucoviscidose utilizando analise por ativacao com neutrons. Parte 1

    Energy Technology Data Exchange (ETDEWEB)

    Bellido, Luis F.; Bellido, Alfredo V

    1997-02-01

    Symptoms pathology, incidence, and gravity of the inherent syndrome called mucoviscidosis, or cystic fibrosis are described in this Part I. The analytical methods used for its diagnosis, both the conventional chemical ones and by neutron activation analysis are also summarised. Finally, an analytical method to study the incidence of mucoviscidosis in Brazil is presented. This , essentially, consists in bromine determination, in fingernails, by resonance neutron activation analysis. (author) 33 refs., 13 figs.

  2. Radioactive waste caracterisation by neutron activation

    OpenAIRE

    Nicol, Tangi

    2016-01-01

    Nuclear activities produce radioactive wastes classified following their radioactive level and decay time. An accurate characterization is necessary for efficient classification and management. Medium and high level wastes containing long lived radioactive isotopes will be stored in deep geological storage for hundreds of thousands years. At the end of this period, it is essential to ensure that the wastes do not represent any risk for humans and environment, not only from radioactive point o...

  3. Cosmic evolution of radio selected active galactic nuclei in the COSMOS field

    CERN Document Server

    Smolcic, V; Schinnerer, E; Bardelli, S; Bondi, M; Birzan, L; Carilli, C L; Ciliegi, P; Ilbert, O; Koekemoer, A M; Merloni, A; Paglione, T; Salvato, M; Scodeggio, M; Scoville, N

    2009-01-01

    We explore the cosmic evolution of radio AGN with low radio powers (L_1.4GHz 5\\times10^25 W/Hz) radio AGN over the same cosmic time interval, constrained using the 3CRR, 6CE, and 7CRS radio surveys by Willott et al. (2001). We demonstrate that this can be explained through differences in black hole fueling and triggering mechanisms, and a dichotomy in host galaxy properties of weak and powerful AGN. Our findings suggest that high and low radio-power AGN activity is triggered in different stages during the formation of massive red galaxies. We show that weak radio AGN occur in the most massive galaxies already at z~1, and they may significantly contribute to the heating of their surrounding medium and thus inhibit gas accretion onto their host galaxies, as recently suggested for the `radio mode' in cosmological models.

  4. Provenience studies using neutron activation analysis: the role of standardization

    Energy Technology Data Exchange (ETDEWEB)

    Harbottle, G

    1980-01-01

    This paper covers the historical background of chemical analysis of archaeological artifacts which dates back to 1790 to the first application of neutron activation analysis to archaeological ceramics and goes on to elaborate on the present day status of neutron activation analysis in provenience studies, and the role of standardization. In principle, the concentrations of elements in a neutron-activated specimen can be calculated from an exact knowledge of neutron flux, its intensity, duration and spectral (energy) distribution, plus an exact gamma ray count calibrated for efficiency, corrected for branching rates, etc. However, in practice it is far easier to compare one's unknown to a standard of known or assumed composition. The practice has been for different laboratories to use different standards. With analyses being run in the thousands throughout the world, a great benefit would be derived if analyses could be exchanged among all users and/or generators of data. The emphasis of this paper is on interlaboratory comparability of ceramic data; how far are we from it, what has been proposed in the past to achieve this goal, and what is being proposed. All of this may be summarized under the general heading of Analytical Quality Control - i.e., how to achieve precise and accurate analysis. The author proposes that anyone wishing to analyze archaeological ceramics should simply use his own standard, but attempt to calibrate that standard as nearly as possible to absolute (i.e., accurate) concentration values. The relationship of Analytical Quality Control to provenience location is also examined.

  5. Radio Properties of Low Redshift Broad Line Active Galactic Nuclei Including Multiple Component Radio Sources

    Science.gov (United States)

    Rafter, Stephen E.

    2010-01-01

    We present results on the radio properties of a low redshift (z FRIIs. From these data we find an FRI/FRII luminosity dividing line like that found by Fanaroff & Riley (1974), where we use our core-only sources as proxies for FRIs, and our multi-component sources for the FRIIs. We find a bimodal distribution for the radio loudness (R = L(radio)/L(opt)) where the lower radio luminosity core-only sources appear as a population separate from the multi-component extended sources, compared with no evidence for bimodality when just the core-only sources are used. We also find that a log(R) value of 1.75 is well suited to separate the FRIs from the FRIIs, and that the R bimodality seen here is really a manifestation of the FRI/FRII break originally found by Fanaroff & Riley (1974). We find modest trends in the radio loud fraction as a function of Eddington ratio and black hole mass, where the fraction of RL AGNs decreases with increasing Eddington ratio, and increases when the black hole mass is above 2 x 108 solar masses.

  6. Mercury mass measurement in fluorescent lamps via neutron activation analysis

    Science.gov (United States)

    Viererbl, L.; Vinš, M.; Lahodová, Z.; Fuksa, A.; Kučera, J.; Koleška, M.; Voljanskij, A.

    2015-11-01

    Mercury is an essential component of fluorescent lamps. Not all fluorescent lamps are recycled, resulting in contamination of the environment with toxic mercury, making measurement of the mercury mass used in fluorescent lamps important. Mercury mass measurement of lamps via instrumental neutron activation analysis (NAA) was tested under various conditions in the LVR-15 research reactor. Fluorescent lamps were irradiated in different positions in vertical irradiation channels and a horizontal channel in neutron fields with total fluence rates from 3×108 cm-2 s-1 to 1014 cm-2 s-1. The 202Hg(n,γ)203Hg nuclear reaction was used for mercury mass evaluation. Activities of 203Hg and others induced radionuclides were measured via gamma spectrometry with an HPGe detector at various times after irradiation. Standards containing an Hg2Cl2 compound were used to determine mercury mass. Problems arise from the presence of elements with a large effective cross section in luminescent material (europium, antimony and gadolinium) and glass (boron). The paper describes optimization of the NAA procedure in the LVR-15 research reactor with particular attention to influence of neutron self-absorption in fluorescent lamps.

  7. Neutron shielding and activation of the MASTU device and surrounds

    CERN Document Server

    Taylor, David; Turner, Andrew; Davis, Andrew

    2014-01-01

    A significant functional upgrade is planned for the Mega Ampere Spherical Tokamak (MAST) device, located at Culham in the UK, including the implementation of a notably greater neutral beam injection power. This upgrade will cause the emission of a substantially increased intensity of neutron radiation for a substantially increased amount of time upon operation of the device. Existing shielding and activation precautions are shown to prove insufficient in some regards, and recommendations for improvements are made, including the following areas: shielding doors to MAST shielded facility enclosure (known as "the blockhouse"); north access tunnel; blockhouse roof; west cabling duct. In addition, some specific neutronic dose rate questions are addressed and answered; those discussed here relate to shielding penetrations and dose rate reflected from the air above the device ("skyshine").

  8. Measurements of neutrons at JET by means of the activation methods

    Energy Technology Data Exchange (ETDEWEB)

    Prokopowicz, R., E-mail: prokopowicz@ifpilm.waw.p [EURATOM-IPPLM Association, 23, Hery St, Warsaw 01-497 (Poland); Bienkowska, B.; Drozdowicz, K.; Jednorog, S.; Kowalska-Strzeciwilk, E. [EURATOM-IPPLM Association, 23, Hery St, Warsaw 01-497 (Poland); Murari, A. [EURATOM-ENEA Fusion Association, Consorzio RFX, Padova I-35127 (Italy); Popovichev, S. [EURATOM-CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Pytel, K.; Scholz, M.; Szydlowski, A. [EURATOM-IPPLM Association, 23, Hery St, Warsaw 01-497 (Poland); Syme, B. [EURATOM-CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Tracz, G. [EURATOM-IPPLM Association, 23, Hery St, Warsaw 01-497 (Poland)

    2011-05-01

    The neutron diagnostics in tokamaks like Joint European Torus (JET) are essential in estimating fusion power. The neutron activation method, supported by neutron transport calculations, is particularly useful for the evaluation of the total neutron yield from a single plasma discharge. This paper presents the results of activation experiments and calculations carried out for JET plasmas, from the selection of the activation materials to their irradiations in the neutron field of JET discharges. Neutron transport calculations were performed, leading to activation coefficients for new materials. The results of the calculations were used to design new composite samples to obtain information on both the yield and the neutron spectrum. The neutron measurements using these new activation materials were performed during the last JET experimental campaigns. The results are compared with neutron transport calculations. Additionally, application of the cadmium difference method allows revelation of the part of thermal neutrons near the tokamak first wall. The advantages of new activation materials and benchmarking the activation method against neutron transport calculations are also discussed.

  9. Towards a methodology for large-sample prompt-gamma neutron-activation analysis

    NARCIS (Netherlands)

    Degenaar, I.H.

    2004-01-01

    Large-sample prompt-gamma neutron-activation analysis, or shortly LS PGNAA, is a method by which mass fractions of elements can be determined in large samples with a mass over 1 kg. In this method the large sample is irradiated with neutrons. Directly (prompt) after absorption of the neutrons photon

  10. Determination of europium content in Li2SiO3(Eu) by neutron activation analysis using Am-Be neutron source.

    Science.gov (United States)

    Naik, Yeshwant; Tapase, Anant Shamrao; Mhatre, Amol; Datrik, Chandrashekhar; Tawade, Nilesh; Kumar, Umesh; Naik, Haladhara

    2016-12-01

    Circulardiscs of Li2SiO3 doped with europium were prepared and a new activation procedure for the neutron dose estimation in a breeder blanket of fusion reactor is described. The amount of europium in the disc was determined by neutron activation analysis (NAA) using an isotopic neutron source. The average neutron absorption cross section for the reaction was calculated using neutron distribution of the Am-Be source and available neutron absorption cross section data for the (151)Eu(n,γ)(152m)Eu reaction, which was used for estimation of europium in the pallet. The cross section of the elements varies with neutron energy, and the flux of the neutrons in each energy range seen by the nuclei under investigation also varies. Neutron distribution spectrum of the Am-Be source was worked out prior to NAA and the effective fractional flux for the nuclear reaction considered for the flux estimation was also determined.

  11. Jet reorientation in active galactic nuclei : two winged radio galaxies

    NARCIS (Netherlands)

    Dennett-Thorpe, J; Scheuer, PAG; Laing, RA; Bridle, AH; Pooley, GG; Reich, W

    2002-01-01

    Winged, or X-shaped, radio sources form a small class of morphologically peculiar extragalactic sources. We present multifrequency radio observations of two such sources. We derive maximum ages since any re-injection of fresh particles of 34 and 17 Myr for the wings of 3C 223.1 and 3C 403 respective

  12. A militarily fielded thermal neutron activation sensor for landmine detection

    Energy Technology Data Exchange (ETDEWEB)

    Clifford, E.T.H. [Bubble Technology Industries, Chalk River (Canada); McFee, J.E. [Defence R and D Canada-Suffield, Medicine Hat (Canada)], E-mail: john.mcfee@drdc-rddc.gc.ca; Ing, H.; Andrews, H.R.; Tennant, D.; Harper, E. [Bubble Technology Industries, Chalk River (Canada); Faust, A.A. [Defence R and D Canada-Suffield, Medicine Hat (Canada)

    2007-08-21

    The Canadian Department of National Defence has developed a teleoperated, vehicle-mounted, multi-sensor system to detect anti-tank landmines on roads and tracks in peacekeeping operations. A key part of the system is a thermal neutron activation (TNA) sensor which is placed above a suspect location to within a 30 cm radius and confirms the presence of explosives via detection of the 10.835 MeV gamma ray associated with thermal neutron capture on {sup 14}N. The TNA uses a 100{mu}g{sup 252}Cf neutron source surrounded by four 7.62cmx7.62cm NaI(Tl) detectors. The system, consisting of the TNA sensor head, including source, detectors and shielding, the high-rate, fast pulse processing electronics and the data processing methodology are described. Results of experiments to characterize detection performance are also described. The experiments have shown that anti-tank mines buried 10 cm or less can be detected in roughly a minute or less, but deeper mines and mines significantly displaced horizontally take considerably longer time. Mines as deep as 30 cm can be detected for long count times (1000 s). Four TNA detectors are now in service with the Canadian Forces as part of the four multi-sensor systems, making it the first militarily fielded TNA sensor and the first militarily fielded confirmation sensor for landmines. The ability to function well in adverse climatic conditions has been demonstrated, both in trials and operations.

  13. Magnetar activity mediated by plastic deformations of neutron star crust

    CERN Document Server

    Lyutikov, Maxim

    2014-01-01

    We advance a "Solar flare" model of magnetar activity, whereas a slow evolution of the magnetic field in the upper crust, driven by electron MHD (EMHD) flows, twists the external magnetic flux tubes, producing persistent emission, bursts and flares. At the same time the neutron star crust plastically relieves the imposed magnetic field stress, limiting the strain $ \\epsilon_t $ to values well below the critical strain $ \\epsilon_{crit}$ of a brittle fracture, $ \\epsilon_t \\sim 10^{-2}\\epsilon_{crit} $. Magnetar-like behavior, occurring near the magnetic equator, takes place in all neutron stars, but to a different extent. The persistent luminosity is proportional to cubic power of the magnetic field (at a given age), and hence is hardly observable in most rotationally powered neutron stars. Giant flares can occur only if the magnetic field exceeds some threshold value, while smaller bursts and flares may take place in relatively small magnetic fields. Bursts and flares are magnetospheric reconnection events t...

  14. Coincidence Prompt Gamma-Ray Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    R.P. gandner; C.W. Mayo; W.A. Metwally; W. Zhang; W. Guo; A. Shehata

    2002-11-10

    The normal prompt gamma-ray neutron activation analysis for either bulk or small beam samples inherently has a small signal-to-noise (S/N) ratio due primarily to the neutron source being present while the sample signal is being obtained. Coincidence counting offers the possibility of greatly reducing or eliminating the noise generated by the neutron source. The present report presents our results to date on implementing the coincidence counting PGNAA approach. We conclude that coincidence PGNAA yields: (1) a larger signal-to-noise (S/N) ratio, (2) more information (and therefore better accuracy) from essentially the same experiment when sophisticated coincidence electronics are used that can yield singles and coincidences simultaneously, and (3) a reduced (one or two orders of magnitude) signal from essentially the same experiment. In future work we will concentrate on: (1) modifying the existing CEARPGS Monte Carlo code to incorporate coincidence counting, (2) obtaining coincidence schemes for 18 or 20 of the common elements in coal and cement, and (3) optimizing the design of a PGNAA coincidence system for the bulk analysis of coal.

  15. RADSAT Benchmarks for Prompt Gamma Neutron Activation Analysis Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Kimberly A.; Gesh, Christopher J.

    2011-07-01

    The accurate and efficient simulation of coupled neutron-photon problems is necessary for several important radiation detection applications. Examples include the detection of nuclear threats concealed in cargo containers and prompt gamma neutron activation analysis for nondestructive determination of elemental composition of unknown samples. High-resolution gamma-ray spectrometers are used in these applications to measure the spectrum of the emitted photon flux, which consists of both continuum and characteristic gamma rays with discrete energies. Monte Carlo transport is the most commonly used simulation tool for this type of problem, but computational times can be prohibitively long. This work explores the use of multi-group deterministic methods for the simulation of coupled neutron-photon problems. The main purpose of this work is to benchmark several problems modeled with RADSAT and MCNP to experimental data. Additionally, the cross section libraries for RADSAT are updated to include ENDF/B-VII cross sections. Preliminary findings show promising results when compared to MCNP and experimental data, but also areas where additional inquiry and testing are needed. The potential benefits and shortcomings of the multi-group-based approach are discussed in terms of accuracy and computational efficiency.

  16. Coarse-scaling adjustment of fine-group neutron spectra for epithermal neutron beams in BNCT using multiple activation detectors

    Science.gov (United States)

    Liu, Yuan-Hao; Nievaart, Sander; Tsai, Pi-En; Liu, Hong-Ming; Moss, Ray; Jiang, Shiang-Huei

    2009-01-01

    In order to provide an improved and reliable neutron source description for treatment planning in boron neutron capture therapy (BNCT), a spectrum adjustment procedure named coarse-scaling adjustment has been developed and applied to the neutron spectrum measurements of both the Tsing Hua Open-pool Reactor (THOR) epithermal neutron beam in Taiwan and the High Flux Reactor (HFR) in The Netherlands, using multiple activation detectors. The coarse-scaling adjustment utilizes a similar idea as the well-known two-foil method, which adjusts the thermal and epithermal neutron fluxes according to the Maxwellian distribution for thermal neutrons and 1/ E distribution over the epithermal neutron energy region. The coarse-scaling adjustment can effectively suppress the number of oscillations appearing in the adjusted spectrum and provide better smoothness. This paper also presents a sophisticated 9-step process utilizing twice the coarse-scaling adjustment which can adjust a given coarse-group spectrum into a fine-group structure, i.e. 640 groups, with satisfactory continuity and excellently matched reaction rates between measurements and calculation. The spectrum adjustment algorithm applied in this study is the same as the well-known SAND-II.

  17. Neutron distribution and induced activity inside a Linac treatment room.

    Science.gov (United States)

    Juste, B; Miró, R; Verdú, G; Díez, S; Campayo, J M

    2015-01-01

    Induced radioactivity and photoneutron contamination inside a radiation therapy bunker of a medical linear accelerator (Linac) is investigated in this work. The Linac studied is an Elekta Precise electron accelerator which maximum treatment photon energy is 15 MeV. This energy exceeds the photonuclear reaction threshold (around 7 MeV for high atomic number metals). The Monte Carlo code MCNP6 has been used for quantifying the neutron contamination inside the treatment room for different gantry rotation configuration. Walls activation processes have also been simulated. The approach described in this paper is useful to prevent the overexposure of patients and medical staff.

  18. Neutron activation study of gold-decorated singlewall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Rafael G.F.; Oliveira, Arno H. de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear; Ladeira, Luiz O.; Lacerda, Rodrigo G.; Oliveira, Sergio de; Pinheiro, Mauricio V.B. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Fisica; Ferreira, Andrea V. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2007-07-01

    Single-wall carbon nanotubes (SWNT) were synthesized by arc discharge technique of doped graphite electrodes and purified by burning the amorphous carbon and removing the metals with hydrochloric acid (HCl). The nanotubes were also functionalized with carboxyl groups (-COOH) by ultrasonification with nitric (HNO{sub 3}) and sulfuric (H{sub 2}SO{sub 4}) acids. The nanotubes were then decorated with gold by reducing chloroauric acid (HAuCl{sub 4}) with UV and hydrazine (N{sub 2}H{sub 4}). Atomic Force Microscope (AFM) images confirmed the decoration with the hydrazine route. The gold concentration in the samples was analyzed by neutron activation analysis. (author)

  19. Evaluation of Am-Li neutron spectra data for active well type neutron multiplicity measurements of uranium

    Science.gov (United States)

    Goddard, Braden; Croft, Stephen; Lousteau, Angela; Peerani, Paolo

    2016-09-01

    Safeguarding nuclear material is an important and challenging task for the international community. One particular safeguards technique commonly used for uranium assay is active neutron correlation counting. This technique involves irradiating unused uranium with (α, n) neutrons from an Am-Li source and recording the resultant neutron pulse signal which includes induced fission neutrons. Although this non-destructive technique is widely employed in safeguards applications, the neutron energy spectra from an Am-Li sources is not well known. Several measurements over the past few decades have been made to characterize this spectrum; however, little work has been done comparing the measured and theoretical spectra of various Am-Li sources to each other. This paper examines fourteen different Am-Li spectra, focusing on how these spectra affect simulated neutron multiplicity results using the code Monte Carlo N-Particle eXtended (MCNPX). Two measurement and simulation campaigns were completed using Active Well Coincidence Counter (AWCC) detectors and uranium standards of varying enrichment. The results of this work indicate that for standard AWCC measurements, the fourteen Am-Li spectra produce similar doubles and triples count rates. The singles count rates varied by as much as 20% between the different spectra, although they are usually not used in quantitative analysis, being dominated by scattering which is highly dependent on item placement.

  20. Accretion/Jet Activity and Narrow [O III] Kinematics in Young Radio Galaxies

    CERN Document Server

    Wu, Qingwen; Humphrey, Andrew

    2009-01-01

    We estimate black hole masses and Eddington ratios for a sample of 81 young radio galaxies (42 CSS +39 GPS). We find that the average black hole (BH) mass of these young radio galaxies is ~8.3, which is less than that of radio loud QSOs and low redshift radio galaxies. The CSS/GPS sources have relatively high Eddington ratios, with an average value of =-0.75, which are similar to those of narrow line Seyfert 1 galaxies (NLS1s). This suggests that young radio galaxies may not only be in the early stages of their radio activity, but also in the early stage of their accretion activity. We find that the young radio galaxies as a class deviate systematically from M_bh-\\sigma relation defined by nearby inactive galaxies, when using [O III] as a surrogate for stellar velocity dispersion, \\sigma_* . We also find that the deviation of the [O III] line width is correlated with the Eddington ratio and sources with Lbol/LEdd~1 have the largest deviations, which are similar to those of radio quiet QSOs/NLS1s (radio jets i...

  1. Type II and IV radio bursts in the active period October-November 2003

    CERN Document Server

    Petoussis, V; Kontogeorgos, A; Moussas, X; Preka-Papadema, P; Hillaris, A; Caroubalos, C; Alissandrakis, C E; Bougeret, J -L; Dumas, G; 10.1063/1.2347978

    2010-01-01

    In this report we present the Type II and IV radio bursts observed and analyzed by the radio spectrograph ARTEMIS IV1, in the 650-20MHz frequency range, during the active period October-November 2003. These bursts exhibit very rich fine structures such fibers, pulsations and zebra patterns which is associated with certain characteristics of the associated solar flares and CMEs.

  2. FPGA applications for single dish activity at Medicina radio telescopes

    Science.gov (United States)

    Bartolin, M.; Nald, G.; Mattan, A.; Maccaferr, A.; De Biagg, M.

    FPGA technologies are gaining major attention in the recent years in the field of radio astronomy. At Medicina radio telescopes, FPGAs have been used in the last ten years for a number of purposes and in this article we will take into exam the applications developed and installed for the Medicina Single Dish 32m Antenna: these range from high performance digital signal processing to instrument control developed on top of smaller FPGAs.

  3. Where the active galaxies live: a panchromatic view of radio-AGN in the AKARI-NEP field

    CERN Document Server

    Karouzos, Marios; Trichas, Markos

    2013-01-01

    We study the host galaxy properties of radio sources in the AKARI-North Ecliptic Pole (NEP) field, using an ensemble of multi-wavelength datasets. We identify both radio-loud and radio-quiet AGN and study their host galaxy properties by means of SED fitting. We investigate the relative importance of nuclear and star-formation activity in radio-AGN and assess the role of radio-AGN as efficient quenchers of star-formation in their host galaxies.

  4. $\\textit{Herschel}$-ATLAS:The connection between star formation and AGN activity in radio-loud and radio-quiet active galaxies

    CERN Document Server

    Gurkan, G; Jarvis, M J; Smith, D J B; Bourne, N; Dunne, L; Maddox, S; Ivison, R J; Fritz, J

    2015-01-01

    We examine the relationship between star formation and AGN activity by constructing matched samples of local ($0radio-loud and radio-quiet AGN in the $\\textit{Herschel}$-ATLAS fields. Radio-loud AGN are classified as high-excitation and low-excitation radio galaxies (HERGs, LERGs) using their emission lines and $\\textit{WISE}$ 22-$\\mu$m luminosity. AGN accretion and jet powers in these active galaxies are traced by [OIII] emission-line and radio luminosity, respectively. Star formation rates (SFRs) and specific star formation rates (SSFRs) were derived using $\\textit{Herschel}$ 250-$\\mu$m luminosity and stellar mass measurements from the SDSS$-$MPA-JHU catalogue. In the past, star formation studies of AGN have mostly focused on high-redshift sources to observe the thermal dust emission that peaks in the far-infrared, which limited the samples to powerful objects. However, with $\\textit{Herschel}$ we can expand this to low redshifts. Our stacking analyses show that SFRs and SSFRs of both radio-l...

  5. Active neutron methods for nuclear safeguards applications using Helium-4 gas scintillation detectors

    Science.gov (United States)

    Lewis, Jason M.

    Active neutron methods use a neutron source to interrogate fissionable material. In this work a 4He gas scintillation fast neutron detection system is used to measure neutrons created by the interrogation. Three new applications of this method are developed: spent nuclear fuel assay, fission rate measurement, and special nuclear material detection. Three active neutron methods are included in this thesis. First a non-destructive plutonium assay technique called Multispectral Active Neutron Interrogation Analysis is developed. It is based on interrogating fuel with neutrons at several different energies. The induced fission rates at each interrogation energy are compared with results from a neutron transport model of the irradiation geometry in a system of equations to iteratively solve the inverse problem for isotopic composition. The model is shown to converge on the correct composition for a material with 3 different fissionable components, a representative neutron absorber, and any neutron transparent material such as oxygen in a variety of geometries. Next an experimental fission rate measurement technique is developed using 4He gas scintillation fast neutron detector. Several unique features of this detector allow it to detect and provide energy information on fast neutrons with excellent gamma discrimination efficiency. The detector can measure induced fission rate by energetically differentiating between interrogation neutrons and higher energy fission neutrons. The detector response to a mono-energetic deuterium-deuterium fusion neutron generator and a 252Cf source are compared to examine the difference in detected energy range. Finally we demonstrate a special nuclear material detection technique by detecting an unambiguous fission neutron signal produced in natural uranium during active neutron interrogation using a deuterium-deuterium neutron generator and a high pressure 4He gas fast neutron scintillation detector. Energy histograms resulting from this

  6. Accretion/jet activity and narrow [O III] kinematics in young radio galaxies

    Institute of Scientific and Technical Information of China (English)

    Andrew; HUMPHREY

    2010-01-01

    We estimate black hole masses and Edenton ratios for a sample of 81 young radio galaxies,which includes 42 compact steep-spectrum(CSS) and 39 gigahertz-peaked spectrum(GPS) sources.We find that the average black hole(BH) mass of these young radio galaxies is〈log Mbh〉-8.3,which is less than that of radio loud QSOs and low redshift radio galaxies(〈 log Mbh〉-9.0).The CSS/GPS sources have relatively high Eddington ratios,with an average value of〈log Lbol/LEdd〉=-0.75,which are similar to those of narrow line Seyfert 1 galaxies(NLS1s).This suggests that young radio galaxies may not only be in the early stages of their radio activity,but also in the early stage of their accretion activity.We find that the young radio galaxies,as a class,systematically deviate from the Mbh-σ relation defined by nearby inactive galaxies,when using σ[O III] as a surrogate for stellar velocity dispersion σ.We also find that the deviation of the [O III] line width,Δσ =σ[O III]-σ[pred],is correlated with the Eddington ratio;sources with Lbol/LEdd-1 have the largest deviations,which are similar to those of radio quiet QSOs/NLS1s(i.e.,sources in which the radio jets are absent or weak),and where σ[pred] is calculated from the Tremaine et al.relation using our estimated BH masses.A similar result has been obtained for 9 linear radio Seyfert galaxies.On the basis of these results,we suggest that,in addition to the possible jet-gas interactions,accretion activities may also play an important role in shaping the kinematics of the narrow [O III] line in young radio galaxies.

  7. Neutron formation temperature gauge and neutron activation analysis brine flow meter. Final report, October 1, 1976--March 31, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Vagelatos, N.; Steinman, D.K.; John, J.

    1978-03-31

    Feasibility studies of nuclear techniques applicable to the determination of geothermal formation temperature and two-phase brine flow downhole have been performed. The formation temperature gauging technique involves injection of fast neutrons into the formation and analysis of the moderated slow neutron energy distribution by appropriately filtered neutron detectors. The scientific feasibility of the method has been demonstrated by analytical computational and experimental evaluation of the system response. A data analysis method has been developed to determine unambiguously the temperature, neutron absorption cross section and neutron moderating power of an arbitrary medium. The initial phase of a program to demonstrate the engineering feasibility of the technique has been performed. A sonde mockup was fabricated and measurements have been performed in a test stand designed to simulate a geothermal well. The results indicate that the formation temperature determined by this method is independent of differences between the temperature in the borehole fluid and the formation, borehole fluid density, and borehole fluid salinity. Estimates of performance specifications for a formation temperature sonde have been made on the basis of information obtained in this study and a conceptual design of a logging system has been developed. The technique for the determination of fluid flow in a well is based on neutron activation analysis of elements present in the brine. An analytical evaluation of the method has been performed. The results warrant further, experimental evaluation.

  8. Instrumental neutron activation analysis of sectioned hair strands for arsenic

    Energy Technology Data Exchange (ETDEWEB)

    Guinn, V.P. [Univ. of Maryland, College Park, MD (United States)

    1996-12-31

    Instrumental neutron activation analysis (INAA) is a valuable and proven method for the quantitative analysis of sectioned human head hair specimens for arsenic - and, if arsenic is found to be present at high concentrations, the approximate times when it was ingested. Reactor-flux thermal-neutron activation of the hair samples produces 26.3-h {sup 76}As, which is then detected by germanium gamma-ray spectrometry, measuring the 559.1-keV gamma-ray peak of {sup 76}As. Even normal levels of arsenic in hair, in the range of <1 ppm up to a few parts per million of arsenic can be measured - and the far higher levels associated with large internal doses of arsenic, levels approaching or exceeding 100 ppm arsenic, are readily and accurately measurable. However, all phases of forensic investigations of possible chronic (or in some cases, acute) arsenic poisoning are important, i.e., not just the analysis phase. All of these phases are discussed in this paper, based on the author`s experience and the experience of others, in criminal cases. Cases of chronic arsenic poisoning often reveal a series of two to four doses, perhaps a few months apart, with increasing doses.

  9. FeltRadio – Experiencing Community-generated WiFi Activities

    DEFF Research Database (Denmark)

    Fritsch, Jonas; Gronvall, Erik

    2016-01-01

    FeltRadio is a portable technology for sensing WiFi through sensorial augmentation and Electric Muscle Stimulation (EMS). The technology enables its wearer to sensorially engage with the radio waves and WiFi activities that have become an integrated part of our everyday lives. The sensorial...... engagement changes people’s experience of WiFi activities, and allows them to participate in wireless communication infrastructures in novel ways. This is both an immediately embodied activity as it is a new form of social awareness. In this paper, we briefly present the FeltRadio technology and show how...

  10. The calibration of DD neutron indium activation diagnostic for Shenguang-III facility

    CERN Document Server

    Song, Zi-Feng; Liu, Zhong-Jie; Zhan, Xia-Yu; Tang, Qi

    2014-01-01

    The indium activation diagnostic was calibrated on an accelerator neutron source in order to diagnose deuterium-deuterium (DD) neutron yields of implosion experiments on Shenguang-III facility. The scattered neutron background of the accelerator room was measured by placing a polypropylene shield in front of indium sample, in order to correct the calibrated factor of this activation diagnostic. The proper size of this shield was given by Monte Carlo simulation software. The affect from some other activated nuclei on the calibration was verified by judging whether the measured curve obeys exponential decay and contrasting the half life of the activated sample. The calibration results showed that the linear range reached up to 100 cps net count rate in the full energy peak of interest, the scattered neutron background of accelerator room was about 9% of the total neutrons and the possible interferences mixed scarcely in the sample. Subtracting the portion induced by neutron background, the calibrated factor of ...

  11. Current status of neutron activation analysis using the Dalat Nuclear Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen Van Suc; Nguyen Mong Sinh [Nuclear Research Institute, Dalat (Viet Nam)

    1999-10-01

    Neutron activation analysis is one of the most sensitive, rapid, accurated methods for determination of trace elements in different materials. A review is made of the current status of the activities and the results in studying and developing NAA (Neutron Activation Analysis) at the Dalat Nuclear Research Institute and applying this method to different sectors of science and technology in Vietnam. (author)

  12. Epithermal Neutron Activation Analysis of the Asian Herbal Plants

    Science.gov (United States)

    Baljinnyam, N.; Jugder, B.; Norov, N.; Frontasyeva, M. V.; Ostrovnaya, T. M.; Pavlov, S. S.

    2011-06-01

    Asian medicinal herbs Chrysanthemum (Spiraea aquilegifolia Pall.) and Red Sandalwood (Pterocarpus Santalinus) are widely used in folk and Ayurvedic medicine for healing and preventing some diseases. The modern medical science has proved that the Chrysanthemum (Spiraea aquilegifolia Pall.) possesses the following functions: reducing blood press, dispelling cancer cell, coronary artery's expanding and bacteriostating and Red Sandalwood (Pterocarpus Santalinus) is recommended against headache, toothache, skin diseases, vomiting and sometimes it is taken for treatment of diabetes. Species of Chrysanthemums were collected in the north-eastern and central Mongolia, and the Red Sandalwood powder was imported from India. Samples of Chrysanthemums (branches, flowers and leaves) (0.5 g) and red sandalwood powder (0.5 g) were subjected to the multi-element instrumental neutron activation analysis using epithermal neutrons (ENAA) at the IBR-2 reactor, Frank Laboratory of Neutron Physics (FLNP) JINR, Dubna. A total of 41 elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Sr, Zr, Mo, Cd, Cs, Ba, La, Hf, Ta, W, Sb, Au, Hg, Ce, Nd, Sm, Eu, Tb, Dy, Yb, Th, U, Lu) were determined. For the first time such a large group of elements was determined in the herbal plants used in Mongolia. The quality control of the analytical results was provided by using certified reference material Bowen Cabbage. The results obtained are compared to the "Reference plant» data (B. Markert, 1992) and interpreted in terms of excess of such elements as Se, Cr, Ca, Fe, Ni, Mo, and rare earth elements.

  13. Analysis of Some Egyptian Cosmetic Samples by Fast Neutron Activation Analysis

    CERN Document Server

    Medhat, M E; Fayez-Hassan, M

    2001-01-01

    A description of D-T neutron generator (NG) is presented. This generator can be used for fast neutron activation analysis applied to determine some selected elements, especially light elements, in different materials. In our work, the concentration of the elements Na, Mg, Al, Si, K, Cl, Ca and Fe, were determined in two domestic brands of face powder by using 14 MeV neutron activation analysis.

  14. Restarting radio activity and dust emission in radio-loud broad absorption line quasars

    CERN Document Server

    Bruni, G; Montenegro-Montes, F M; Brienza, M; González-Serrano, J I

    2015-01-01

    Broad absorption line quasars (BAL QSOs) are objects showing absorption from relativistic outflows, with velocities up to 0.2c. These manifest, in about 15% of quasars, as absorption troughs on the blue side of UV emission lines, such as C iv and Mg ii. In this work, we complement the information collected in the cm band for our previously presented sample of radio loud BAL QSOs with new observations at m and mm bands. Our aim is to verify the presence of old, extended radio components in the MHz range, and probe the emission of dust (linked to star formation) in the mm domain. We observed 5 sources from our sample, already presenting hints of low-frequency emission, with the GMRT at 235 and 610 MHz. Other 17 sources (more than half the sample) were observed with bolometer cameras at IRAM-30m and APEX. All sources observed with the GMRT present extended emission at a scale of tens of kpc. In some cases these measurements allow us to identify a second component in the SED, at frequencies below 1.4 GHz, beyond ...

  15. Active detection of shielded SNM with 60-keV neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Hagmann, C; Dietrich, D; Hall, J; Kerr, P; Nakae, L; Newby, R; Rowland, M; Snyderman, N; Stoeffl, W

    2008-07-08

    Fissile materials, e.g. {sup 235}U and {sup 239}Pu, can be detected non-invasively by active neutron interrogation. A unique characteristic of fissile material exposed to neutrons is the prompt emission of high-energy (fast) fission neutrons. One promising mode of operation subjects the object to a beam of medium-energy (epithermal) neutrons, generated by a proton beam impinging on a Li target. The emergence of fast secondary neutrons then clearly indicates the presence of fissile material. Our interrogation system comprises a low-dose 60-keV neutron generator (5 x 10{sup 6}/s), and a 1 m{sup 2} array of scintillators for fast neutron detection. Preliminary experimental results demonstrate the detectability of small quantities (370 g) of HEU shielded by steel (200 g/cm{sup 2}) or plywood (30 g/cm{sup 2}), with a typical measurement time of 1 min.

  16. A kinematically beamed, low energy pulsed neutron source for active interrogation

    Science.gov (United States)

    Dietrich, Dan; Hagmann, Chris; Kerr, Phil; Nakae, Les; Rowland, Mark; Snyderman, Neal; Stoeffl, Wolfgang; Hamm, Robert

    2005-12-01

    We are developing a new active interrogation system based on a kinematically focused low energy neutron beam. The key idea is that one of the defining characteristics of special nuclear materials (SNM) is the ability for low energy or thermal neutrons to induce fission. Thus by using low energy neutrons for the interrogation source we can accomplish three goals: (1) energy discrimination allows us to measure the prompt fast fission neutrons produced while the interrogation beam is on; (2) neutrons with an energy of approximately 60-100 keV do not fission 238U and Thorium, but penetrate bulk material nearly as far as high energy neutrons do and (3) below about 100 keV neutrons lose their energy by kinematical collisions rather than via the nuclear (n, 2n) or (n, n‧) processes thus further simplifying the prompt neutron induced background. 60 keV neutrons create a low radiation dose and readily thermal capture in normal materials, thus providing a clean spectroscopic signature of the intervening materials. The kinematically beamed source also eliminates the need for heavy backward and sideway neutron shielding. We have designed and built a very compact pulsed neutron source, based on an RFQ proton accelerator and a lithium target. We are developing fast neutron detectors that are nearly insensitive to the ever-present thermal neutron and neutron capture induced gamma ray background. The detection of only a few high energy fission neutrons in time correlation with the linac pulse will be a clear indication of the presence of SNM.

  17. Neutron activation analysis for the demonstration of amphibolite rock-weathering activity of a yeast.

    Science.gov (United States)

    Rades-Rohkohl, E; Hirsch, P; Fränzle, O

    1979-12-01

    Neutron activation analysis was employed in a survey of weathering abilities of rock surface microorganisms. A yeast isolated from an amphibolite of a megalithic grave was found actively to concentrate, in media and in or on cells, iron and other elements when grown in the presence of ground rock. This was demonstrated by comparing a spectrum of neutron-activated amphibolite powder (particle size, 50 to 100 mum) with the spectra of neutron-activated, lyophilized yeast cells which had grown with or without amphibolite powder added to different media. The most active yeast (IFAM 1171) did not only solubilize Fe from the rock powder, but significant amounts of Co, Eu, Yb, Ca, Ba, Sc, Lu, Cr, Th, and U were also mobilized. The latter two elements occurred as natural radioactive isotopes in this amphibolite. When the yeast cells were grown with neutron-activated amphibolite, the cells contained the same elements. Furthermore, the growth medium contained Fe, Co, and Eu which had been solubilized from the amphibolite. This indicates the presence, in this yeast strain, of active rockweathering abilities as well as of uptake mechanisms for solubilized rock components.

  18. Active Detection of Small Quantities of Shielded Highly-Enriched Uranium Using Low-Dose 60-keV Neutron Interrogation

    Energy Technology Data Exchange (ETDEWEB)

    Kerr, P; Rowland, M; Dietrich, D; Stoeffl, W; Wheeler, B; Nakae, L; Howard, D; Hagmann, C; Newby, J; Porter, R

    2006-08-16

    Active interrogation with low-energy neutrons provides a search technique for shielded highly-enriched uranium. We describe the technique and show initial results using a low-dose 60 keV neutron beam. This technique produces a clear induced fission signal in the presence of small quantities of {sup 235}U. The technique has been validated with low-Z and high-Z shielding materials. The technique uses a forward-directed beam of 60 keV neutrons to induce fission in {sup 235}U. The induced fission produces fast neutrons which are then detected as the signature for {sup 235}U. The beam of neutrons is generated with a 1.93 MeV proton beam impinging on a natural lithium target. The proton beam is produced by a radio-frequency quadrupole (RFQ) LINAC. The 60 keV neutron beam is forward directed because the {sup 7}Li(p,n) reaction is just at threshold for the proton energy of 1.93 MeV.

  19. Measurements of the neutron activation cross sections for Bi and Co at 386 MeV.

    Science.gov (United States)

    Yashima, H; Sekimoto, S; Ninomiya, K; Kasamatsu, Y; Shima, T; Takahashi, N; Shinohara, A; Matsumura, H; Satoh, D; Iwamoto, Y; Hagiwara, M; Nishiizumi, K; Caffee, M W; Shibata, S

    2014-10-01

    Neutron activation cross sections for Bi and Co at 386 MeV were measured by activation method. A quasi-monoenergetic neutron beam was produced using the (7)Li(p,n) reaction. The energy spectrum of these neutrons has a high-energy peak (386 MeV) and a low-energy tail. Two neutron beams, 0° and 25° from the proton beam axis, were used for sample irradiation, enabling a correction for the contribution of the low-energy neutrons. The neutron-induced activation cross sections were estimated by subtracting the reaction rates of irradiated samples for 25° irradiation from those of 0° irradiation. The measured cross sections were compared with the findings of other studies, evaluated in relation to nuclear data files and the calculated data by Particle and Heavy Ion Transport code System code.

  20. Computational characterization and experimental validation of the thermal neutron source for neutron capture therapy research at the University of Missouri

    Energy Technology Data Exchange (ETDEWEB)

    Broekman, J. D. [University of Missouri, Research Reactor Center, 1513 Research Park Drive, Columbia, MO 65211-3400 (United States); Nigg, D. W. [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415 (United States); Hawthorne, M. F. [University of Missouri, International Institute of Nano and Molecular Medicine, 1514 Research Park Dr., Columbia, MO 65211-3450 (United States)

    2013-07-01

    Parameter studies, design calculations and neutronic performance measurements have been completed for a new thermal neutron beamline constructed for neutron capture therapy cell and small-animal radiobiology studies at the University of Missouri Research Reactor. The beamline features the use of single-crystal silicon and bismuth sections for neutron filtering and for reduction of incident gamma radiation. The computational models used for the final beam design and performance evaluation are based on coupled discrete-ordinates and Monte Carlo techniques that permit detailed modeling of the neutron transmission properties of the filtering crystals with very few approximations. Validation protocols based on neutron activation spectrometry measurements and rigorous least-square adjustment techniques show that the beam produces a neutron spectrum that has the anticipated level of thermal neutron flux and a somewhat higher than expected, but radio-biologically insignificant, epithermal neutron flux component. (authors)

  1. NOS/NGS activities to support development of radio interferometric surveying techniques

    Science.gov (United States)

    Carter, W. E.; Dracup, J. F.; Hothem, L. D.; Robertson, D. S.; Strange, W. E.

    1980-01-01

    National Geodetic Survey activities towards the development of operational geodetic survey systems based on radio interferometry are reviewed. Information about the field procedures, data reduction and analysis, and the results obtained to date is presented.

  2. Application of neutron activation analysis system in Xi'an pulsed reactor

    CERN Document Server

    Zhang Wen Shou; Yu Qi

    2002-01-01

    Neutron Activation Analysis System in Xi'an Pulsed Reactor is consist of rabbit fast radiation system and experiment measurement system. The functions of neutron activation analysis are introduced. Based on the radiation system. A set of automatic data handling and experiment simulating system are built. The reliability of data handling and experiment simulating system had been verified by experiment

  3. CHANG-ES - VIII. Uncovering hidden AGN activity in radio polarization

    Science.gov (United States)

    Irwin, Judith A.; Schmidt, Philip; Damas-Segovia, A.; Beck, Rainer; English, Jayanne; Heald, George; Henriksen, Richard N.; Krause, Marita; Li, Jiang-Tao; Rand, Richard J.; Wang, Q. Daniel; Wiegert, Theresa; Kamieneski, Patrick; Paré, Dylan; Sullivan, Kendall

    2017-01-01

    We report on C-band (5-7 GHz) observations of the galaxy, NGC 2992, from the Continuum Halos in Nearby Galaxies - an EVLA Survey (CHANG-ES) sample. This galaxy displays an embedded nuclear double-lobed radio morphology within its spiral disc, as revealed in linearly polarized emission but not in total intensity emission. The radio lobes are kpc-sized, similar to what has been observed in the past for other Seyfert galaxies, and show ordered magnetic fields. NGC 2992 has shown previous evidence for AGN-related activity, but not the linearly polarized radio features that we present here. We draw attention to this galaxy as the first clear example (and prototype) of bipolar radio outflow that is revealed in linearly polarized emission only. Such polarization observations, which are unobscured by dust, provide a new tool for uncovering hidden weak active galactic nucleus (AGN) activity which may otherwise be masked by brighter unpolarized emission within which it is embedded. The radio lobes observed in NGC 2992 are interacting with the surrounding interstellar medium (ISM) and offer new opportunities to investigate the interactions between nuclear outflows and the ISM in nearby galaxies. We also compare the radio emission with a new CHANDRA X-ray image of this galaxy. A new CHANG-ES image of NGC 3079 is also briefly shown as another example as to how much more obvious radio lobes appear in linear polarization as opposed to total intensity.

  4. Neutron activation analysis: Modelling studies to improve the neutron flux of Americium–Beryllium source

    National Research Council Canada - National Science Library

    Abdessamad Didi; Ahmed Dadouch; Otman Jaï; Jaouad Tajmouati; Hassane El Bekkouri

    2017-01-01

    Americium–beryllium (Am-Be; n, γ) is a neutron emitting source used in various research fields such as chemistry, physics, geology, archaeology, medicine, and environmental monitoring, as well as in the forensic sciences...

  5. Determination of hydrogen in niobium by cold neutron prompt gamma ray activation analysis and neutron incoherent scattering

    Energy Technology Data Exchange (ETDEWEB)

    R.L. Paul; H.H. Cheu-Maya; G.R. Myneni

    2002-11-01

    The presence of trace amounts of hydrogen in niobium is believed to have a detrimental effect on the mechanical and superconducting properties. Unfortunately, few techniques are capable of measuring hydrogen at these levels. We have developed two techniques for measuring hydrogen in materials. Cold neutron prompt gamma-ray activation analysis (PGAA) has proven useful for the determination of hydrogen and other elements in a wide variety of materials. Neutron incoherent scattering (NIS), a complementary tool to PGAA, has been used to measure trace hydrogen in titanium. Both techniques were used to study the effects of vacuum heating and chemical polishing on the hydrogen content of superconducting niobium.

  6. Clinical applications of in vivo neutron-activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Cohn, S.H.

    1982-01-01

    In vivo neutron activation has opened a new era of both clinical diagnosis and therapy evaluation, and investigation into and modelling of body composition. The techniques are new, but it is already clear that considerable strides can be made in increasing accuracy and precision, increasing the number of elements susceptible to measurement, enhancing uniformity, and reducing the dose required for the measurement. The work presently underway will yield significant data on a variety of environmental contaminants such as Cd. Compositional studies are determining the level of vital constituents such as nitrogen and potassium in both normal subjects and in patients with a variety of metabolic disorders. Therapeutic programs can be assessed while in progress.

  7. Neutron activation analysis of multimetallic accumulation in dolomites

    Directory of Open Access Journals (Sweden)

    Zovko Emira

    2008-01-01

    Full Text Available The reason for exploring polymetallic ores, which are found in dolomite structures of the Veovača and Borovica zone near Vareš, lies in the fact that there is very little information about its chemical structure. The isolated concentrates that we analyzed from surface mines, have shown significant difference in quantity of trace elements. Deep probing of the whole area was not performed, but there are presumptions that there are roots of ore-rich dolomites in the areas of 30 - 40 km. The future concept of exploitation of these mines in the Vareš zone would probably require deeper probing. There are prospects for finding higher quality deposits with significant quantities of polymetallic components. By the method of neutron activation analysis the existence of mercury in amounts of about 0.4 % was confirmed. Because of the presence of mercury, these concentrates are not appropriate for pyrometallurgy, since it may result in environment contamination.

  8. In-vivo neutron activation analysis: principles and clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Cohn, S.H.

    1982-01-01

    In vivo neutron activation has opened a new era of both clinical diagnosis and therapy evaluation, and investigation into and modelling of body composition. The techniques are new, but it is already clear that considerable strides can be made in increasing accuracy and precision, increasing the number of elements susceptible to measurement, enhancing uniformity, and reducing the dose required for the measurement. The work presently underway will yield significant data on a variety of environmental contaminants such as Cd. Compositional studies are determining the level of vital constituents such as nitrogen and potassium in both normal subjects and in patients with a variety of metabolic disorders. Therapeutic programs can be assessed while in progress. It seems likely that by the end of this century there will have been significant progress with this research tool, and exciting insights obtained into the nature and dynamics of human body composition.

  9. Geeks, meta-Geeks, and gender trouble: activism, identity, and low-power FM radio.

    Science.gov (United States)

    Dunbar-Hester, Christina

    2008-04-01

    In this paper, I consider the activities of a group of individuals who tinker with and build radio hardware in an informal setting called 'Geek Group'. They conceive of Geek Group as a radical pedagogical activity, which constitutes an aspect of activism surrounding citizen access to low-power FM radio. They are also concerned with combating the gendered nature of hardware skills, yet in spite of their efforts men tend to have more skill and familiarity with radio hardware than women. Radio tinkering has a long history as a masculine undertaking and a site of masculine identity construction. I argue that this case represents an interplay between geek, activist, and gendered identities, all of which are salient for this group, but which do not occur together without some tension.

  10. Accretion Disk Model of Short-Timescale Intermittent Activity in Young Radio Sources

    CERN Document Server

    Czerny, Bozena; Janiuk, Agnieszka; Nikiel-Wroczynski, Blazej; Stawarz, Lukasz

    2009-01-01

    We associate the existence of short-lived compact radio sources with the intermittent activity of the central engine caused by a radiation pressure instability within an accretion disk. Such objects may constitute a numerous sub-class of Giga-Hertz Peaked Spectrum sources, in accordance with the population studies of radio-loud active galaxies, as well as detailed investigations of their radio morphologies. We perform the model computations assuming the viscosity parametrization as proportional to a geometrical mean of the total and gas pressure. The implied timescales are consistent with the observed ages of the sources. The duration of an active phase for a moderate accretion rate is short enough (< 10^3-10^4 years) that the ejecta are confined within the host galaxy and thus these sources cannot evolve into large size radio galaxies unless they are close to the Eddington limit.

  11. Measurement of neutron flux spectra in a Tungsten Benchmark by neutron foil activation method

    OpenAIRE

    Negoita, Cezar Ciprian

    2004-01-01

    The nuclear design of fusion devices such as ITER (International Thermonuclear Experimental Reactor), which is an experimental fusion reactor based on the "tokamak" concept, rely on the results of neutron physical calculations. These depend on the knowledge of the neutron and photon flux spectra which is particularly important because it permits to anticipate the possible answers of the whole structure to phenomena such as nuclear heating, tritium breeding, atomic displaceme...

  12. Medical application of in vivo neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Cohn, S.H.; Ellis, K.J.; Vartsky, D.; Zanzi, I.; Aloia, J.F.

    1978-01-01

    The clinical usefulness of total body neutron activation analysis (TBNAA) was clearly established at an IAEA panel meeting in Vienna in 1972. It is best demonstrated by the studies involving the measurement of total-body calcium. This measurement provides data useful for the diagnosis and management of metabolic bone disorders. It should be emphasized, however, that while most of the applications to date have involved calcium and phosphorus, the measurement of sodium, chlorine and nitrogen also appear to be useful clinically. Total-body calcium measurements utilizing TBNAA have been used in studies of osteoporosis to establish absolute and relative deficits of calcium in patients with this disease in comparison to a normal contrast population. Changes in total-body calcium (skeletal mass) have also been useful for quantitating the efficacy of various therapies in osteoporosis. Serial measurements over periods of years provide long-term balance data by direct measurement with a higher precision (+- 2%) than is possible by the use of any other technique. In the renal osteodystrophy observed in patients with renal failure, disorders of both calcium and phosphorus, as well as electrolyte disturbances, have been studied. The measure of total-body levels of these elements gives the clinician useful data upon which to design dialysis therapy. The measurement of bone changes in endocrine dysfunction has been studied, particularly in patients with thyroid and parathyroid disorders. In parathyroidectomy, the measurement of total-body calcium, post-operatively, can indicate the degree of bone resorption. Skeletal metabolism and body composition in acromegaly and Cushing's disease have also been investigated by TBNAA. Levels of cadmium in liver and kidney have also been measured in-vivo by prompt-gamma neutron activation and associated with hypertension, emphysema and cigarette smoking.

  13. No radio pulsations detected from SGR 1627-41 following renewed X- ray activity

    Science.gov (United States)

    Camilo, F.; Sarkissian, J.

    2008-06-01

    Starting on May 28, 2008, the SGR 1627-41 displayed X-ray bursting and enhanced flux after nearly 10 years of relative inactivity (ATEL #1548, #1549, #1555). Two magnetars are known to emit radio pulses (Camilo et al. 2007, ApJ, 666, L93), and in at least one case these are transient and have followed an X-ray outburst after many years in quiescence (Camilo et al. 2006, Nature, 442, 892). Therefore, although previous radio searches of SGR 1627-41 have been unsuccessful, we are searching for radio emission following its recent renewed burst of activity.

  14. Tables for simplifying calculations of activities produced by thermal neutrons

    Science.gov (United States)

    Senftle, F.E.; Champion, W.R.

    1954-01-01

    The method of calculation described is useful for the types of work of which examples are given. It is also useful in making rapid comparison of the activities that might be expected from several different elements. For instance, suppose it is desired to know which of the three elements, cobalt, nickel, or vanadium is, under similar conditions, activated to the greatest extent by thermal neutrons. If reference is made to a cross-section table only, the values may be misleading unless properly interpreted by a suitable comparison of half-lives and abundances. In this table all the variables have been combined and the desired information can be obtained directly from the values of A 3??, the activity produced per gram per second of irradiation, under the stated conditions. Hence, it is easily seen that, under similar circumstances of irradiation, vanadium is most easily activated even though the cross section of one of the cobalt isotopes is nearly five times that of vanadium and the cross section of one of the nickel isotopes is three times that of vanadium. ?? 1954 Societa?? Italiana di Fisica.

  15. Thermal, intermediate and fast neutron flux measurements using activation detectors; Mesure des flux de neutrons thermiques, intermediaires et rapides au moyen de detecteurs par activation

    Energy Technology Data Exchange (ETDEWEB)

    Brisbois, J.; Lott, M.; Manent, G. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    The problem of neutron flux measurements using activation detectors is studied in the particular case of protection research. It is shown how it possible, it is possible, using a known thermal flux, to organise a coherent calibration system for all the detectors. The rapid neutron detectors are calibrated with respect to a reference detector (phosphorus) in a natural uranium converter; the intermediate neutron detectors with respect to gold in the axial channel of ZOE. This method makes it possible to minimise the errors due to the activation cross-sections. A brief description is given of the counting room of the Pile Safety Study Service, as well of the practical utilisation characteristics of the counters employed. (authors) [French] Le probleme de la mesure des flux de neutrons au moyen de detecteurs par activation est etudie dans le cas particulier des etudes de protections. On montre comment, a partir d'un flux thermique connu, on peut organiser un systeme coherent d'etalonnage de tous les detecteurs. Les detecteurs de neutrons rapides sont etalonnes par rapport a un detecteur de reference (phosphore) dans un convertisseur en uranium naturel; les detecteurs de neutrons intermediaires, par rapport a l'or dans le canal axial de ZOE, Cette methode permet de minimiser les erreurs dues aux sections efficaces d'activation. On decrit sommairement la salle de comptage du Service d'Etudes de Protections de Piles et on indique les caracteristiques d'emploi pratique des detecteurs utilises. (auteurs)

  16. Real-Time Active Cosmic Neutron Background Reduction Methods

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-09-01

    Neutron counting using large arrays of pressurized 3He proportional counters from an aerial system or in a maritime environment suffers from the background counts from the primary cosmic neutrons and secondary neutrons caused by cosmic ray-induced mechanisms like spallation and charge-exchange reaction. This paper reports the work performed at the Remote Sensing Laboratory–Andrews (RSL-A) and results obtained when using two different methods to reduce the cosmic neutron background in real time. Both methods used shielding materials with a high concentration (up to 30% by weight) of neutron-absorbing materials, such as natural boron, to remove the low-energy neutron flux from the cosmic background as the first step of the background reduction process. Our first method was to design, prototype, and test an up-looking plastic scintillator (BC-400, manufactured by Saint Gobain Corporation) to tag the cosmic neutrons and then create a logic pulse of a fixed time duration (~120 μs) to block the data taken by the neutron counter (pressurized 3He tubes running in a proportional counter mode). The second method examined the time correlation between the arrival of two successive neutron signals to the counting array and calculated the excess of variance (Feynman variance Y2F)1 in the neutron count distribution from Poisson distribution. The dilution of this variance from cosmic background values ideally would signal the presence of man-made neutrons.2 The first method has been technically successful in tagging the neutrons in the cosmic-ray flux and preventing them from being counted in the 3He tube array by electronic veto—field measurement work shows the efficiency of the electronic veto counter to be about 87%. The second method has successfully derived an empirical relationship between the percentile non-cosmic component in a neutron flux and the Y2F of the measured neutron count distribution. By using shielding materials alone, approximately 55% of the neutron flux

  17. Search for reaction-in-flight neutrons using thulium activation at the National Ignition Facility

    Science.gov (United States)

    Grim, Gary; Rundberg, Robert; Tonchev, Anton; Fowler, Malcolm; Wilhelmy, Jerry; Archuleta, Tom; Bionta, Richard; Boswell, Mitzi; Gostic, Julie; Griego, Jeff; Knittel, Kenn; Klein, Andi; Moody, Ken; Shaughnessy, Dawn; Wilde, Carl; Yeamans, Charles

    2013-10-01

    We report on measurements of reaction-in-flight (RIF) neutrons at the National Ignition Facility. RIF neutrons are produced in cryogenically layered implision by up-scattered deuterium, or tritium ions that undergo subsequent fusion reactions. The rate of RIF neutron production is proportional to the fuel areal density (| | R) and ion-stopping length in the dense fuel assembly. Thus, RIF neutrons provide information on charge particle stopping in a strongly coupled plasma, where perturbative modeling breaks down. To measure RIF neutrons, a set of thulium activation foils was placed 50 cm from layered cryogenic implosions at the NIF. The reaction 169Tm(n,3n)167Tm has a neutron kinetic energy threshold of 14.96 MeV. We will present results from initial experiments performed during the spring of 2013. Prepared by LANL under Contract DE-AC-52-06-NA25396, TSPA, LA-UR-13-22085.

  18. Measurement of neutron-induced activation cross-sections using spallation source at JINR and neutronic validation of the Dubna code

    Indian Academy of Sciences (India)

    Manish Sharma; V Kumar; H Kumawat; J Adam; V S Barashenkov; S Ganesan; S Golovatiouk; S K Gupta; S Kailas; M I Krivopustov; H S Palsania; V Pronskikh; V M Tsoupko-Sitnikov; N Vladimirova; H Westmeier; W Westmeier

    2007-02-01

    A beam of 1 GeV proton coming from Dubna Nuclotron colliding with a lead target surrounded by 6 cm paraffin produces spallation neutrons. A Th-foil was kept on lead target (neutron spallation source) in a direct stream of neutrons for activation and other samples of 197Au, 209Bi, 59Co, 115In and 181Ta were irradiated by moderated beam of neutrons passing through 6 cm paraffin moderator. The gamma spectra of irradiated samples were analyzed using gamma spectrometry and DEIMOS software to measure the neutron cross-section. For this purpose neutron fluence at the positions of samples is also estimated using PREPRO software. The results of cross-sections for reactions 232Th(, ), 232Th(, 2), 197Au(, ), 197Au(, ), 197Au(, ), 59Co(, ), 59Co(, ), 181Ta(, ) and 181Ta(, ) are given in this paper. Neutronics validation of the Dubna Cascade Code is also done using cross-section data by other experiments.

  19. Active Neutron Interrogation of Non-Radiological Materials with NMIS

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Mark E [ORNL; Mihalczo, John T [ORNL

    2012-02-01

    The Nuclear Materials Identification System (NMIS) at Oak Ridge National Laboratory (ORNL), although primarily designed for analyzing special nuclear material, is capable of identifying nonradiological materials with a wide range of measurement techniques. This report demonstrates four different measurement methods, complementary to fast-neutron imaging, which can be used for material identification: DT transmission, DT scattering, californium transmission, and active time-tagged gamma spectroscopy. Each of the four techniques was used to evaluate how these methods can be used to identify four materials: aluminum, polyethylene, graphite, and G-10 epoxy. While such measurements have been performed individually in the past, in this project, all four measurements were performed on the same set of materials. The results of these measurements agree well with predicted results. In particular, the results of the active gamma spectroscopy measurements demonstrate the technique's applicability in a future version of NMIS which will incorporate passive and active gamma-ray spectroscopy. This system, designated as a fieldable NMIS (FNMIS), is under development by the US Department of Energy Office of Nuclear Verification.

  20. Development of Distinction Method of Production Area of Ginsengs by Using a Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Jin; Chung, Yong Sam; Sun, Gwang Min; Lee, Yu Na; Yoo, Sang Ho [KAERI, Daejeon (Korea, Republic of)

    2010-05-15

    Distinction of production area of Korean ginsengs has been tried by using neutron activation techniques such as an instrumental neutron activation analysis (INAA) and a prompt gamma activation analysis (PGAA). A distribution of elements has varied according to the part of plant clue to the difference of enrichment effect and influence from a soil where the plants have been grown. So correlation study between plants and soil has been an Issue. In this study, the distribution of trace elements within a Korean ginseng was investigated by using an instrumental neutron activation analysis

  1. Investigation of distribution of elements in a Korean ginseng by using a neutron activation method

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yu Na; Sun, Gwang Min; Chung, Yong Sam; Kim, Young Jin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-10-15

    The Distinction of production areas of Korean ginsengs has been tried by using neutron activation techniques such as an instrumental neutron activation analysis (INAA) and a prompt gamma activation analysis (PGAA). This study was done as a part of those efforts. As is well known, the distribution of elements varies according to the part of plant due to the difference of enrichment effect and influence from a soil where the plants have been grown. So a correlation study between plants and soil is an important issue. In this study, the distribution of trace elements within a Korean ginseng was investigated by using an instrumental neutron activation analysis.

  2. Computer programs for absolute neutron activation analysis on the nuclear data 6620 data acquisition system

    Energy Technology Data Exchange (ETDEWEB)

    Wade, J.W.; Emery, J.F.

    1982-03-01

    Five computer programs that provide multielement neutron activation analysis are discussed. The software package was designed for use on the Nuclear Data 6620 Data Acquisition System and interacts with existing Nuclear Data Corporation software. The programs were developed to make use of the capabilities of the 6620 system to analyze large numbers of samples and assist in a large sample workload that had begun in the neutron activation analysis facility of the Oak Ridge Research Reactor. Nuclear Data neutron activation software is unable to perform absolute activation analysis and therefore was inefficient and inadequate for our applications.

  3. Neutron transport calculation for Activation Evaluation for Decommissioning of PET cyclotron Facility

    Science.gov (United States)

    Nobuhara, Fumiyoshi; Kuroyanagi, Makoto; Masumoto, Kazuyoshi; Nakamura, Hajime; Toyoda, Akihiro; Takahashi, Katsuhiko

    2017-09-01

    In order to evaluate the state of activation in a cyclotron facility used for the radioisotope production of PET diagnostics, we measured the neutron flux by using gold foils and TLDs. Then, the spatial distribution of neutrons and induced activity inside the cyclotron vault were simulated with the Monte Calro calculation code for neutron transport and DCHAIN-SP for activation calculation. The calculated results are in good agreement with measured values within factor 3. Therefore, the adaption of the advanced evaluation procedure for activation level is proved to be important for the planning of decommissioning of these facilities.

  4. FY16 Status Report on NEAMS Neutronics Activities

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C. H. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Shemon, E. R. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Smith, M. A. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Jung, Y. S. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

    2016-09-30

    The goal of the NEAMS neutronics effort is to develop a neutronics toolkit for use on sodium-cooled fast reactors (SFRs) which can be extended to other reactor types. The neutronics toolkit includes the high-fidelity deterministic neutron transport code PROTEUS and many supporting tools such as a cross section generation code MC2-3, a cross section library generation code, alternative cross section generation tools, mesh generation and conversion utilities, and an automated regression test tool. The FY16 effort for NEAMS neutronics focused on supporting the release of the SHARP toolkit and existing and new users, continuing to develop PROTEUS functions necessary for performance improvement as well as the SHARP release, verifying PROTEUS against available existing benchmark problems, and developing new benchmark problems as needed. The FY16 research effort was focused on further updates of PROTEUS-SN and PROTEUS-MOCEX and cross section generation capabilities as needed.

  5. Calculation of thermal neutron self-shielding correction factors for aqueous bulk sample prompt gamma neutron activation analysis using the MCNP code

    Energy Technology Data Exchange (ETDEWEB)

    Nasrabadi, M.N. [Department of Physics, Faculty of Science, University of Kashan, Km. 6, Ravand Road, Kashan (Iran, Islamic Republic of)], E-mail: mnnasri@kashanu.ac.ir; Jalali, M. [Isfahan Nuclear Science and Technology Research Institute, Atomic Energy organization of Iran (Iran, Islamic Republic of); Mohammadi, A. [Department of Physics, Faculty of Science, University of Kashan, Km. 6, Ravand Road, Kashan (Iran, Islamic Republic of)

    2007-10-15

    In this work thermal neutron self-shielding in aqueous bulk samples containing neutron absorbing materials is studied using bulk sample prompt gamma neutron activation analysis (BSPGNAA) with the MCNP code. The code was used to perform three dimensional simulations of a neutron source, neutron detector and sample of various material compositions. The MCNP model was validated against experimental measurements of the neutron flux performed using a BF{sub 3} detector. Simulations were performed to predict thermal neutron self-shielding in aqueous bulk samples containing neutron absorbing solutes. In practice, the MCNP calculations are combined with experimental measurements of the relative thermal neutron flux over the sample's surface, with respect to a reference water sample, to derive the thermal neutron self-shielding within the sample. The proposed methodology can be used for the determination of the elemental concentration of unknown aqueous samples by BSPGNAA where knowledge of the average thermal neutron flux within the sample volume is required.

  6. Trace elements in coloured opals using neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    McOrist, G.D.; Smallwood, A. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    Neutron activation analysis (NAA) is a technique particularly suited to analysing opals since it is non-destructive and the silica matrix of opals is not prone to significant activation. It was used to determine the concentration of trace elements in 50 samples of orange, yellow, green, blue and pink opals as well as 18 samples of colourless opals taken from a number of recognised fields in Australia, Peru, Mexico and USA. The results were then evaluated to determine if a relationship existed between trace element content and opal colour. The mean concentration of most of the elements found in orange, yellow and colourless opals were similar with few exceptions. This indicated that, for these samples, colour is not related to the trace elements present. However, the trace element profile of the green, pink and blue opals was found to be significantly different with each colour having a much higher concentration of certain trace elements when compared with all other opals analysed. 7 refs.

  7. Feasibility of culvert IED detection using thermal neutron activation

    Science.gov (United States)

    Faust, Anthony A.; McFee, John E.; Clifford, Edward T. H.; Andrews, Hugh Robert; Mosquera, Cristian; Roberts, William C.

    2012-06-01

    Bulk explosives hidden in culverts pose a serious threat to the Canadian and allied armies. Culverts provide an opportunity to conceal insurgent activity, avoid the need for detectable surface disturbances, and limit the applicability of conventional sub-surface sensing techniques. Further, in spite of the large masses of explosives that can be employed, the large sensor{target separation makes detection of the bulk explosive content challeng- ing. Defence R&D Canada { Sueld and Bubble Technology Industries have been developing thermal neutron activation (TNA) sensors for detection of buried bulk explosives for over 15 years. The next generation TNA sensor, known as TNA2, incorporates a number of improvements that allow for increased sensor-to-target dis- tances, making it potentially feasible to detect large improvised explosive devices (IEDs) in culverts using TNA. Experiments to determine the ability of TNA2 to detect improvised explosive devices in culverts are described, and the resulting signal levels observed for relevant quantities of explosives are presented. Observations conrm that bulk explosives detection using TNA against a culvert-IED is possible, with large charges posing a detection challenge at least as dicult as that of a deeply buried anti-tank landmine. Because of the prototype nature of the TNA sensor used, it is not yet possible to make denitive statements about the absolute sensitivity or detection time. Further investigation is warranted.

  8. Development of active environmental and personal neutron dosemeters.

    Science.gov (United States)

    Nakamura, T; Nunomiya, T; Sasaki, M

    2004-01-01

    For neutron dosimetry in the radiation environment surrounding nuclear facilities, two types of environmental neutron dosemeters, the high-sensitivity rem counter and the high-sensitivity multi-moderator, the so-called Bonner ball, have been developed and the former is commercially available from Fuji Electric Co. By using these detectors, the cosmic ray neutrons at sea level have been sequentially measured for about 3 y to investigate the time variation of neutron spectrum and ambient dose equivalent influenced by cosmic and terrestrial effects. Our Bonner ball has also been selected as the neutron detector in the International Space Station and has already been used to measure neutrons in the US experimental module. The real time wide-range personal neutron dosemeter which uses two silicon semiconductor detectors has been developed for personal dosimetry and is commercially available from Fuji Electric Co. This dosemeter has good characteristics, fitted to the fluence-to-dose conversion factor in the energy range from thermal energies to several tens of mega-electron-volts and is now widely used in various nuclear facilities.

  9. Activation analysis of indium, KCl, and melamine by using a laser-induced neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sungman; Lee, Kitae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Cha, Hyungki [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2014-04-15

    A laser-induced repetitively operated fast neutron source with a neutron yield of 4 x 10{sup 5} n/pulse and a pulse repetition rate of 5 Hz, which was developed using a deuterated polystyrene film target and a 24-TW femtosecond laser, was applied for laser activation analyses of indium, KCl, and melamine samples. The nuclear reactions of the measured gamma spectra for the activated samples were identified as (n, γ), (n, n'), and (n, 2n) reactions. These indicate possible usage of the neutron source for practical activation analyses of various materials.

  10. In-situ soil composition and moisture measurement by surface neutron activation analysis

    Science.gov (United States)

    Waring, C.; Smith, C.; Marks, A.

    2009-04-01

    Neutron activation analysis is widely known as a laboratory technique dependent upon a nuclear reactor to provide the neutron flux and capable of precise elemental analysis. Less well known in-situ geochemical analysis is possible with isotopic (252Cf & 241Am) or compact accelerator (D-T, D-D fusion reaction) neutron sources. Prompt gamma neutron activation analysis (PGNAA) geophysical borehole logging has been applied to mining issues for >15 years (CSIRO) using isotopic neutron sources and more recently to environmental and hydro-geological applications by ANSTO. Similarly, sophisticated geophysical borehole logging equipment based on inelastic neutron scattering (INS) has been applied in the oil and gas industry by large oilfield services companies to measure oil saturation indices (carbon/oxygen) using accelerator neutron sources. Recent advances in scintillation detector spectral performance has enabled improved precision and detection limits for elements likely to be present in soil profiles (H, Si, Al, Fe, Cl) and possible detection of many minor to trace elements if sufficiently abundant (Na, K, Mg, Ca, S, N, + ). To measure carbon an accelerator neutron source is required to provide fast neutrons above 4.8 MeV. CSIRO and ANSTO propose building a soil geochemical analysis system based on experience gained from building and applying PGNA borehole logging equipment. A soil geochemical analysis system could effectively map the 2D geochemical composition of the top 50cm of soil by dragging the 1D logging equipment across the ground surface. Substituting an isotopic neutron source for a D-T accelerator neutron source would enable the additional measurement of elemental carbon. Many potential ambiguities with other geophysical proxies for soil moisture may be resolved by direct geochemical measurement of H. Many other applications may be possible including time series in-situ measurements of soil moisture for differential drainage, hydrology, land surface

  11. A Study of the Fitting Accuracy of the Active Reflector for a Large Spherical Radio Telescope

    Institute of Scientific and Technical Information of China (English)

    Xiao-Qiang Tang; Jin-Song Wang; Qi-Ming Wang

    2003-01-01

    We propose a spatial three-degree-of-freedom (DOF) parallel mechanism combining two degrees of rotations and one degree of translation to support the active reflector units of a large spherical radio telescope. The kinematics, workspace and accuracy of the mechanism are analyzed. One-dimensional and two-dimensional fitting errors to the working region of active reflector are investigated. Dimensional parameters of the mechanism and active reflector unit are examined with respect to the requirement of fitting accuracy. The result of accuracy analysis shows the effectiveness and feasibility of the proposed mechanism, and gives a design rule to guarantee the highest working frequency required by large radio telescope.

  12. Two non-destructive neutron inspection techniques: prompt gamma-ray activation analysis and cold neutron tomography

    OpenAIRE

    Baechler, Sébastien; Dousse, Jean-Claude; Jolie, Jan

    2005-01-01

    Deux techniques d’inspection non-destructives utilisant des faisceaux de neutrons froids ont été développées à la source de neutrons SINQ de l’Institut Paul Scherrer : (1) l’analyse par activation neutronique prompte (PGAA) et (2) la tomographie neutronique. L’analyse par PGA (Prompt Gamma-ray Activation) est une méthode nucléaire qui permet de déterminer la concentration d’éléments présents dans un échantillon. Cette technique consiste à détecter les rayons gamma prompts émis par l’échantill...

  13. Essential trace elements in edible mushrooms by Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Patricia L.C.; Maihara, Vera A.; Castro, Lilian P. de [Instituto de Pesquisa e Energetica e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mail: patricialandim@ig.com.br; vmaihara@ipen.br; lilian.Pavanelli@terra.com.br; Figueira, Rubens C.L. [Universidade Cruzeiro do Sul, Sao Paulo, SP (Brazil)]. E-mail: figueiraru@yahoo.com.br

    2007-07-01

    Mushrooms are excellent nutritional sources since they provide proteins, fibers and mineral, such as K, P, Fe. They have also been the focus of medical research. In Brazil mushrooms are not consumed in large quantities by the general population since people know little about the nutritional and medicinal benefits that mushrooms offer. Hence, this study intends to contribute to a better understanding of the essential element content in edible mushrooms, which are currently commercialized in Sao Paulo state. Br Fe, K, Na and Zn concentrations were determined by Instrumental Neutron Activation Analysis in the following mushroom species: Shitake (Lentinus edodes), Shimeji (Pleurotus ssp), Paris Champignon (Agaricus bisporus), Hiratake ( Pleurotus ssp) and Eringue (Pleurotus Eryngu. The mushroom samples were acquired from commercial establishments in the city of Sao Paulo and directly from the producers. Essential element contents in mushrooms varied between Br 0.03 to 4.1 mg/kg; Fe 20 to 267 mg/kg; K 1.2 to 5.3 g/kg, Na 10 to 582 mg/kg and Zn 60 to 120 mg/kg. The results confirm that mushrooms can be considered a good source of K, Fe and Zn. The low Na level is a good nutritional benefit for the consumer. (author)

  14. Elementary concentration of Peruibe black mud by neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Torrecilha, Jefferson K.; Ponciano, Ricardo; Silva, Paulo S.C da, E-mail: jeffkoy@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The Peruibe Black Mud is used in therapies such as psoriasis, peripheral dermatitis, acne, seborrehea, myalgia arthritis and rheumatic non-articular processes. This material is characterized by is fine organic matter particles, sulphate reducing bacteria and a high content of potential reduction ions. Although this material is particles, sulphate reducing bacteria and a high content of potential reduction ions. Although this material is considered natural, it may not be free of possible adverse health effects, like toxic chemical elements, when used for therapeutic purposes. In the therapeutic treatments involving clays, clays are used in mud form also called peloids, obtained by maturation process. Five in natura and three maturated Black Mud samples were collected in Peruibe city, Sao Paulo State, Brazil. To investigate the distribution of major, trace and rare earth elements in the in natura and maturated clays that constitute the Peruibe Black Mud, neutron activation analysis (NAA) was used. A comparison between in natura and maturated mud shows that major, trace and rare earth elements follow the same order in both types. Generally, the concentrations in the maturated mud are slightly lower than in natura mud. Enrichment on the upper continental crust could be observed for the elements As, Br, Sb and Se, in these types of mud. (author)

  15. Neutron activation analysis and provenance study of Tupiguarani Tradition pottery

    Energy Technology Data Exchange (ETDEWEB)

    Faria, Gleikam Lopes de Oliveira [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/ CNEN-MG), Belo Horizonte, MG (Brazil). Curso de Mestrado em Ciencia e Tecnologia das Radiacoes, Minerais e Materiais], e-mail: gleikam@yahoo.com.br; Menezes, Maria Angela de B.C. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/ CNEN-MG), Belo Horizonte, MG (Brazil). Servico de Reator e Tecnicas Analiticas. Lab. de Ativacao Neutronica], e-mail: menezes@cdtn.br; Ribeiro, Loredana; Jacome, Camila [Cooperativa dos Empreendedores em Acoes Culturais - COOP. CULTURA, Belo Horizonte, MG (Brazil). Lab. de Arqueologia], e-mail: loredana.ribeiro@gmail.com

    2009-07-01

    Archaeology can fill the gap between ancient population and modern society elucidating the evidences found in archaeological sites. The fingerprint identified, that is the chemical composition of the ceramics, can help understanding this connection between the past and the present. The Tupiguarani Tradition vestiges found by archaeologists will be a way to know about the last two millennia of the Brazilian prehistory. This archaeological site is located along the coast of the Brazilian State of Espirito Santo, where the main evidence is a pretty ceramic with the occurrence of plastic and painted decoration. When the Portuguese settlers arrived in this region, in sixteenth century, several Missoes Jesuiticas (Jesuitical Missions) were built along the Brazilian coast. In spite of living within the Mission and been catechized, the Indians kept on producing traditional handicraft, as the decorated ceramic, however, they introduced European elements to the decoration. During the research expeditions made to the archaeological site of the Tupiguarani Tradition, many sherds were found. The identification and classification of ceramics through a multielemental chemistry analysis will be used to determine if they have the same origin. This paper shows the first elemental concentration results of the sherds collected from archaeological site determined at CDTN/CNEN, Belo Horizonte, Minas Gerais, using the TRIGA Mark I IPR-R1 nuclear reactor, applying the neutron activation technique, k{sub 0}-method. (author)

  16. Inorganic constituents in herbal medicine by neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Rodolfo D.M.R.; Francisconi, Lucilaine S.; Silva, Paulo S.C. da, E-mail: pscsilva@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN- SP), Sao Paulo, SP (Brazil)

    2011-07-01

    The demand for herbal medicines is growing worldwide. The expansion of interest has required the standardization of the sector with implementation and constant review of technical standards for production and marketing of these medicines in order to ensure the safe use, therapeutic efficacy and quality of the products. According to data from the World Health Organization, approximately 80% of world population has resorted to the benefits of certain herbs with therapeutic action popularly recognized. Despite the vast flora and the extensive use of medicinal plants by the population, it is a consensus that scientific studies on the subject are insufficiency. Therefore, it is necessary to stimulate such studies in view of the importance of the results of both individual and social field. The determination of major, minor and trace elements and the research of metabolic processes and their impacts on human health are of great importance due to the growth of environmental pollution that directly affects the plants and therefore the phytotherapics. Therefore, the objective of this work was to determine the content of inorganic constituents in herbal medicine: moisture, total ash and the elements As, Ba, Br, Ca, Cs, Co, Cr, Fe, Hf, K, Na, Rb, Sb, Sc, Se, Ta, Th, U, Zn and Zr by neutron activation analysis in order to verify the quality of the products. It was observed that the elemental concentrations varied in a wide range from plant to plant and elements with higher concentrations were Ba, Fe, Cr and Zn. (author)

  17. Response of thunderstorm activity in data of neutron monitoring at Tien Shan

    Science.gov (United States)

    Antonova, Valentina; Kryukov, Sergey; Lutsenko, Vadim

    2015-04-01

    We present results of the study of data of the monitoring of high-energy and thermal neutrons at Tien Shan at different stages of thunderstorm activity. The data of the neutron monitoring were used taking into account the barometric effect. The intensity of the neutron component of cosmic rays is recorded in seven energy ranges. The electric field has values of ~ 100 V/m under fair weather conditions. Standard deviation of minute values of the neutron monitor data at the high altitude station does not exceed 0.5-0.6 %. Found that the standard deviation of the data during thunderstorms always exceeds these values. We selected events during the passage of thunderstorm clouds over the high altitude station without lightning discharges or with a small number of them. It was found that the particle rate of the neutron monitor changes in antiphase with the electric field changes. Atmospheric electric field of positive polarity decreases the count rate of the neutron monitor, and negative polarity - increases. Change of the count rate occurs at values of electric field ≥ 10-15 kV/m and reaches 2 %. The neutron monitor at the high-altitude station has the ability to measure the energy of recorded particles through determination of their multiplicity. We experimentally established that the sensitivity of the detected particles to change in Ez increases with decreasing their energy. The upper energy threshold of sensitivity of neutrons to change electric field is ~10 GeV. The physical mechanism of effect is based on lead nucleus capture of soft negative muons with the subsequent generation of neutrons. It is known that 7% of the neutron monitor count rate caused by negative muons. Absence of this effect in thermal neutrons data confirms the conclusion since the main difference of the thermal neutrons detector from the neutron monitor is the absence of the lead. In the active phase of a thunderstorm in the formed thundercloud the picture of distribution of charges is

  18. Effect of high current electron beam in a 30 MeV radio frequency linac for neutron-time-of-flight applications

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, B., E-mail: biswaranjan.nayak1@gmail.com; Acharya, S.; Rajawat, R. K. [Accelerator and Pulsed Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); DasGupta, K. [Accelerator and Pulsed Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Beam Technology Development Group, BARC, Mumbai 400085 (India)

    2016-01-15

    A high power pulsed radio frequency electron linac is designed by BARC, India to accelerate 30 MeV, 10 A, 10 ns beam for neutron-time-of-flight applications. It will be used as a neutron generator and will produce ∼10{sup 12}–10{sup 13} n/s. It is essential to reduce the beam instability caused by space charge effect and the beam cavity interaction. In this paper, the wakefield losses in the accelerating section due to bunch of RMS (Root mean square) length 2 mm (at the gun exit) is analysed. Loss and kick factors are numerically calculated using CST wakefield solver. Both the longitudinal and transverse wake potentials are incorporated in beam dynamics code ELEGANT to find the transverse emittance growth of the beam propagating through the linac. Beam loading effect is examined by means of numerical computation carried out in ASTRA code. Beam break up start current has been estimated at the end of the linac which arises due to deflecting modes excited by the high current beam. At the end, transverse beam dynamics of such high current beam has been analysed.

  19. Characteristics and application of spherical-type activation detectors in neutron spectrum measurements at a boron neutron capture therapy (BNCT) facility

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Heng-Xiao; Chen, Wei-Lin [Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 300, Taiwan, ROC (China); Liu, Yuan-Hao [Neuboron Medtech Ltd., Nanjing, Jiangsu Province 21112 (China); Sheu, Rong-Jiun, E-mail: rjsheu@mx.nthu.edu.tw [Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 300, Taiwan, ROC (China); Department of Engineering and System Science, National Tsing Hua University, Hsinchu 300, Taiwan, ROC (China)

    2016-03-01

    A set of spherical-type activation detectors was developed aiming to provide better determination of the neutron spectrum at the Tsing Hua Open-pool Reactor (THOR) BNCT facility. An activation foil embedded in a specially designed spherical holder exhibits three advantages: (1) minimizing the effect of neutron angular dependence, (2) creating response functions with broadened coverage of neutron energies by introducing additional moderators or absorbers to the central activation foil, and (3) reducing irradiation time because of improved detection efficiencies to epithermal neutron beam. This paper presents the design concept and the calculated response functions of new detectors. Theoretical and experimental demonstrations of the performance of the detectors are provided through comparisons of the unfolded neutron spectra determined using this method and conventional multiple-foil activation techniques.

  20. Present and Future Activities on Neutron Imaging in Argentina

    Science.gov (United States)

    Tartaglione, Aureliano; Blostein, Jerónimo; Cantargi, Florencia; Marín, Julio; Baruj, Alberto; Meyer, Gabriel; Santisteban, Javier; Sánchez, Fernando

    We present here a short review of the main work which has been done in the latest years in neutron imaging in Argentina, and the future plans for the development of this technique in the country, mainly focused in the design of a new neutron imaging instrument to be installed in the future research reactor RA10. We present here the results of the implementation of the technique in samples belonging to the Argentinean cultural heritage and experiments related with hydrogen storage. At the same time, the Argentinean RA10 project for the design and construction of a 30 MW multipurpose research reactor is rapidly progressing. It started to be designed by the National Atomic Energy Commission (CNEA) and the technology company INVAP SE, both from Argentina, in June 2010. The construction will start in the beginning of 2015 in the Ezeiza Atomic Center, at 36 km from Buenos Aires City, and is expected to be finished by 2020. One of the main aims of the project is to offer to the Argentinean scientific and technology system new capabilities based on neutron techniques. We present here the conceptual design of a neutron imaging facility which will use one of the cold neutron beams, and will be installed in the reactor hall. Preliminary simulation results show that at the farthest detection position, at about 17 m from the cold source, a uniform neutron beam on a detection screen with an intensity of about 108 n/cm2/s is expected.

  1. Constraints on long-lived remnants of neutron star binary mergers from late-time radio observations of short duration gamma-ray bursts

    CERN Document Server

    Metzger, Brian D

    2013-01-01

    The coalescence of a binary neutron star (NS) system may in some cases produce a massive NS remnant that is long-lived and, potentially, indefinitely stable to gravitational collapse. Such a remnant has been proposed as an explanation for the late X-ray emission observed following some short duration gamma-ray bursts (GRBs) and as possible electromagnetic counterparts to the gravitational wave chirp. A stable NS merger remnant necessarily possesses a large rotational energy > 1e52 erg, the majority of which is ultimately deposited into the surrounding circumburst medium (CBM) at mildly relativistic velocities. We present Very Large Array radio observations of 7 short GRBs, some of which possessed temporally extended X-ray emission, on timescales of ~1-3 years following the initial burst. No radio sources were detected, with typical upper limits ~0.3 mJy at 1.4 GHz. A basic model for the synchrotron emission from the blast wave is used to constrain the presence of a long-lived NS merger remnant in each system....

  2. A Multi-parameter Model for Radio Dichotomy of Active Galactic Nuclei and Jets

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Based on the coexistence of the Blandford-Znajek and magnetic coupling processes in black hole (BH)accretion disc, a multi-parameter model for jet powers and radio loudness of active galactic nuclei (AGNs) is studied. It turns out that radio-loudness of AGNs could be governed by five parameters: (i) the BH spin, (ii) a power-law index of the variation of the magnetic field on the disc; (iii) a parameter determining the position of the inner edge of the disc, (iv)the ratio of the pressure of the magnetic field on the horizon to the ram pressure of the innermost parts of an accretion flow, and (v) the ratio of the angular velocity of the open field lines to that of the horizon. The observed dichotomy between radio-loud and radio-quiet AGNs is well interpreted by the effects of the above parameters. Furthermore, we discuss the derivative of radio loudness of AGNs with respect to each parameter separately. In addition, the effect of the screw instability on radio loudness of A GNs is discussed.

  3. HerMES: Disentangling active galactic nuclei and star formation in the radio source population

    CERN Document Server

    Rawlings, J I; Symeonidis, M; Bock, J; Cooray, A; Farrah, D; Guo, K; Hatziminaoglou, E; Ibar, E; Oliver, S J; Roseboom, I G; Scott, Douglas; Seymour, N; Vaccari, M; Wardlow, J L

    2015-01-01

    We separate the extragalactic radio source population above ~50 uJy into active galactic nuclei (AGN) and star-forming sources. The primary method of our approach is to fit the infrared spectral energy distributions (SEDs), constructed using Spitzer/IRAC and MIPS and Herschel/SPIRE photometry, of 380 radio sources in the Extended Chandra Deep Field-South. From the fitted SEDs, we determine the relative AGN and star-forming contributions to their infrared emission. With the inclusion of other AGN diagnostics such as X-ray luminosity, Spitzer/IRAC colours, radio spectral index and the ratio of star-forming total infrared flux to k-corrected 1.4 GHz flux density, qIR, we determine whether the radio emission in these sources is powered by star formation or by an AGN. The majority of these radio sources (60 per cent) show the signature of an AGN at some wavelength. Of the sources with AGN signatures, 58 per cent are hybrid systems for which the radio emission is being powered by star formation. This implies that r...

  4. The radio-loud active nucleus in the "dark lens" galaxy J1218+2953

    CERN Document Server

    Frey, S; Campbell, R M; Moor, A

    2010-01-01

    Context: There is a possibility that the optically unidentified radio source J1218+2953 may act as a gravitational lens, producing an optical arc ~4" away from the radio position. Until now, the nature of the lensing object has been uncertain since it is not detected in any waveband other than the radio. The estimated high mass-to-light ratio could even allow the total mass of this galaxy to be primarily in the form of dark matter. In this case, J1218+2953 could be the first known example of a "dark lens". Aims: We investigate the nature of J1218+2953 by means of high-resolution radio imaging observations to determine whether there is a radio-loud active galactic nucleus (AGN) in the position of the lensing object. Methods: We report on Very Long Baseline Interferometry (VLBI) observations with the European VLBI Network (EVN) at 1.6 and 5 GHz. Results: Our images, having angular resolutions of ~1 to ~10 milli-arcseconds (mas), reveal a rich and complex radio structure extending to almost 1". Based on its radi...

  5. Praseodymium activation detector for measuring bursts of 14 MeV neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Meehan, Tim, E-mail: meehanbt@nv.doe.go [National Security Technologies, LLC, P.O. Box 98521, North Las Vegas, NV 89030 (United States); Hagen, E.C. [National Security Technologies, LLC, P.O. Box 98521, North Las Vegas, NV 89030 (United States); Ruiz, C.L.; Cooper, G.W. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185 (United States)

    2010-08-21

    A new, accurate, neutron activation detection scheme for measuring pulsed neutrons has been designed and tested. The detection system is sensitive to neutrons with energies above 10 MeV; importantly, it is insensitive to gamma radiation <10 MeV and to lower-energy (e.g., fission and thermal) neutrons. It is based upon the use of {sup 141}Pr, an element that has a single, naturally occurring isotope, a significant n,2n cross-section, and decays by positron emission that result in two coincident 511 keV photons. Neutron fluences are thus inferred by relating measured reaction product decay activity to fluence. Specific sample activity is measured using the sum-peak method to count gamma-ray coincidences from the annihilation of the positron decay products. The system was tested using 14 and 2.45 MeV neutron bursts produced by NSTec Dense Plasma Focus Laboratory fusion sources. Lead, copper, beryllium, and silver activation detectors were compared. The detection method allows measurement of 14 MeV neutron yield with a total error of {approx}18%.

  6. 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.

  7. Dosimetric optimization of postproduction neutron-activated Erbium-170-oxide-enriched pancreatin

    Energy Technology Data Exchange (ETDEWEB)

    Borm, J.J.J.; Bruno, M.J.; Goeij, J.J.M. de [Academic Medical Center, Amsterdam (Netherlands)]|[Delft Univ. of Technology, Mekelweg (Netherlands)]|[Nordmark Arzneimittel GmbH, Uetersen (Germany)] [and others

    1995-05-01

    The feasibility of postproduction neutron activation of an enteric-coated pancreatic enzyme preparation for in vivo gastric emptying studies has been investigated. During production of this multicomponent preparation, small amounts of {sup 170}Er-enriched erbium oxide, suitable for neutron activation, were added. Postproduction neutron irradiation of the labeled preparation resulted in short-lived (7.5 hr) gamma-emitting {sup 171}Er. Various radiocontaminants, however, are produced also. Because of variations in activation yields, half-lives, decay schemes and radiotoxicities, both major and trace consitituents were considered for optimization of both dosimetry and the diagnostic measurement. Conditions were optimized for the best ratio of the committed dose equivalent due to {sup 171}Er to the total committed dose equivalent. The results show that postproduction neutron activation of a {sup 170}Er-enriched multicomponent preparation can be performed safely within the guidelines set by the WHO for experiments in humans involving radioactive materials. 9 refs., 3 tabs.

  8. Estimates of iodine in biological materials by epithermal neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sato, T. (Tokyo Metropolitan Inst. for Neurosciences, Fuchu (Japan)); Kato, T. (Tohoku Univ., Sendai (Japan). Coll. of General Education)

    1982-01-01

    Iodine abundances in NBS biological SRMs and various organs of rats were evaluated by epithermal neutron activation analysis with a boron carbide filter. The detectability of iodine in different biological materials by this method is discussed.

  9. THE FUNDAMENTAL PLANE FOR RADIO MAGNETARS

    Energy Technology Data Exchange (ETDEWEB)

    Rea, Nanda; Torres, Diego F. [Institut de Ciencies de l' Espai (CSIC-IEEC), Campus UAB, Torre C5, 2a Planta, 08193 Barcelona (Spain); Pons, Jose A. [Departament de Fisica Aplicada, Universitat d' Alacant, Ap. Correus 99, 03080 Alacant (Spain); Turolla, Roberto [Dipartimento di Fisica e Astronomia, Universita di Padova, via F. Marzolo 8, I-35131 Padova (Italy)

    2012-03-20

    High magnetic fields are a distinguishing feature of neutron stars and the existence of sources (the soft gamma repeaters, SGRs, and the anomalous X-ray pulsars) hosting an ultramagnetized neutron star (or magnetar) has been recognized in the past few decades. Magnetars are believed to be powered by magnetic energy and not by rotation, as with normal radio pulsars. Until recently, the radio quietness and magnetic fields typically above the quantum critical value (B{sub Q} {approx_equal} 4.4 Multiplication-Sign 10{sup 13} G) were among the characterizing properties of magnetars. The recent discovery of radio-pulsed emission from a few of them, and of a low dipolar magnetic field SGR, weakened further the idea of a clean separation between normal pulsars and magnetars. In this Letter, we show that radio emission from magnetars might be powered by rotational energy, similarly to what occurs in normal radio pulsars. The peculiar characteristics of magnetars radio emission should be traced in the complex magnetic geometry of these sources. Furthermore, we propose that magnetar radio activity or inactivity can be predicted from the knowledge of the star's rotational period, its time derivative, and the quiescent X-ray luminosity.

  10. Neutrons formed by heavy ions and activation induced in different materials; Neutrons crees par ions lourds et activation induite dans divers materiaux

    Energy Technology Data Exchange (ETDEWEB)

    Clapier, F.; Pauwels, N.; Proust, J.

    1995-12-31

    This work deals with the Spiral project and more particularly with the neutrons flux formed by heavy ions and the activation induced in different materials. Indeed, the beams power suggests the interest of different materials behaviour study for allowing a possible selection to optimize radioprotection. Moreover, it is important to establish the activation mechanisms in order to be able to extrapolate the measures realized at 400 W (actual GANIL) to those of the future running taking into account the radioisotopes real mixtures formed during the reaction and their daughter products. A best knowledge of energizing and angular neutrons distributions is searched too. (O.L.). 11 refs., 23 figs., 9 tabs.

  11. Neutron induced background gamma activity in low-level Ge-spectroscopy systems

    Science.gov (United States)

    Jovančević, N.; Krmar, M.; Mrda, D.; Slivka, J.; Bikit, I.

    2010-01-01

    Two high purity germanium (HPGe) detectors were located in two different passive shields: one in pre-WW II iron and the second in commercial low background lead. Gamma lines emitted after neutron capture, as well as after inelastic scattering on the germanium crystal were detected and then analyzed. The thermal and fast neutron fluxes were calculated and their values were compared for the two different kinds of detector shield. Several materials having different neutron slowing-down properties were packed in Marinelli geometry, positioned on the lead shielded detector and measured for around 10 6 s. The main goal was to estimate a possible influence of the sample on the intensity of the neutron induced Ge gamma lines. On the iron-shielded detector a massive (3 in. thick) NaI Compton suppression system showed a measurable activity from neutron capture and inelastic scattering on sodium and iodine nuclei.

  12. Preliminary engineering assessment of the HCLL and HCPB Neutron Activation System

    Energy Technology Data Exchange (ETDEWEB)

    Calderoni, Pattrick; Leichtle, Dieter [Fusion for Energy, Barcelona, (Spain); Angelone, Maurizio [ENEA, Unita Tecnica Fusione, Frascati, (Italy); Klix, Axel [KIT, Eggenstein-Leopoldshafen, (Germany)

    2015-07-01

    The Neutron Activation System (NAS) is one of the four types of neutronics sensors considered for the testing of the HCLL and HCPB Test Blanket Module (TBM) in ITER. It measures the absolute neutron flux intensity with information on the neutron spectrum in selected positions of the TBM. The working principle of the NAS is as follows: the system moves small activation probes (capsules) into selected positions in the TBM (irradiation ends) by means of pneumatic transport with pressurized helium gas; the capsules are irradiated for a selected period, depending on their materials composition (several tens of seconds up to the full plasma pulse length); immediately after the irradiation they are extracted and transported to a gamma spectrometer by means of the same pneumatic transport system; the gamma spectrometer determines the induced gamma activity; the neutron flux and neutron fluence is calculated from the measured gamma activity and the known activation cross section of the materials in the activation probe; after the measurement the capsule is sent either to a disposal or storage (for later measurement). This paper summarizes the results of the feasibility assessment of the TBM NAS in the conceptual design phase, including design justification, identification of requirements based on the expected operating conditions in ITER and preliminary engineering assessment of the activation materials, irradiation ends integration in the modules design and the counting station. (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

    D. L. Chichester; E. H. Seabury

    2008-10-01

    Experiments have been performed at Idaho National Laboratory to study methodology and instrumentation for performing neutron active interrogation die-away analyses for the purpose of detecting shielded fissionable material. Here we report initial work using a portable DT electronic neutron generator with a He-3 fast neutron detector to detect shielded fissionable material including >2 kg quantities of enriched uranium and plutonium. Measurements have been taken of bare material as well as of material hidden within a large plywood cube. Results from this work have demonstrated the efficacy of the die-away neutron measurement technique for quickly detecting the presence of special nuclear material hidden within plywood shields by analyzing the time dependent neutron signals in-between neutron generator pulses. Using a DT electronic neutron generator operating at 300 Hz with a yield of approximately 0.36 x 10**8 neutrons per second, 2.2 kg of enriched uranium hidden within a 0.60 m x 0.60 m x 0.70 m volume of plywood was positively detected with a measurement signal 2-sigma above the passive background within 1 second. Similarly, for a 500 second measurement period a lower detection limit of approaching the gram level could be expected with the same simple set-up.

  14. Study of the magnetospheres of active regions on the sun by radio astronomy techniques

    Science.gov (United States)

    Bogod, V. M.; Kal'tman, T. I.; Peterova, N. G.; Yasnov, L. V.

    2017-01-01

    In the 1990s, based on detailed studies of the structure of active regions (AR), the concept of the magnetosphere of the active region was proposed. This includes almost all known structures presented in the active region, ranging from the radio granulation up to noise storms, the radiation of which manifests on the radio waves. The magnetosphere concept, which, from a common point of view, considers the manifestations of the radio emission of the active region as a single active complex, allows one to shed light on the relation between stable and active processes and their interrelations. It is especially important to identify the basic ways of transforming nonthermal energy into thermal energy. A dominant role in all processes is attributed to the magnetic field, the measurement of which on the coronal levels can be performed by radio-astronomical techniques. The extension of the wavelength range and the introduction of new tools and advanced modeling capabilities makes it possible to analyze the physical properties of plasma structures in the AR magnetosphere and to evaluate the coronal magnetic fields at the levels of the chromosphere-corona transition zone and the lower corona. The features and characteristics of the transition region from the S component to the B component have been estimated.

  15. The Evolution of Radio Loud Active Galactic Nuclei as a Function of Black Hole Spin

    CERN Document Server

    Garofalo, David; Sambruna, Rita M

    2010-01-01

    Recent work on the engines of active galactic nuclei jets suggests their power depends strongly and perhaps counter-intuitively on black hole spin. We explore the consequences of this on the radio-loud population of active galactic nuclei and find that the time evolution of the most powerful radio galaxies and radio-loud quasars fits into a picture in which black hole spin varies from retrograde to prograde with respect to the accreting material. Unlike the current view, according to which jet powers decrease in tandem with a global downsizing effect, we argue for a drop in jet power resulting directly from the paucity of retrograde accretion systems at lower redshift $z$ caused by a continuous history of accretion dating back to higher $z$. In addition, the model provides simple interpretations for the basic spectral features differentiating radio-loud and radio-quiet objects, such as the presence or absence of disk reflection, broadened iron lines and signatures of disk winds. We also briefly describe our m...

  16. Study of Correlations Between Radio Jet Velocity and Supermassive Black Hole Mass in Active Galaxies

    Directory of Open Access Journals (Sweden)

    Timothy Pennucci

    2006-01-01

    Full Text Available Previous research has shown that numerous characteristics of many host galaxies, such as stellar velocity dispersion and bulge luminosity, are governed by the central supermassive black hole (SMBH. This same SMBH is also thought to be the origin of radio jets propagating outward from the nucleus of these galaxies. It was then hypothesized that the mass of a SMBH influences and correlates with the initial radio jet velocity in active galaxies. Mass and velocity data were collected for 48 radio galaxies but as a result from projection effects due to the nature of active galaxies, apparent transverse velocity replaced intrinsic velocity in this study as the dependent variable. From these transverse velocities, the minimum intrinsic velocities of the radio jets were calculated for further investigation. Three apparent transverse velocity groups arise in the results that may be weakly correlated to SMBH mass. The calculated minimum intrinsic velocity data supports this correlation. These results are qualitative in nature and need to be tested on additional samples. While no direct conclusion can be made, the positive trends produced in this research between SMBH mass and radio jet velocity may later aid in further studies and galactic evolutionary research.

  17. CHANG-ES VIII: Uncovering Hidden AGN Activity in Radio Polarization

    CERN Document Server

    Irwin, Judith A; Damas-Segovia, A; Beck, Rainer; English, Jayanne; Heald, George; Henriksen, Richard N; Krause, Marita; Li, Jiang-Tao; Rand, Richard J; Wang, Q Daniel; Wiegert, Theresa; Kamieneski, Patrick; Paré, Dylan; Sullivan, Kendall

    2016-01-01

    We report on C-band (5 - 7 GHz) observations of the galaxy, NGC~2992, from the CHANG-ES sample. This galaxy displays an embedded nuclear double-lobed radio morphology within its spiral disk, as revealed in linearly polarized emission but {\\it not} in total intensity emission. The radio lobes are kpc-sized, similar to what has been observed in the past for other Seyfert galaxies, and show ordered magnetic fields. NGC~2992 has shown previous evidence for AGN-related activity, but not the linearly polarized radio features that we present here. We draw attention to this galaxy as the first clear example (and prototype) of bipolar radio outflow that is revealed in linearly polarized emission only. Such polarization observations, which are unobscured by dust, provide a new tool for uncovering hidden weak AGN activity which may otherwise be masked by brighter unpolarized emission within which it is embedded. The radio lobes observed in NGC~2992 are interacting with the surrounding interstellar medium and offer new o...

  18. SWAN - Detection of explosives by means of fast neutron activation analysis

    Science.gov (United States)

    Gierlik, M.; Borsuk, S.; Guzik, Z.; Iwanowska, J.; Kaźmierczak, Ł.; Korolczuk, S.; Kozłowski, T.; Krakowski, T.; Marcinkowski, R.; Swiderski, L.; Szeptycka, M.; Szewiński, J.; Urban, A.

    2016-10-01

    In this work we report on SWAN, the experimental, portable device for explosives detection. The device was created as part of the EU Structural Funds Project "Accelerators & Detectors" (POIG.01.01.02-14-012/08-00), with the goal to increase beneficiary's expertise and competencies in the field of neutron activation analysis. Previous experiences and budged limitations lead toward a less advanced design based on fast neutron interactions and unsophisticated data analysis with the emphasis on the latest gamma detection and spectrometry solutions. The final device has been designed as a portable, fast neutron activation analyzer, with the software optimized for detection of carbon, nitrogen and oxygen. SWAN's performance in the role of explosives detector is elaborated in this paper. We demonstrate that the unique features offered by neutron activation analysis might not be impressive enough when confronted with practical demands and expectations of a generic homeland security customer.

  19. Evaluation of the neutron activation of JET in-vessel components following DT irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Vuolo, M.; Bonifetto, R.; Dulla, S. [Dipartimento Energia, Politecnico di Torino, I-10129 Torino (Italy); Heinola, K. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Association EURATOM-TEKES, University of Helsinki, PO Box 64, 00560 Helsinki (Finland); Lengar, I. [Association EURATOM-MESCS, Reactor Physics Division, Jožef Stefan Institute, Ljubljana (Slovenia); Ravetto, P., E-mail: piero.ravetto@polito.it [Dipartimento Energia, Politecnico di Torino, I-10129 Torino (Italy); Richard, L.Savoldi [Dipartimento Energia, Politecnico di Torino, I-10129 Torino (Italy); Villari, R. [Associazione EURATOM-ENEA sulla Fusione, Via Enrico Fermi 45, 00044 Frascati, Rome (Italy); Widdowson, A. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Zanino, R. [Dipartimento Energia, Politecnico di Torino, I-10129 Torino (Italy)

    2014-10-15

    Highlights: The temporal evolution of the radioactive species in the in-vessel components after the end of the JET-DT campaign is calculated; Different levels of neutron irradiation are assumed; The neutron flux in the selected components is calculated by the MCNP5 code; The neutron spectra are input to the FISPACT code that computes the evolution of the radioactive species; For each irradiation scenario, the time behavior of the contact dose rate is determined. Abstract: The forthcoming deuterium–tritium (DT) campaign at the Joint European Torus (JET) will induce a significant activation of the system components. In the present work we evaluate the temporal evolution of the radioactive species in the main in-vessel components after the end of the future DT campaign, assuming different levels of neutron irradiation. The neutron flux in the selected components is calculated by the MCNP5 code using the emission source by a typical DT plasma. The resulting neutron spectra are then input to the FISPACT code that computes the evolution of the radioactive species generated by the neutron activation process. For each irradiation scenario, the time behavior of the contact dose rate is determined.

  20. Development of the prototype pneumatic transfer system for ITER neutron activation system.

    Science.gov (United States)

    Cheon, M S; Seon, C R; Pak, S; Lee, H G; Bertalot, L

    2012-10-01

    The neutron activation system (NAS) measures neutron fluence at the first wall and the total neutron flux from the ITER plasma, providing evaluation of the fusion power for all operational phases. The pneumatic transfer system (PTS) is one of the key components of the NAS for the proper operation of the system, playing a role of transferring encapsulated samples between the capsule loading machine, irradiation stations, counting stations, and disposal bin. For the validation and the optimization of the design, a prototype of the PTS was developed and capsule transfer tests were performed with the developed system.

  1. Commercial Radio Broadcasts of Propaganda: An Activity for Teaching about World War II.

    Science.gov (United States)

    Chilcoat, George W.

    1983-01-01

    By using propaganda commercial radio broadcasts which occurred during the Second World War as the basis for classroom activities, teachers can help students capture the emotional drama of various topics of the war, as well as certain themes still applicable in contemporary society, and stimulate student curiosity about the past. (RM)

  2. Estimating temporal independence of radio-telemetry data on animal activity

    NARCIS (Netherlands)

    Salvatori, V.; Skidmore, A.K.; Corsi, F.; Meer, van der F.

    1999-01-01

    Radio-telemetry is an excellent tool for gathering data on the biology of animals and their interactions with the environment they inhabit. Many methods have been developed for analyses of spatial information, on home range size and utilization density. Activity patterns are often described using

  3. Commercial Radio Broadcasts of Propaganda: An Activity for Teaching about World War II.

    Science.gov (United States)

    Chilcoat, George W.

    1983-01-01

    By using propaganda commercial radio broadcasts which occurred during the Second World War as the basis for classroom activities, teachers can help students capture the emotional drama of various topics of the war, as well as certain themes still applicable in contemporary society, and stimulate student curiosity about the past. (RM)

  4. Determining the solar wind speed above active regions using remote radio-wave observations.

    Science.gov (United States)

    Bougeret, J L; Fainberg, J; Stone, R G

    1983-11-04

    A new technique has made it possible to measure the velocity of portions of the solar wind during its flow outward from the sun. This analysis utilizes spacecraft (ISEE-3) observations of radio emission generated in regions of the solar wind associated with solar active regions. By tracking the source of these radio waves over periods of days, it is possible to measure the motion of the emission regions. Evidence of solar wind acceleration during this outward flow, consistent with theoretical models, has also been obtained.

  5. First Radio Astronomy Examination of the Low-Frequency Broadband Active Antenna Subarray

    Directory of Open Access Journals (Sweden)

    A. A. Stanislavsky

    2014-01-01

    Full Text Available We present the 25-element active antenna array and its remote control in the framework of the GURT project, the Ukrainian Radio Telescope of a new age. To implement beamforming, the array is phased with the help of discrete cable delay lines in analog manner. The remote control of the array is carried out through the paired encoder and decoder that can transmit parallel data about antenna codes serially. The microcontroller provides the online interaction between personal computer and beamformers with the help of the encoder-decoder system through wires or wireless. The antenna pattern has been measured by radio astronomy methods.

  6. Neutron activation analysis via nuclear decay kinetics using gamma-ray spectroscopy at SFU

    Science.gov (United States)

    Domingo, Thomas; Chester, Aaron; Starosta, Krzysztof; Williams, Jonathan

    2016-09-01

    Gamma-ray spectroscopy is a powerful tool used in a variety of fields including nuclear and analytical chemistry, environmental science, and health risk management. At SFU, the Germanium detector for Elemental Analysis and Radiation Studies (GEARS), a low-background shielded high-purity germanium gamma-ray detector, has been used recently in all of the above fields. The current project aims to expand upon the number of applications for which GEARS can be used while enhancing its current functionality. A recent addition to the SFU Nuclear Science laboratory is the Thermo Scientific P 385 neutron generator. This device provides a nominal yield of 3 ×108 neutrons/s providing the capacity for neutron activation analysis, opening a major avenue of research at SFU which was previously unavailable. The isotopes created via neutron activation have a wide range of half-lives. To measure and study isotopes with half-lives above a second, a new analogue data acquisition system has been installed on GEARS allowing accurate measurements of decay kinetics. This new functionality enables identification and quantification of the products of neutron activation. Results from the neutron activation analysis of pure metals will be presented.

  7. A precise method to determine the activity of a weak neutron source using a germanium detector

    CERN Document Server

    Duke, M J M; Krauss, C B; Mekarski, P; Sibley, L

    2015-01-01

    A standard high purity germanium detector (HPGe) was used to determine the neutron activity of a weak americium-beryllium (AmBe) neutron source. Gamma rays were created through 27Al(n,n'), 27Al(n,gamma) and 1H(n,gamma) reactions induced by the neutrons on aluminum and acrylic disks. A Monte Carlo simulation was developed to model the efficiency of the detector system. The activity of our neutron source was determined to be 305.6 +/- 4.9 n/s. The result is consistent for the different gamma rays and was verified using additional simulations and measurements of the 4483 keV gamma ray produced directly from the AmBe source.

  8. The peculiar radio galaxy 4C 35.06: a case for recurrent AGN activity?

    CERN Document Server

    Shulevski, A; Barthel, P D; Murgia, M; van Weeren, R J; White, G J; Brüggen, M; Kunert-Bajraszewska, M; Jamrozy, M; Best, P N; Röttgering, H J A; Chyzy, K T; de Gasperin, F; Bîrzan, L; Brunetti, G; Brienza, M; Rafferty, D A; Anderson, J; Beck, R; Deller, A; Zarka, P; Schwarz, D; Mahony, E; Orrú, E; Bell, M E; Bentum, M J; Bernardi, G; Bonafede, A; Breitling, F; Broderick, J W; Butcher, H R; Carbone, D; Ciardi, B; de Geus, E; Duscha, S; Eislöffel, J; Engels, D; Falcke, H; Fallows, R A; Fender, R; Ferrari, C; Frieswijk, W; Garrett, M A; Grießmeier, J; Gunst, A W; Heald, G; Hoeft, M; Hörandel, J; Horneffer, A; van der Horst, A J; Intema, H; Juette, E; Karastergiou, A; Kondratiev, V I; Kramer, M; Kuniyoshi, M; Kuper, G; Maat, P; Mann, G; McFadden, R; McKay-Bukowski, D; McKean, J P; Meulman, H; Mulcahy, D D; Munk, H; Norden, M J; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Rowlinson, A; Scaife, A M M; Serylak, M; Sluman, J; Smirnov, O; Steinmetz, M; Swinbank, J; Tagger, M; Tang, Y; Tasse, C; Thoudam, S; Toribio, M C; Vermeulen, R; Vocks, C; Wijers, R A M J; Wise, M W; Wucknitz, O

    2015-01-01

    Using observations obtained with the LOw Fequency ARray (LOFAR), the Westerbork Synthesis Radio Telescope (WSRT) and archival Very Large Array (VLA) data, we have traced the radio emission to large scales in the complex source 4C 35.06 located in the core of the galaxy cluster Abell 407. At higher spatial resolution (~4"), the source was known to have two inner radio lobes spanning 31 kpc and a diffuse, low-brightness extension running parallel to them, offset by about 11 kpc (in projection). At 62 MHz, we detect the radio emission of this structure extending out to 210 kpc. At 1.4 GHz and intermediate spatial resolution (~30"), the structure appears to have a helical morphology. We have derived the characteristics of the radio spectral index across the source. We show that the source morphology is most likely the result of at least two episodes of AGN activity separated by a dormant period of around 35 Myr. The AGN is hosted by one of the galaxies located in the cluster core of Abell 407. We propose that it ...

  9. NGC5252: a pair of radio-emitting active galactic nuclei?

    CERN Document Server

    Yang, Xiaolong; Paragi, Zsolt; Liu, Xiang; An, Tao; Bianchi, Stefano; Ho, Luis C; Cui, Lang; Zhao, Wei; Wu, Xiaocong

    2016-01-01

    The X-ray source CXO J133815.6+043255 has counterparts in the UV, optical, and radio bands. Based on the multi-band investigations, it has been recently proposed by Kim et al. (2015) as a rarely-seen off-nucleus ultraluminous X-ray (ULX) source with a black hole mass of >= 10^4 solar mass in the nearby Seyfert galaxy NGC 5252. To explore its radio properties at very high angular resolution, we performed very long-baseline interferometry (VLBI) observations with the European VLBI Network (EVN) at 1.7 GHz. We find that the radio counterpart is remarkably compact among the known ULXs. It does not show a resolved structure with a resolution of a few milliarcsecond (mas), and the total recovered flux density is comparable to that measured in earlier sub-arcsecond-resolution images. The compact radio structure, the relatively flat spectrum, and the high radio luminosity are consistent with a weakly accreting supermassive black hole in a low-luminosity active galactic nucleus. The nucleus of NGC 5252 itself has simi...

  10. Energy Storage and Release through the Solar Activity Cycle Models Meet Radio Observations

    CERN Document Server

    Nindos, Alexander

    2012-01-01

    For nearly sixty years, radio observations have provided a unique insight into the physics of the active and quiescent solar atmosphere. Thanks to the variety of emission mechanisms and to the large altitude range available to observations, fundamental plasma parameters have been measured from the low chromosphere to the upper corona and interplanetary medium. This book presents current research in solar radio astronomy and shows how well it fits in the exceptional scientific context brought by the current space solar observatories. It essentially contains contributed research and review papers presented during the 2010 Community of European Solar Radio Astronomers (CESRA) meeting, which took place in Belgium in June 2010. This book is aimed at graduate students and researchers working in solar physics and space science. Previously published in Solar Physics journal, Vol. 273/2, 2011.

  11. Characterizing Interference in Radio Astronomy Observations through Active and Unsupervised Learning

    Science.gov (United States)

    Doran, G.

    2013-01-01

    In the process of observing signals from astronomical sources, radio astronomers must mitigate the effects of manmade radio sources such as cell phones, satellites, aircraft, and observatory equipment. Radio frequency interference (RFI) often occurs as short bursts (< 1 ms) across a broad range of frequencies, and can be confused with signals from sources of interest such as pulsars. With ever-increasing volumes of data being produced by observatories, automated strategies are required to detect, classify, and characterize these short "transient" RFI events. We investigate an active learning approach in which an astronomer labels events that are most confusing to a classifier, minimizing the human effort required for classification. We also explore the use of unsupervised clustering techniques, which automatically group events into classes without user input. We apply these techniques to data from the Parkes Multibeam Pulsar Survey to characterize several million detected RFI events from over a thousand hours of observation.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-12-11

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

  13. [Evaluation of calcium content in the human spine by in vivo neutron activation].

    Science.gov (United States)

    Zaĭchik, V E; Dubrovin, A P; Korelo, A M; Morukov, B V

    1993-01-01

    A technique of in vivo neutron activation analysis (NAA) of calcium levels in lumbar, thoracic and cervical segments of the spinal column separately and as a whole has been developed. Special device provides selective irradiation by neutrons of a vertebral segment under study while a highly-sensitive spectrometric unit registers radionuclides induced in bone tissue during radiation exposure. For radiation exposure 5 or 10 238Pu-Be neutron sources with 5.10(7) neutrons s-1 output of each source are used. The spectrometric unit consists of 4 scintillation detectors with NaI (Tl) crystals of 150 mm in diameter and 100 mm- thickness arranged in a line tightly one after another. The time of exposure depends on the number and mutual arrangement of the neutron sources and is selected given the dose equivalent at depth of positioning of the spinal cord does not exceed 1 cZv (REM), the quality factor for fast neutrons equals 10. The recording duration is 20 min, the intervals between radiation exposure and recording do not exceed 3 min. The magnitude of the total error of an individual measurement estimated by reproducibility of the data obtained in 2 series of in vivo NAA of the spinal calcium levels in 6 volunteers with the use of 5 neutron sources amounts to an average of 4.8%. When used 10 sources, this error can be reduced to 2.0-3.2%.

  14. Do Radio-loud Active Galactic Nuclei really follow the same MBH-σ* Relation as Normal Galaxies?

    Institute of Scientific and Technical Information of China (English)

    Yi Liu; Dong-Rong Jiang

    2006-01-01

    In an examination of the relationship between the black hole mass MBH and stellar velocity dispersion σ* in radio-loud active galactic nuclei (AGNs), we studied two effects which may cause uncertainties in the black hole mass estimates of radio-loud AGNs: the relativistic beaming effect on the observed optical continuum radiation and the orientation effect on the broad emission line width. After correcting these two effects, we re-examined the MBH-σ[OⅢ] relation for a sample of radio-loud and radio-quiet AGNs, and found the relation for radio-loud AGNs still deviated from that for nearby normal galaxies and radio-quiet AGNs. We also found there is no significant correlation between radio jet power and narrow [OⅢ] line width, indicating absence of strong interaction between radio jet and narrow line region. It may be that the deviation of the MBH- σ* relation of radio-loud AGNs is intrinsic,or that the [OⅢ] line width is not a good indicator of σ* for radio-loud AGNs.

  15. 3D neutronic calculations: CAD-MCNP methodology applied to vessel activation in KOYO-F

    Science.gov (United States)

    Herreras, Y.; Lafuente, A.; Sordo, F.; Cabellos, O.; Perlado, J. M.

    2008-05-01

    This paper presents a methodology for 3D neutronic calculations suitable for complex and extensive geometries. The geometry of the system design is first fully modelled with a CAD program, and subsequently processed through a MCNP-CAD interface in order to generate an MCNP geometry file. Neutronic irradiation results are finally achieved running the MCNPX program, where the geometry input card used is directly the MCNP-CAD interface output. This methodology enables accurate neutronic calculations for complex geometries characterised by high detail levels. This procedure will be applied to the Fast Ignition Fusion Reactor KOYO-F to determine first neutron fluxes calculations along the blanket as well as the material activation in the reduced martensitic 9Cr-1Mo steel vessel.

  16. Benchmarking of activation reaction distribution in an intermediate energy neutron field.

    Science.gov (United States)

    Ogawa, Tatsuhiko; Morev, Mikhail N; Hirota, Masahiro; Abe, Takuya; Koike, Yuya; Iwai, Satoshi; Iimoto, Takeshi; Kosako, Toshiso

    2011-07-01

    Neutron-induced reaction rate depth profiles inside concrete shield irradiated by intermediate energy neutron were calculated using a Monte-Carlo code and compared with an experiment. An irradiation field of intermediate neutron produced in the forward direction from a thick (stopping length) target bombarded by 400 MeV nucleon(-1) carbon ions was arranged at the heavy ion medical accelerator in Chiba. Ordinary concrete shield of 90 cm thickness was installed 50 cm downstream the iron target. Activation detectors of aluminum, gold and gold covered with cadmium were inserted at various depths. Irradiated samples were extracted after exposure and gamma-ray spectrometry was performed for each sample. Comparison of experimental and calculated shows good agreement for both low- and high-energy neutron-induced reaction except for (27)Al(n,X)(24)Na reaction at the surface.

  17. 3D neutronic calculations: CAD-MCNP methodology applied to vessel activation in KOYO-F

    Energy Technology Data Exchange (ETDEWEB)

    Herreras, Y; Cabellos, O; Perlado, J M [Instituto de Fusion Nuclear (DENIM)/ETSII/Universidad Politecnica, Madrid (Spain); Lafuente, A; Sordo, F [Universidad Politecnica de Madrid (UPM), Madrid (Spain)], E-mail: yuri@denim.upm.es

    2008-05-15

    This paper presents a methodology for 3D neutronic calculations suitable for complex and extensive geometries. The geometry of the system design is first fully modelled with a CAD program, and subsequently processed through a MCNP-CAD interface in order to generate an MCNP geometry file. Neutronic irradiation results are finally achieved running the MCNPX program, where the geometry input card used is directly the MCNP-CAD interface output. This methodology enables accurate neutronic calculations for complex geometries characterised by high detail levels. This procedure will be applied to the Fast Ignition Fusion Reactor KOYO-F to determine first neutron fluxes calculations along the blanket as well as the material activation in the reduced martensitic 9Cr-1Mo steel vessel.

  18. Determination of Lithium by Instrumental Neutron Activation Analysis

    DEFF Research Database (Denmark)

    Heydorn, Kaj; Skanborg, Preben Zacho; Gwozdz, R.

    1977-01-01

    The fast transfer system in the DR 2 reactor for irradiation at a thermal neutron flux density of 1013 n·cm−2·sec−1 was used for the determination of lithium by the7Li(n, γ)8Li reaction. β-counting with a large perspex Cerenkov detector begun at 0.3 s after the end of irradiation, and multi...

  19. Neutron-Activated Gamma-Emission: Technology Review

    Science.gov (United States)

    2012-01-01

    defined in MCNPX to simulate the -spectra collected by NaI detectors (cell 6) from target (cell 3...numerical simulation. Safety issues are of great interest to users and are calculated in section 6. Ideas to increase target distance and reduce...neutron emission, target scatter, and gamma collection processes were simulated using MCNPX . MCNPX is a legacy code from Los Alamos National

  20. Radar activities of the DFVLR Institute for Radio Frequency Technology

    Science.gov (United States)

    Keydel, W.

    1983-01-01

    Aerospace research and the respective applications microwave tasks with respect to remote sensing, position finding and communication are discussed. The radar activities are directed at point targets, area targets and volume targets; they center around signature research for earth and ocean remote sensing, target recognition, reconnaissance and camouflage and imaging and area observation radar techniques (SAR and SLAR). The radar activities cover a frequency range from 1 GHz up to 94 GHz. The radar program is oriented to four possible application levels: ground, air, shuttle orbits and satellite orbits. Ground based studies and measurements, airborne scatterometers and imaging radars, a space shuttle radar, the MRSE, and follow on experiments are considered.

  1. Radar activities of the DFVLR Institute for Radio Frequency Technology

    Science.gov (United States)

    Keydel, W.

    1983-01-01

    Aerospace research and the respective applications microwave tasks with respect to remote sensing, position finding and communication are discussed. The radar activities are directed at point targets, area targets and volume targets; they center around signature research for earth and ocean remote sensing, target recognition, reconnaissance and camouflage and imaging and area observation radar techniques (SAR and SLAR). The radar activities cover a frequency range from 1 GHz up to 94 GHz. The radar program is oriented to four possible application levels: ground, air, shuttle orbits and satellite orbits. Ground based studies and measurements, airborne scatterometers and imaging radars, a space shuttle radar, the MRSE, and follow on experiments are considered.

  2. Estimating temporal independence of radio-telemetry data on animal activity

    Science.gov (United States)

    Salvatori; Skidmore; Corsi; van der Meer F

    1999-06-21

    Radio-telemetry is an excellent tool for gathering data on the biology of animals and their interactions with the environment they inhabit. Many methods have been developed for analyses of spatial information, on home range size and utilization density. Activity patterns are often described using radio-tracking data, but no generally accepted method is currently available specifically for determining the temporal independence of this type of data for statistical inference. Activity rhythms have generally been analysed by ecologists with the assumption that data are temporally independent, or by subjectively fixing an independence interval, based on attributes of their ranging behaviour. Although some good approximations of activity patterns can be obtained in these ways, we underline the need for a functionally correct method of estimating independence interval. Here we use semi-variograms to estimate the minimum interval required for the readings to be sequentially independent. This geostatistical tool is applied to the analysis of data on activity of Chilean foxes (Pseudalopex culpaeus) and Chacoan peccaries (Catagonus wagneri). Data were collected in the field by radio-tracking over 24-hr periods, with readings on activity state taken every 15 min. The spatial dimension in which the theory of geostatistics lies has been transferred into the time dimension, so that the correlation interval is expressed in time units (min). Time of independence as estimated by the variogram was 110 min for foxes, while data on peccaries indicated that they have long periods of activity, more suitable for time-series analysis. Copyright 1999 Academic Press.

  3. Neutron activation determination of gold in technogenic raw materials with different mineral composition

    Directory of Open Access Journals (Sweden)

    Yudakov Aleksandr A.

    2015-01-01

    Full Text Available The methods used to determine the gold content in the technogenic objects of gold mining were analyzed regarding their non-homogeneity and complexity of chemical and mineral compositions. A possible application of the neutron activation analysis with the use of the californium source of neutrons for determining the content of fine-grained and extra-fine-grained gold in the technogenic objects, including the bottom-ash waste of energy providers, is considered. It was demonstrated that the chemical composition of the sample affects the neuron flux distribution in the sample, which can essentially distort the results of the neutron activation analysis. In order to eliminate possible systematic errors investigations of the effect of the sample mineral composition on the results of the gold determination using the neutron activation analysis were carried out. Namely, a large mass of rock (3-5 kg was loaded into an activation zone using four matrix types such as silicate, carbon-containing, iron-containing, and titanium magnetite. It was shown that there wereno significant difference between the dispersal of the fluxes of thermal and resonance neutrons emitted from 252Cf during activation of the gold-containing technogenic samples with different mineral compositions.

  4. Neutron Activation Analysis of Soil Samples from Different Parts of Edirne in Turkey*

    Science.gov (United States)

    Zaim, N.; Dogan, C.; Camtakan, Z.

    2016-05-01

    The concentrations of constituent elements were determined in soil samples collected from different parts of the Maritza Basin, Edirne, Turkey. Neutron activation analysis, an extremely accurate technique, and the comparator method (using a standard) were applied for the first time in this region. After preparing the soil samples for neutron activation analysis, they were activated with thermal neutrons in a nuclear reactor, TRIGA-MARK II, at Istanbul Technical University. The activated samples were analyzed using a high-efficiency high-purity germanium detector, and gamma spectrometry was employed to determine the elemental concentration in the samples. Eight elements (chromium, manganese, cobalt, zinc, arsenic, molybdenum, cadmium, and barium) were qualitatively and quantitatively identified in 36 samples. The concentrations of some elements in the soil samples were high compared with values reported in the literature.

  5. Development of Enhanced, Permanently-Installed, Neutron Activation Diagnostic Hardware for NIF

    Science.gov (United States)

    Edwards, E. R.; Jedlovec, D. R.; Carrera, J. A.; Yeamans, C. B.

    2016-05-01

    Neutron activation diagnostics are baseline neutron yield and flux measurement instruments at the National Ignition Facility. Up to 19 activation samples are distributed around the target chamber. Currently the samples must be removed to be counted, creating a 1-2 week data turn-around time and considerable labor costs. An improved system consisting of a commercially available LaBr3(Ce) scintillator and Power over Ethernet electronics is under development. A machined zirconium-702 cap over the detector is the activation medium to measure the 90Zr(n,2n)89Zr reaction. The detectors are located at the current neutron activation diagnostic sites and monitored remotely. Because they collect data in real time yield values are returned within a few hours after a NIF shot.

  6. Delayed triggering of radio Active Galactic Nuclei in gas-rich minor mergers in the local Universe

    Science.gov (United States)

    Shabala, S. S.; Deller, A.; Kaviraj, S.; Middelberg, E.; Turner, R. J.; Ting, Y. S.; Allison, J. R.; Davis, T. A.

    2016-10-01

    We examine the processes triggering star formation and Active Galactic Nucleus (AGN) activity in a sample of 25 low redshift (z 107 K) brightness temperature required for an mJIVE-20 detection allows us to unambiguously identify the radio AGN in our sample. We find three such objects. Our VLBI AGN identifications are classified as Seyferts or LINERs in narrow line optical diagnostic plots; mid-infrared colours of our targets and the comparison of Hα star formation rates with integrated radio luminosity are also consistent with the VLBI identifications. We reconstruct star formation histories in our galaxies using optical and UV photometry, and find that these radio AGN are not triggered promptly in the merger process, consistent with previous findings for non-VLBI samples of radio AGN. This delay can significantly limit the efficiency of feedback by radio AGN triggered in galaxy mergers. We find that radio AGN hosts have lower star formation rates than non-AGN radio-selected galaxies at the same starburst age. Conventional and VLBI radio imaging shows these AGN to be compact on arcsecond scales. Our modeling suggests that the actual sizes of AGN-inflated radio lobes may be much larger than this, but these are too faint to be detected in existing observations. Deep radio imaging is required to map out the true extent of the AGN, and to determine whether the low star formation rates in radio AGN hosts are a result of the special conditions required for radio jet triggering, or the effect of AGN feedback.

  7. Delayed triggering of radio active galactic nuclei in gas-rich minor mergers in the local Universe

    Science.gov (United States)

    Shabala, S. S.; Deller, A.; Kaviraj, S.; Middelberg, E.; Turner, R. J.; Ting, Y. S.; Allison, J. R.; Davis, T. A.

    2017-02-01

    We examine the processes triggering star formation and active galactic nucleus (AGN) activity in a sample of 25 low-redshift (z 107 K) brightness temperature required for an mJIVE-20 detection allows us to unambiguously identify the radio AGN in our sample. We find three such objects. Our VLBI AGN identifications are classified as Seyferts or low-ionization nuclear emission-line regions (LINERs) in narrow line optical diagnostic plots; mid-infrared colours of our targets and the comparison of Hα star formation rates with integrated radio luminosity are also consistent with the VLBI identifications. We reconstruct star formation histories in our galaxies using optical and UV photometry, and find that these radio AGN are not triggered promptly in the merger process, consistent with previous findings for non-VLBI samples of radio AGN. This delay can significantly limit the efficiency of feedback by radio AGN triggered in galaxy mergers. We find that radio AGN hosts have lower star formation rates than non-AGN radio-selected galaxies at the same starburst age. Conventional and VLBI radio imaging shows these AGN to be compact on arcsecond scales. Our modelling suggests that the actual sizes of AGN-inflated radio lobes may be much larger than this, but these are too faint to be detected in existing observations. Deep radio imaging is required to map out the true extent of the AGN, and to determine whether the low star formation rates in radio AGN hosts are a result of the special conditions required for radio jet triggering, or the effect of AGN feedback.

  8. High Sensitive Neutron-Detection by Using a Self-Activation of Iodine-Containing Scintillators for the Photo-Neutron Monitoring around X-ray Radiotherapy Machines

    Science.gov (United States)

    Nohtomi, Akihiro; Wakabayashi, Genichiro; Kinoshita, Hiroyuki; Honda, Soichiro; Kurihara, Ryosuke; Fukunaga, Junichi; Umezu, Yoshiyuki; Nakamura, Yasuhiko; Ohga, Saiji; Nakamura, Katsumasa

    A novel method for evaluating the neutron dose-equivalent as well as neutron fluence around high-energy X-ray radiotherapy machines has been proposed and examined by using the self-activation of a CsI scintillator. Several filtering conditions were used to extract energy information of the neutron field. The shapes of neutron energy spectra were assumed to be practically unchanged at each three energy regions (thermal, epi-thermal and fast regions) for different irradiations around an X-ray linac whose acceleration potential was fixed to be a certain value. In order to know the actual neutron energy spectrum, an unfolding process was carried out for saturated activities of 128I generated inside the CsI scintillator under different filtering conditions; the response function matrix for each filtering condition was calculated by a Monte Carlo simulation. As the result, neutron dose-equivalent was estimated to be 0.14 (mSv/Gy) at 30 cm from the isocenter of linac. It has been revealed that fast neutron component dominated the total dose-equivalent.

  9. Analytical capabilities of the new thermal neutron prompt gamma-ray activation analysis instrument at the National Institute of Standards and Technology Center for Neutron Research

    Energy Technology Data Exchange (ETDEWEB)

    Mackey, E.A. [National Institute of Standards and Technology, Analytical Chemistry Division, Gaithersburg, MD (United States); Anderson, D.L. [US Food and Drug Administration, Elemental Research Branch, College Park, MD (United States)

    2004-07-01

    A new thermal neutron prompt gamma-ray activation analysis (PGAA) instrument was designed and built to replace the original PGAA system at the National Institute of Standards and Technology's Center for Neutron Research. The new PGAA instrument was constructed to achieve a reduction of the fast neutron beam component, a reduction of background gamma-radiation (including gamma-ray lines that directly interfere with element analyses, low-energy scattered gamma rays, and Compton scattered gamma rays), improvement in element sensitivities and limits of detection (LODs), and a simplified instrument set-up procedure. (orig.)

  10. Disentangling star formation and AGN activity in powerful infrared luminous radio galaxies at 1 < z < 4

    Science.gov (United States)

    Drouart, G.; Rocca-Volmerange, B.; De Breuck, C.; Fioc, M.; Lehnert, M.; Seymour, N.; Stern, D.; Vernet, J.

    2016-09-01

    High-redshift radio galaxies present signs of both star formation and AGN activity, making them ideal candidates to investigate the connection and coevolution of AGN and star formation in the progenitors of present-day massive galaxies. We make use of a sample of 11 powerful radio galaxies spanning 1 relative contribution of the AGN and star formation by combining the galaxy evolution code PÉGASE.3 with an AGN torus model. We find that three components are necessary to reproduce the observed SEDs: an evolved and massive stellar component, a submm bright young starburst, and an AGN torus. We find that powerful radio galaxies form at very high-redshift, but experience episodic and important growth at 1 mass of the associated starburst varies from 5 to 50% of the total mass of the system. The properties of star formation differ from source to source, indicating no general trend of the star formation properties in the most infrared luminous high-redshift radio galaxies and no correlation with the AGN bolometric luminosity. Moreover, we find that AGN scattered light have a very limited impact on broad-band SED fitting on our sample. Finally, our analysis also suggests a wide range in origins for the observed star formation,which we partially constrain for some sources.

  11. Discovery of Millimeter-Wave Excess Emission in Radio-Quiet Active Galactic Nuclei

    CERN Document Server

    Behar, Ehud; Laor, Ari; Horesh, Assaf; Stevens, Jamie; Tzioumis, Tasso

    2015-01-01

    The physical origin of radio emission in Radio Quiet Active Galactic Nuclei (RQ AGN) remains unclear, whether it is a downscaled version of the relativistic jets typical of Radio Loud (RL) AGN, or whether it originates from the accretion disk. The correlation between 5 GHz and X-ray luminosities of RQ AGN, which follows $L_R = 10^{-5}L_X$ observed also in stellar coronae, suggests an association of both X-ray and radio sources with the accretion disk corona. Observing RQ AGN at higher (mm-wave) frequencies, where synchrotron self absorption is diminished, and smaller regions can be probed, is key to exploring this association. Eight RQ AGN, selected based on their high X-ray brightness and variability, were observed at 95 GHz with the CARMA and ATCA telescopes. All targets were detected at the $1-10$ mJy level. Emission excess at 95~GHz of up to $\\times 7$ is found with respect to archival low-frequency steep spectra, suggesting a compact, optically-thick core superimposed on the more extended structures that...

  12. Measuring the kinetic power of active galactic nuclei in the radio mode

    Science.gov (United States)

    Merloni, Andrea; Heinz, Sebastian

    2007-10-01

    We have studied the relationship among nuclear radio and X-ray power, Bondi rate and the kinetic luminosity of sub-Eddington active galactic nucleus (AGN) jets, as estimated from the pdV work done to inflate the cavities and bubbles observed in the hot X-ray-emitting atmospheres of their host galaxies and clusters. Besides the recently discovered correlation between jet kinetic and Bondi power, we show that a clear correlation exists also between Eddington-scaled kinetic power and bolometric luminosity, given by log(Lkin/LEdd) = (0.49 +/- 0.07) log(Lbol/LEdd) - (0.78 +/- 0.36). The measured slope suggests that these objects are in a radiatively inefficient accretion mode, and have been used to put stringent constraints on the properties of the accretion flow. Interestingly, we found no statistically significant correlations between Bondi power and bolometric AGN luminosity, apart from that induced by their common dependence on Lkin, thus confirming the idea that most of the accretion power emerges from these systems in kinetic form. We have then analysed the relation between kinetic power and radio core luminosity. Combining the measures of jet power with estimators of the unbeamed radio flux of the jet cores as, for example, the so-called Fundamental Plane of active black holes, we are able to determine, in a statistical sense, both the probability distribution of the mean jet Lorentz factor, which peaks at Γm ~ 7, and the intrinsic relationship between kinetic and radio core luminosity (and thus the jet radiative efficiency), which we estimate as logLkin = (0.81 +/- 0.11) logLR + 11.9+4.1-4.4, in good agreement with theoretical predictions of synchrotron jet models. With the aid of these findings, quantitative assessments of kinetic feedback from supermassive black holes in the radio mode (i.e. at low dimensionless accretion rates) will be possible based on accurate determinations of the central engine properties alone, such as mass, radio core and/or X

  13. Analysis of Neutron Induced Gamma Activity in Lowbackground Ge - Spectroscopy Systems

    Science.gov (United States)

    Jovančević, Nikola; Krmar, Midrag

    Neutron interactions with materials of Ge-spectroscopy systems are one of the main sources of background radiation in low-level gamma spectroscopy measurements. Because of that detailed analysis of neutron induced gamma activity in low-background Ge-spectroscopy systems was done. Two HPGe detectors which were located in two different passive shields: one in pre-WW II made iron and the second in commercial low background lead were used in the experiment. Gamma lines emitted after neutron capture, as well as after inelastic scattering on the germanium crystal and shield materials (lead, iron, hydrogen, NaI) were detected and then analyzed. The thermal and fast neutron fluxes were calculated and their values were compared for the two different kinds of detector shield. The relative intensities of several gamma lines emitted after the inelastic scattering of neutrons (created by cosmic muons) in 56Fe were report. These relative intensities of detected gamma lines of 56Fe are compared with the results collected in the same iron shield by the use of the 252Cf neutrons.

  14. Low Temperature Irradiation Applied to Neutron Activation Analysis of Mercury In Human Whole Blood

    Energy Technology Data Exchange (ETDEWEB)

    Brune, D.

    1966-02-15

    The distribution of mercury in human whole blood has been studied by means of neutron activation analysis. During the irradiation procedure the samples were kept at low temperature by freezing them in a cooling device in order to prevent interferences caused by volatilization and contamination. The mercury activity was separated by means of distillation and ion exchange techniques.

  15. Simultaneous Determination of Arsenic, Manganese, and Selenium in Biological Materials by Neutron-Activation Analysis

    DEFF Research Database (Denmark)

    Heydorn, Kaj; Damsgaard, Else

    1973-01-01

    A new method was developed for the simultaneous determination of arsenic, manganese, and selenium in biological material by thermal-neutron activation analysis. The use of 81 mSe as indicator for selenium permitted a reduction of activation time to 1 hr for a 1 g sample, and the possibility of loss...

  16. The cross-section data from neutron activation experiments on niobium in the NPI p-7Li quasi-monoenergetic neutron field

    Directory of Open Access Journals (Sweden)

    Simakov S.P.

    2010-10-01

    Full Text Available The reaction of protons on 7Li target produces the high-energy quasi- monoenergetic neutron spectrum with the tail to lower energies. Proton energies of 19.8, 25.1, 27.6, 30.1, 32.6, 35.0 and 37.4 MeV were used to obtain quasi-monoenergetic neutrons with energies of 18, 21.6, 24.8, 27.6, 30.3, 32.9 and 35.6 MeV, respectively. Nb cross-section data for neutron energies higher than 22.5 MeV do not exist in the literature. Nb is the important material for fusion applications (IFMIF as well. The variable-energy proton beam of NPI cyclotron is utilized for the production of neutron field using thin lithium target. The carbon backing serves as the beam stopper. The system permits to produce neutron flux density about 109  n/cm2/s in peak at 30 MeV neutron energy. The niobium foils of 15 mm in diameter and approx. 0.75 g weight were activated. The nuclear spectroscopy methods with HPGe detector technique were used to obtain the activities of produced isotopes. The large set of neutron energies used in the experiment allows us to make the complex study of the cross-section values. The reactions (n,2n, (n,3n, (n,4n, (n,He3, (n,α and (n,2nα are studied. The cross-sections data of the (n,4n and (n,2nα are obtained for the first time. The cross-sections of (n,2n and (n,α reactions for higher neutron energies are strongly influenced by low energy tail of neutron spectra. This effect is discussed. The results are compared with the EAF-2007 library.

  17. On the radio dichotomy of active galactic nuclei

    CERN Document Server

    Cao, Xinwu

    2016-01-01

    It is still a mystery why only a small fraction of active galactic nuclei (AGNs) contain relativistic jets. Strong magnetic field is a necessary ingredient for jet formation, however, the advection of the external field in a geometrically thin disk is inefficient. The gas with a small angular velocity may fall from the Bondi radius $R_{\\rm B}$ nearly freely to the circularization radius $R_{\\rm c}$, and a thin accretion disk is formed within $R_{\\rm c}$. We suggest that the external magnetic field is substantially enhanced in this region, and the magnetic field at $R_{\\rm c}$ can be sufficiently strong to drive outflows from the disk if the angular velocity of the gas is low at $R_{\\rm B}$. The magnetic field is efficiently dragged in the disk, because most angular momentum of the disk is removed by the outflows that leads to a significantly high radial velocity. The strong magnetic field formed in this way may accelerate jets in the region near the black hole either by the Blandford-Payne or/and Blandford-Zn...

  18. Error analysis and distribution of the driving mechanism for large spherical radio telescope active reflector

    Institute of Scientific and Technical Information of China (English)

    Huang Peng; Tang Xiaoqiang; Wang Liping; Yao Rui

    2008-01-01

    In order to reduce the cost, 3-PRS mechanism is introduced into the application of supporting the active reflector unit of large radio telescope. The kinematic model of 3-PRS mechanism with rotational joint errors is derived to solve the error problem in actual engineering application. Then based on the error model, inverse and forward kinematics are analyzed. Because the solutions can not be analytically expressed, a numerical method is applied. Afterwards, the parasitic motion errors are analyzed using search method and empirical formulas of the maximum parasitic motion error are put forward. Finally, the tolerance is distributed using empirical formulas to avoid interference between adjacent reflector units. The analyses provide a theoretical basis for the design and installation of large radio telescope active reflector.

  19. Validation of MCNP NPP Activation Simulations for Decommissioning Studies by Analysis of NPP Neutron Activation Foil Measurement Campaigns

    Directory of Open Access Journals (Sweden)

    Volmert Ben

    2016-01-01

    Full Text Available In this paper, an overview of the Swiss Nuclear Power Plant (NPP activation methodology is presented and the work towards its validation by in-situ NPP foil irradiation campaigns is outlined. Nuclear Research and consultancy Group (NRG in The Netherlands has been given the task of performing the corresponding neutron metrology. For this purpose, small Aluminium boxes containing a set of circular-shaped neutron activation foils have been prepared. After being irradiated for one complete reactor cycle, the sets have been successfully retrieved, followed by gamma-spectrometric measurements of the individual foils at NRG. Along with the individual activities of the foils, the reaction rates and thermal, intermediate and fast neutron fluence rates at the foil locations have been determined. These determinations include appropriate corrections for gamma self-absorption and neutron self-shielding as well as corresponding measurement uncertainties. The comparison of the NPP Monte Carlo calculations with the results of the foil measurements is done by using an individual generic MCNP model functioning as an interface and allowing the simulation of individual foil activation by predetermined neutron spectra. To summarize, the comparison between calculation and measurement serve as a sound validation of the Swiss NPP activation methodology by demonstrating a satisfying agreement between measurement and calculation. Finally, the validation offers a chance for further improvements of the existing NPP models by ensuing calibration and/or modelling optimizations for key components and structures.

  20. Large sample neutron activation analysis: a challenge in cultural heritage studies.

    Science.gov (United States)

    Stamatelatos, Ion E; Tzika, Faidra

    2007-07-01

    Large sample neutron activation analysis compliments and significantly extends the analytical tools available for cultural heritage and authentication studies providing unique applications of non-destructive, multi-element analysis of materials that are too precious to damage for sampling purposes, representative sampling of heterogeneous materials or even analysis of whole objects. In this work, correction factors for neutron self-shielding, gamma-ray attenuation and volume distribution of the activity in large volume samples composed of iron and ceramic material were derived. Moreover, the effect of inhomogeneity on the accuracy of the technique was examined.

  1. Corrections in the gold foil activation method for determination of neutron beam density

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage

    1967-01-01

    example for a reactor beam transmitted through a 30 cm Bi filter. The effective cross section differs 0.5% from the capture cross section at 2200 m/s. For a 20 mg/cm2 Au foil the correction for beam attenuation and hardening through the foil is 0.7% and the activity correction is 1.5%.......A finite foil thickness and deviation in the cross section from the 1ν law imply corrections in the determination of neutron beam densities by means of foil activation. These corrections, which depend on the neutron velocity distribution, have been examined in general and are given in a specific...

  2. Measurement of neutron induced activation of the SCT end-cap module

    CERN Document Server

    Linhart, V; Kolros, A; Lebel, C; Leroy, C; Pospísil, S; Stekl, I; Vobecky, M

    2005-01-01

    Results of the experimental study of the induced radioactivity generated by neutron irradiation in the semiconductor tracker end-cap module are presented. The purpose of the experiment was to identify the radioisotopes produced in the module by neutron interactions. The irradiation was done in the active zone of the VR-1 CTU Prague reactor. The identification and quantification of radioisotopes were based on detailed analysis of gamma-ray spectra, which were measured with a HPGe-detector. The nuclear processes of all 26 observed radioisotopes and their activities at the end of the irradiation were determined.

  3. Availability of essential trace elements in Ayurvedic Indian medicinal herbs using instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Singh, V.; Garg, A.N. [Nagpur Univ. (India). Dept. of Chemistry

    1997-01-01

    Specific parts of several plants (fruits, leaves, stem, bark and roots) often used as medicines in the Indian Ayurvedic system have been analysed for 20 elements (As, Ba, Br, Ca, Cl, Co, Cr, Cu, Fe, K, Mn, Mo, Na, P, Rb, Sb, Sc, Se, Sr and Zn) by employing instrumental neutron activation analysis (INAA). The samples were irradiated with thermal neutrons in a nuclear reactor and the induced activity was counted using high resolution gamma ray spectrometry. Most of the medicinal herbs have been found to be rich in one or more of the elements under study. (Author).

  4. Ground tests with active neutron instrumentation for the planetary science missions

    Energy Technology Data Exchange (ETDEWEB)

    Litvak, M.L., E-mail: litvak@mx.iki.rssi.ru [Space Research Institute, RAS, Moscow 117997 (Russian Federation); Mitrofanov, I.G.; Sanin, A.B. [Space Research Institute, RAS, Moscow 117997 (Russian Federation); Jun, I. [Jet Propulsion Laboratory, Pasadena, CA USA (United States); Kozyrev, A.S. [Space Research Institute, RAS, Moscow 117997 (Russian Federation); Krylov, A.; Shvetsov, V.N.; Timoshenko, G.N. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Starr, R. [Catholic University of America, Washington DC (United States); Zontikov, A. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    2015-07-11

    We present results of experimental work performed with a spare flight model of the DAN/MSL instrument in a newly built ground test facility at the Joint Institute for Nuclear Research. This instrument was selected for the tests as a flight prototype of an active neutron spectrometer applicable for future landed missions to various solid solar system bodies. In our experiment we have fabricated simplified samples of planetary material and tested the capability of neutron activation methods to detect thin layers of water/water ice lying on top of planetary dry regolith or buried within a dry regolith at different depths.

  5. First principle active neutron coincidence counting measurements of uranium oxide

    Science.gov (United States)

    Goddard, Braden; Charlton, William; Peerani, Paolo

    2014-03-01

    Uranium is present in most nuclear fuel cycle facilities ranging from uranium mines, enrichment plants, fuel fabrication facilities, nuclear reactors, and reprocessing plants. The isotopic, chemical, and geometric composition of uranium can vary significantly between these facilities, depending on the application and type of facility. Examples of this variation are: enrichments varying from depleted (~0.2 wt% 235U) to high enriched (>20 wt% 235U); compositions consisting of U3O8, UO2, UF6, metallic, and ceramic forms; geometries ranging from plates, cans, and rods; and masses which can range from a 500 kg fuel assembly down to a few grams fuel pellet. Since 235U is a fissile material, it is routinely safeguarded in these facilities. Current techniques for quantifying the 235U mass in a sample include neutron coincidence counting. One of the main disadvantages of this technique is that it requires a known standard of representative geometry and composition for calibration, which opens up a pathway for potential erroneous declarations by the State and reduces the effectiveness of safeguards. In order to address this weakness, the authors have developed a neutron coincidence counting technique which uses the first principle point-model developed by Boehnel instead of the "known standard" method. This technique was primarily tested through simulations of 1000 g U3O8 samples using the Monte Carlo N-Particle eXtended (MCNPX) code. The results of these simulations showed good agreement between the simulated and exact 235U sample masses.

  6. NUCLEAR RADIO JET FROM A LOW-LUMINOSITY ACTIVE GALACTIC NUCLEUS IN NGC 4258

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Akihiro [The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuou-ku, Sagamihara, Kanagawa 252-5210 (Japan); Kohno, Kotaro [Institute of Astronomy, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Nakanishi, Kouichiro [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Kameno, Seiji [Department of Physics, Faculty of Science, Kagoshima University, 1-21-35 Korimoto, Kagoshima, Kagoshima 890-0065 (Japan); Inoue, Makoto [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Hada, Kazuhiro [INAF, Istituto di Radioastronomia, via Gobetti 101, Bologna I-40129 (Italy); Sorai, Kazuo [Department of Physics, Graduate School of Science, Hokkaido University, Kita 10 Nishi 8, Sapporo 060-0810 (Japan)

    2013-03-01

    The nearby low-luminosity active galactic nucleus (LLAGN) NGC 4258 has a weak radio continuum component at the galactic center. We investigate its radio spectral properties on the basis of our new observations using the Nobeyama Millimeter Array at 100 GHz and archival data from the Very Large Array at 1.7-43 GHz and the James Clerk Maxwell telescope at 347 GHz. The NGC 4258 nuclear component exhibits (1) an intra-month variable and complicated spectral feature at 5-22 GHz and (2) a slightly inverted spectrum at 5-100 GHz ({alpha} {approx} 0.3; F {sub {nu}}{proportional_to}{nu}{sup {alpha}}) in time-averaged flux densities, which are also apparent in the closest LLAGN M81. These similarities between NGC 4258 and M81 in radio spectral natures in addition to previously known core shift in their AU-scale jet structures produce evidence that the same mechanism drives their nuclei. We interpret the observed spectral property as the superposition of emission spectra originating at different locations with frequency-dependent opacity along the nuclear jet. Quantitative differences between NGC 4258 and M81 in terms of jet/counter jet ratio, radio loudness, and degree of core shift can be consistently understood by fairly relativistic speeds ({Gamma} {approx}> 3) of jets and their quite different inclinations. The picture established from the two closest LLAGNs is useful for understanding the physical origin of unresolved and flat/inverted spectrum radio cores that are prevalently found in LLAGNs, including Sgr A*, with starved supermassive black holes in the present-day universe.

  7. RADIO-SELECTED BINARY ACTIVE GALACTIC NUCLEI FROM THE VERY LARGE ARRAY STRIPE 82 SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Hai [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52245 (United States); Myers, A. D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Djorgovski, S. G.; Yan, Lin [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Wrobel, J. M. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Stockton, A. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

    2015-01-20

    Galaxy mergers play an important role in the growth of galaxies and their supermassive black holes. Simulations suggest that tidal interactions could enhance black hole accretion, which can be tested by the fraction of binary active galactic nuclei (AGNs) among galaxy mergers. However, determining the fraction requires a statistical sample of binaries. We have identified kiloparsec-scale binary AGNs directly from high-resolution radio imaging. Inside the 92 deg{sup 2} covered by the high-resolution Very Large Array survey of the Sloan Digital Sky Survey (SDSS) Stripe 82 field, we identified 22 grade A and 30 grade B candidates of binary radio AGNs with angular separations less than 5'' (10 kpc at z = 0.1). Eight of the candidates have optical spectra for both components from the SDSS spectroscopic surveys and our Keck program. Two grade B candidates are projected pairs, but the remaining six candidates are all compelling cases of binary AGNs based on either emission line ratios or the excess in radio power compared to the Hα-traced star formation rate. Only two of the six binaries were previously discovered by an optical spectroscopic search. Based on these results, we estimate that ∼60% of our binary candidates would be confirmed once we obtain complete spectroscopic information. We conclude that wide-area high-resolution radio surveys offer an efficient method to identify large samples of binary AGNs. These radio-selected binary AGNs complement binaries identified at other wavelengths and are useful for understanding the triggering mechanisms of black hole accretion.

  8. Development of an Interdisciplinary STEM Classroom Activity for Radio Receiver Technology

    Science.gov (United States)

    Davis, Kristina

    2015-01-01

    Introduction The development of a mini STEM-based classroom activity designed to integrate these two fields into one project for middle school aged students is presented here. This lesson involves small groups of students constructing a small AM radio receivers. The lesson surrounding the activity focuses on both the physical nature of electromagnetic and AC waves, circuit design, practical applications to AM radio broadcasting, and research applications of radio telescopes. These tools have shown a significant increase in the lesson's primary concept understanding among 6th grade students, as well as net positive STEM awareness and enthusiasm.Content The primary teaching point for the students to consider and learn during this lesson is 'How does scientific application influence engineering design, and vice versa?' The lesson surrounds the hands-on activity of having students construct their own AM radio receiver. Wave theory and the use of radio instruments for astronomy research are also taught in a traditional lecture format. The activity is designed to complement middle school curriculum, although it has been tested and found suitable for high school and older students as well as the general public.Evaluation and ImpactThe evaluation tool that used for the student groups in this project was a Fryer chart, which is a four panel chart with the main topic listed in the center and a single question in each of the four panels. The students are asked to answer the questions in the chart before and after they participate in the lesson activity, each time in a different colored pencil so that the scores can be given to each student before and after they participated in the activity. Student scores improved from 4.5 to 17.9 out of a total of 20 possible points. This is an overall increase of 67% of the total possible points. The questions asked on the quiz cover the range of wave theory, circuit design, and scientific explanation. This factor of improvement shows that

  9. Bayesian calibration of reactor neutron flux spectrum using activation detectors measurements: Application to CALIBAN reactor

    Energy Technology Data Exchange (ETDEWEB)

    Cartier, J. [Commissariat a l' Energie Atomique et aux Energies Alternatives CEA, DAM, DIF, F-91297 Arpajon (France); Casoli, P. [Commissariat a l' Energie Atomique et aux Energies Alternatives CEA, DAM, Valduc, F-21120 Is sur Tille (France); Chappert, F. [Commissariat a l' Energie Atomique et aux Energies Alternatives CEA, DAM, DIF, F-91297 Arpajon (France)

    2013-07-01

    In this paper, we present calibration methods in order to estimate reactor neutron flux spectrum and its uncertainties by using integral activation measurements. These techniques are performed using Bayesian and MCMC framework. These methods are applied to integral activation experiments in the cavity of the CALIBAN reactor. We estimate the neutron flux and its related uncertainties. The originality of this work is that these uncertainties take into account measurements uncertainties, cross-sections uncertainties and model error. In particular, our results give a very good approximation of the total flux and indicate that neutron flux from MCNP simulation for energies above about 5 MeV seems to overestimate the 'real flux'. (authors)

  10. Measuring neutron yield and ρR anisotropies with activation foils at the National Ignition Facility

    Directory of Open Access Journals (Sweden)

    Bleuel D.L.

    2013-11-01

    Full Text Available Neutron yields at the National Ignition Facility (NIF are measured with a suite of diagnostics, including activation of ∼20–200 g samples of materials undergoing a variety of energy-dependent neutron reactions. Indium samples were mounted on the end of a Diagnostic Instrument Manipulator (DIM, 25–50 cm from the implosion, to measure 2.45 MeV D-D fusion neutron yield. The 336.2 keV gamma rays from the 4.5 hour isomer of 115mIn produced by (n,n′ reactions are counted in high-purity germanium detectors. For capsules producing D-T fusion reactions, zirconium and copper are activated via (n,2n reactions at various locations around the target chamber and bay, measuring the 14 MeV neutron yield to accuracies on order of 7%. By mounting zirconium samples on ports at nine locations around the NIF chamber, anisotropies in the primary neutron emission due to fuel areal density asymmetries can be measured to a relative precision of 3%.

  11. Analysis of the neutron component at high altitude mountains using active and passive measurement devices

    Energy Technology Data Exchange (ETDEWEB)

    Hajek, M. E-mail: mhajek@ati.ac.at; Berger, T.; Schoener, W.; Vana, N

    2002-01-01

    The European Council directive 96/29/Euratom requires dosimetric precautions if the effective dose exceeds 1 mSv/a. On an average, this value is exceeded by aircrew members. Roughly half of the radiation exposure at flight altitudes is caused by cosmic ray-induced neutrons. Active ({sup 6}LiI(Eu)-scintillator) and passive (TLDs) Bonner sphere spectrometers were used to determine the neutron energy spectra atop Mt. Sonnblick (3105 m) and Mt. Kitzsteinhorn (3029 m). Further measurements in a mixed radiation field at CERN as well as in a proton beam of 62 MeV at Paul Scherrer Institute, Switzerland, confirmed that not only neutrons but also charged particles contribute to the readings of active detectors, whereas TLD-600 and TLD-700 in pair allow the determination of the thermal neutron flux. Unfolding of the detector data obtained atop both mountains shows two relative maxima around 1 MeV and 85 MeV, which have to be considered for the assessment of the biologically relevant dose equivalent. By convoluting the spectra with appropriate conversion functions the neutron dose equivalent rate was determined to be 150{+-}15 nSv/h. The total dose equivalent rate determined by the HTR-method was 210{+-}15 nSv/h. The results are in good agreement with LET-spectrometer and Sievert counter measurements carried out simultaneously.

  12. A bismuth activation counter for high sensitivity pulsed 14 MeV neutrons

    Science.gov (United States)

    Burns, E. J. T.; Thacher, P. D.; Hassig, G. J.; Decker, R. D.; Romero, J. A.; Barrett, K. P.

    2011-08-01

    We have built a fast neutron bismuth activation counter that measures activation counts from pulsed 14-MeV neutron generators for incident neutron fluences between 30 and 300 neutrons/cm2 at 15.2 cm (6 in.). The activation counter consists of a large bismuth germanate (BGO) detector surrounded by a bismuth metal shield in front of and concentric with the cylindrical detector housing. The 14 MeV neutrons activate the 2.6-millisecond (ms) isomer in the shield and the detector by the reaction 209Bi (n,2nγ) 208mBi. The use of millisecond isomers and activation counting times minimizes the background from other activated materials and the environment. In addition to activation, the bismuth metal shields against other outside radiation sources. We have tested the bismuth activation counter, simultaneously, with two data acquisition systems (DASs) and both give similar results. The two-dimensional (2D) DAS and three dimensional (3D) DAS both consist of pulse height analysis (PHA) systems that can be used to discriminate against gamma radiations below 300 keV photon energy, so that the detector can be used strictly as a counter. If the counting time is restricted to less than 25 ms after the neutron pulse, there are less than 10 counts of background for single pulse operation in all our operational environments tested so far. High-fluence neutron generator operations are restricted by large dead times and pulse height saturation. When we operate our 3D DAS PHA system in list mode acquisition (LIST), real-time corrections to dead time or live time can be made on the scale of 1 ms time windows or dwell times. The live time correction is consistent with nonparalyzable models for dead time of 1.0±0.2 μs for our 3D DAS and 1.5±0.3 μs for our 2D DAS dominated by our fixed time width analog to digital converters (ADCs). With the same solid angle, we have shown that the bismuth activation counter has a factor of 4 increase in sensitivity over our lead activation counter

  13. Luminescent and Scintillating Properties of Lanthanum Fluoride Nanocrystals in Response to Gamma/Neutron Irradiation: Codoping with Ce Activator, Yb Wavelength Shifter, and Gd Neutron Captor

    CERN Document Server

    Vargas, José M; Sidelnik, Iván; Brito, David Rondón; Palomino, Luis A Rodríguez; Mayer, Roberto E

    2016-01-01

    A novel concept for detection and spectroscopy of gamma rays, and detection of thermal neutrons based on codoped lanthanum fluoride nanocrystals containing gadolinium is presented.The trends of colloidal synthesis of the mentioned material, LaF3 co-doped with Ce as the activator, Yb as the wavelength-shifter and Gd as the neutron captor, is reported. Nanocrystals of the mentioned material were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), optical absorption, and photoluminescence spectroscopy. Gamma detection and its potential spectroscopy feature have been confirmed. The neutron detection capability has been confirmed by experiments performed using a 252Cf neutron source.

  14. Energy distribution of the neutron flux measurements at the Chilean Reactor RECH-1 using multi-foil neutron activation and the Expectation Maximization unfolding algorithm.

    Science.gov (United States)

    Molina, F; Aguilera, P; Romero-Barrientos, J; Arellano, H F; Agramunt, J; Medel, J; Morales, J R; Zambra, M

    2017-08-04

    We present a methodology to obtain the energy distribution of the neutron flux of an experimental nuclear reactor, using multi-foil activation measurements and the Expectation Maximization unfolding algorithm, which is presented as an alternative to well known unfolding methods such as GRAVEL. Self-shielding flux corrections for energy bin groups were obtained using MCNP6 Monte Carlo simulations. We have made studies at the at the Dry Tube of RECH-1 obtaining fluxes of 1.5(4)×10(13)cm(-2)s(-1) for the thermal neutron energy region, 1.9(5)×10(12)cm(-2)s(-1) for the epithermal neutron energy region, and 4.3(11)×10(11)cm(-2)s(-1) for the fast neutron energy region. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Applied research and development of neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Yong Sam; Moon, Jong Hwa; Kim, Sun Ha; Bak, Sung Ryel; Park, Yong Chul; Kim, Young Ki; Chung, Hwan Sung; Park, Kwang Won; Kang, Sang Hun

    2000-05-01

    This report is written for results of research and development as follows : improvement of neutron irradiation facilities, counting system and development of automation system and capsules for NAA in HANARO ; improvement of analytical procedures and establishment of analytical quality control and assurance system; applied research and development of environment, industry and human health and its standardization. For identification and standardization of analytical method, environmental biological samples and polymer are analyzed and uncertainity of measurement are estimated. Also data intercomparison and proficency test were performed. Using airborne particulate matter chosen as a environmental indicators, trace elemental concentrations of sample collected at urban and rural site are determined and then the calculation of statistics and the factor analysis are carried out for investigation of emission source. International cooperation research project was carried out for utilization of nuclear techniques.

  16. Exploration of Adiabatic Resonance Crossing Through Neutron Activator Design for Thermal and Epithermal Neutron Formation in (99)Mo Production and BNCT Applications.

    Science.gov (United States)

    Khorshidi, Abdollah

    2015-10-01

    A feasibility study was performed to design thermal and epithermal neutron sources for radioisotope production and boron neutron capture therapy (BNCT) by moderating fast neutrons. The neutrons were emitted from the reaction between (9)Be, (181)Ta, and (184)W targets and 30 MeV protons accelerated by a small cyclotron at 300 μA. In this study, the adiabatic resonance crossing (ARC) method was investigated by means of (207)Pb and (208)Pb moderators, graphite reflector, and boron absorber around the moderator region. Thermal/epithermal flux, energy, and cross section of accumulated neutrons in the activator were examined through diverse thicknesses of the specified regions. Simulation results revealed that the (181)Ta target had the highest neutron yield, and also tungsten was found to have the highest values in both surface and volumetric flux ratio. Transmutation in the (98)Mo sample through radiative capture was investigated for the natural lead moderator. When the sample radial distance from the target was increased inside the graphite region, the production yield had the greatest value of activity. The potential of the ARC method is a replacement or complements the current reactor-based supply sources of BNCT purposes.

  17. Neutron activation analysis of phytotherapic obtained from medicinal plants; Analise por ativacao com neutrons de fitoterapicos obtidos de plantas medicinais

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Henrique S. [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas]. E-mail: hs_moreira@hotmail.com; Saiki, Mitiko; Vasconcellos, Marina B.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mails: mitiko@ipen.br; mbvascon@ipen.br

    2007-07-01

    This paper determines the inorganic constituents in phytotherapic samples for posterior study of the relationship existent among the concentrations of the found elements and the their possible therapeutical effects. The samples of phytotherapic pills (Centella asiatica, Ginkgo biloba and Ginseng) were analysed by using neutron activation analysis (NAA). The As, Br, Ca, Co, Cr, Cs, Fe, K, La, Na, Rb, Sc, Se and Zn samples were determined in the phytotherapics, The Centella asiatica presented the higher concentrations of Br, Co, Cr, Fe, K, La, Na, Rb, Sc, Se and Zn. In the sample of Ginko biloba, higher levels of As and Ca were found, while in the sample ol Ginseng the element As were not detected. The found results have shown the the NAA method is appropriated for analysing this type of materials due to his simplicity, multielemental capacity and quality of the results obtained. (author)

  18. Target preparation and neutron activation analysis a successful story at IRMM

    CERN Document Server

    Robouch, P; Eguskiza, M; Maguregui, M I; Pommé, S; Ingelbrecht, C

    2002-01-01

    The main task of a target producer is to make well characterized and homogeneous deposits on specific supports. Alpha and/or gamma spectrometry are traditionally used to monitor the quality of actinide deposits. With the increasing demand for enriched stable isotope targets, other analytical techniques, such as ICP-MS and NAA, are needed. This paper presents the application of neutron activation analysis to quality control of 'thin' targets, 'thicker' neutron dosimeters and 'thick' bronze disks prepared by the Reference Materials Unit at the Institute of Reference Materials and Measurements.

  19. Thermally-Activated Post-Glitch Response of the Neutron Star Inner Crust and Core

    CERN Document Server

    Link, Bennett

    2013-01-01

    Pinning of superfluid vortices is predicted to prevail throughout much of a neutron star. Here I develop a description of the coupling through thermally-activated vortex slippage}, and calculate the post-glitch response of a neutron star to a spin glitch. The theory has three robust conclusions: 1) If vortex pinning occurs in the core, typical large glitches decouple the core superfluid from the charged components over observable timescales. Core response to a glitch has a distinct observational signature that could be identified through analyses of existing and future timing data. 2) Post-glitch response over short timescales (days) in pulsars with large glitches (fractional spin jumps of $\\Delta\

  20. Neutron activation of natural zinc samples at kT = 25 keV

    OpenAIRE

    Reifarth, R.; Dababneh, S.; Heil, M.; Käppeler, F.; Plag, R.; Sonnabend, K.; Uberseder, E.

    2013-01-01

    The neutron-capture cross sections of 64Zn, 68Zn, and 70Zn have been measured with the activation technique in a quasistellar neutron spectrum corresponding to a thermal energy of kT = 25 keV. By a series of repeated irradiations with different experimental conditions, an uncertainty of 3% could be achieved for the 64Zn(n,g)65Zn cross section and for the partial cross section 68Zn(n,g)69Zn-m feeding the isomeric state in 69Zn. For the partial cross sections 70Zn(n,g)71Zn-m and 70Zn(n,g)71Zn-g...

  1. Abundance of lanthanoids in rock salts determined by neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Honda, Teruyuki; Nozaki, Tetsuya [Musashi Inst. of Tech., Kawasaki, Kanagawa (Japan). Atomic Energy Research Lab.; Yui, Mitsuaki; Kikawada, Yoshikazu; Oi, Takao

    1998-06-01

    Contents of lanthanoids (Ln`s) of rock salts have been measured by the neutron activation analysis. Original salt samples were treated in advance of neutron irradiation so that Ln`s were enriched and amounts of interfering nuclides were reduced. The contents of Ln`s were at ppt-sub ppb levels and were comparable with or slightly lower than those of solar salts. The Ln abundance patterns of the salts were those with relative depletion in the heavy Ln`s, thus having negative slopes. It was indicated that, when salt deposit was formed, Ln`s were taken up by anhydrite more preferentially than by halite. (author)

  2. Radiochemical neutron activation analysis for certification of ion-implanted phosphorus in silicon.

    Science.gov (United States)

    Paul, Rick L; Simons, David S; Guthrie, William F; Lu, John

    2003-08-15

    A radiochemical neutron activation analysis procedure has been developed, critically evaluated, and shown to have the necessary sensitivity, chemical specificity, matrix independence, and precision to certify phosphorus at ion implantation levels in silicon. 32P, produced by neutron capture of 31P, is chemically separated from the sample matrix and measured using a beta proportional counter. The method is used here to certify the amount of phosphorus in SRM 2133 (Phosphorus Implant in Silicon Depth Profile Standard) as (9.58 +/- 0.16) x 10(14) atoms x cm(-2). A detailed evaluation of uncertainties is given.

  3. Neutron-Activation Analysis of Biological Material with High Radiation Levels

    Energy Technology Data Exchange (ETDEWEB)

    Samsahl, K.

    1966-09-15

    A method has been developed for the chemical separation and subsequent gamma-spectrometric analysis of the alkali metals, the alkaline earths, the rare earths, chromium, hafnium, lanthanum, manganese, phosphorus, scandium and silver in neutron-activated biological material. The separation steps, being fully automatic, are based on a combination of ion-exchange and partition chromatography and require 40 min.

  4. Research activities on structure materials of spallation neutron source at SINQ

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.S.; Dai, Y. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    With the growing interests on powerful spallation neutron sources, especially with liquid metal targets, and accelerator driven energy systems, spallation materials science and technology have been received wide attention. At SINQ, material research activities are focused on: a) liquid metal corrosion; b) radiation damage; and c) interaction of corrosion and radiation damage. (author) 1 fig., refs.

  5. Archaeologist looks at x-ray fluorescence vs. neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Artzy, M.

    1976-04-01

    X-ray fluorescence (XRE) and neutron activation analysis (NAA) are compared; a periodic table of the elements showing their sensitivity to each method is included. It is proposed to use both methods to make chemical abundances measurements on archaeological samples, including Bichrome Ware and Palestinian samples. The intent is to see if NAA can be replaced by XRF. (DLC)

  6. The determination of platinum in tissue of different human organs by means of neutron activation analysis

    DEFF Research Database (Denmark)

    Rietz, Bernd; Heydorn, Kaj; Krarup-Hansen, Anders

    2002-01-01

    . It was demonstrated that radiochemical neutron activation analysis can be used for these studies because of its sensitivity and precision and a low detection limit for platinum (similar to1 ng). Tissues of the following organs were analyzed for platinum: liver, kidney, testis, lung, pancreas and muscle. This study...

  7. A package for gamma-ray spectrum analysis and routine neutron activation analysis

    Indian Academy of Sciences (India)

    M E Medhat; A Abdel-Hafiez; Z Awaad; M A Ali

    2005-08-01

    A package for gamma spectrum analysis (PGSA) was developed using object oriented Borland C++ design for MS-windows. This package consists of five programs which can be used for gamma-ray spectrum analysis and routine neutron activation analysis. The advantages of PGSA are its simple algorithms and its need for only minimum amount of input information.

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

    Science.gov (United States)

    Chichester, D L; Seabury, E H; Zabriskie, J M; Wharton, J; Caffrey, A J

    2009-06-01

    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 (2 x 10(8) n/s), deuterium-deuterium (DD) fusion (2.5 MeV) neutron generators (1 x 10(7) n/s), and (252)Cf spontaneous fission neutron sources (6.96 x 10(7) n/s, 30 microg). 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 3.8m tall, an entrance maze, and a fully integrated electrical interlock system; the smaller test vault is designed for (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.

  9. Thick activation detectors for neutron spectrometry using different unfolding methods: sensitivity analysis and dose calculation

    Energy Technology Data Exchange (ETDEWEB)

    Medkour Ishak-Boushaki, Ghania, E-mail: gmedkour@yahoo.com [Laboratoire SNIRM-Faculte de Physique, Universite des Sciences et de la Technologie Houari Boumediene, BP 32 El-Alia BabEzzouar, Algiers (Algeria); Boukeffoussa, Khelifa [Laboratoire SNIRM-Faculte de Physique, Universite des Sciences et de la Technologie Houari Boumediene, BP 32 El-Alia BabEzzouar, Algiers (Algeria); Idiri, Zahir [Centre de Recherche Nucleaire d' Alger, 02 Boulevard Frantz-Fanon, BP 399, Algiers (Algeria); Allab, Malika [Laboratoire SNIRM-Faculte de Physique, Universite des Sciences et de la Technologie Houari Boumediene, BP 32 El-Alia BabEzzouar, Algiers (Algeria)

    2012-03-15

    This paper discusses the use of threshold detectors of extended sizes for low intensity neutron fields' characterization. The detectors were tested by the measurement of the neutron spectrum of an {sup 241}Am-Be source. Integral quantities characterizing the neutron field, required for radiological protection, have been derived by unfolding the measured data. A good agreement is achieved between the obtained results and those deduced using Bonner spheres. In addition, a sensitivity analysis of the results to the deconvolution procedure is given. - Highlights: Black-Right-Pointing-Pointer Low intensity neutron fields' characterization using thick threshold detectors. Black-Right-Pointing-Pointer Low activity {sup 241}Am-Be neutron source spectrum measurement. Black-Right-Pointing-Pointer Integral quantities required for radiological protection have been derived. Black-Right-Pointing-Pointer The results are in good agreement with those deduced using Bonner spheres. Black-Right-Pointing-Pointer The results are not very sensitive to the chosen deconvolution procedure.

  10. Design studies related to an in vivo neutron activation analysis facility for measuring total body nitrogen.

    Science.gov (United States)

    Stamatelatos, I E; Chettle, D R; Green, S; Scott, M C

    1992-08-01

    Design studies relating to an in vivo prompt capture neutron activation analysis facility measuring total body nitrogen are presented. The basis of the design is a beryllium-graphite neutron collimator and reflector configuration for (alpha, n) type radionuclide neutron sources (238PuBe or 241AmBe), so as to reflect leaking, or out-scattered, neutrons towards the subject. This improves the ratio of thermal neutron flux to dose and the spatial distribution of thermal flux achieved with these sources, whilst retaining their advantage of long half-lives as compared to 252Cf based systems. The common problem of high count-rate at the detector, and therefore high nitrogen region of interest background due to pile-up, is decreased by using a set of smaller (5.1 cm diameter x 10.2 cm long) NaI(Tl) detectors instead of large ones. The facility described presents a relative error of nitrogen measurement of 3.6% and a nitrogen to background ratio of 2.3 for 0.45 mSv skin dose (assuming ten 5.1 cm x 10.2 cm NaI(Tl) detectors).

  11. Design studies related to an in vivo neutron activation analysis facility for measuring total body nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Stamatelatos, I.E.M.; Chettle, D.R.; Green, S.; Scott, M.C. (Birmingham Univ. (United Kingdom). School of Physics and Space Research)

    1992-08-01

    Design studies relating to an in vivo prompt capture neutron activation analysis facility measuring total body nitrogen are presented. The basis of the design is a beryllium-graphite neutron collimator and reflector configuration for ({alpha}, n) type radionuclide neutron sources ({sup 238}PuBe or {sup 241}AmBe), so as to reflect leaking, or out-scattered, neutrons towards the subject. This improves the ratio of thermal neutron flux to dose and the spatial distribution of thermal flux achieved with these sources, whilst retaining their advantage of long half-lives as compared to {sup 252}Cf based systems. The common problem of high count-rate at the detector, and therefore high nitrogen region of interest background due to pile-up, is decreased by using a set of smaller (5.1 cm diameter x 10.2 cm long) NaI(Tl) detectors instead of large ones. The facility described presents a relative error of nitrogen measurement of 3.6% and a nitrogen to background ratio of 2.3 for 0.45 mSv skin dose (assuming ten 5.1 cm x 10.2 cm NaI(Tl) detectors). (author).

  12. The fast neutron fluence and the activation detector activity calculations using the effective source method and the adjoint function

    Energy Technology Data Exchange (ETDEWEB)

    Hep, J.; Konecna, A.; Krysl, V.; Smutny, V. [Calculation Dept., Skoda JS plc, Orlik 266, 31606 Plzen (Czech Republic)

    2011-07-01

    This paper describes the application of effective source in forward calculations and the adjoint method to the solution of fast neutron fluence and activation detector activities in the reactor pressure vessel (RPV) and RPV cavity of a VVER-440 reactor. Its objective is the demonstration of both methods on a practical task. The effective source method applies the Boltzmann transport operator to time integrated source data in order to obtain neutron fluence and detector activities. By weighting the source data by time dependent decay of the detector activity, the result of the calculation is the detector activity. Alternatively, if the weighting is uniform with respect to time, the result is the fluence. The approach works because of the inherent linearity of radiation transport in non-multiplying time-invariant media. Integrated in this way, the source data are referred to as the effective source. The effective source in the forward calculations method thereby enables the analyst to replace numerous intensive transport calculations with a single transport calculation in which the time dependence and magnitude of the source are correctly represented. In this work, the effective source method has been expanded slightly in the following way: neutron source data were performed with few group method calculation using the active core calculation code MOBY-DICK. The follow-up neutron transport calculation was performed using the neutron transport code TORT to perform multigroup calculations. For comparison, an alternative method of calculation has been used based upon adjoint functions of the Boltzmann transport equation. Calculation of the three-dimensional (3-D) adjoint function for each required computational outcome has been obtained using the deterministic code TORT and the cross section library BGL440. Adjoint functions appropriate to the required fast neutron flux density and neutron reaction rates have been calculated for several significant points within the RPV

  13. Nuclear Radio Jet from Low-Luminosity Active Galactic Nucleus in NGC 4258

    CERN Document Server

    Doi, Akihiro; Nakanishi, Kouichiro; Kameno, Seiji; Inoue, Makoto; Hada, Kazuhiro; Sorai, Kazuo

    2013-01-01

    The nearby low-luminosity active galactic nucleus (LLAGN) NGC 4258 has a weak radio continuum component at the galactic center. We investigate its radio spectral properties on the basis of our new observations using the Nobeyama Millimeter Array at 100 GHz and archival data from the Very Large Array (VLA) at 1.7-43 GHz and James Clerk Maxwell Telescope at 347 GHz. The NGC 4258 nuclear component exhibits (1) an intra-month variable and complicated spectral feature at 5-22 GHz and (2) a slightly inverted spectrum at 5-100 GHz (a spectral index of ~0.3) in a time-averaged flux density, which are also apparent in the closest LLAGN M81. These similarities between NGC 4258 and M81 in radio spectral natures in addition to previously known core shift in their AU-scale jet structures produce evidence that the same mechanism drives their nuclei. We interpret the observed spectral property as the superposition of emission spectra originating at different locations with frequency-dependent opacity along the nuclear jet. ...

  14. Nuclear Radio Continuum Emission of Low-Luminosity Active Galactic Nucleus NGC 4258

    CERN Document Server

    Doi, Akihiro; Nakanishi, Kouichiro; Kameno, Seiji; Inoue, Makoto; Hada, Kazuhiro; Sorai, Kazuo

    2011-01-01

    The nearby low-luminosity active galactic nucleus (LLAGN) NGC 4258 has a weak radio continuum emission at the galactic center. Quasi-simultaneous multi-frequency observations using the Very Large Array (VLA) from 5 GHz (6 cm) to 22 GHz (1.3 cm) showed inverted spectra in all epochs, which were intra-month variable, as well as complicated spectral features that cannot be represented by a simple power law, indicating multiple blobs in nuclear jets. Using the Nobeyama Millimeter Array (NMA), we discovered a large amplitude variable emission at 100 GHz (3 mm), which had higher flux densities at most epochs than those of the VLA observations. A James Clerk Maxwell Telescope (JCMT) observation at 347 GHz (850 micron) served an upper limit of dust contamination. The inverted radio spectrum of the nucleus NGC 4258 is suggestive of an analogy to our Galactic center Sgr A*, but with three orders of magnitude higher radio luminosity. In addition to the LLAGN M 81, we discuss the nucleus of NGC 4258 as another up-scaled ...

  15. Intermittent Jet Activity in the Radio Galaxy 4C29.30?

    Energy Technology Data Exchange (ETDEWEB)

    Jamrozy, M.; /Jagiellonian U., Astron. Observ.; Konar, C.; Saikia, D.J.; /NCRA, Ganeshkhind; Stawarz, L.; /Jagiellonian U., Astron. Observ. /KIPAC, Menlo Park /SLAC; Mack,; /Bologna, Ist. Radioastronomia; Siemiginowska, A.; /Harvard-Smithsonian Ctr. Astrophys.

    2007-04-02

    We present radio observations at frequencies ranging from 240 to 8460 MHz of the radio galaxy 4C29.30 (J0840+2949) using the Giant Metrewave Radio Telescope (GMRT), the Very Large Array (VLA) and the Effelsberg telescope. We report the existence of weak extended emission with an angular size of {approx} 520 arcsec (639 kpc) within which a compact edge-brightened double-lobed source with a size of 29 arcsec (36 kpc) is embedded. We determine the spectrum of the inner double from 240 to 8460 MHz and show that it has a single power-law spectrum with a spectral index is {approx} 0.8. Its spectral age is estimated to be 33 Myr. The extended diffuse emission has a steep spectrum with a spectral index of {approx} 1.3 and a break frequency 240 MHz. The spectral age is {approx}>200 Myr, suggesting that the extended diffuse emission is due to an earlier cycle of activity. We reanalyze archival x-ray data from Chandra and suggest that the x-ray emission from the hotspots consists of a mixture of nonthermal and thermal components, the latter being possibly due to gas which is shock heated by the jets from the host galaxy.

  16. J1216+0709 : A radio galaxy with three episodes of AGN jet activity

    CERN Document Server

    Singh, Veeresh; Kharb, Preeti; Srivastava, Shweta; Janardhan, P

    2016-01-01

    We report the discovery of a `Triple-Double Radio Galaxy (TDRG)' J1216+0709 detected in deep low-frequency Giant Metrewave Radio Telescope (GMRT) observations. J1216+0709 is only the third radio galaxy, after B0925+420 and Speca, with three pairs of lobes resulting from three different episodes of AGN jet activity. The 610 MHz GMRT image clearly displays an inner pair of lobes, a nearly co-axial middle pair of lobes and a pair of outer lobes that is bent w.r.t. the axis of inner pair of lobes. The total end-to-end projected sizes of the inner, middle, and outer lobes are 40$^{{\\prime}{\\prime}}$ ($\\sim$ 95 kpc), 1$^{\\prime}$.65 ($\\sim$ 235 kpc) and 5$^{\\prime}$.7 ($\\sim$ 814 kpc), respectively. Unlike the outer pair of lobes both the inner and middle pairs of lobes exhibit asymmetries in arm-lengths and flux densities, but in opposite sense, i.e., the eastern sides are farther and also brighter that the western sides, thus suggesting the possibility of jet being intrinsically asymmetric rather than due to rela...

  17. Steep-Spectrum Radio Emission from the Low-Mass Active Galactic Nucleus GH 10

    CERN Document Server

    Wróbel, J M; Ho, L C; Ulvestad, J S

    2008-01-01

    GH 10 is a broad-lined active galactic nucleus (AGN) energized by a black hole of mass 800,000 Solar masses. It was the only object detected by Greene et al. in their Very Large Array (VLA) survey of 19 low-mass AGNs discovered by Greene & Ho. New VLA imaging at 1.4, 4.9, and 8.5 GHz reveals that GH 10's emission has an extent of less than 320 pc, has an optically-thin synchrotron spectrum with a spectral index -0.76+/-0.05, is less than 11 percent linearly polarized, and is steady - although poorly sampled - on timescales of weeks and years. Circumnuclear star formation cannot dominate the radio emission, because the high inferred star formation rate, 18 Solar masses per year, is inconsistent with the rate of less than 2 Solar masses per year derived from narrow Halpha and [OII] 3727 emission. Instead, the radio emission must be mainly energized by the low-mass black hole. GH 10's radio properties match those of the steep-spectrum cores of Palomar Seyfert galaxies, suggesting that, like those Seyferts, t...

  18. Delayed triggering of radio Active Galactic Nuclei in gas-rich minor mergers in the local Universe

    CERN Document Server

    Shabala, Stanislav; Kaviraj, Sugata; Middelberg, Enno; Turner, Ross; Ting, Yuan-Sen; Allison, James; Davis, Tim

    2016-01-01

    We examine the processes triggering star formation and Active Galactic Nucleus (AGN) activity in a sample of 25 low redshift ($z10^7$ K) brightness temperature required for an mJIVE-20 detection allows us to unambiguously identify the radio AGN in our sample. We find three such objects. Our VLBI AGN identifications are classified as Seyferts or LINERs in narrow line optical diagnostic plots; mid-infrared colours of our targets and the comparison of H$\\alpha$ star formation rates with integrated radio luminosity are also consistent with the VLBI identifications. We reconstruct star formation histories in our galaxies using optical and UV photometry, and find that these radio AGN are not triggered promptly in the merger process, consistent with previous findings for non-VLBI samples of radio AGN. This delay can significantly limit the efficiency of feedback by radio AGN triggered in galaxy mergers. We find that radio AGN hosts have lower star formation rates than non-AGN radio-selected galaxies at the same star...

  19. Neutron Albedo

    CERN Document Server

    Ignatovich, V K

    2005-01-01

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

  20. Stratospheric gravity wave activities inferred through the GPS radio occultation technique; Ondas de gravidade na estratosfera terrestre inferida atraves da tecnica de radio ocultacao de GPS

    Energy Technology Data Exchange (ETDEWEB)

    Wrasse, Cristiano Max [Universidade do Vale do Paraiba (UNIVAP), Instituto de Pesquisa e Desenvolvimento (IPeD), Sao Jose dos Campos, SP (Brazil); Takahashi, Hisao; Fechine, Joaquim; Denardini, Clezio Marcos [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil); Wickert, Jens, E-mail: cmw@univap.br, E-mail: hisaotak@laser.inpe.br, E-mail: joaquim@laser.inpe.br, E-mail: denardin@dae.inpe.br, E-mail: jens.wickert@gfz-potsdam.de [GeoForschungsZentrum, Potsdam (GFZ), Department of Geodesy and Remote Sensing (Germany)

    2007-07-01

    Stratospheric gravity wave activities were deduced from GPS radio occultation temperature profiles obtained by CHAMP satellite between 2001 and 2005. Potential energy profiles are used to analyze the gravity wave activity over South America. The results showed an inter-annual variation of the potential energy integrated between 24 and 34 km of altitude. The gravity wave activity is more concentrated around the equatorial region. In order to evaluate the seasonal variation of the gravity wave activity, a mean potential energy was determined over (10 deg N-10 deg S) and (100 deg W-20 deg W). The results showed a lower gravity wave activity during winter time, while during spring time the mean potential energy showed an increase in the wave activity. The results of the mean potential energy also showed that the gravity wave activity in the lower stratosphere exhibits a higher wave activity during 2002 and 2004 and a lower wave activity during 2003 and 2005. (author)

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

    Science.gov (United States)

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

    2011-10-01

    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 240Pu [1]. On the other hand, identification of shielded uranium requires active methods using neutron or photon sources [2]. 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 [3,4]. 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 [4,5]. 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, the 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 1×10 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 2×10 4 n/cm 2 s.

  2. 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.

  3. The sign of active galactic nucleus quenching in a merger remnant with radio jets

    CERN Document Server

    Ichikawa, Kohei; Shidatsu, Megumi; Kawamuro, Taiki; Matsuoka, Kenta

    2015-01-01

    We investigate optical, infrared, and radio active galactic nucleus (AGN) signs in the merger remnant Arp 187, which hosts luminous jets launched in the order of $10^5$ yr ago but whose present-day AGN activity is still unknown. We find AGN signs from the optical BPT diagram and infrared [OIV]25.89 $\\mu$m line, originating from the narrow line regions of AGN. On the other hand, Spitzer/IRS show the host galaxy dominated spectra, suggesting that the thermal emission from the AGN torus is considerably small or already diminished. Combining the black hole mass, the upper limit of radio luminosity of the core, and the fundamental plane of the black hole enable us to estimate X-ray luminosity, which gives $<10^{40}$ erg s$^{-1}$. Those results suggest that the AGN activity of Arp 187 has already been quenched, but the narrow line region is still alive owing to the time delay of emission from the past AGN activity.

  4. Results from the CDE phase activity on neutron dosimetry for the international fusion materials irradiation facility test cell

    CERN Document Server

    Esposito, B; Maruccia, G; Petrizzi, L; Bignon, G; Blandin, C; Chauffriat, S; Lebrun, A; Recroix, H; Trapp, J P; Kaschuck, Y

    2000-01-01

    The international fusion materials irradiation facility (IFMIF) project deals with the study of an accelerator-based, deuterium-lithium source, producing high energy neutrons at sufficient intensity and irradiation volume to test samples of candidate materials for fusion energy reactors. IFMIF would also provide calibration and validation of data from fission reactor and other accelerator based irradiation tests. This paper describes the activity on neutron/gamma dosimetry (necessary for the characterization of the specimens' irradiation) performed in the frame of the IFMIF conceptual design evaluation (CDE) neutronics tasks. During the previous phase (conceptual design activity (CDA)) the multifoil activation method was proposed for the measurement of the neutron fluence and spectrum and a set of suitable foils was defined. The cross section variances and covariances of this set of foils have now been used for tests on the sensitivity of the IFMIF neutron spectrum determination to cross section uncertainties...

  5. Evaluation of Hylife-II and Sombrero using 175- and 566- group neutron transport and activation cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Cullen, D; Latkowski, J; Sanz, J

    1999-06-18

    Recent modifications to the TART Monte Carlo neutron and photon transport code enable calculation of 566-group neutron spectra. This expanded group structure represents a significant improvement over the 50- and 175-group structures that have been previously available. To support use of this new capability, neutron activation cross section libraries have been created in the 175- and 566-group structures starting from the FENDL/A-2.0 pointwise data. Neutron spectra have been calculated for the first walls of the HYLIFE-II and SOMBRERO inertial fusion energy power plant designs and have been used in subsequent neutron activation calculations. The results obtained using the two different group structures are compared to each other as well as to those obtained using a 175-group version of the EAF3.1 activation cross section library.

  6. Evaluation of HYLIFE-II and Sombrero using 175- and 566-group neutron transport and activation cross sections

    CERN Document Server

    Latkowski, J F; Sanz, J

    2000-01-01

    Recent modifications to the TART Monte Carlo neutron and photon transport code allow enable calculation of 566-group neutron spectra. This expanded group structure represents a significant improvement over the 50- and 175-group structures that have been previously available. To support use of this new capability, neutron activation cross-section libraries have been created in the 175- and 566-group structures starting from the FENDL/A-2.0 pointwise data. Neutron spectra have been calculated for the first walls of the HYLIFE-II and Sombrero inertial fusion energy power plant designs and have been used in subsequent neutron activation calculations. The results obtained using the two different group structures are compared with each other as well as to those obtained using a 175-group version of the EAF3.1 activation cross-section library.

  7. Cyclic neutron activation for non-destructive characterization of radioactive waste; Zyklische Neutronen-Aktivierung zur Zerstoerungsfreien Charakterisierung radioaktiver Abfaelle

    Energy Technology Data Exchange (ETDEWEB)

    Havenith, Andreas; Kettler, John [RWTH Aachen (Germany). Inst. fuer Nuklearen Brennstoffkreislauf; Mauerhofer, Eric [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energie und Klimaforschung

    2011-07-01

    In Germany about 100.000 casks with low-level radioactive waste are actually stored in federal collection sites or at the nuclear power plants. Due to the incomplete documentation these casks have to be characterized with respect to their composition. In order to avoid the opening of the casks a new non-destructive characterization method was developed by the authors based on the prompt and delayed gamma-neutron-activation analyses using 14 MeV neutrons. the main challenge was to determine the self-shielding of neutrons and photons dependent on the sample composition. Computerized MNCP calculations and experiments were performed. The multi-element analysis is based on the gamma spectroscopy during neutron activation. A new measuring system (MEDINA - multi-element detection based on instrumental neutron activation) was built esp. for the characterization of 200-l casks used in the repository KONRAD.

  8. Software for neutron activation analysis at reactor IBR-2, FLNP, JINR

    CERN Document Server

    Zlokazov, V B

    2004-01-01

    A Delphi program suite, developed for processing gamma-spectra of induced activity of nuclei, obtained from the neutron activation measurements at the reactor IBR-2, FLNF, JINR, is reported. This suite contains components, intended for carrying out all the operations of the analysis cycle, starling with a data acquisition program for gamma -spectrometers Gamma (written in C++ Builder) and including Delphi programs for steps of the analysis. (6 refs).

  9. H I absorption towards low-luminosity radio-loud active galactic nuclei of different accretion modes and WISE colours

    Science.gov (United States)

    Chandola, Yogesh; Saikia, D. J.

    2017-02-01

    H I absorption studies of active galaxies enable us to probe their circumnuclear regions and the general interstellar medium and study the supply of gas that may trigger nuclear activity. In this article, we investigate the dependence of the detection rate of H I absorption on the nature of radio galaxies based on their emission-line spectra and on the nature of host galaxies based on WISE colours and their radio structure, which may help us understand the different accretion modes. We find significant differences in the distributions of W2-W3 colour for sources with H I absorption detections and non-detections. We report a high detection rate of H I absorption in those galaxies with WISE infrared colours W2-W3 > 2, typical of gas-rich systems, along with a compact radio structure. The H I detection rate for low-excitation radio galaxies (LERGs) with W2-W3 > 2 and compact radio structure is high (70.6 ± 20.4 per cent). In high-excitation radio galaxies (HERGs), compact radio structure in the nuclear or circumnuclear region could give rise to absorption by gas in the dusty torus, in addition to gas in the interstellar medium. However, the higher specific star-formation rate (sSFR) for LERGs with W2-W3 > 2 suggests that H I absorption may be largely due to star-forming gas in their hosts. LERGs with extended radio structure tend to have significantly lower values of W2-W3 compared with those with compact structure. Extended radio sources and those with W2-W3 < 2 have low H I detection rates.

  10. Analysis of the neutron component at high altitude mountains using active and passive measurement devices

    CERN Document Server

    Hajek, M; Schoener, W; Vana, N

    2002-01-01

    The European Council directive 96/29/Euratom requires dosimetric precautions if the effective dose exceeds 1 mSv/a. On an average, this value is exceeded by aircrew members. Roughly half of the radiation exposure at flight altitudes is caused by cosmic ray-induced neutrons. Active ( sup 6 LiI(Eu)-scintillator) and passive (TLDs) Bonner sphere spectrometers were used to determine the neutron energy spectra atop Mt. Sonnblick (3105 m) and Mt. Kitzsteinhorn (3029 m). Further measurements in a mixed radiation field at CERN as well as in a proton beam of 62 MeV at Paul Scherrer Institute, Switzerland, confirmed that not only neutrons but also charged particles contribute to the readings of active detectors, whereas TLD-600 and TLD-700 in pair allow the determination of the thermal neutron flux. Unfolding of the detector data obtained atop both mountains shows two relative maxima around 1 MeV and 85 MeV, which have to be considered for the assessment of the biologically relevant dose equivalent. By convoluting the ...

  11. Development of a prompt gamma activation analysis facility using diffracted polychromatic neutron beam

    CERN Document Server

    Byun, S H; Choi, H D

    2002-01-01

    A prompt gamma activation analysis facility has recently been developed at Hanaro, the 24 MW research reactor in the Korea Atomic Energy Research Institute. Polychromatic thermal neutrons are extracted by setting pyrolytic graphite crystals at a Bragg angle of 45 deg. . The detection system comprises a large single n-type HPGe detector, signal electronics and a fast ADC. Neutron beam characterization was performed both theoretically and experimentally. The neutron flux was measured to be 7.9x10 sup 7 n/cm sup 2 s in a 1x1 cm sup 2 beam area at the sample position with a uniformity of 12%. The corresponding Cd-ratio for gold was found to be 266. The beam quality was compared with other representative thermal neutron prompt gamma activation analysis. The detection efficiency was calibrated up to 11 MeV using a set of radionuclides and the (n,gamma) reactions of N and Cl. Finally, the sensitivities and the detection limits were obtained for several elements.

  12. Device for the collection of radio-active materials in the form of dust or powder

    Energy Technology Data Exchange (ETDEWEB)

    Hellriegel, W.

    1980-05-14

    The dust contaminated with radio-activity formed when drilling cement and concrete is sucked in by suction plant via a line into a closed container. The container itself stands in a barrel with or without concrete shielding. The suction plant produces the subpressure in the container via a suction line. This is fixed on the lid of the container and has a filter at its suction opening inside the container. The filter consists of several fibre air-filter mats, which are arranged inside the filter housing at an angle to the air and dust flow and displaced relative to each other.

  13. Proton Neutron Gamma-X Detection (PNGXD): An introduction to contrast agent detection during proton therapy via prompt gamma neutron activation

    Science.gov (United States)

    Gräfe, James L.

    2017-09-01

    Proton therapy is an alternative external beam cancer treatment modality to the conventional linear accelerator-based X-ray radiotherapy. An inherent by-product of proton-nuclear interactions is the production of secondary neutrons. These neutrons have long been thought of as a secondary contaminant, nuisance, and source of secondary cancer risk. In this paper, a method is proposed to use these neutrons to identify and localize the presence of the tumor through neutron capture reactions with the gadolinium-based MRI contrast agent. This could provide better confidence in tumor targeting by acting as an additional quality assurance tool of tumor position during treatment. This effectively results in a neutron induced nuclear medicine scan. Gadolinium (Gd), is an ideal candidate for this novel nuclear contrast imaging procedure due to its unique nuclear properties and its widespread use as a contrast agent in MRI. Gd has one of the largest thermal neutron capture cross sections of all the stable nuclides, and the gadolinium-based contrast agents localize in leaky tissues and tumors. Initial characteristics of this novel concept were explored using the Monte Carlo code MCNP6. The number of neutron capture reactions per Gy of proton dose was found to be approximately 50,000 neutron captures/Gy, for a 8 cm3 tumor containing 300 ppm Gd at 8 cm depth with a simple simulation designed to represent the active delivery method. Using the passive method it is estimated that this number can be up to an order of magnitude higher. The thermal neutron distribution was found to not be localized within the spread out Bragg peak (SOBP) for this geometrical configuration and therefore would not allow for the identification of a geometric miss of the tumor by the proton SOBP. However, this potential method combined with nuclear medicine imaging and fused with online CBCT and prior MRI or CT imaging could help to identify tumor position during treatment. More computational and

  14. Study on a novel panel support concept for radio telescopes with active surface

    Science.gov (United States)

    Yang, Dehua; Zhou, Guohua; Okoh, Daniel; Li, Guoping; Cheng, Jingquan

    2010-07-01

    Generally, panels of radio telescopes are mainly shaped in trapezoid and each is supported/positioned by four adjustors beneath its vertexes. Such configuration of panel supporting system is essentially hyper-static, and the panel is overconstrained from a kinematic point of view. When the panel is to be adjusted and/or actuated, it will suffer stress from its adjusters and hence its shape is to be distorted. This situation is not desirable for high precision panels, such as glass based panels especially used for sub-millimeter and shorter wavelength telescopes with active optics/active panel technology. This paper began with a general overview of panel patterns and panel supports of existing radio telescopes. Thereby, we proposed a preferable master-slave active surface concept for triangular and/or hexagonal panel pattern. In addition, we carry out panel error sensitivity analysis for all the 6 degrees of freedom (DOF) of a panel to identify what DOFs are most sensitive for an active surface. And afterwards, based on the error sensitivity analysis, we suggested an innovative parallel-series concept hexapod well fitted for an active panel to correct for all of its 6 rigid errors. A demonstration active surface using the master-slave concept and the hexapod manifested a great save in cost, where only 486 precision actuators are needed for 438 panels, which is 37% of those actuators needed by classic segmented mirror active optics. Further, we put forward a swaying-arm based design concept for the related connecting joints between panels, which ensures that all the panels attached on to it free from over-constraints when they are positioned and/or actuated. Principle and performance of the swaying-arm connecting mechanism are elaborated before a practical cablemesh based prototype active surface is presented with comprehensive finite element analysis and simulation.

  15. Computational investigation of the neutron shielding and activation characteristics of borated concrete with polyethylene aggregate

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.J.; Jang, J.G.; Lee, H.K., E-mail: leeh@kaist.ac.kr

    2014-09-15

    This paper presents the result of a computational study to investigate the neutron shielding and activation characteristics of concretes containing boron carbide and polyethylene. Various mixes were considered with changes in the contents of boron carbide and polyethylene aggregate. The Monte Carlo simulation code MCNP-5 was utilized to determine the transmission of neutron through concrete at different energies from 0.1 eV to 1 MeV, and ORIGEN-S code was then used to predict activation characteristics of the concretes. It was shown that the replacement of polyethylene in borated concrete greatly enhanced the shielding efficiency of the concrete, and total activity levels of the concrete were considerably decreased with this replacement. Furthermore, double-layered structures having the first layer of polyethylene aggregate-replaced concrete and the second layer of 2 wt% borated concrete are shown to improve shielding efficiency more significantly than monolithic structures.

  16. Development of an accelerator driven neutron activator for medical radioisotope production

    Science.gov (United States)

    Abbas, K.; Buono, S.; Burgio, N.; Cotogno, G.; Gibson, N.; Maciocco, L.; Mercurio, G.; Santagata, A.; Simonelli, F.; Tagziria, H.

    2009-04-01

    A compact, accelerator driven, neutron activator based on a modified version of the Adiabatic Resonance Crossing (ARC) concept has been developed, with the aim of efficiently utilising ion-beam generated neutrons for the production of radioactive nanoparticles for brachytherapy. Extensive Monte Carlo simulations have been carried out to optimise the design of the activator, which is based on a hybrid approach, coupling a lead buffer and a graphite reflector. Computational Fluid Dynamic methods have been used for the thermal-hydraulic design of the neutron-generating beryllium target to ensure efficient water cooling under high proton beam currents. The facility has been tested under various experimental configurations, and the activation yields of different materials, measured with γ-spectrometry techniques, have been compared with theoretical predictions. In this paper the main elements of the activator are described, and calculated and measured results for pure Au, Mo, Ho, and Re foils as well as for Re and Ho nanoparticle samples are presented. A satisfactory agreement between experiment and theory was found, confirming that the improved ARC activator developed in this work is suitable for isotope production for certain applications such as brachytherapy.

  17. Deuteron and neutron induced activation in the Eveda accelerator materials: implications for the accelerator maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, M.; Sanz, J.; Garcia, N.; Cabellos, O. [Madrid Univ. Politecnica, C/ Jose Gutierrez Abascal, lnstituto de Fusion Nuclear (Spain); Sauvan, R. [Universidad Nacional de Educacion a Distancia (UNED), Madrid (Spain); Moreno, C.; Sedano, L.A. [CIEMAT-Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, Association Euratom-CIEMAT, Madrid (Spain)

    2007-07-01

    Full text of publication follows: The IFMIF (International Fusion Materials Irradiation Facility) is an accelerator-based DLi neutron source designed to test fusion reactor candidate materials for high fluence neutrons. Before deciding IFMIF construction, an engineering design and associated experimental data acquisition, defined as EVEDA, has been proposed. Along the EVEDA accelerator, deuteron beam losses collide with the accelerator materials, producing activation and consequent radiations responsible of dose. Calculation of the dose rates in the EVEDA accelerator room is necessary in order to analyze the feasibility for manual maintenance. Dose rates due to the activation produced by the deuteron beam losses interaction with the accelerator materials, will be calculated with the ACAB activation code, using EAF2007 library for deuteron activation cross-sections. Also, dose rates from the activation induced by the neutron source produced by the interaction of deuteron beam losses with the accelerator materials and the deuterium implanted in the structural lattice, will be calculated with the SRIM2006, TMAP7, DROSG2000/NEUYIE, MCNPX and ACAB codes. All calculations will be done for the EVEDA accelerator with the room temperature DTL structure, which is based on copper cavities for the DTL. Some calculations will be done for the superconducting DTL structure, based on niobium cavities for the DTL working at cryogenic temperature. Final analysis will show the dominant mechanisms and major radionuclides contributing to the surface dose rates. (authors)

  18. Method of demonstrating calcium in human foot by neutron activation of (. cap alpha. , N)-sources

    Energy Technology Data Exchange (ETDEWEB)

    Zaychik, V.E.; Kondrashov, A.E.; Morukov, B.V.

    Bone demineralization during long-term exposure to weightlessness and hypokinesia is presently a universally recognized fact. A method is described which employs neutron activation analysis for a direct quantitative in vivo assay of calcium in the human foot. When the foot is exposed to neutrons, the stable nuclide Ca/sup 46/ is converted into the radionuclide Ca/sup 49/. The gamma radiation emitted by Ca/sup 49/ is then measured spectrometrically. A special device, developed for the delivery of neutrons to the foot, consists of a stainless steel tank filled with water, surrounded on the side by lithium-containing screens. A cassette with neutron sources is at the bottom of the tank and can be delivered to the desired position in channel-driver carriers. A special footrest provides support during irradiation. The spectrometry unit, consisting of 4 scintillation counters, also is equipped with a specially designed footrest. The maximum relative error of a single measurement did not exceed 4.82%. The mean equivalent dose in the foot was about 1 rem, a dose low enough to permit examinations three times a year, if necessary.

  19. 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.

  20. A multi-layered active target for the study of neutron-unbound nuclides at NSCL

    Science.gov (United States)

    Freeman, Jessica; Gueye, Paul; Redpath, Thomas; MoNA Collaboration

    2017-01-01

    The characteristics of neutron-unbound nuclides were investigated using a multi-layered Si/Be active target designed for use with the MoNA/LISA setup at the National Superconducting Cyclotron (NSCL). The setup consists of the MoNA/LISA arrays (for neutron detection) and a superconducting sweeper magnet (for charged separation) to identify products following the decay of neutron unbound states. The segmented target consisted of three 700 mg/cm2 beryllium targets and four 0.14 mm thick 62x62 mm2 silicon detectors. As a commissioning experiment for the target the decay of two-neutron unbound 26O populated in a one-proton removal reaction from a radioactive 27F beam was performed. The 27F secondary radioactive beam from the NSCL's Coupled Cyclotron Facility was produced from the fragmentation of a 140 MeV/u 48Ca beam incident on a thick beryllium target and then cleanly selected by the A1900 fragment separator. The energy loss and position spectra of the incoming beam and reaction products were used to calibrate the Silicon detectors to within 1.5% in both energy and position. A dedicated Geant4 model of the target was developed to simulate the energy loss within the target. A description of the experimental setup, simulation work, and energy and position calibration will be presented. DoE/NNSA - DE-NA0000979.

  1. Determination of the neutron activation profile of core drill samples by gamma-ray spectrometry.

    Science.gov (United States)

    Gurau, D; Boden, S; Sima, O; Stanga, D

    2017-08-04

    This paper provides guidance for determining the neutron activation profile of core drill samples taken from the biological shield of nuclear reactors using gamma spectrometry measurements. Thus, it provides guidance for selecting a model of the right form to fit data and using least squares methods for model fitting. The activity profiles of two core samples taken from the biological shield of a nuclear reactor were determined. The effective activation depth and the total activity of core samples along with their uncertainties were computed by Monte Carlo simulation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. RADIO OBSERVATIONS OF THE STAR FORMATION ACTIVITIES IN THE NGC 2024 FIR 4 REGION

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Minho; Kang, Miju [Korea Astronomy and Space Science Institute, 776 Daedeokdaero, Yuseong, Daejeon 305-348 (Korea, Republic of); Lee, Jeong-Eun, E-mail: minho@kasi.re.kr [School of Space Research, Kyung Hee University, Yongin, Gyeonggi 446-701 (Korea, Republic of)

    2015-07-15

    Star formation activities in the NGC 2024 FIR 4 region were studied by imaging centimeter continuum sources and water maser sources using several archival data sets from the Very Large Array. The continuum source VLA 9 is elongated in the northwest–southeast direction, consistent with the FIR 4 bipolar outflow axis, and has a flat spectrum in the 6.2–3.6 cm interval. The three water maser spots associated with FIR 4 are also distributed along the outflow axis. One of the spots is located close to VLA 9, and another one is close to an X-ray source. Examinations of the positions of compact objects in this region suggest that the FIR 4 cloud core contains a single low-mass protostar. VLA 9 is the best indicator of the protostellar position. VLA 9 may be a radio thermal jet driven by this protostar, and it is unlikely that FIR 4 contains a high-mass young stellar object (YSO). A methanol 6.7 GHz maser source is located close to VLA 9, at a distance of about 100 AU. The FIR 4 protostar must be responsible for the methanol maser action, which suggests that methanol class II masers are not necessarily excited by high-mass YSOs. Also discussed are properties of other centimeter continuum sources in the field of view and the water masers associated with FIR 6n. Some of the continuum sources are radio thermal jets, and some are magnetically active young stars.

  3. Coronal Radio Sounding Experiments with Mars Express: Scintillation Spectra during Low Solar Activity

    Science.gov (United States)

    Efimov, A. I.; Lukanina, L. A.; Samoznaev, L. N.; Rudash, V. K.; Chashei, I. V.; Bird, M. K.; Pätzold, M.; Tellmann, S.

    2010-03-01

    Coronal radio sounding observations were carried out with the radio science experiment MaRS on the ESA spacecraft Mars Express during the period from 25 August to 22 October 2004. Differential frequency and log-amplitude fluctuations of the dual-frequency signals were recorded during a period of low solar activity. The data are applicable to low heliographic latitudes, i.e. to slow solar wind. The mean frequency fluctuation and power law index of the frequency fluctuation temporal spectra are determined as a function of heliocentric distance. The radial dependence of the frequency fluctuation spectral index α reflects the previously documented flattening of the scintillation power spectra in the solar wind acceleration region. Temporal spectra of S-band and X-band normalized log-amplitude fluctuations were investigated over the range of fluctuation frequencies 0.01 Hzperiod of high solar activity. Ranging measurements are presented and compared with frequency and log-amplitude scintillation data. Evidence for a weak increase in the fractional electron density turbulence level is obtained in the range 10-40 solar radii.

  4. Verification of the viability of virions detection using neutron activation analysis; Verificacao da viabilidade de deteccao de virions atraves da analise por ativacao com neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Wacha, R.; Silva, A.X. da; Crispim, V.R [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear; Couceiro, J.N.S.S. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Microbiologia Professor Paulo de Goes. Dept. de Virologia

    2002-07-01

    The use of nuclear techniques, as Neutron Activation Analysis, can be an alternative way for the microbiological diagnosis, bringing a significant profit in the analysis time, for not needing pre cultivated samples in appropriate way. In this technique, the samples are collected and submitted to a thermal neutron beam. The interaction of these neutrons with the samples generates gamma rays whose energy spectre is a characteristic of the elemental composition of these samples. Of this done one, a virus presence can be detected in the sample through the distinction of its respective elemental compositions allowing, also, carrying through the analysis in real time. In this work, computational simulations had been become fulfilled using the radiation transport code based on the Monte Carlo Method, MCNP4B, to verify the viability of the application of this system for the virus particle detection in its natural collection environment. (author)

  5. Reproducibility of neutron activated Sm-153 oral dose formulations intended for human administration

    Energy Technology Data Exchange (ETDEWEB)

    Yeong, C.H. [Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur (Malaysia); Blackshaw, P.E. [Medical Physics and Clinical Engineering, Nottingham University Hospitals NHS Trust, Nottingham NG7 2UH (United Kingdom); Ng, K.H.; Abdullah, B.J.J. [Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur (Malaysia); Blaauw, M. [Reactor Institute Delft, Faculty of Applied Sciences, Delft University of Technology, 2628 CJ Delft (Netherlands); Dansereau, R.J. [Procter and Gamble Pharmaceuticals, 8700 Mason-Montgomery Rd, Mason (United States); Perkins, A.C., E-mail: alan.perkins@nottingham.ac.uk [Medical Physics and Clinical Engineering, Nottingham University Hospitals NHS Trust, Nottingham NG7 2UH (United Kingdom); Radiological and Imaging Sciences and Nottingham Digestive Diseases Biomedical Research Unit, University of Nottingham, Nottingham NG7 2UH (United Kingdom)

    2011-09-15

    Neutron activation of Sm-152 offers a method of radiolabeling for the in vivo study of oral dose formulations by gamma scintigraphy. Reproducibility measurements are needed to ensure the robustness of clinical studies. 204 enteric-coated guaifenesin core tablets (10 mg of Sm{sub 2}O{sub 3}) were irradiated by thermal neutrons to achieve 1 MBq at 48 h. Administered activities were 0.86{+-}0.03 MBq. Good reproducibility (CV=3.5%) was observed over 24 weeks ensuring that volunteer doses were within the dose reference level of 0.8 mSv. - Highlights: > 204 enteric-coated guaifenesin core tablets were irradiated by thermal neutrons. > Activity measured at 48 h after irradiation was 1.01{+-}0.03 MBq. > Activity administered per subject was 0.88{+-}0.03 MBq. > Good reproducibility (CV=3.5%) of Sm-153 radioactivity was obtained. > Effective doses to volunteers were within dose reference level of 0.8 mSv.

  6. A History of In Vivo Neutron Activation Analysis in Measurement of Aluminum in Human Subjects.

    Science.gov (United States)

    Mohseni, Hedieh K; Chettle, David R

    2016-01-01

    Aluminum, as an abundant metal, has gained widespread use in human life, entering the body predominantly as an additive to various foods and drinking water. Other major sources of exposure to aluminum include medical, cosmetic, and occupational routes. As a common environmental toxin, with well-known roles in several medical conditions such as dialysis encephalopathy, aluminum is considered a potential candidate in the causality of Alzheimer's disease. Aluminum mostly accumulates in the bone, which makes bone an indicator of the body burden of aluminum and an ideal organ as a proxy for the brain. Most of the techniques developed for measuring aluminum include bone biopsy, which requires invasive measures, causing inconvenience for the patients. There has been a considerable effort in developing non-invasive approaches, which allow for monitoring aluminum levels for medical and occupational purposes in larger populations. In vivo neutron activation analysis, a method based on nuclear activation of isotopes of elements in the body and their subsequent detection, has proven to be an invaluable tool for this purpose. There are definite challenges in developing in vivo non-invasive techniques capable of detecting low levels of aluminum in healthy individuals and aluminum-exposed populations. The following review examines the method of in vivo neutron activation analysis in the context of aluminum measurement in humans focusing on different neutron sources, interference from other activation products, and the improvements made in minimum detectable limits and patient dose over the past few decades.

  7. Measurements of 60Co in spoons activated by neutrons during the JCO criticality accident at Tokai-mura in 1999.

    Science.gov (United States)

    Gasparro, J; Hult, M; Komura, K; Arnold, D; Holmes, L; Johnston, P N; Laubenstein, M; Neumaier, S; Reyss, J-L; Schillebeeckx, P; Tagziria, H; Van Britsom, G; Vasselli, R

    2004-01-01

    Neutron activated items from the vicinity of the place where the JCO criticality accident occurred have been used to determine the fluence of neutrons around the facility and in nearby residential areas. By using underground laboratories for measuring the activation products, it is possible to extend the study to also cover radionuclides with very low activities from long-lived radionuclides. The present study describes gamma-ray spectrometry measurements undertaken in a range of underground laboratories for the purpose of measuring (60)Co more than 2 years after the criticality event. The measurements show that neutron fluence determined from (60)Co activity is in agreement with previous measurements using the short-lived radionuclides (51)Cr and (59)Fe. Limits on contamination of the samples with (60)Co are evaluated and shown to not greatly affect the utility of neutron fluence determinations using (60)Co activation.

  8. The affect of industrial activities on zinc in alluvial Egyptian soil determined using neutron activation analysis

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Thirty-two surface (0-20 cm) soil samples were collected from different locations in Egypt representing non-polluted,moderately and highly polluted soils.The aim of this study was to evaluate total Zn content in alluvial soils of Nile Delta in Egypt by using the delayed neutron activation analysis technique (DNAA),in the irradiation facilities of the first Egyptian research reactor (ET-RR-1).The gamma-ray spectra were recorded with a hyper pure germanium detection system.The well resolved gamma-ray peak at 1116.0 kev was efficiently used for 65Zn content determination.Zn content in non-polluted soil samples ranged between 74.1 and 103.8 ppm with an average of 98.5 + 5.1 ppm.Zn content in moderately polluted soils ranged between 136.0 and 232.5 ppm with an average of 180.1 + 32.6 ppm.The highest Zn levels ranging from 240.0 and 733.0 ppm with an average of 410.3 + 54.4 ppm,were observed in soil samples collected from,either highly polluted agricultural soils exposed to prolonged irrigation with industrial wastewater or surface soil samples from industrial sites.

  9. The affect of industrial activities on zinc in alluvial Egyptian soil determined using neutron activation analysis.

    Science.gov (United States)

    Abdel-Sabour, M F; Abdel-Basset, N

    2002-07-01

    Thirty-two surface (0-20 cm) soil samples were collected from different locations in Egypt representing non-polluted, moderately and highly polluted soils. The aim of this study was to evaluate total Zn content in alluvial soils of Nile Delta in Egypt by using the delayed neutron activation analysis technique (DNAA), in the irradiation facilities of the first Egyptian research reactor (ET-RR-1). The gamma-ray spectra were recorded with a hyper pure germanium detection system. The well resolved gamma-ray peak at 1116.0 keV was efficiently used for 65Zn content determination. Zn content in non-polluted soil samples ranged between 74.1 and 103.8 ppm with an average of 98.5 +/- 5.1 ppm. Zn content in moderately polluted soils ranged between 136.0 and 232.5 ppm with an average of 180.1 +/- 32.6 ppm. The highest Zn levels ranging from 240.0 and 733.0 ppm with an average of 410.3 +/- 54.4 ppm, were observed in soil samples collected from, either highly polluted agricultural soils exposed to prolonged irrigation with industrial wastewater or surface soil samples from industrial sites.

  10. Neutron activation analysis and atomic absorption spectrophotometry for the analysis of fresh, pasteurised and powder milk

    Energy Technology Data Exchange (ETDEWEB)

    Wasim, M.; Rehman, S.; Arif, M.; Fatima, I.; Zaidi, J.H. [Pakistan Inst. of Nuclear Science and Technology, Islamabad (Pakistan). Chemistry Div.

    2012-07-01

    This study shows the application of semi-absolute k{sub 0} instrumental neutron activation analysis (k{sub 0}-INAA), epithermal neutron activation analysis (ENAA) and atomic absorption spectrophotometry (AAS) for the determination of 21 elements (Br, Ca, Cl, Co, Cr, Cs, Cu, Fe, Hf, I, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sc Sr, and Zn) in different types of milk samples. The ENAA was required for the determination of iodine, AAS for Cu, Ni and Pb and the rest of the elements were measured by k{sub 0}-INAA. Thirteen elements (Br, Ca, Cl, Cs, Cu, Fe, K, Mg, Na, P, Rb, Sr and Zn) were identified in all milk samples. Ni was detected in eleven and Pb in two samples. Concentrations of most of the elements were within the ranges of the world reported data. The data was further explored by principal component analysis to find relationships between samples and elements. (orig.)

  11. Uncertainties in measuring trace amounts of cobalt and europium with low-flux neutron activation analysis

    Directory of Open Access Journals (Sweden)

    Burnham Steven

    2017-01-01

    Full Text Available Neutron activation analysis is widely used for identification of elements and their quantities even in trace amounts in the samples of almost any type. The challenges in detecting trace amounts of particular elements are often associated with the neutron flux produced at the research reactors. Low-flux neutron activation analysis usually presents the biggest challenge when analyzing trace quantities of elements with lower magnitude of radiative capture cross-sections. In this paper, we present the methodology and the quantified uncertainties associated with the detection of trace amounts of cobalt and europium, using as an example concrete aggregates. Recent growing interest is in improving structural concrete (increasing its strength but reducing its activation in nuclear power plant environments. Aside from buildings, structural concrete is also used as a biological shield in nuclear power plant that become radioactive after exposure to neutron flux. Due to radiative capture interactions, artificial radionuclides are generated to high enough concentrations that classify concrete as low-level radioactive waste at the time of the plant's decommissioning. Disposal of this concrete adds to the expense of nuclear power plant financing and its construction. Three radionuclides, 60Co, 152Eu, and 154Eu, account for 99 % of total residual radioactivity of nuclear power plant decommissioned concrete. IAEA document RS-G-1.7, Application of the Concepts of Exclusion, Exemption, and Clearance, specifies clearance levels of radionuclides specific activities: a specific activity lower than 0.1 Bqg-1 for 60Co and 152Eu, and 154Eu allows for a concrete to be recycled after decommissioning of the nuclear power plant. Therefore, low-flux neutron activation analysis is used to test the detection limits of trace elements in samples of cement, coarse, and fine concrete aggregates. These samples are irradiated at the University of Utah's 100 kW TRIGA Reactor at

  12. Elemental analysis of rain- and fresh water by neutron activation analysis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Analysis of rain-and fresh water for trace constituents is a manda tory part of environmental monitoring. This text gives a survey of neutron activation analysis (NAA) within the framework of current environmental water research pro grammes, based on the practice developed in co-operation with the Dutch Energy Research Centre at Petten (ECN). While the procedures reported in literature cover about thirty five elements, our routine procedures of instrumental neutron activation analysis (INAA) is limited to ten to fifteen elements. The use of some dedicated ra diochemical separations (RNAA) adds another six, some of which are speciated as well. Current contributions of NAA to water analysis center on determination and speciation of anionic trace elements, notably Br, I, As. and Se, on the assay of some ultra traces like Ag, Au and Hg and on validation.

  13. Heavy metals in the benthic animals from hydrothermal vents: Results of neutron activation analysis

    Science.gov (United States)

    Shmelev, I. P.; Kuznetsov, A. A.; Galkin, S. V.

    2009-06-01

    A series of samples of inhabitants of hydrothermal vents were collected during the 12th cruise of R/V Akademik Mstislav Keldysh in Guaymas Basin (the Gulf of California) and the Axial Seamount area (Juan de Fuca Ridge). The concentrations of trace and heavy metals in the tissues of Ridgeia piscesae, Riftia pachyptila, and Paralvinella palmiformis were analyzed. The neutron-activation analysis revealed significantly higher concentrations of uranium in the tissues of Paralvinella palmiformis as compared to the ambient seawater. The possible reasons for such phenomenon are discussed. The data obtained by the neutron-activation method are compared with those obtained by the atomic-absorption method for the same tissues analyzed.

  14. Neutron flux variations near the Earth’s crust. A possible tectonic activity detection

    Directory of Open Access Journals (Sweden)

    B. M. Kuzhevskij

    2003-01-01

    Full Text Available The present work contains some results of observations of neutron flux variations near the Earth’s surface. The Earth’s crust is determined to be a significant source of thermal and slow neutrons, originated from the interaction between the nuclei of the elements of the Earth’s crust and the atmosphere and α-particles, produced by decay of radioactive gases (Radon, Thoron and Actinon. In turn, variations of radioactive gases exhalation is connected with geodynamical processes in the Earth’s crust, including tectonic activity. This determined relation between the processes in the Earth’s crust and neutrons’ flux allow to use variations of thermal and slow neutrons’ flux in order to observe increasing tectonic activity and to develop methods for short-term prediction of natural hazards.

  15. A neutron activation analysis procedure for the determination of uranium, thorium and potassium in geologic samples

    Science.gov (United States)

    Aruscavage, P. J.; Millard, H.T.

    1972-01-01

    A neutron activation analysis procedure was developed for the determination of uranium, thorium and potassium in basic and ultrabasic rocks. The three elements are determined in the same 0.5-g sample following a 30-min irradiation in a thermal neutron flux of 2??1012 n??cm-2??sec-1. Following radiochemical separation, the nuclides239U (T=23.5 m),233Th (T=22.2 m) and42K (T=12.36 h) are measured by ??-counting. A computer program is used to resolve the decay curves which are complex owing to contamination and the growth of daughter activities. The method was used to determine uranium, throium and potassium in the U. S. Geological Survey standard rocks DTS-1, PCC-1 and BCR-1. For 0.5-g samples the limits of detection for uranium, throium and potassium are 0.7, 1.0 and 10 ppb, respectively. ?? 1972 Akade??miai Kiado??.

  16. Activation foils unfolding for neutron spectrometry: Comparison of different deconvolution methods

    Energy Technology Data Exchange (ETDEWEB)

    Tripathy, S.P. [Radiation Safety Systems Division, BARC, Mumbai 400085 (India)], E-mail: sam.tripathy@gmail.com; Sunil, C. [Radiation Safety Systems Division, BARC, Mumbai 400085 (India); Nandy, M. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064 (India); Sarkar, P.K. [Radiation Safety Systems Division, BARC, Mumbai 400085 (India); Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064 (India); Sharma, D.N. [Radiation Safety Systems Division, BARC, Mumbai 400085 (India); Mukherjee, B. [Deutsches Elektronen-Synchrotron, LLRF Group, D-22607 Hamburg (Germany)

    2007-12-21

    The results obtained from the activation foils measurement are unfolded using two different deconvolution methods such as BUNKI and genetic algorithm (GA). The spectra produced by these codes agree fairly with each other and are comparable with that measured previously for the same system using NE213 liquid scintillator and by unfolding the neutron-induced proton pulse height distribution using two different methods, viz. FERDOR and BUNKI. The details of various unfolding procedures used in this work are reported in this paper.

  17. Utilization of ko-factors for quality assurance in neutron activation analysis

    DEFF Research Database (Denmark)

    Heydorn, K.; Damsgaard, E.

    1994-01-01

    Multielement certification analysis by instrumental neutron activation analysis requires simultaneous irradiation of several elemental comparator standards in order to ascertain traceability. Internal consistency of different comparators may be checked by calculation of k0-ratios, which show large...... deviations from unity in case of stoichiometric or other gross errors. Quality assurance based on the Analysis of Precision of k0-ratios from replicate analyses detects unexpected variability associated with inaccurate comparator standards. In two actual cases of cerification lack of statistical control...

  18. Identification of the provenience of Majolica from sites in the Caribbean using neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Olin, J.S.; Sayre, E.V.

    1975-01-01

    Tin-enamelled earthenware pottery from five early Spanish Colonial sites in the Dominican Republic and Venezuela were sampled and analyzed by neutron activation analysis in an attempt to determine whether these sherds had a common source. The tentative conclusion was that although several sources were indicated for the specimens analyzed the overall similarity in composition indicated that these sources were probably closely related. (JSR)

  19. An application of a simple computer program for neutron activation analysis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A simple computer program is designed for estimation of elemental concentration values in complex samples by neutron activation analysis technique. The program is applied for an Egyptian cement sample which irradiated at the Egyptian Research Reactor-1(ET-RR-1). The data obtained is compared with the reported values. The time consumed for such calculations has a remarkable reduction in comparison with the routine work.

  20. Rapid determination of halogenes in milk by instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Alfassi, Z.B.; Lavi, N.

    1985-07-01

    The absolute concetrations of iodine, bromine and chlorine in milk were determined by epithermal neutron activation followed by high resolution gamma-ray spectrometry. Two kinds of milk commonly consumed in Israel were investigated. The concentration of iodine, bromine and chlorine were found to be 0.18-0.30 ..mu..g/ml, 2.02-2.85 ..mu..g/ml and 0.65 mg/ml, respectively. The method is fast, selective, accurate and highly sensitive.

  1. Radiochemical neutron activation analysis of rare earth elements in peridotitic rocks

    Energy Technology Data Exchange (ETDEWEB)

    Joron, J.L. (Laboratoire d' Analyse par Activation Pierre Sue, Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)); Ottonello, G. (Consiglio Nationale delle Ricerche, Pisa (Italy). Ist. di Petrografia)

    1985-02-01

    A radiochemical neutron activation analytical method based on various methods published earlier was used to determine rare earth elements (REE). The method involves a post-irradiation sample fusion, two separate ion-exchange chromatographic stages, and, finally, a fluoride precipitation. The RNAA procedure is capable of providing very precise REE data for peridotitic samples and was used for the analysis of rocks from several geodynamic environments.

  2. Instrumental neutron activation analysis of soil and sediment samples from Siwa Oasis, Egypt

    Science.gov (United States)

    Badawy, Wael M.; Ali, Khaled; El-Samman, Hussein M.; Frontasyeva, Marina V.; Gundorina, Svetlana F.; Duliu, Octavian G.

    2015-07-01

    Instrumental neutron activation analysis was used to study geochemical peculiarities of the Siwa Oasis in the Western Egyptian Desert. A total of 34 elements were determined in soil and sediment samples (Na, Mg, Al, Cl, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Br, Rb, Sr, Zr, Sb, I, Cs, Ba, La, Ce, Nd, Eu, Tb, Dy, Tm, Yb, Hf, Ta, Th, and U). For data interpretation Cluster analysis was applied. Comparison with the available literature data was carried out.

  3. Event based neutron activation spectroscopy and analysis algorithm using MLE and metaheuristics

    OpenAIRE

    Wallace Barton

    2014-01-01

    Techniques used in neutron activation analysis are often dependent on the experimental setup. In the context of developing a portable and high efficiency detection array, good energy resolution and half-life discrimination are difficult to obtain with traditional methods [1] given the logistic and financial constraints. An approach different from that of spectrum addition and standard spectroscopy analysis [2] was needed. The use of multiple detectors prompts the need for a flexible storage o...

  4. Salvinia auriculata: Aquatic bioindicator studied by instrumental neutron activation analysis (INAA)

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira Soares, Daniel Cristian; Figueiredo de Oliveira, Ester [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN), Avenida Antonio Carlos, 6627 Pampulha, CEP 30123-970 Belo Horizonte, Minas Gerais (Brazil); Fatima Silva, Gracia Divina de; Duarte, Lucienir Pains [Departamento de Quimica, ICEx, Nucleo de estudos de Plantas Medicinais (NEPLAM), Universidade Federal de Minas Gerais, Avenida Antonio Carlos, 6627 Pampulha, 31270-901 Belo Horizonte, Minas Gerais (Brazil); Pott, Vali Joana [Empresa Brasileira de Agropecuaria (EMBRAPA), BR 262 km 4, Caixa Postal 154, CEP 79002-970 Campo Grande, Mato Grosso do Sul (Brazil); Vieira Filho, Sidney Augusto [Escola de Farmacia, DEFAR, Universidade Federal de Ouro Preto, Rua Costa Sena, 171, CEP 35400-000 Ouro Preto, Minas Gerais (Brazil)], E-mail: bibo@ef.ufop.br

    2008-05-15

    Through instrumental neutron activation analysis (INAA) the elemental chemical composition of Salvinia auriculata and Ouro Preto city public water was determined. Elements Ce, Th, Cr, Hf, Sb, Sc, Rb, Fe, Zn, Co, Au, La and Br were quantified. High chromium concentration was determined in this plant. But, chromium was determined only in low concentrations in the water. The results indicate the great capacity of this plant to absorb and accumulate inorganic elements.

  5. Application of neutron activation in hydrometallurgical process of lead chloride extraction from boulangerit

    OpenAIRE

    Zovko Emira; Islamović Safija

    2010-01-01

    In this work, a neutron activation analysis for the identification of radiochemical elements in the ore concentrate of zone Vareš, Bosnia and Hercegovina, has been applied. The possibility of dissolving ore concentrate from iron(III) chloride was examined. To follow the dissolving lead (II) sulphide yield from the ore concentrates, in addition to radioisotope labeling process, it is necessary to use a gravimetric analysis of the extracted lead(II) chloride. Based on kinetic measurements of di...

  6. Revision and extensions of neutron capture cross-sections in the European activation file EAF-3

    Energy Technology Data Exchange (ETDEWEB)

    Kopecky, J.; Delfini, M.G.; Kamp, H.A.J. van der; Nierop, D.

    1992-07-01

    This report contains an extensive description of the work performed to compile, extend and revise the neutron capture data subfile of the European Activation File (EAF-3). The starter was the EAF-1 data file from 1989. The present version, EAF/NG-3, contains (n, [gamma]) excitation functions for all nuclides (729 targets) with half-lives exceeding 1/2 day in the mass range from H-1 to Cm-248. (author). 35 refs.; 9 figs.; 7 tabs.

  7. An application of a simple computer program for neutron activation analysis.

    Science.gov (United States)

    Abdel Basset, N

    2001-01-01

    A simple computer program is designed for estimation of elemental concentration values in complex samples by neutron activation analysis technique. The program is applied for an Egyptian cement sample which irradiated at the Egyptian Research Reactor-1(ET-RR-1). The data obtained is compared with the reported values. The time consumed for such calculations has a remarkable reduction in comparison with the routine work.

  8. Neutron activation analysis in archaeological and solar energy research; Neutronenaktivierungsanalyse in Archaeometrie und Solarenergieforschung

    Energy Technology Data Exchange (ETDEWEB)

    Stieghorst, Christian

    2016-06-23

    For 80 years now, neutron activation analysis (NAA) has been providing reliable data of the elemental composition for different materials in various scientific fields. Today, there are still many applications for NAA, and new methods based on neutron activation were developed during the last couple of years. In this work the focus was on the precise elemental analysis of different materials. For the provenance studies of ancient Roman limestone objects the elemental composition of samples and quarries were compared by using geochemical indicators and multivariate statistics of the elemental composition dataset, which was previously produced by using instrumental neutron activation analysis (INAA). The samples of this work originated from different archeological sites and quarries in the French region of Lorraine as well as samples from excavations in the Belgian city of Tongeren. Various objects could successfully assign to one of the Lorraine quarries via principle component analysis (PCA) and support vector machines (SVM).The aim of the co-operation between the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, Germany, and the Institute of Nuclear Chemistry in Mainz, Germany, was to reduce the energy and cost consumption during the production process of multicrystalline solar cells at a constant efficiency level. The test ingots were produced at the ISE and measured with NAA. The colleagues' work on this topic was focused on INAA measurements of the 3d transition metals and a new developed method for phosphorus detection. In this work prompt-gamma neutron activation analysis (PGAA) was used to measure the dopand boron as well as hydrogen. The PGAA facility of the FRM II reactor close to the city of Munich was used for this purposes. For the measurement of boron amounts below the PGAA detection limit in the medium ppb{sub w}-range a new method developed at the FRM II by Lichtinger was tested. A qualitative boron detection was successful.

  9. A neutron activation system for Ho, HoZr and Sm brachytherapy seeds for breast radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Wagner L., E-mail: wagner.leite@ifmg.edu.br [Instituto Federal de Minas Gerais (IFMG), Congonhas, MG (Brazil). Departamento de Fisica; Campos, Tarcisio P.R., E-mail: tprcampos@pq.cnpq.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

    2015-07-01

    This paper addresses a device designed for transmuting nuclides by means of neutron capture reactions. The device is composed by a neutron generator based on d-d reactions, a neutron moderator and a reflection system, enclosed by a radiation shield. The project was modeled on the CST electromagnetic code. Afterwards, a nuclear investigation was carried out by MCNP5 code, where the final activities of a large set of 0.5 x 1.8 mm cylindrical, biodegradable and biocompatible, Ho-165 (Ho and HoZr) and Sm-152 breast brachytherapy seeds were evaluated, considering the neutron capture reactions. The accelerator-head equipotential profiles and the optical beam of deuterons with its energy map were presented. The neutronic evaluation allowed estimating a neutron yield of 10{sup 13} n s{sup -1}. From the seed's group, an individual Ho-166 seed reached activity of 100 MBq in 58 h operation time. Moreover, Sm-153 seed reached 120 MBq during a period of 64 h of operation. The system shows to be able to provide the neutron activation of brachytherapy seeds with suitable individual specific activity able for controlling breast tumors. (author)

  10. New Measurements and Calculations to Characterize the Caliban Pulsed Reactor Cavity Neutron Spectrum by the Foil Activation Method

    Energy Technology Data Exchange (ETDEWEB)

    Jacquet, X.; Casoli, P.; Authier, N.; Rousseau, G. [CEA, Centre de Valduc, 21120 Is-sur-Tille (France); Barsu, C. [Pl. de la fontaine, 25410 Corcelles-Ferrieres (France)

    2011-07-01

    Caliban is a cylindrical metallic core reactor mainly composed of uranium 235. It is operated by the Criticality and Neutron Science Research Laboratory located at the French Atomic Energy Commission research center in Valduc. As with other fast burst reactors, Caliban is used extensively for determining the responses of electronic parts or other objects and materials to neutron-induced displacements. Therefore, Caliban's irradiation characteristics, and especially its central cavity neutron spectrum, have to be very accurately evaluated. The foil activation method has been used in the past by the Criticality and Neutron Science Research Laboratory to evaluate the neutron spectrum of the different facilities it operated, and in particular to characterize the Caliban cavity spectrum. In order to strengthen and to improve our knowledge of the Caliban cavity neutron spectrum and to reduce the uncertainties associated with the available evaluations, new measurements have been performed on the reactor and interpreted by the foil activation method. A sensor set has been selected to sample adequately the studied spectrum. Experimental measured reaction rates have been compared to the results from UMG spectrum unfolding software and to values obtained with the activation code Fispact. Experimental and simulation results are overall in good agreement, although gaps exist for some sensors. UMG software has also been used to rebuild the Caliban cavity neutron spectrum from activation measurements. For this purpose, a default spectrum is needed, and one has been calculated with the Monte-Carlo transport code Tripoli 4 using the benchmarked Caliban description. (authors)

  11. 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.

  12. Using Paid Radio Advertisements to Promote Physical Activity Among Arkansas Tweens

    Directory of Open Access Journals (Sweden)

    Appathurai Balamurugan, MD, MPH

    2005-11-01

    Full Text Available Introduction The level of physical activity among children is a growing concern. Evidence shows that many children aged 9 to 13 years (tweens do not participate in any organized physical activity during their nonschool hours, and some do not engage in any free-time physical activity. Physical inactivity is associated with a host of chronic diseases such as diabetes and cardiovascular disease. Paid media advertisements have been an effective method of promoting physical activity. Methods From March 10, 2003, through June 29, 2003, we aired paid radio advertisements in six major Arkansas metropolitan areas to promote physical activity among tweens. In September 2003, we surveyed 295 Arkansas tweens by telephone to assess their exposure to the advertisements and the impact of the advertisements on their intent to participate in physical activity. In the same telephone survey, we also asked questions about the respondents’ physical activity level. The data were weighted so that the results would be representative of the areas surveyed. The statistical analysis was performed using SPSS, version 11.5 (SPSS Inc, Chicago, Ill. Results Of the tweens surveyed, 56.4% (95% confidence interval [CI], 50.7%–62.1% reported hearing the radio advertisements. Of the tweens who heard the advertisement messages, 76.1% (95% CI, 69.4%–82.8% said the messages made them more likely to get involved in physical activity. Younger tweens (aged 9 and 10 years were less likely to have heard the advertisements than older tweens (aged 11 to 13 years. However, the advertisements were more likely to cause younger tweens to want to get involved in physical activity (odds ratio [OR] = 6.89, P = .003 than older tweens. Of the tweens surveyed, 74.9% (95% CI, 70.0%–79.8% reported that they were involved in nonschool-sponsored sports, and 45.3% (95% CI, 39.6%–51.0% were involved in school-sponsored sports. Conclusion Paid media advertisements may be an effective way to

  13. Radiography apparatus using gamma rays emitted by water activated by fusion neutrons

    Science.gov (United States)

    Smith, D.L.; Ikeda, Yujiro; Uno, Yoshitomo

    1996-11-05

    Radiography apparatus includes an arrangement for circulating pure water continuously between a location adjacent a source of energetic neutrons, such as a tritium target irradiated by a deuteron beam, and a remote location where radiographic analysis is conducted. Oxygen in the pure water is activated via the {sup 16}O(n,p){sup 16}N reaction using {sup 14}N-MeV neutrons produced at the neutron source via the {sup 3}H(d,n){sup 4}He reaction. Essentially monoenergetic gamma rays at 6.129 (predominantly) and 7.115 MeV are produced by the 7.13-second {sup 16}N decay for use in radiographic analysis. The gamma rays have substantial penetrating power and are useful in determining the thickness of materials and elemental compositions, particularly for metals and high-atomic number materials. The characteristic decay half life of 7.13 seconds of the activated oxygen is sufficient to permit gamma ray generation at a remote location where the activated water is transported, while not presenting a chemical or radioactivity hazard because the radioactivity falls to negligible levels after 1--2 minutes. 15 figs.

  14. Progress report on neutron activation analysis at Dalat Nuclear Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Tuan, Nguyen Ngoc [Nuclear Research Institute, Dalat (Viet Nam)

    2003-03-01

    Neutron Activation Analysis (NAA) is one of most powerful techniques for the simultaneous multi-elements analysis. This technique has been studied and applied to analyze major, minor and trace elements in Geological, Biological and Environmental samples at Dalat Nuclear Research Reactor. At the sixth Workshop, February 8-11, 1999, Yojakarta, Indonesia we had a report on Current Status of Neutron Activation Analysis using Dalat Nuclear Research Reactor. Another report on Neutron Activation Analysis at the Dalat Nuclear Research Reactor also was presented at the seventh Workshop in Taejon, Korea from November 20-24, 2000. So in this report, we would like to present the results obtained of the application of NAA at NRI for one year as follows: (1) Determination of the concentrations of noble, rare earth, uranium, thorium and other elements in Geological samples according to requirement of clients particularly the geologists, who want to find out the mineral resources. (2) The analysis of concentration of radionuclides and nutrient elements in foodstuffs to attend the program on Asian Reference Man. (3) The evaluation of the contents of trace elements in crude oil and basement rock samples to determine original source of the oil. (4) Determination of the elemental composition of airborne particle in the Ho Chi Minh City for studying air pollution. The analytical data of standard reference material, toxic elements and natural radionuclides in seawater are also presented. (author)

  15. Measurement and theoretical estimation of induced activity in natIn by high energy neutrons

    Indian Academy of Sciences (India)

    Maitreyee Nandy; P K Sarkar; N Nakao; T Shibata

    2009-10-01

    Induced radioactivity in natural indium (natIn) foils by high energy neutrons was measured at the KENS Facility, KEK, Japan, where a 16.7 cm thick W target was bombarded by protons of 500 MeV. High energy neutrons consequently produced irradiated the In targets placed at different depths inside a 4 m thick concrete shield placed at the beam exit. The measured activities were compared with the results calculated using the nuclear reaction model codes ALICE-91 and EMPIRE-2.18. To estimate the induced activity, excitation functions of the various radionuclides were calculated using the two codes and folded with the appropriate neutron energy distribution at different depths of the concrete shield. The calculated excitation functions of a given nuclide were found to vary widely from one another in some cases. The performances of the codes for different input parameters like level densities and inverse cross-sections are reported in this paper. Our analysis shows that neither of the two codes reproduced all the measured activities satisfactorily, requiring further improvements in the models adopted.

  16. Obscured flat spectrum radio active galactic nuclei as sources of high-energy neutrinos

    Science.gov (United States)

    Maggi, G.; Buitink, S.; Correa, P.; de Vries, K. D.; Gentile, G.; Tavares, J. León; Scholten, O.; van Eijndhoven, N.; Vereecken, M.; Winchen, T.

    2016-11-01

    Active galactic nuclei (AGN) are believed to be one of the main source candidates for the high-energy (TeV-PeV) cosmic neutrino flux recently discovered by the IceCube neutrino observatory. Nevertheless, several correlation studies between AGN and the cosmic neutrinos detected by IceCube show no significance. Therefore, in this article we consider a specific subclass of AGN for which an increased neutrino production is expected. This subclass contains AGN for which their high-energy jet is pointing toward Earth. Furthermore, we impose the condition that the jet is obscured by gas or dust surrounding the AGN. A method is presented to determine the total column density of the obscuring medium, which is probed by determining the relative x-ray attenuation with respect to the radio flux as obtained from the AGN spectrum. The total column density allows us to probe the interaction of the jet with the surrounding matter, which leads to additional neutrino production. Finally, starting from two different source catalogs, this method is applied to specify a sample of low redshift radio galaxies for which an increased neutrino production is expected.

  17. Invisible Active Galactic Nuclei. II Radio Morphologies & Five New HI 21 cm Absorption Line Detections

    CERN Document Server

    Yan, Ting; Darling, Jeremy; Momjian, Emmanuel; Sharma, Soniya; Kanekar, Nissim

    2015-01-01

    We have selected a sample of 80 candidates for obscured radio-loud active galactic nuclei and presented their basic optical/near-infrared (NIR) properties in Paper 1. In this paper, we present both high-resolution radio continuum images for all of these sources and HI 21cm absorption spectroscopy for a few selected sources in this sample. A-configuration 4.9 and 8.5 GHz VLA continuum observations find that 52 sources are compact or have substantial compact components with size 0.1 Jy at 4.9 GHz. The most compact 36 sources were then observed with the VLBA at 1.4 GHz. One definite and 10 candidate Compact Symmetric Objects (CSOs) are newly identified, a detection rate of CSOs ~3 times higher than the detection rate previously found in purely flux-limited samples. Based on possessing compact components with high flux densities, 60 of these sources are good candidates for absorption-line searches. Twenty seven sources were observed for HI 21cm absorption at their photometric or spectroscopic redshifts with only ...

  18. Molecular gas and nuclear activity in early-type galaxies: any link with radio-loudness?

    CERN Document Server

    Baldi, Ranieri D; Capetti, Alessandro; Giovannini, Gabriele; Casasola, Viviana; Perez-Torres, Miguel A; Kuno, Nario

    2014-01-01

    Aims. We want to study the amount of molecular gas in a sample of nearby early-type galaxies (ETGs) which host low-luminosity Active Galactic Nuclei (AGN). We look for possible differences between the radio-loud (RL) and radio-quiet (RQ) AGN. Methods. We observed the CO(1-0) and CO(2-1) spectral lines with the IRAM 30m and NRO 45m telescopes for eight galaxies. They belong to a large sample of 37 local ETGs which host both RQ and RL AGN. We gather data from the literature for the entire sample. Results. We report the new detection of CO(1-0) emission in four galaxies (UGC0968, UGC5617, UGC6946, and UGC8355) and CO(2-1) emission in two of them (UGC0968 and UGC5617). The CO(2-1)/CO(1-0) ratio in these sources is $\\sim0.7\\pm0.2$. Considering both the new observations and the literature, the detection rate of CO in our sample is 55 $\\pm$ 9%, with no statistically significant difference between the hosts of RL and RQ AGNs. For all the detected galaxies we converted the CO luminosities into the molecular masses, $M...

  19. Photoneutron Flux Measurement via Neutron Activation Analysis in a Radiotherapy Bunker with an 18 MV Linear Accelerator

    Directory of Open Access Journals (Sweden)

    Çeçen Yiğit

    2017-01-01

    Full Text Available In cancer treatment, high energy X-rays are used which are produced by linear accelerators (LINACs. If the energy of these beams is over 8 MeV, photonuclear reactions occur between the bremsstrahlung photons and the metallic parts of the LINAC. As a result of these interactions, neutrons are also produced as secondary radiation products (γ,n which are called photoneutrons. The study aims to map the photoneutron flux distribution within the LINAC bunker via neutron activation analysis (NAA using indium-cadmium foils. Irradiations made at different gantry angles (0°, 90°, 180° and 270° with a total of 91 positions in the Philips SLI-25 linear accelerator treatment room and location-based distribution of thermal neutron flux was obtained. Gamma spectrum analysis was carried out with high purity germanium (HPGe detector. Results of the analysis showed that the maximum neutron flux in the room occurred at just above of the LINAC head (1.2x105 neutrons/cm2.s which is compatible with an americium-beryllium (Am-Be neutron source. There was a 90% decrease of flux at the walls and at the start of the maze with respect to the maximum neutron flux. And, just in front of the LINAC door, inside the room, neutron flux was measured less than 1% of the maximum.

  20. Workplace testing of the new single sphere neutron spectrometer based on Dysprosium activation foils (Dy-SSS)

    Science.gov (United States)

    Bedogni, R.; Gómez-Ros, J. M.; Esposito, A.; Gentile, A.; Chiti, M.; Palacios-Pérez, L.; Angelone, M.; Tana, L.

    2012-08-01

    A photon insensitive passive neutron spectrometer consisting of a single moderating polyethylene sphere with Dysprosium activation foils arranged along three perpendicular axes was designed by CIEMAT and INFN. The device is called Dy-SSS (Dy foil-based Single Sphere Spectrometer). It shows nearly isotropic response in terms of neutron fluence up to 20 MeV. The first prototype, previously calibrated with 14 MeV neutrons, has been recently tested in workplaces having different energy and directional distributions. These are a 2.5 MeV nearly mono-chromatic and mono-directional beam available at the ENEA Frascati Neutron Generator (FNG) and the photo-neutron field produced in a 15 MV Varian CLINAC DHX medical accelerator, located in the Ospedale S. Chiara (Pisa). Both neutron spectra are known through measurements with a Bonner Sphere Spectrometer. In both cases the experimental response of the Dy-SSS agrees with the reference data. Moreover, it is demonstrated that the spectrometric capability of the new device are independent from the directional distribution of the neutron field. This opens the way to a new generation of moderation-based neutron instruments, presenting all advantages of the Bonner sphere spectrometer without the disadvantage of the repeated exposures. This concept is being developed within the NESCOFI@BTF project of INFN (Commissione Scientifica Nazionale 5).

  1. FY15 Status Report on NEAMS Neutronics Activities

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C. H. [Argonne National Lab. (ANL), Argonne, IL (United States); Shemon, E. R. [Argonne National Lab. (ANL), Argonne, IL (United States); Smith, M. A. [Argonne National Lab. (ANL), Argonne, IL (United States); Connaway, H. M. [Argonne National Lab. (ANL), Argonne, IL (United States); Aliberti, G. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-30

    This report summarizes the current status of NEAMS activities in FY2015. The tasks this year are (1) to improve solution methods for steady-state and transient conditions, (2) to develop features and user friendliness to increase the usability and applicability of the code, (3) to improve and verify the multigroup cross section generation scheme, (4) to perform verification and validation tests of the code using SFRs and thermal reactor cores, and (5) to support early users of PROTEUS and update the user manuals.

  2. Optical identification of radio-loud active galactic nuclei in the ROSAT-Green-Bank sample with SDSS spectroscopy

    Institute of Scientific and Technical Information of China (English)

    De-Liang Wang; Jian-Guo Wang; Xiao-Bo Dong

    2009-01-01

    Results of extended and refined optical identification of 181 radio/X-ray sources in the RASS-Green Bank (RGB) catalog are presented (Brinkmann et al.1997)which have been spectroscopically observed in the Sloan Digital Sky Survey (SDSS)DR5.The SDSS spectra of the optical counterparts are modeled in a careful and selfconsistent way by incorporating the host galaxy's starlight.Optical emission line parameters are presented,which are derived accurately and reliably,along with the radio 1.4-5 GHz spectral indices estimated using (non-simultaneous) archival data.For 72 sources,the identifications are presented for the first time.It is confirmed that the majority of strong radio/X-ray emitters are radio-loud active galactic nuclei (AGNs),particularly blazars.Taking advantage of the high spectral quality and resolution and our refined spectral modeling,we are able to disentangle narrow line radio galaxies (NLRGs),as vaguely termed in most previous identification work,into SeyfertⅡgalaxies and LINERs (low-ionization nuclear emission regions),based on the standard emission line diagnostics.The NLRGs in the RGB sample,mostly belonging to'weak line radio galaxies',are found to have optical spectra consistent predominantly with LINERs,and only a small fraction with SeyfertⅡgalaxies.A small number of LINERs have radio power as high as 1023-1026W Hz-1 at 5 GHz,being among the strongest radio emitting LINERs known so far.Two sources are identified with radio-loud narrow line Seyfert 1 galaxies (NLSIs),a class of rare objects.The presence is also confirmed of fiat-spectrum radio quasars whose radio-optical-X-ray effective spectral indices are similar to those of High-energy peaked BL Lacs (HBLs),as suggested by Padovani et al.,although it is still a debate as to whether this is the case for their actual spectral energy distributions.

  3. Analysis of human enamel and dentine by neutron activation analysis; Analise de esmalte e dentina de humanos pelo metodo de ativacao com neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Marco A.B. [Sao Paulo Univ., SP (Brazil). Inst. de Quimica]. E-mail: vankfire@gmail.com; Adachi, Eduardo M.; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    2005-07-01

    Determination of trace elements in dental tissues has been of great interest to study the correlation between element composition and caries as well as food habits of individuals. In the present study dentine and enamel samples from healthy individuals were analysed by neutron activation analysis. The teeth were provided form dental clinics, and they were previously washed using purified water and acetone. Then they were dried at 40 deg C and ground in a agate mortar. The samples and element standards were irradiated with thermal neutrons at the IEA-R1 nuclear reactor. Long irradiations of 8 h under thermal neutron flux of 5x10{sup 12} n cm{sup -2} s{sup -1} were used for Ca, Na, Sr and Zn determinations. In short irradiations of 15 s and under neutron flux of 10{sup 12} n cm{sup -2} s{sup -1} the elements Mg, Mn, Na e Sr were determined. The induced gamma activities of the samples and standards were measured using a hyperpure Ge detector coupled to a gamma ray spectrometer. Elemental concentrations were calculated by comparative method. Results obtained showed that Ca, Mg and Na are present in both tissues at the level of percentages and the elements Mn, Sr and Zn at the {mu}g g{sup -1} levels. For quality control of the results the certified reference materials NIST 1400 Bone Ash and NIST 1486 Bone Meal were analysed. (author)

  4. Analysis of calibration data for the uranium active neutron coincidence counting collar with attention to errors in the measured neutron coincidence rate

    Energy Technology Data Exchange (ETDEWEB)

    Croft, Stephen [Oak Ridge National Laboratory (ORNL), One Bethel Valley Road, Oak Ridge, TN (United States); Burr, Tom [International Atomic Energy Agency (IAEA), Vienna (Austria); Favalli, Andrea [Los Alamos National Laboratory (LANL), MS E540, Los Alamos, NM 87545 (United States); Nicholson, Andrew [Oak Ridge National Laboratory (ORNL), One Bethel Valley Road, Oak Ridge, TN (United States)

    2016-03-01

    The declared linear density of {sup 238}U and {sup 235}U in fresh low enriched uranium light water reactor fuel assemblies can be verified for nuclear safeguards purposes using a neutron coincidence counter collar in passive and active mode, respectively. The active mode calibration of the Uranium Neutron Collar – Light water reactor fuel (UNCL) instrument is normally performed using a non-linear fitting technique. The fitting technique relates the measured neutron coincidence rate (the predictor) to the linear density of {sup 235}U (the response) in order to estimate model parameters of the nonlinear Padé equation, which traditionally is used to model the calibration data. Alternatively, following a simple data transformation, the fitting can also be performed using standard linear fitting methods. This paper compares performance of the nonlinear technique to the linear technique, using a range of possible error variance magnitudes in the measured neutron coincidence rate. We develop the required formalism and then apply the traditional (nonlinear) and alternative approaches (linear) to the same experimental and corresponding simulated representative datasets. We find that, in this context, because of the magnitude of the errors in the predictor, it is preferable not to transform to a linear model, and it is preferable not to adjust for the errors in the predictor when inferring the model parameters.

  5. Neutronics and activation analysis of lithium-based ternary alloys in IFE blankets

    Energy Technology Data Exchange (ETDEWEB)

    Jolodosky, Alejandra, E-mail: aleja311@berkeley.edu [University of California Berkeley, Berkeley, CA 94706 (United States); Kramer, Kevin [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA (United States); Meier, Wayne; DeMuth, James; Reyes, Susana [TerraPower, Bellevue, WA 98005 (United States); Fratoni, Massimiliano [University of California Berkeley, Berkeley, CA 94706 (United States)

    2016-06-15

    Highlights: • Monte Carlo calculations were performed on numerous lithium ternary alloys. • Elements with high neutron multiplication performed well with low absorbers. • Enriching lithium decreases minimum lithium concentration of alloys by 60% or more. • Alloys that performed well neutronically were selected for activation calculations. • Alloys activated, except LiBaBi, do not pose major environmental or safety concerns. - Abstract: An attractive feature of using liquid lithium as the breeder and coolant in fusion blankets is that it has very high tritium solubility and results in very low levels of tritium permeation throughout the facility infrastructure. However, lithium metal vigorously reacts with air and water and presents plant safety concerns. The Lawrence Livermore National Laboratory is carrying an effort to develop a lithium-based ternary alloy that maintains the beneficial properties of lithium (e.g. high tritium breeding and solubility) and at the same time reduces overall flammability concerns. This study evaluates the neutronics performance of lithium-based alloys in the blanket of an inertial fusion energy chamber in order to inform such development. 3-D Monte Carlo calculations were performed to evaluate two main neutronics performance parameters for the blanket: tritium breeding ratio (TBR), and the fusion energy multiplication factor (EMF). It was found that elements that exhibit low absorption cross sections and higher q-values such as Pb, Sn, and Sr, perform well with those that have high neutron multiplication such as Pb and Bi. These elements meet TBR constrains ranging from 1.02 to 1.1. However, most alloys do not reach EMFs greater than 1.15. Additionally, it was found that enriching lithium with {sup 6}Li significantly increases the TBR and decreases the minimum lithium concentration by more than 60%. The amount of enrichment depends on how much total lithium is in the alloy to begin with. Alloys that performed well in the TBR

  6. Neutron activation determination of iridium, gold, platinum, and silver in geologic samples

    Science.gov (United States)

    Millard, H.T.

    1987-01-01

    Low-level methods for the determination of iridium and other noble metals have become increasingly important in recent years due to interest in locating abundance anomalies associated with the Cretaceous and Tertiary (K-T) boundary. Typical iridium anomalies are in the range of 1 to 100 ??g/kg (ppb). Thus methods with detection limits near 0.1 ??g/kg should be adequate to detect K-T boundary anomalies. Radiochemical neutron activation analysis methods continue to be required although instrumental neutron activation analysis techniques employing elaborate gamma-counters are under development. In the procedure developed in this study samples irradiated in the epithermal neutron facility of the U. S. Geological Survey TRIGA Reactor (Denver, Colorado) are treated with a mini-fire assay technique. The iridium, gold, and silver are collected in a 1-gram metallic lead button. Primary contaminants at this stage are arsenic and antimony. These can be removed by heating the button with a mixture of sodium perioxide and sodium hydroxide. The resulting 0.2-gram lead bead is counted in a Compton suppression spectrometer. Carrier yields are determined by reirradiation of the lead beads. This procedure has been applied to the U.S.G.S. Standard Rock PCC-1 and samples from K-T boundary sites in the Western Interior of North America. ?? 1987 Akade??miai Kiado??.

  7. Radio Counterparts of Compact Binary Mergers Detectable in Gravitational Waves: A Simulation for an Optimized Survey

    Science.gov (United States)

    Hotokezaka, K.; Nissanke, S.; Hallinan, G.; Lazio, T. J. W.; Nakar, E.; Piran, T.

    2016-11-01

    Mergers of binary neutron stars and black hole-neutron star binaries produce gravitational-wave (GW) emission and outflows with significant kinetic energies. These outflows result in radio emissions through synchrotron radiation. We explore the detectability of these synchrotron-generated radio signals by follow-up observations of GW merger events lacking a detection of electromagnetic counterparts in other wavelengths. We model radio light curves arising from (i) sub-relativistic merger ejecta and (ii) ultra-relativistic jets. The former produce radio remnants on timescales of a few years and the latter produce γ-ray bursts in the direction of the jet and orphan-radio afterglows extending over wider angles on timescales of weeks. Based on the derived light curves, we suggest an optimized survey at 1.4 GHz with five epochs separated by a logarithmic time interval. We estimate the detectability of the radio counterparts of simulated GW-merger events to be detected by advanced LIGO and Virgo by current and future radio facilities. The detectable distances for these GW merger events could be as high as 1 Gpc. Around 20%-60% of the long-lasting radio remnants will be detectable in the case of the moderate kinetic energy of 3\\cdot {10}50 erg and a circum-merger density of 0.1 {{cm}}-3 or larger, while 5%-20% of the orphan-radio afterglows with kinetic energy of 1048 erg will be detectable. The detection likelihood increases if one focuses on the well-localizable GW events. We discuss the background noise due to radio fluxes of host galaxies and false positives arising from extragalactic radio transients and variable active galactic nuclei, and we show that the quiet radio transient sky is of great advantage when searching for the radio counterparts.

  8. Estimation of the Performance of Multiple Active Neutron Interrogation Signatures for Detecting Shielded HEU

    Energy Technology Data Exchange (ETDEWEB)

    David L. Chichester; Scott J. Thompson; Scott M. Watson; James T. Johnson; Edward H. Seabury

    2012-10-01

    A comprehensive modeling study has been carried out to evaluate the utility of multiple active neutron interrogation signatures for detecting shielded highly enriched uranium (HEU). The modeling effort focused on varying HEU masses from 1 kg to 20 kg; varying types of shields including wood, steel, cement, polyethylene, and borated polyethylene; varying depths of the HEU in the shields, and varying engineered shields immediately surrounding the HEU including steel, tungsten, and cadmium. Neutron and gamma-ray signatures were the focus of the study and false negative detection probabilities versus measurement time were used as a performance metric. To facilitate comparisons among different approaches an automated method was developed to generate receiver operating characteristic (ROC) curves for different sets of model variables for multiple background count rate conditions. This paper summarizes results or the analysis, including laboratory benchmark comparisons between simulations and experiments. The important impact engineered shields can play towards degrading detectability and methods for mitigating this will be discussed.

  9. Performance of an improved thermal neutron activation detector for buried bulk explosives

    Energy Technology Data Exchange (ETDEWEB)

    McFee, J.E., E-mail: jemcfee@gmail.com [Defence R and D Canada – Suffield, Medicine Hat (Canada); Faust, A.A. [Defence R and D Canada – Suffield, Medicine Hat (Canada); Andrews, H.R.; Clifford, E.T.H. [Bubble Technology Industries Inc., Chalk River (Canada); Mosquera, C.M. [Defence R and D Canada – Suffield, Medicine Hat (Canada)

    2013-06-01

    First generation thermal neutron activation (TNA) sensors, employing an isotopic source and NaI(Tl) gamma ray detectors, were deployed by Canadian Forces in 2002 as confirmation sensors on multi-sensor landmine detection systems. The second generation TNA detector is being developed with a number of improvements aimed at increasing sensitivity and facilitating ease of operation. Among these are an electronic neutron generator to increase sensitivity for deeper and horizontally displaced explosives; LaBr{sub 3}(Ce) scintillators, to improve time response and energy resolution; improved thermal and electronic stability; improved sensor head geometry to minimize spatial response nonuniformity; and more robust data processing. The sensor is described, with emphasis on the improvements. Experiments to characterize the performance of the second generation TNA in detecting buried landmines and improvised explosive devices (IEDs) hidden in culverts are described. Performance results, including comparisons between the performance of the first and second generation systems are presented.

  10. Routine determination of trace elements in fly ashes by instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Szopa, Z.; Dybczynski, R.; Kulisa, K.; Sterlinski, S. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

    1994-12-31

    A method making possible routine determination of 24 trace elements in fly ashes by instrumental neutron activation analysis (INAA) is described. The method employs elemental standards, and the correction for neutron flux gradient in the irradiation package is performed with the aid of Au flux monitors. Important features of the method as: detectability, precision and accuracy are discussed in detail. Reliability of the method was demonstrated by the analysis of several certified reference materials (CRMs). Special attention was devoted to comparison of the experimentally obtained detection limits with those predicted by computer spectra simulation (CSS) method. The elemental enrichment factors calculated for Polish coal fly ash were compared with those typical for Chinese and Canadian fly ashes. (author). 21 refs, 7 figs.

  11. Studies on application of radiation and radioisotopes -Studies on application of neutron activation analysis-

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yong Sam; Jung, Yung Joo; Jung, Eui Sik; Lee, Sang Mee [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Kim, Nak Bae [Korea Institute of Geology, Mining and Materials, Taejon (Korea, Republic of)

    1995-07-01

    To apply Neutron activation analysis to routine analysis of environmental samples utilizing the research reactor (TRIGA MK-III), improving effects of analytical sensitivity have been investigated using both of thermal and epithermal neutron irradiating technique. Identification and development of analytical procedure was carried out using three kinds of standard reference materials (urban particulate matter, coal fly ash, soil). In addition, the confidence of this method was established by participation in collaborative research for the training and apply of international credit of analytical procedure. Practical studies on air dust samples have also been carried out regionally and seasonally. For the investigation on emission source of special element, enrichment factor was calculated in urban and rural area. Besides, a suitable process of biological sample (pine needle) analyses has been established by carrying out identification of uncertainty using standard reference material. The concentration of elements in practical samples were also determined regionally and seasonally. 14 figs, 26 tabs, 67 refs. (Author).

  12. Elemental analysis of some Egyptian ores and industrial iron samples by neutron activation analysis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Elemental analysis of iron ore samples and first industrial iron production prepared by the Egyptian Iron and Steel Company of Helwan near Cairo were determined by instrumental neutron activation analysis technique. Five samples from each kind were irradiated for a 48 hours at a thermal neutron flux of 4x1012 n/(cm2.s) in the first Egyptian research reactor ET-PP-1. Also the pneumatic irradiation rabbit system (PIRS) attached to the reactor in Inshass, was used to measure the elements of short-life time.The gamma-ray spectra were recorded by means of the hyper pure germanium detection system. The concentration percentage values of major, minor and trace elements are presented. The long and short lived isotopes were considered. A comparative study and a discussion on the elemental concentration values are given.

  13. Elemental analysis of two Egyptian iron ores and produced industrial iron samples by neutron activation analysis.

    Science.gov (United States)

    Sroo, A; Abdel-Basset, N; Abdel-Haleem, A S; Hassan, A M

    2001-03-01

    Elemental analysis of two iron ores and initial industrial iron production prepared by the Egyptian Iron and Steel Company of Helwan near Cairo were performed by the instrumental neutron activation analysis technique. Five samples of each type were irradiated for 48 h in a thermal neutron flux of 4 x 10(12) n/cm2 s in the first Egyptian research reactor ET-RR-1. Also, the Pneumatic Irradiation Rabbit System (PIRS), attached to the reactor ET-RR-1 in Inshass, was used to measure short-life elements. The gamma-ray spectra were obtained with a hyper pure germanium detection system. The concentration percentage values of major, minor and trace elements are presented. Implications of the elemental concentration values obtained are presented.

  14. Elemental analysis of two Egyptian iron ores and produced industrial iron samples by neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sroor, A.; Abdel-Basset, N.; Abdel-Haleem, A.S.; Hassan, A.M

    2001-03-01

    Elemental analysis of two iron ores and initial industrial iron production prepared by the Egyptian Iron and Steel Company of Helwan near Cairo were performed by the instrumental neutron activation analysis technique. Five samples of each type were irradiated for 48 h in a thermal neutron flux of 4x10{sup 12} n/cm{sup 2} s in the first Egyptian research reactor ET-RR-1. Also, the Pneumatic Irradiation Rabbit System (PIRS), attached to the reactor ET-RR-1 in Inshass, was used to measure short-life elements. The {gamma}-ray spectra were obtained with a hyper pure germanium detection system. The concentration percentage values of major, minor and trace elements are presented. Implications of the elemental concentration values obtained are presented.

  15. Elemental analysis of some Egyptian ores and industrial iron samples by neutron activation analysis.

    Science.gov (United States)

    Srror, A; Abdel-Basset, N; Abdel-Haleem, A S; Hassan, A M

    2001-01-01

    Elemental analysis of iron ore samples and first industrial iron production prepared by the Egyptian Iron and Steel Company of Helwan near Cairo were determined by instrumental neutron activation analysis technique. Five samples from each kind were irradiated for a 48 hours at a thermal neutron flux of 4 x 10(12) n/(cm2.s) in the first Egyptian research reactor ET-RR-1. Also the Pneumatic irradiation Rabbit system (PIRS) attached to the reactor in Inshass, was used to measure the elements of short-life time. The gamma-ray spectra were recorded by means of the hyper pure germanium detection system. The concentration percentage values of major, minor and trace elements are presented. The long and short lived isotopes were considered. A comparative study and a discussion on the elemental concentration values are given.

  16. A new active method for the measurement of slow-neutron fluence in modern radiotherapy treatment rooms

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, F; Iglesias, A [Departamento de Fisica de Particulas, Universidad de Santiago, 15782-Santiago (Spain); Doblado, F Sanchez [Hospital Universitario Virgen Macarena, Radiofisica and Departamento de Fisiologia Medica y Biofisica, Facultad de Medicina, Universidad de Sevilla (Spain)], E-mail: faustino.gomez@usc.es

    2010-02-21

    This work focuses on neutron monitoring at clinical linac facilities during high-energy modality radiotherapy treatments. Active in-room measurement of neutron fluence is a complex problem due to the pulsed nature of the fluence and the presence of high photon background, and only passive methods have been considered reliable until now. In this paper we present a new active method to perform real-time measurement of neutron production around a medical linac. The device readout is being investigated as an estimate of patient neutron dose exposure on each radiotherapy session. The new instrument was developed based on neutron interaction effects in microelectronic memory devices, in particular using neutron-sensitive SRAM devices. This paper is devoted to the description of the instrument and measurement techniques, presenting the results obtained together with their comparison and discussion. Measurements were performed in several standard clinical linac facilities, showing high reliability, being insensitive to the photon fluence and EM pulse present inside the radiotherapy room, and having detector readout statistical relative uncertainties of about 2% on measurement of neutron fluence produced by 1000 monitor units irradiation runs.

  17. A Cooperative Bayesian Nonparametric Framework for Primary User Activity Monitoring in Cognitive Radio Network

    CERN Document Server

    Saad, Walid; Poor, H Vincent; Başar, Tamer; Song, Ju Bin

    2012-01-01

    This paper introduces a novel approach that enables a number of cognitive radio devices that are observing the availability pattern of a number of primary users(PUs), to cooperate and use \\emph{Bayesian nonparametric} techniques to estimate the distributions of the PUs' activity pattern, assumed to be completely unknown. In the proposed model, each cognitive node may have its own individual view on each PU's distribution, and, hence, seeks to find partners having a correlated perception. To address this problem, a coalitional game is formulated between the cognitive devices and an algorithm for cooperative coalition formation is proposed. It is shown that the proposed coalition formation algorithm allows the cognitive nodes that are experiencing a similar behavior from some PUs to self-organize into disjoint, independent coalitions. Inside each coalition, the cooperative cognitive nodes use a combination of Bayesian nonparametric models such as the Dirichlet process and statistical goodness of fit techniques ...

  18. An investigation of the neutron flux in bone-fluorine phantoms comparing accelerator based in vivo neutron activation analysis and FLUKA simulation data

    Energy Technology Data Exchange (ETDEWEB)

    Mostafaei, F.; McNeill, F.E.; Chettle, D.R.; Matysiak, W.; Bhatia, C.; Prestwich, W.V.

    2015-01-01

    We have tested the Monte Carlo code FLUKA for its ability to assist in the development of a better system for the in vivo measurement of fluorine. We used it to create a neutron flux map of the inside of the in vivo neutron activation analysis irradiation cavity at the McMaster Accelerator Laboratory. The cavity is used in a system that has been developed for assessment of fluorine levels in the human hand. This study was undertaken to (i) assess the FLUKA code, (ii) find the optimal hand position inside the cavity and assess the effects on precision of a hand being in a non-optimal position and (iii) to determine the best location for our γ-ray detection system within the accelerator beam hall. Simulation estimates were performed using FLUKA. Experimental measurements of the neutron flux were performed using Mn wires. The activation of the wires was measured inside (1) an empty bottle, (2) a bottle containing water, (3) a bottle covered with cadmium and (4) a dry powder-based fluorine phantom. FLUKA was used to simulate the irradiation cavity, and used to estimate the neutron flux in different positions both inside, and external to, the cavity. The experimental results were found to be consistent with the Monte Carlo simulated neutron flux. Both experiment and simulation showed that there is an optimal position in the cavity, but that the effect on the thermal flux of a hand being in a non-optimal position is less than 20%, which will result in a less than 10% effect on the measurement precision. FLUKA appears to be a code that can be useful for modeling of this type of experimental system.

  19. Measurement and calculations of long-lived radionuclide activity forming in the fast neutron field in some ITER construction steels

    Energy Technology Data Exchange (ETDEWEB)

    Pohorecki, W., E-mail: poho@agh.edu.pl [AGH University of Science and Technology, Faculty of Energy and Fuels, Al. Mickiewicza 30, 30-059 Krakow (Poland); Jodłowski, P. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Al. Mickiewicza 30, 30-059 Krakow (Poland); Pytel, K.; Prokopowicz, R. [National Centre for Nuclear Research, ul. Sołtana 7, 05-400 Otwock-Świerk (Poland)

    2014-10-15

    Highlights: • Measurement and calculations of long-lived gamma-emitting radionuclide activity forming in the fission reactor fast neutron field were done, in some ITER construction steels. • The neutron flux density was measured by means of activation foil method and unfolding technique. • Activity calculations were done by means of FISPACT-II code using the activation libraries EAF-2010 and TALYS-2011. • The activity measurements were done by means of gamma-ray spectrometry. - Abstract: Measurement and calculations of long-lived gamma-emitting radionuclide activity forming in the fission reactor fast neutron field were done, for some ITER construction steels. The activation was conducted in fast neutron irradiation channel of the MARIA research fission reactor (Poland). The dimensions of steel samples were 10 mm × 10 mm × 1 mm and mass was approximately 0.8 g. The neutron flux density was measured by means of activation foil method and unfolding technique; fraction of neutrons above 1 keV was 95%. The activation lasted 242 h and cooling took 100 days; the mean neutron flux density was 2.9E12 n/(cm{sup 2} s) (neutrons above 500 keV are 53% of total) whereas total fluency 2.53E18 cm{sup −2}. The activity measurements were done by means of gamma-ray spectrometry. Activity calculations were done by means of FISPACT-II code using the activation libraries EAF-2010 and TENDL-2011 and experimentally determined neutron flux. Measured activity of long-lived gamma emitting radionuclides was, in average, about 6.3 MBq/g 100 days after activation; the dominant radionuclides were {sup 58}Co and {sup 54}Mn (about 81% and 14% of total activity respectively). The C/E ratio differs for particular radionuclides and is in the range 0.86–0.92 for {sup 51}Cr, 0.93–1.21 for {sup 54}Mn, 0.77–0.98 for {sup 57}Co, 0.91–1.21 for {sup 58}Co, 1.17–1.27 for {sup 59}Fe, and 1.75–2.44 for {sup 60}Co.

  20. Effect and suppression of parasitic surface damage in neutron irradiated CMOS Monolithic Active Pixel Sensors

    CERN Document Server

    Deveaux, M; Scharrer, P; Stroth, J

    2016-01-01

    CMOS Monolithic Active Pixel Sensors (MAPS) were chosen as sensor technology for the vertex detectors of STAR, CBM and the upgraded ALICE-ITS. They also constitute a valuable option for tracking devices at future e+e- colliders. Those applications require a substantial tolerance to both, ionizing and non-ionizing radiation. To allow for a focused optimization of the radiation tolerance, prototypes are tested by irradiating the devices either with purely ionizing radiation (e.g. soft X-rays) or the most pure sources of non-ionizing radiation available (e.g. reactor neutrons). In the second case, it is typically assumed that the impact of the parasitic $\\gamma$-rays found in the neutron beams is negligible. We checked this assumption by irradiating MAPS with $\\gamma$-rays and comparing the radiation damage generated with the one in neutron irradiated sensors. We conclude that the parasitic radiation doses may cause non-negligible radiation damage. Based on the results we propose a procedure to recognize and to ...

  1. Determination of uranium fission product interference factor for molybdenum quantification by instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro Junior, Ibere S.; Saiki, Mitiko; Genezini, Frederico A.; Zahn, Guilherme S., E-mail: ibere@usp.br, E-mail: mitiko@ipen.br, E-mail: fredzini@ipen.br, E-mail: gzahn@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Instrumental Neutron Activation Analysis (INAA) is a technique that provides high precision and accuracy results for the concentration determinations of several elements in different kinds of matrices. However, if the sample contains high uranium concentration in their composition, INAA can provide inaccurate results due to uranium fission product interferences. The molybdenum is one of these elements that suffers interference by uranium fission product, because the {sup 99}Mo radioisotope formed by {sup 98}Mo neutron capture, used in INAA, is the same that formed in the uranium fission. This kind of interference can be solved by separation of uranium before irradiation or by determining the uranium interference factor to the radioisotope of interest and applying the correction. The present study aims at the following: (1) determination of the Mo interference factor (F{sub Exp}{sup Mo}) due to the uranium fission product {sup 99}Mo by irradiating standards of Mo and U with known masses of these elements (experimental interference factor); (2) determination of the theoretical F{sub Th}{sup Mo}, in this case it was necessary to determine the epithermal to thermal neutron flux ratio and use the reported nuclear parameters; (3) comparison of the results of the interference factor obtained with values reported in the literature. The interference factor for Mo analysis was obtained in a position 14b shelf 3 of the IEA-R1 nuclear research reactor. (author)

  2. A prompt gamma neutron activation analysis facility using a diffracted beam

    Science.gov (United States)

    Harling, Otto K.; Chabeuf, Jean-Michel; Lambert, Frédérique; Yasuda, Gopika

    1993-12-01

    A prompt gamma neutron activation analysis facility has been constructed at the MIT Research Reactor using a diffracted beam from a multilayered graphite monochromator. A beam of 0.0143 eV neutrons of intensity 6 × 10 6{n}/{cm 2}s is available at the sample position. Backgrounds are low due to the use of the diffracted beam and are further improved by a sapphire crystal in the beam line. This design allowed the Ge detecting crystal to be placed close to the sample position, 4 cm, with a resultant high detection efficiency. The sensitivity of the facility is reported for several representative pure elements. The major impetus for the construction of this facility was the need for accurate analyses of 10B in biological samples for neutron capture therapy research. Detailed results for this type of analysis are provided. The sensitivity of this diffracted beam facility currently exceeds that of two representative direct beam facilities using reactors of twice the power of the MITR-II. Possible major improvements in sensitivity, more than an order of magnitude, and in background levels are outlined for future development.

  3. SU-E-T-543: Measurement of Neutron Activation From Different High Energy Varian Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Thatcher, T; Madsen, S; Sudowe, R [University of Nevada, Las Vegas, Las Vegas, NV (United States); Meigooni, A Soleimani [University of Nevada, Las Vegas, Las Vegas, NV (United States); Comprehensive Cancer Center of Nevada, Las Vegas, Nevada (United States)

    2015-06-15

    Purpose: Linear accelerators producing photons above 10 MeV may induce photonuclear reactions in high Z components of the accelerator. These liberated neutrons can then activate the structural components of the accelerator and other materials in the beam path through neutron capture reactions. The induced activity within the accelerator may contribute to additional dose to both patients and personnel. This project seeks to determine the total activity and activity per activated isotope following irradiation in different Varian accelerators at energies above 10 MeV. Methods: A Varian 21IX accelerator was used to irradiate a 30 cm × 30 cm × 20 cm solid water phantom with 15 MV x-rays. The phantom was placed at an SSD of 100 cm and at the center of a 20 cm × 20 cm field. Activation induced gamma spectra were acquired over a 5 minute interval after 1 and 15 minutes from completion of the irradiation. All measurements were made using a CANBERRA Falcon 5000 Portable HPGe detector. The majority of measurements were made in scattering geometry with the detector situated at 90° to the incident beam, 30 cm from the side of the phantom and approximately 10 cm from the top. A 5 minute background count was acquired and automatically subtracted from all subsequent measurements. Photon spectra were acquired for both open and MLC fields. Results: Based on spectral signatures, nuclides have been identified and their activities calculated for both open and MLC fields. Preliminary analyses suggest that activities from the activation products in the microcurie range. Conclusion: Activation isotopes have been identified and their relative activities determined. These activities are only gross estimates since efficiencies have not been determined for this source-detector geometry. Current efforts are focused on accurate determination of detector efficiencies using Monte Carlo calculations.

  4. Analysis of medicinal plant extracts by neutron activation method; Analise de extratos de plantas medicinais pelo metodo de ativacao com neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Vaz, Sandra Muntz

    1995-12-31

    This dissertation has presented the results from analysis of medicinal plant extracts using neutron activation method. Instrumental neutron activation analysis was applied to the determination of the elements Al, Br, Ca, Ce, Cl, Cr, Cs, Fe, K, La, Mg, Mn, Na, Rb, Sb, Sc and Zn in medicinal extracts obtained from Achyrolcline satureoides DC, Casearia sylvestris, Centella asiatica, Citrus aurantium L., Solano lycocarpum, Solidago microglossa, Stryphnondedron barbatiman and Zingiber officinale R. plants. The elements Hg and Se were determined using radiochemical separation by means of retention of Se in HMD inorganic exchanger and solvent extraction of Hg by bismuth diethyl-dithiocarbamate solution. Precision and accuracy of the results have been evaluated by analysing reference materials. The therapeutic action of some elements found in plant extracts analyzed was briefly discussed 70 refs., 13 figs., 15 tabs

  5. Development of Monte Carlo code for coincidence prompt gamma-ray neutron activation analysis

    Science.gov (United States)

    Han, Xiaogang

    Prompt Gamma-Ray Neutron Activation Analysis (PGNAA) offers a non-destructive, relatively rapid on-line method for determination of elemental composition of bulk and other samples. However, PGNAA has an inherently large background. These backgrounds are primarily due to the presence of the neutron excitation source. It also includes neutron activation of the detector and the prompt gamma rays from the structure materials of PGNAA devices. These large backgrounds limit the sensitivity and accuracy of PGNAA. Since most of the prompt gamma rays from the same element are emitted in coincidence, a possible approach for further improvement is to change the traditional PGNAA measurement technique and introduce the gamma-gamma coincidence technique. It is well known that the coincidence techniques can eliminate most of the interference backgrounds and improve the signal-to-noise ratio. A new Monte Carlo code, CEARCPG has been developed at CEAR to simulate gamma-gamma coincidence spectra in PGNAA experiment. Compared to the other existing Monte Carlo code CEARPGA I and CEARPGA II, a new algorithm of sampling the prompt gamma rays produced from neutron capture reaction and neutron inelastic scattering reaction, is developed in this work. All the prompt gamma rays are taken into account by using this new algorithm. Before this work, the commonly used method is to interpolate the prompt gamma rays from the pre-calculated gamma-ray table. This technique works fine for the single spectrum. However it limits the capability to simulate the coincidence spectrum. The new algorithm samples the prompt gamma rays from the nucleus excitation scheme. The primary nuclear data library used to sample the prompt gamma rays comes from ENSDF library. Three cases are simulated and the simulated results are benchmarked with experiments. The first case is the prototype for ETI PGNAA application. This case is designed to check the capability of CEARCPG for single spectrum simulation. The second

  6. Neutron activation analysis of medullar and cortical bone tissues from animals; Analise por ativacao com neutrons de tecidos osseos medular e cortical de animais

    Energy Technology Data Exchange (ETDEWEB)

    Takata, Marcelo Kazuo; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Supervisao de Radioquimica

    2000-07-01

    In this work, neutron activation analysis was applied in the determination of the elements Ba, Br, Ca, Cl, Cr, Fe, K, Mg, Mn, Na, P, Rb, Sb, Sc, Sr and Zn present in animal bone tissues. The obtained results indicated a significant difference between the elemental concentrations present in medullar and cortical tissues. The results obtained for bone tissues from distinct animal species were also different. (author)

  7. New thermal neutron prompt {gamma}-ray activation analysis instrument at the National Institute of Standards and Technology Center for Neutron Research

    Energy Technology Data Exchange (ETDEWEB)

    Mackey, E.A. E-mail: lmackey@nist.gov; Anderson, D.L.; Liposky, P.J.; Lindstrom, R.M.; Chen-Mayer, H.; Lamaze, G.P

    2004-11-01

    A new thermal neutron prompt {gamma}-ray activation analysis (PGAA) instrument was designed and built to replace the original PGAA system at the NIST Center for Neutron Research. By placing a sapphire filter in the neutron beam shutter assembly, the fast neutron fluence rate was reduced by a factor of 5 and low-energy (50-200 keV) {gamma}-ray intensities were reduced by factors of 5-10. The thermal neutron fluence rate was reduced by only a factor of 1.13. A new external beam tube, sample chamber, beam stop, and support structure were built and a new detection system installed. The new beam tube is made of two cylindrical aluminum sections lined with a lithiated polymer. Both sections are kept under vacuum to reduce the number of neutrons scattered by air into the beam tube walls. The sample chamber is also fabricated from aluminum and lined with lithiated polymer, and may be evacuated to minimize the number of neutrons scattered and absorbed by air. The beam tube and sample chamber assembly is suspended from the aluminum support structure. The detection system consists of a 40% efficient (relative) germanium detector (resolution 2.0 at 1332.5 keV) and a bismuth germanate Compton suppressor. The detection system is shielded by lead, surrounded by borated and lithiated polyethylene, and placed on a table attached to the support structure. The new, more compact beam stop is welded to the support structure. Capture {gamma}-ray photopeaks from H, B, C, N, Na, Al, Fe, Ge, I and Pb in the background spectrum were either of lower intensity or eliminated with the new PGAA instrument. The more efficient detection system, positioned closer to the sample, yielded element sensitivity increases of 5-50%. Limits of detection have been greatly reduced compared with those of the original instrument due to reduced Compton and scattered {gamma}-ray backgrounds (especially in the low-energy region), increased sensitivities, and reduction of background {gamma}-ray photopeak

  8. The innermost regions of relativistic jets and their magnetic fields in radio-loud Active Galactic Nuclei

    CERN Document Server

    Donnarumma, I; Costamante, L; D'Ammando, F; Giovannini, G; Giommi, P; Giroletti, M; Grandi, P; Jorstad, S G; Marscher, A P; Orienti, M; Pacciani, L; Savolainen, T; Stamerra, A; Tavecchio, F; Torresi, E; Tramacere, A; Turriziani, S; Vercellone, S; Zech, A

    2015-01-01

    This is a White Paper in support of the mission concept of the Large Observatory for X-ray Timing (LOFT), proposed as a medium-sized ESA mission. We discuss the potential of LOFT for the study of radio-loud Active Galactic Nuclei. For a summary, we refer to the paper.

  9. Au Foil Activation Measurement and Simulation of the Concrete Neutron Shielding Ability for the Proposed New SANRAD Facility

    Science.gov (United States)

    Radebe, M. J.; Korochinsky, S.; Strydom, W. J.; De Beer, F. C.

    The purpose of this study was to measure the effective neutron shielding characteristics of the new shielding material designed and manufactured to be used for the construction of the new SANRAD facility at Necsa, South Africa, through Au foil activation as well as MCNP simulations. The shielding capability of the high density shielding material was investigated in the worst case region (the neutron beam axis) of the experimental chamber for two operational modes. The everyday operational mode includes the 15 cm thick poly crystalline Bismuth filter at room temperature (assumed) to filter gamma-rays and some neutron spectrum energies. The second mode, dynamic imaging, will be conducted without the Bi-filter. The objective was achieved through a foil activation measurement at the current SANRAD facility and MCNP calculations. Several Au foilswere imbedded at different thicknesses(two at each position) of shielding material up to 80 cm thick to track the attenuation of the neutron beam over distance within the shielding material. The neutron flux and subsequently the associated dose rates were calculated from the activation levels of the Au foils. The concrete shielding material was found to provide adequate shielding for all energies of neutrons emerging from beam port no-2 of the SAFARI-1 research reactorwithin a thickness of 40 cm of concrete.

  10. Application of neural networks for unfolding neutron spectra measured by means of Bonner spheres and activation foils

    CERN Document Server

    Braga, C C

    2001-01-01

    A neural network structure has been used for unfolding neutron spectra measured by means of a Bonner Sphere Spectrometer set and a foil activation set using several neutron induced reactions. The present work used the SNNS (Stuttgart Neural Network Simulator) as the interface for designing, training and validation of the Multilayer Perceptron network. The back-propagation algorithm was applied. The Bonner Sphere set chosen has been calibrated at the National Physical Laboratory, United Kingdom, and uses gold activation foils as thermal neutron detectors. The neutron energy covered by the response functions goes from 0.0001 eV to 14 MeV. The foil activation set chosen has been irradiated at the IEA-R1 research reactor and measured at the Nuclear Metrology Laboratory of IPEN-CNEN/SP. Two types of neutron spectra were numerically investigated: monoenergetic and continuous The unfolded spectra were compared to a conventional method using code SAND-II as part of the neutron dosimetry system SAIPS. Good results wer...

  11. A Radio-Telemetry System for Navigation and Recording Neuronal Activity in Free-Roaming Rats

    Institute of Scientific and Technical Information of China (English)

    Dian Zhang; Yanling Dong; Megan Li; Houjun Wang

    2012-01-01

    A radio-telemetry recording system is presented which is applied to stimulate specific brain areas and record neuronal activity in a free-roaming rat.The system consists of two major parts:stationary section and mobile section.The stationary section contains a laptop,a Micro Control Unit (MCU),an FM transmitter and a receiver.The mobile section is composed of the headstage and the backpack (which includes the mainboard,FM transmitter,and receiver),which can generate biphasic microcurrent pulses and simultaneously acquire neuronal activity.Prior to performing experiments,electrodes are implanted in the Ventral Posterolateral (VPL) thalamic nucleus,primary motor area (M 1) and Medial Forebrain Bundle (MFB) of the rat.The stationary section modulates commands from the laptop for stimulation and demodulates signals for neuronal activity recording.The backpack is strapped on the back of the rat and executes commands from the stationary section,acquires neuronal activity,and transmits the neuronal activity singles of the waking rat to the stationary section.All components in the proposed system are commercially available and are fabricated from Surface Mount Devices (SMD) in order to reduce the size (25 mm × 15 mm × 2 mm) and weight (10 g with battery).During actual experiments,the backpack,which is powered by a rechargeable Lithium battery (4 g),can generate biphasic microcurrent pulse stimuli and can also record neuronal activity via the FM link with a maximum transmission rate of 1 kbps for more than one hour within a 200 m range in an open field or in a neighboring chamber.The test results show that the system is able to remotely navigate and control the rat without any prior training,and acquire neuronal activity with desirable features such as small size,low power consumption and high precision when compared with a commercial 4-channel bio-signal acquisition and processing system.

  12. Neutron-activation analysis of hot particles from the vicinity of the Chernobyl Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Lyul`, A.Yu.; Kolesov, G.M.; Cherkezyan, V.O. [V.I. Vernadskii Institute of Geochemistry and Analytical Chemistry, Moscow (Russian Federation)

    1994-04-10

    A considerable portion of the radioactive contamination of the surface layers of soil after the accident at the Chernobyl Nuclear Power Plant was caused by hot particles or aggregates with a diameter of several tens microns and a specific activity >n{center_dot}10{sup {minus}11} Ci. They consist of primary particles of the dispersed material of the nuclear fuel and secondary particles formed as a result of the interaction of the fuel and uranium fission products with the structural materials of the reactor and the destroyed active zone. The radionuclide composition of the hot particles characterizes the nuclear fuel used and the temperature conditions in the reactor during the first weeks after the accident and their chemical composition reflects the conditions and processes leading to their formation, which must be known in order; to ascertain the mechanism of the formation of the radioactive emission from the reactor and to evaluate the degree of ecological danger posed by the particles. All this promotes the urgency and importance of studying the radiation-chemical characteristics of such hot particles. Their small sizes and masses impose definite restrictions; on the investigative methods used, which must be highly sensitive and must offer the possibility of performing a nondestructive analysis. One such method is neutron-activation analysis. The purpose of the present investigation was to apply instrumental neutron-activation analysis to the simultaneous determination of the elemental composition of hot particles and establishment of the isotopic composition of the uranium in them.

  13. Magnetic Neutral Line-Associated Radio Sources and Evolution of the Active Region NOAA 7321

    Science.gov (United States)

    Uralov, A. M.; Nakajima, H.; Zandanov, V. G.; Grechnev, V. V.

    1999-12-01

    We report evolution of the active region NOAA~7321 in which radio sources associated with magnetic neutral lines (so-called Neutral Line Associated Source, NLS) were studied on the basis of data of Nobeyama Radioheliograph. We provide physical interpretation of the NLS in terms of topological magnetic reconnection model and discuss their relation to evolution of the active region. Two kinds of the NLS were observed at 17~GHz, i.e. rising and stationary sources. Their presence was associated with substantial expansion of the active region's magnetosphere and accompanied by gradual evolution of spine-like structures visible in soft X-rays before long-duration flares. We suggest that the rising 17~GHz source corresponded to a ``horizontal'' current sheet moving upward which was not bright in soft X-rays. Bright X-ray spine was a boundary of that current sheet. Formation of X-points are believed to be responsible for the presence of low-lying stationary sources arranged along the photospheric neutral line.

  14. L'analyse par activation de neutrons de réacteur

    Science.gov (United States)

    Meyer, G.

    2003-02-01

    Quand les neutrons traversent la matière, certains sont transmis sans interaction, les autres interagissent avec le milieu traversé par diffusion et par absorption. Ce phénomène d'absorption est utilisé pour se protéger des neutrons, mais aussi pour les détecter; il peut également être utilisé pour identifier les noyaux “absorbants" et ainsi analyser le milieu traversé. En effet par différentes réactions nucléaires (n,γ), (n,p), (n,α), (n,fission), on obtient des noyaux résiduels qui sont souvent radioactifs; on dit que l'échantillon est “activé". Si l'on connaît le rendement d'activation et donc le pourcentage de noyaux ainsi “transmutés", les mesures de radioactivité induite vont permettre de déterminer la composition de l'échantillon irradié. Cette méthode dite d'analyse par activation neutronique est pratiquée depuis la découverte du neutron. Elle a permis grâce à sa sélectivité et à sa sensibilité d'avoir accès au domaine des traces et des ultra-traces dans des champs d'application très divers comme la métallurgie, l'archéologie, la biologie, la géochimie etc...

  15. Instrumental neutron activities analysis of Marrubium vulgare L., a valuable medicinal herb

    Energy Technology Data Exchange (ETDEWEB)

    Nedjimi, Bouzid [Djelfa Univ. (Algeria). Lab. of Exploration and Valorization of Steppe Ecosystem; Beladel, Brahim [Djelfa Univ. (Algeria). Dept. of Physics

    2016-08-01

    Twenty two chemical elements were identified by Instrumental neutron activation analysis in Marrubium vulgare (Lamiaceae) a traditional medicine plant, used indigenously in Mediterranean basin to cure several diseases. The precision of the results was assessed by analyzing the certified reference material GBW 07605 (GSV-4) Tea leaves. Results showed that K was the dominant chemical element in studied plant (4.40%). The Ca and Fe mass fractions were also relatively high. However potential toxic elements in this Lamiaceae plant were within the safety limits suggested by WHO/FAO.

  16. Neutron activation analysis of low-level element contents in silicon wafers

    Energy Technology Data Exchange (ETDEWEB)

    Goerner, W. [Bundesanstalt fuer Materialforschung und -pruefung, Berlin (Germany); Berger, A. [Bundesanstalt fuer Materialforschung und -pruefung, Berlin (Germany); Niese, S. [Verein fuer Kernverfahrenstechnik und Analytik Rossendorf e.V. (VKTA), Dresden (Germany); Koehler, M. [Verein fuer Kernverfahrenstechnik und Analytik Rossendorf e.V. (VKTA), Dresden (Germany); Matthes, M. [Verein fuer Kernverfahrenstechnik und Analytik Rossendorf e.V. (VKTA), Dresden (Germany); Gawlik, D. [Hahn-Meitner-Institut, Berlin (Germany)

    1997-03-01

    Semiconductor silicon is among the purest materials having ever been produced by modern technology. Thus, it is quite suitable as a primary reference material validating the correctness and the detection capabilities of developed analytical methods. Among them neutron activation analysis plays a competitive role. The U.S. National Institute of Science and Technology (NIST) has initiated and carried out an interlaboratory comparison in order to study the spread of analytical results worldwide evolved by several laboratories dealing with specimens of extreme purity. The outcome of the experiment was intended to review the capabilities of NAA as well as to differentiate between bulk and surface contamination. (orig./DG)

  17. Neutron activation analysis of chemical impurities in manipulated samples of omeprazole

    Energy Technology Data Exchange (ETDEWEB)

    Sepe, Fernanda Peixoto; Leal, Alexandre Soares; Gomes, Tatiana Cristina Bomfim; Menezes, Maria Angela de Barros Correia; Silva, Maria Aparecida, E-mail: asleal@cdtn.br [Nuclear Technology Development Centre/Brazilian Commission for Nuclear Energy (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    In this work, samples of Omeprazole (C{sub 17}H{sub 19}N{sub 3}O{sub 3}S), a largely used drug in the treatment of dyspepsia and peptic ulcer, were acquired from five different pharmacies of manipulation - or retail pharmacies which prepare personalized drugs under medical recommendation - in Belo Horizonte/Brazil and investigated using the k{sub 0} - Neutron Activation Analysis (NAA). The preliminary results showed the presence of elements not foreseen in the original formula. It confirms the potential risk offered by medicines without suitable inspection. (author)

  18. Optimal design of measurement network for neutronic activity field reconstruction by data assimilation

    Energy Technology Data Exchange (ETDEWEB)

    Bouriquet, Bertrand, E-mail: bertrand.bouriquet@cerfacs.fr [Sciences de l' Univers au CERFACS, URA CERFACS/CNRS No 1875, 42 avenue Gaspard Coriolis, F-31057 Toulouse Cedex 01 (France); Argaud, Jean-Philippe; Cugnart, Romain [Electricite de France, 1 avenue du General de Gaulle, F-92141 Clamart Cedex (France)

    2012-02-01

    An optimal reconstruction of the neutronic activity field can be determined for a nuclear reactor core using a data assimilation framework to merge information from models and measurements. In this paper, we focus on solving the inverse problem of determining an optimal repartition of the measuring instruments within the core, to get the best possible results from the data assimilation reconstruction procedure. The position optimisation is realised using a Simulated Annealing algorithm, based on the Metropolis-Hastings proposition. Moreover, algebraic improvements of data assimilation have been developed, optimising their computational performance, and are presented here.

  19. Elemental analysis of soil and hair sample by instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Yong Sam; Quraishi, Shamshad Begum; Moon, Jong Hwa; Kim, Sun Ha; Baek, Sung Yeoil; Kang, Sang Hoon; Lim, Jong Myoung; Cho, Hyun Je; Kim, Young Jin

    2004-03-01

    Myanmar soil sample was analyzed by using the instrumental neutron activation analysis. The elemental concentrations in the sample, altogether 34 elements, Al As, Ba, Ce, Co, Cr, Cs, Eu, Fe, Ga, Gd, Hf, Ir, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Se, Sm, Th, Ti, V, Yb, Zn and Zr were determined. The concentration of 17 elements (Al, Au, Br, Ca, Cl, Cr, Cu, Co, Fe, Hg, K, Na, Mn, Mg, Sb, Se, Zn) in human hair samples were determined by INAA For quality control of analytical method, certified reference material was used.

  20. Quantitative radiological characterization of waste. Integration of gamma spectrometry and passive/active neutron assay

    Energy Technology Data Exchange (ETDEWEB)

    Simone, Gianluca; Mauro, Egidio; Gagliardi, Filippo; Gorello, Edoardo [Nucleco S.p.A., Rome (Italy)

    2016-06-15

    The radiological characterization of drums through Non-Destructive Assay (NDA) techniques commonly relies on gamma spectrometry. This paper introduces the procedure developed in Nucleco for the NDA radiological characterization of drums when the presence of Special Nuclear Material (SNM) is expected/observed. The procedure is based on the integration of a gamma spectrometry in SGS mode (Segmented Gamma Scanner) and a passive/active neutron assay. The application of this procedure is discussed on a real case of drums. The extension of the integration procedure to other gamma spectrometry systems is also discussed.

  1. Chemical characterization of tin-lead glazed ceramics from Aragon (Spain) by neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Inanez, J.G. [Smithsonian Institution, Suitland, MD (United States). Museum Conservation Inst.; Barcelona Univ. (Spain). Facultat de Geografia i Historia; Speakman, R.J. [Smithsonian Institution, Suitland, MD (United States). Museum Conservation Inst.; Buxeda i Garrigos, J. [Barcelona Univ. (Spain). Facultat de Geografia i Historia; Glascock, M.D. [Missouri Univ., Columbia, MO (United States). Research Reactor Center

    2010-07-01

    Majolica pottery was the most characteristic tableware produced in Spain during the Medieval and Renaissance periods. A study of the three main production centers in the historical region of Aragon during Middle Ages and Renaissance was conducted on a set of 71 samples. The samples were analyzed by instrumental neutron activation analysis (INAA), and the resulting data were interpreted using an array of multivariate statistical procedures. Our results show a clear discrimination among different production centers allowing a reliable provenance attribution of ceramic sherds from the Aragonese workshops. (orig.)

  2. Multi-element determination in medicinal Juniper tree (Juniperus phoenicea by instrumental neutron activation analysis

    Directory of Open Access Journals (Sweden)

    Bouzid Nedjimi

    2015-04-01

    Full Text Available Red Juniper (Juniperus phoenicea, a local medicinal tree was collected and analyzed for 18 essential, non-essential and toxic elements using instrumental neutron activation analysis (INAA. The GBW 07605 (GSV-4 standard reference material was analyzed simultaneously with the plant samples, the results shown a good recovery and reproducibility of the method. Ca, K and Fe have been detected in good levels in this plant clarifying their possible contribution to curative properties. The data obtained in the present work will be helpful in the synthesis of new synthetic drugs which can be used for medicinal purpose.

  3. Concentration of 17 Elements in Subcellular Fractions of Beef Heart Tissue Determined by Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wester, P.O.

    1964-12-15

    Subcellular fractions of beef heart tissue are investigated, by means of neutron activation analysis, with respect to their concentration of 17 different elements. A recently developed ion-exchange technique combined with gamma spectrometry is used. The homogeneity of the subcellular fractions is examined electron microscopically. The following elements are determined: As, Ba, Br, Cas Co, Cs, Cu, Fe, Hg, La, Mo, P, Rb, Se, Sm, W and Zn. The determination of Ag, Au, Cd, Ce, Cr, Sb and Sc is omitted, in view of contamination. Reproducible and characteristic patterns of distribution are obtained for all elements studied.

  4. Performance of neutron activation analysis in the evaluation of bismuth iodide purification methodology

    Energy Technology Data Exchange (ETDEWEB)

    Armelin, Maria Jose A.; Ferraz, Caue de Mello; Hamada, Margarida M., E-mail: marmelin@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Lab. de Analise por Ativacao Neutronica

    2015-07-01

    Bismuth tri-iodide (BrI{sub 3}) is an attractive material for using as a semiconductor. In this paper, BiI{sub 3} crystals have been grown by the vertical Bridgman technique using commercially available powder. The impurities were evaluated by instrumental neutron activation analysis (INAA). The results show that INAA is an analytical method appropriate for monitoring the impurities of: Ag, As, Br, Cr, K, Mo, Na and Sb in the various stages of the BiI{sub 3} purification methodology. (author)

  5. Integral test on activation cross section of tag gas nuclides using fast neutron spectrum fields

    Energy Technology Data Exchange (ETDEWEB)

    Aoyama, Takafumi; Suzuki, Soju [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center

    1997-03-01

    Activation cross sections of tag gas nuclides, which will be used for the failed fuel detection and location in FBR plants, were evaluated by the irradiation tests in the fast neutron spectrum fields in JOYO and YAYOI. The comparison of their measured radioactivities and the calculated values using the JENDL-3.2 cross section set showed that the C/E values ranged from 0.8 to 2.8 for the calibration tests in YAYOI and that the present accuracies of these cross sections were confirmed. (author)

  6. Neutron capture cross-section of fission products in the European activation file EAF-3

    Energy Technology Data Exchange (ETDEWEB)

    Kopecky, J.; Delfini, M.G.; Kamp, H.A.J. van der; Gruppelaar, H.; Nierop, D. (Netherlands Energy Research Foundation (ECN), Petten (Netherlands))

    1992-05-01

    This paper contains a description of the work performed to extend and revise the neutron capture data in the European Activation File (EAF-3) with emphasis on nuclides in the fission-product mass range. The starter was the EAF-1 data file from 1989. The present version, EAF/NG-3, contains (n,[gamma]) excitation functions for all nuclides (729 targets) with half-lives exceeding 1/2 day in the mass range from H-1 to Cm-248. The data file is equipped with a preliminary uncertainty file, that will be improved in the near future. (author). 19 refs.; 5 figs.; 3 tabs.

  7. Neutron activation analysis and Mossbauer spectroscopy research on coloring mechanism of Chinese Ru porcelain

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The characteristic spectrum and its main wavelength of Ru porcelain glaze are measured by color difference instrument to determine the relations between glaze color and its main wavelength. The content of the 30 coloring elements in Ru porcelain is determined by neutron activation analysis (NAA), which showed that iron is the major coloring element. M?ssbauer spectroscopy analysis shows that the iron element in the glaze exists in the form of structural iron (Fe2+, Fe3+). The quantitative relationship between the main wavelength of glaze in various colors and the relative content of structural iron (Fe2+/Fe3+) is determined. Thus the coloring mechanism of Ru porcelain is investigated entirely.

  8. The optical counterpart of sax j1808.4{3658 in quiescence: evidence of an active radio pulsar?

    Directory of Open Access Journals (Sweden)

    L. Burderi

    2004-01-01

    Full Text Available La contraparte optica del pulsar binario SAX J1808.4-3658 que emite en rayos X con un per odo de milisegundos, ha sido detectada durante su estapa de quietud a V = 21.5 mag; lo cual es inconsistente con la d ebil emisi on de la estrella compa~nera. Proponemos que la emisi on en el optico de este sistema durante su etapa de quietud es debida a la irradiaci on de la estrella compa~nera y a un disco de acreci on permanente provocado por la energ a rotacional producida por el r apido giro de la estrella de neutrones que act ua como un dipolo magn etico rotante (radio pulsar. En este escenario, la compa~nera se comporta como un bol ometro, reprocesando en el optico parte de la potencia emitida por el pulsar. La fracci on reprocesada depende s olo de par ametros conocidos del sistema binario; la temperatura de cuerpo negro asociada a la estrella compa~nera puede predecirse y rati carse con observaciones. Nuestros c alculos indican que las magnitudes opticas observadas son totalmente compatibles con esta hip otesis. En el caso de que esto sea as , la luminosidad observada en el optico puede ser la primera evidencia de que hay un radio pulsar activo en este sistema en quietud.

  9. The 12B counter: an active dosemeter for high-energy neutrons.

    Science.gov (United States)

    Leuschner, A

    2005-01-01

    High-energy accelerators can produce strong time-structured radiation fields. Such dose shots are generated at linear machines with low duty cycles as well as at circular machines when complete fills are instantaneously lost. The main dose component behind thick shielding is due to high-energy neutrons occurring at that time structure. Dosemeters based on Geiger-Mueller tubes or proportional counters fail here completely. The 12B counter, a novel dosemeter made of a plastic scintillator using carbon activation for event-like exposure, has been introduced. High-energy neutrons activate the carbon nuclei by three inelastic reactions. The decay patterns with half-lives between 20 ms and 20 min can be exploited depending on the time structure of the radiation field. The response of the 12B counter was measured along with some other dosemeters, both active and passive, in the radiation field behind the lateral concrete shielding of a 7.5 GeV proton transfer line.

  10. Experimental determination of detection limits for performing neutron activation analysis for gold in the field

    Energy Technology Data Exchange (ETDEWEB)

    Jarzemba, M.S.; Weldy, J.; Pearcy, E.; Prikryl, J.; Pickett, D.

    1999-11-01

    Measurements are presented of gold concentration in rock/soil samples by delayed neutron activation analysis using a device and method that are potentially field portable. The device consists of a polyethylene moderator and {sup 252}Cf as the source of neutrons for activating the samples and a high-purity germanium detector to measure the 412-keV gamma-ray emissions from activated gold. This information is used to extract the gold concentration in the sample. Two types of samples were investigated: (1) pure SiO{sub 2} doped with a known amount of gold chloride and (2) US Geological Survey standards. The former types were used to evaluate optimum device performance and to calibrate the device and method. The latter types were used to show typical system performance for the intended application (field exploration for gold deposits). It was found that the device was capable of determining gold concentrations to {approximately}10 ppb with a turnaround time (the sum of irradiation, decay, and counting times) of {approximately}10 days. For samples where the gold concentration was much higher (i.e., gold ore), turnaround times are {approximately}2 days and could be shortened further by sacrificing accuracy (e.g., lessening irradiation, decay, and counting times) or by augmenting source strength.

  11. Development of Pneumatic Transfer Irradiation Facility (PTS no.2) for Neutron Activation Analysis at HANARO Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-03-15

    A pneumatic transfer irradiation system (PTS) is one of the most important facilities used during neutron irradiation of a target material for instrumental neutron activation analysis (INAA) in a research reactor. In particular, a fast pneumatic transfer system is essential for the measurement of a short half-life nuclide and a delayed neutron counting system. The pneumatic transfer irradiation system (PTS no.2) involving a manual system and an automatic system for delayed neutron activation analysis (DNAA) were reconstructed with new designs of a functional improvement at the HANARO research reactor in 2006. In this technical report, the conception, design, operation and control of PTS no.2 was described. Also the experimental results and the characteristic parameters measured by a mock-up test, a functional operation test and an irradiation test of these systems, such as the transfer time of irradiation capsule, automatic operation control by personal computer, delayed neutron counting system, the different neutron flux, the temperature of the irradiation position with an irradiation time, the radiation dose rate when the rabbit is returned, etc. are reported to provide a user information as well as a reactor's management and safety.

  12. Thiamethoxam: Assessing flight activity of honeybees foraging on treated oilseed rape using radio frequency identification technology.

    Science.gov (United States)

    Thompson, Helen; Coulson, Mike; Ruddle, Natalie; Wilkins, Selwyn; Harkin, Sarah

    2016-02-01

    The present study was designed to assess homing behavior of bees foraging on winter oilseed rape grown from seed treated with thiamethoxam (as Cruiser OSR), with 1 field drilled with thiamethoxam-treated seed and 2 control fields drilled with fungicide-only-treated seed. Twelve honeybee colonies were used per treatment group, 4 each located at the field edge (on-field site), at approximately 500 m and 1000 m from the field. A total of nearly 300 newly emerged bees per colony were fitted (tagged) with Mic3 radio frequency identification (RFID) transponders and introduced into each of the 36 study hives. The RFID readers fitted to the entrances of the test colonies were used to monitor the activity of the tagged bees for the duration of the 5-wk flowering period of the crop. These activity data were analyzed to assess any impact on flight activity of bees foraging on the treated compared with untreated crops. Honeybees were seen to be actively foraging within all 3 treatment groups during the exposure period. The data for the more than 3000 RFID-tagged bees and more than 90 000 foraging flights monitored throughout the exposure phase for the study follow the same trends across the treatment and controls and at each of the 3 apiary distances, indicating that there were no effects from foraging on the treated crop. Under the experimental conditions, there was no effect of foraging on thiamethoxam-treated oilseed rape on honeybee flight activity or on their ability to return to the hive. © 2015 SETAC.

  13. Application and facility of neutron activation analysis in HANARO research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Y.S. [Korea Atomic Energy Research Institute, Taejon (Korea)

    2001-11-01

    The facilities for neutron activation analysis in the HANARO research reactor are described and the main applications of NAA in Korea are reviewed. The sample irradiation tube, automatic and manual pneumatic transfer system, were installed at three irradiation holes at the end of 1995. One irradiation hole is lined with a cadmium tube for epithermal NAA. The performance of the NAA facility was examined to identify the characteristics of tube transfer system, irradiation sites and custom made polythylene irradiation capsule. The available thermal neutron flux with each irradiation site are in the range of 3 x 10{sup 13} {approx} 1 x 10{sup 14} n/cm{sup 2}{center_dot}s and cadmium ratios are 15 {approx} 250. For an automatic sample changer for gamma-ray counting, a domestic product was designed and manufactured. An integrated computer program (Labview) for the calculation of content was developed. Neutron activation analysis has been applied in the trace component analysis of nuclear, geological, biological, environmental and high purity materials and various polymers for research and development. Improvement of analytical procedures and establishment of an analytical quality control and assurance system were studied. Applied research and development for the environment, industry and human health by NAA and its standardization was carried out. For the application of the Korea Laboratory Accreditation Scheme (KOLAS), evaluation of measurement uncertainty and proficiency testing of reference materials was performed. Also to verify the reliability and validity of analytical results, intercomparison studies between laboratories were carried out. In this paper, analytical services, national cooperation and the results of the researches are summarized. (author)

  14. Improved detectability in medical microwave radio-thermometers as obtained by active antennas.

    Science.gov (United States)

    Jacobsen, Svein; Klemetsen, Øystein

    2008-12-01

    Microwave radiometry is a spectral measurement technique for resolving blackbody radiation of heated matter above absolute zero. The emission levels vary with frequency and are at body temperatures maximized in the infrared spectral band. Medical radio-thermometers are mostly noninvasive short-range instruments that can provide temperature distributions in subcutaneous biological tissues when operated in the microwave region. However, a crucial limitation of the microwave radiometric observation principle is the extremely weak signal level of the thermal noise emitted by the lossy material (-174 dBm/Hz at normal body temperature). To improve the radiometer SNR, we propose to integrate a tiny, moderate gain, low-noise preamplifier (LNA) close to the antenna terminals as to obtain increased detectability of deep seated thermal gradients within the volume under investigation. The concept is verified experimentally in a lossy phantom medium by scanning an active antenna across a thermostatically controlled water phantom with a hot object embedded at 38 mm depth. Three different setups were investigated with decreasing temperature contrasts between the target and ambient medium. As a direct consequence of less ripple on the raw radiometric signal, statistical analysis shows a marked increase in signal-to-clutter ratio of the brightness temperature spatial scan profiles, when comparing active antenna operation with conventional passive setups.

  15. Neutron flux measurements at the TRIGA reactor in Vienna for the prediction of the activation of the biological shield

    Energy Technology Data Exchange (ETDEWEB)

    Merz, Stefan [Vienna University of Technology, Atominstitut, Stadionallee 2, 1020 Vienna (Austria); Djuricic, Mile [Vienna University of Technology, Atominstitut, Stadionallee 2, 1020 Vienna (Austria); Nuclear Engineering Seibersdorf, 2444 Seibersdorf (Austria); Villa, Mario; Boeck, Helmuth [Vienna University of Technology, Atominstitut, Stadionallee 2, 1020 Vienna (Austria); Steinhauser, Georg, E-mail: georg.steinhauser@ati.ac.at [Vienna University of Technology, Atominstitut, Stadionallee 2, 1020 Vienna (Austria)

    2011-11-15

    The activation of the biological shield is an important process for waste management considerations of nuclear facilities. The final activity can be estimated by modeling using the neutron flux density rather than the radiometric approach of activity measurements. Measurement series at the TRIGA reactor Vienna reveal that the flux density next to the biological shield is in the order of 10{sup 9} cm{sup -2} s{sup -1} at maximum power; but it is strongly influenced by reactor installations. The data allow the estimation of the final waste categorization of the concrete according to the Austrian legislation. - Highlights: > Neutron activation is an important process for the waste management of nuclear facilities. > Biological shield of the TRIGA reactor Vienna has been topic of investigation. > Flux values allow a categorization of the concrete concerning radiation protection legislation. > Reactor installations are of great importance as neutron sources into the biological shield. > Every installation shows distinguishable flux profiles.

  16. The link between accretion mode and environment in radio-loud active galaxies

    CERN Document Server

    Ineson, Judith; Hardcastle, Martin J; Kraft, Ralph P; Evans, Daniel A; Jarvis, Matt J

    2015-01-01

    The interactions between radio-loud AGN and their environments play an important r\\^{o}le in galaxy and cluster evolution. Recent work has demonstrated fundamental differences between High and Low Excitation Radio Galaxies (HERGs and LERGs), and shown that they may have different relationships with their environments. In the Chandra Large Project ERA (Environments of Radio-loud AGN), we made the first systematic X-ray environmental study of the cluster environments of radio galaxies at a single epoch (z~0.5), and found tentative evidence for a correlation between radio luminosity and cluster X-ray luminosity. We also found that this relationship appeared to be driven by the LERG sub-population (Ineson et al. 2013). We have now repeated the analysis with a low redshift sample (z~0.1), and found strong correlations between radio luminosity and environment richness and between radio luminosity and central density for the LERGs but not for the HERGs. These results are consistent with models in which the HERGs are...

  17. Summary report for ITER task - D10: Update and implementation of neutron transport and activation codes and processed libraries

    Energy Technology Data Exchange (ETDEWEB)

    Attaya, H.

    1995-01-01

    The primary goal of this task is to provide the capabilities in the activation code RACC, to treat pulsed operation modes. In addition, it is required that the code utilizes the same spatial mesh and geometrical models as employed in the one or multidimensional neutron transport codes used in ITER design. This would ensure the use of the same neutron flux generated by those codes to calculate the different activation parameters. It is also required to have the capabilities for generating graphical outputs for the calculated activation parameters.

  18. A multi-wavelength study of nuclear activity and environment of a low power radio galaxy CTD 86

    CERN Document Server

    Pandge, M B; Singh, K P; Patil, M K

    2012-01-01

    We present multiwavelength X-ray, optical and radio study of the Fanaroff & Riley class I radio galaxy CTD 86 based on \\xmm{}, \\rosat{}, Sloan Digital Sky Survey (SDSS), Vainu Bappu Telescope (VBT) observations and the Faint Images of the Radio Sky at Twenty centimeters (FIRST) survey. X-ray emission from CTD 86 originates from two components - diffuse thermal emission from hot gas ($kT\\sim 0.9\\kev$, $n_e\\sim 10^{-3}{\\rm cm^{-3}}$, $L_X \\sim 5\\times10^{42}{\\rm ergs s^{-1}}$ and size $\\sim 186{\\rm kpc}$), and a central point source representing the active nucleus. The hot gaseous environment of CTD 86 is similar to those found in galaxy groups or bright early-type galaxies. We found no clear signature of radio-lobes interacting with the diffuse hot gas. X-ray emission from the active nucleus is well described by an intrinsically absorbed ($N_H \\sim 5.9\\times10^{22}{\\rm cm^{-2}}$) power law ($\\Gamma \\sim 1.5$) with a $2-10\\kev$ luminosity $L_X \\sim 2.1\\times10^{42}{\\rm ergs s^{-1}}$. CTD 86 has a weak optic...

  19. Spectral Index Studies of the Diffuse Radio Emission in Abell 2256: Implications to Merger Activity

    CERN Document Server

    Ruta, Kale

    2010-01-01

    We present a multi-wavelength analysis of the merging rich cluster of galaxies Abell 2256. We have observed A2256 at 150 MHz using the Giant Metrewave Radio Telescope and successfully detected the diffuse radio halo and the relic emission over an extent $\\sim1.2$ Mpc$^2$. Using this 150 MHz image and the images made using archival observations from the VLA (1369 MHz) and the WSRT (350 MHz), we have produced spectral index images of the diffuse radio emission in A2256. These spectral index images show a distribution of flat spectral index (S$\\propto\

  20. In vivo neutron activation analysis: body composition studies in health and disease

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, K.J.; Cohn, S.H.

    1984-01-01

    In vivo analysis of body elements by neutron activation is an important tool in medical research. It has provided a direct quantitative measure of body composition of human beings in vivo. Basic physiological differences related to age, sex, race, and body size have been assessed by this noninvasive technique. The diagnosis and management of patients with various metabolic disorders and diseases has also been demonstrated. Two major facilities at Brookhaven are being utilized exclusively for in vivo neutron activation analysis (IVNAA) of calcium, phosphorus, sodium, chlorine, nitrogen, hydrogen, and potassium. These elements serve as the basis for a four compartment model of body composition: protein, water, mineral ash, and fat. Variations in these compartments are demonstrated in clinical research programs investigating obesity, anorexia, cancer, renal failure, osteoporosis, and normal aging. IVNAA continues to provide a unique approach to the evaluation of clinical diagnosis, efficacy of therapeutic regimens, and monitoring of the aging process. Classical balance studies usually require the patient to be admitted to a hospital for extended periods of confinement. IVNAA, however, allows for clinical management of the patient on an out-patient basis, an important aspect for treatment of chronic diseases. 25 references, 3 figures, 5 tables.

  1. Improvement of analytical capabilities of neutron activation analysis laboratory at the Colombian Geological Survey

    Science.gov (United States)

    Parrado, G.; Cañón, Y.; Peña, M.; Sierra, O.; Porras, A.; Alonso, D.; Herrera, D. C.; Orozco, J.

    2016-07-01

    The Neutron Activation Analysis (NAA) laboratory at the Colombian Geological Survey has developed a technique for multi-elemental analysis of soil and plant matrices, based on Instrumental Neutron Activation Analysis (INAA) using the comparator method. In order to evaluate the analytical capabilities of the technique, the laboratory has been participating in inter-comparison tests organized by Wepal (Wageningen Evaluating Programs for Analytical Laboratories). In this work, the experimental procedure and results for the multi-elemental analysis of four soil and four plant samples during participation in the first round on 2015 of Wepal proficiency test are presented. Only elements with radioactive isotopes with medium and long half-lives have been evaluated, 15 elements for soils (As, Ce, Co, Cr, Cs, Fe, K, La, Na, Rb, Sb, Sc, Th, U and Zn) and 7 elements for plants (Br, Co, Cr, Fe, K, Na and Zn). The performance assessment by Wepal based on Z-score distributions showed that most results obtained |Z-scores| ≤ 3.

  2. Preparation of palladium impregnated alumina adsorbents: Thermal and neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, Sumanta; Gupta, N.K.; Roy, S.P.; Dash, S.; Kumar, A.; Bamankar, Y.R.; Rao, T.V. Vittal [Product Development Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kumar, N. [Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Naik, Y., E-mail: ynaik@barc.gov.in [Product Development Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2016-02-10

    Highlights: • Pd/Al{sub 2}O{sub 3} composite microspheres particles with high surface area were prepared sol–gel process. • Scanning electron microscopy (SEM) studies on silver coated particle. • Content of the palladium was determined using Neutron Activation Analysis (NAA). • Decomposition study has been done by quadrupole mass analyser. - Abstract: Pd/Al{sub 2}O{sub 3} composite microspheres particles with high surface area were prepared sol–gel process. The decomposition of dried gel-particles was studied by TGA/DTA and FT-IR technique. TGA studies indicated that formation of palladium is marked by a broad exothermic peak with a loss of water and oxidation of trapped HMTA/Urea nitrate mixture. The main decomposition reaction took place in the temperature range of 660–1250 K in helium and relatively lower temperature of 400 K to 1250 K in oxygen. Optical microscopy indicated that the distribution of palladium is uniform. SEM studies on silver coated particle indicated that there was surface erosion of some gel spheres while in few of them micro cracks were seen at high resolution. Content of the palladium was determined using Neutron Activation Analysis (NAA). Decomposition at various temperatures was studied using Residual gas analyser and decomposition species were identified using quadrupole mass analyser.

  3. Determination of uranium and thorium by neutron activation analysis applied to fossil samples dating

    Energy Technology Data Exchange (ETDEWEB)

    Ticianelli, Regina B.; Figueiredo, Ana Maria Graciano; Zahn, Guilherme S. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Kinoshita, Angela; Baffa, Oswaldo [Universidade de Sao Paulo (FFCRLP/USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto. Dept. de Fisica

    2011-07-01

    Electron Spin Resonance (ESR) dating is based on the fact that ionizing radiation can create stable free radicals in insulating materials, like tooth enamel and bones. The concentration of these radicals - determined by ESR - is a function of the dose deposed in the sample along the years. The accumulated dose of radiation, called Archaeological Dose, is produced by the exposition to environmental radiation provided by U, Th, K and cosmic rays. If the environmental dose rate in the site where the fossil sample is found is known, it is possible to convert this dose into the age of the sample. The annual dose rate coming from the radioactive elements present in the soil and in the sample itself can be calculated by determining the U, Th and K concentration. Therefore, the determination of the dose rate depends on the concentration of these main radioactive elements. Neutron Activation Analysis has the sensitivity and the accuracy necessary to determine U, Th and K with this objective. Depending on the composition of the sample, the determination of U and Th can be improved irradiating the sample inside a Cd capsule, reducing the thermal neutron incidence on the sample and, therefore, diminishing the activation of possible interfering nuclides. In this study the optimal irradiation and counting conditions were established for U and Th determination in fossil teeth and soil. (author)

  4. Radiography of Spanish Radio

    Directory of Open Access Journals (Sweden)

    Dra. Emma Rodero Antón

    2007-01-01

    Full Text Available In its eighty years of existence, radio has been always characterized to adapt to the social, cultural and technological transformations. Thus it has been until this moment. Nevertheless, some years ago, the authors and professionals of this medium have been detecting a stagnation that affects to its structure. At a time in continuous technological evolution, radio demands a deep transformation. For that reason, from the conviction of which the future radio, public and commercial, will necessarily have to renew itself, in this paper we establish ten problems and their possible solutions to the radio crisis in order to draw an x-ray of radio in Spain. Radio has future, but it is necessary to work actively by it. That the radio continues being part of sound of our life, it will depend on the work of all: companies, advertisers, professionals, students, investigators and listeners.

  5. Neutron activation analysis at the Livermore pool-type reactor for the environmental research program. [Identification of trace element contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Ragaini, R.C.; Heft, R.E.; Garvis, D.

    1976-07-02

    Instrumental neutron activation analysis is a technique of trace analysis using measurements of radioactivity induced in the sample by exposure to a source of neutrons. The induced activity is measured by the emitted gamma radiation. Each gamma emitter can then be identified by the energy of the photopeaks produced as the nuclide decays and by the half-life of the neutron-induced activity. A complex computer program GAMANAL has been used to accomplish the major tasks of nuclide identification and quantification. The nuclide data output from GAMANAL is processed by a second computer code NADAC, which develops elemental abundance data from disintegration rates observed. The methods are those employed at the Livermore Pool-Type Reactor in support of the environmental research trace element analysis program. Among the procedures described and discussed are sample preparation, irradiation, analysis, and application of the technique.

  6. Monte-Carlo Simulations of Radiation-Induced Activation in a Fast-Neutron and Gamma- Based Cargo Inspection System

    CERN Document Server

    Bromberger, B; Brandis, M; Dangendorf, V; Goldberg, M B; Kaufmann, F; Mor, I; Nolte, R; Schmiedel, M; Tittelmeier, K; Vartsky, D; Wershofen, H

    2012-01-01

    An air cargo inspection system combining two nuclear reaction based techniques, namely Fast-Neutron Resonance Radiography and Dual-Discrete-Energy Gamma Radiography is currently being developed. This system is expected to allow detection of standard and improvised explosives as well as special nuclear materials. An important aspect for the applicability of nuclear techniques in an airport inspection facility is the inventory and lifetimes of radioactive isotopes produced by the neutron and gamma radiation inside the cargo, as well as the dose delivered by these isotopes to people in contact with the cargo during and following the interrogation procedure. Using MCNPX and CINDER90 we have calculated the activation levels for several typical inspection scenarios. One example is the activation of various metal samples embedded in a cotton-filled container. To validate the simulation results, a benchmark experiment was performed, in which metal samples were activated by fast-neutrons in a water-filled glass jar. T...

  7. Neutron, gamma and Roentgen fluorescent activation analysis of hair of children suffering from bronchial asthma

    Energy Technology Data Exchange (ETDEWEB)

    Alekseeva, O.A.; Belov, A.G.; Frontasyeva, M.V.; Gundorina, S.F.; Gustova, M.V.; Kusmenko, L.G.; Perelygin, V.P. E-mail: pergam@cv.jinr.ru; Zaverioukha, O.S

    2001-06-01

    The aim of present study was the multiparametric study of dangerous microelements content in the hair of children under school and primary school age which included 12 children ill with bronchial asthma and 11 control group persons in the town of Troitsk, Moscow Region. The hair specimens with weight 15-220 mg were analysed with the application of epithermal neutron activation analysis conducted at experimental installation REGATA and neutron source-unique Pulsed Fast Reactor IBR-2, with the application of combined gamma-neutron irradiation at Microtron MT-25 and with Roentgen Fluorescence Analysis device of JINR. The data of elements content in hair were obtained with solid state track detectors and semiconductor electronic spectrometers. The solid state track detectors provide the determination of U, Th, Bi and Be elements at the level of sensitivity up to 10{sup -8}-10{sup -9} g/g. These data were compared with more representative information about dangerous microelements concentration obtained with NAA and RFA analyses. The obtained concentrations of most elements vary in a wide range, but in agreement with the known data. The highest degree of element dispersion was observed for U, Th, Pb, I, Br, Sb, Co, K and Be (the radiation coefficient was higher than 100-200%). The presented analysis of results shows that in the clinical picture there is some proved correlation between an increased content of some element in hair and symptoms of their accumulation in the organism of ill children, the revelation of which is the basic idea of our examination.

  8. Evaluation of neutron flux parameters in irradiation sites of research reactor using the Westcott-formalism for the k0 neutron activation analysis method

    Science.gov (United States)

    Kasban, H.; Hamid, Ashraf

    2015-12-01

    Instrumental Neutron Activation Analysis using k0 (k0-INAA) method has been used to determine a number of elements in sediment samples collected from El-Manzala Lake in Egypt. k0-INAA according to Westcott's formalism has been implemented using the complete irradiation kit of the fast pneumatic rabbit and some selected manually loaded irradiation sites for short and long irradiation at Egypt Second Research Reactor (ETRR-2). Zr-Au and Co sets as neutron flux monitors are used to determine the neutron flux parameters (f and α) in each irradiation sites. Two reference materials IAEA Soil-7 samples have been inserted and implemented for data validation and an internal monostandard multi monitor used (k0 based IM-NAA). It was given a good agreement between the experimental analyzed values and that obtained of the certified values. The major and trace elements in the sediment samples have been evaluated with the use of Co as an internal and Au as an external monostandard comparators. The concentrations of the elements (Cr, Mn and Zn) in the sediment samples of the present work are discussed regarding to those obtained from other sites.

  9. Trace elements determination in human bone tissue by neutron activation analysis; Determinacao de elementos de traco em tecido osseo humano pelo metodo de ativacao com neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Takata, Marcelo K.; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Div. de Radioquimica; Sumita, Nairo M.; Saldiva, Paulo H.N.; Pasqualucci, Carlos A. [Sao Paulo Univ., SP (Brazil). Faculdade de Medicina. Lab. Experimental de Poluicao Atmosferica

    2002-07-01

    Determination of trace elements in human bones is of the great interest for evaluating nutritional state and for prevention, control and study of several diseases caused by mineral or trace element imbalance. In this study, neutron activation analysis (NAA) was applied for trace elements in human rib bone tissue. Elements Ba, Br, Ca, Cl, Fe, K, Mg, Mn, Na, P, Rb, Sr and Zn were determined in total bone tissue and in its subcompartments (cortical and trabecular tissue) separately. Irradiations were performed at IEA-R1 nuclear research reactor of IPEN-CNEN/SP. Short irradiations of 4 minutes were carried out under thermal neutron flux of 4.5x10{sup 11} n cm{sup -2} s{sup -1} and long irradiations of 16 hours under neutron flux of 10{sup 12} n cm{sup -2} s{sup -1}. Results obtained showed a variability between elemental concentrations found for bones from different individuals. A comparative study made between the data obtained for cortical and trabecular bones indicated that these two tissues present different elemental concentrations. Concentrations of Ca, Mg, Na and P obtained for cortical tissue were the same magnitude of those published data. (author)

  10. RadioAstron -- a Telescope with a Size of 300 000 km: Main Parameters and First Observational Results

    CERN Document Server

    Kardashev, N S; 10.1134/S1063772913030025

    2013-01-01

    The Russian Academy of Sciences and Federal Space Agency, together with the participation of many international organizations, worked toward the launch of the RadioAstron orbiting space observatory with its onboard 10-m reflector radio telescope from the Baikonur cosmodrome on July 18, 2011. Together with some of the largest ground-based radio telescopes and a set of stations for tracking, collecting, and reducing the data obtained, this space radio telescope forms a multi-antenna ground-space radio interferometer with extremely long baselines, making it possible for the first time to study various objects in the Universe with angular resolutions a million times better than is possible with the human eye. The project is targeted at systematic studies of compact radio-emitting sources and their dynamics. Objects to be studied include supermassive black holes, accretion disks, and relativistic jets in active galactic nuclei, stellar-mass black holes, neutron stars and hypothetical quark stars, regions of format...

  11. Improvement of photocatalytic activity of silver nanoparticles by radio frequency oxygen plasma irradiation

    Science.gov (United States)

    Fang, Yingcui; Zhang, Bing; Hong, Liu; Yao, Damao; Xie, Zhiqiang; Jiang, Yang

    2015-07-01

    Photocatalytic activity (PA) of silver nanoparticles (AgNPs) induced by radio frequency (RF) oxygen plasma irradiation (OPI) is investigated in this paper. An improvement in PA by 365% and 181% has been achieved when 15 nm AgNPs irradiated by oxygen plasma for 2 s were used to degrade 10-5 M Rhodamine 6 G (R6G) under ultraviolet (UV) and visible lights, respectively. The PA caused by OPI is better than that induced by the localized surface plasma resonance (LSPR) of AgNPs. The mechanism for the improvement was explored by scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS) and UV-vis absorption spectra. The OPI-induced formation of AgO/AgNP and Ag2O/AgNP-heterogeneous photocatalysts and electrophilic oxygen are considered to be responsible for the PA improvement. This investigation deepens our understanding of oxygen-assisted photocatalysis of AgNPs and provides a practical approach using solar light for broad spectra photocatalysis with high efficiency.

  12. Radio Observations of the Star Formation Activities in the NGC 2024 FIR 4 Region

    CERN Document Server

    Choi, Minho; Lee, Jeong-Eun

    2015-01-01

    Star formation activities in the NGC 2024 FIR 4 region were studied by imaging centimeter continuum sources and water maser sources using several archival data sets from the Very Large Array. The continuum source VLA 9 is elongated in the northwest-southeast direction, consistent with the FIR 4 bipolar outflow axis, and has a flat spectrum in the 6.2-3.6 cm interval. The three water maser spots associated with FIR 4 are also distributed along the outflow axis. One of the spots is located close to VLA 9, and another one is close to an X-ray source. Examinations of the positions of compact objects in this region suggest that the FIR 4 cloud core contains a single low-mass protostar. VLA 9 is the best indicator of the protostellar position. VLA 9 may be a radio thermal jet driven by this protostar, and it is unlikely that FIR 4 contains a high-mass young stellar object (YSO). A methanol 6.7 GHz maser source is located close to VLA 9, at a distance of about 100 AU. The FIR 4 protostar must be responsible for the ...

  13. Applied research and development of neutron activation analysis - The study on human health and environment by neutron activation analysis of biological samples

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Seung Yeon; Yoo, Jong Ik; Lee, Jae Kwang; Lee, Sung Jun; Lee, Sang Sun; Jeon, Ki Hong; Na, Kyung Won; Kang, Sang Hun [Yonsei University, Seoul (Korea)

    2000-04-01

    With the development of the precise quantitative analytical method for the analysis of trace elements in the various biological samples such as hair and food, evaluation in view of health and environment to the trace elements in various sources which can be introduced inside human body was done. The trace elemental distribution in Korean total diet and representative food stuff was identified first. With the project the elemental distributions in supplemental healthy food and Korean and Chinese origin oriental medicine were identified. The amount of trace elements ingested with the hair analysis of oriental medicine takers were also estimated. The amounts of trace elements inhaled with the analysis of foundry air, blood and hair of foundry workers were also estimated. The basic estimation method in view of health and environment with the neutron activation analysis of biological samples such as foods and hair was established with the result. Nationwide usage system of the NAA facility in Hanaro in many different and important areas of biological area can be initiated with the results. The output of the project can support public heath, environment, and medical research area. The results can be applied for the process of micronutrients enhanced health food production and for the health safety and health status enhancement with the additional necessary data expansion and the development of various evaluation technique. 19 refs., 7 figs., 23 tabs. (Author)

  14. A new concept of fusion neutron monitoring for PF-1000 device

    Directory of Open Access Journals (Sweden)

    Jednorog Slawomir

    2017-03-01

    Full Text Available The power output of plasma experiments and fusion reactors is a crucial parameter. It is determined by neutron yields that are proportional and directly related to the fusion yield. The number of emitted neutrons should be known for safety reasons and for neutron budget management. The PF-1000 is the large plasma facility based on the plasma focus phenomenon. PF-1000 is operating in the Institute of Plasma Physics and Laser Microfusion in Warsaw. Neutron yield changes during subsequent pulses, which is immanent part of this type device and so it must be monitored in terms of neutron emission. The reference diagnostic intended for this purpose is the silver activation counter (SAC used for many years. Our previous studies demonstrated the applicability of radio-yttrium for neutron yield measurements during the deuterium campaign on the PF-1000 facility. The obtained results were compared with data from silver activation counter and shown linear dependence but with some protuberances in local scale. Correlation between results for both neutron monitors was maintained. But the yttrium monitor registered the fast energy neutron that reached measurement apparatus directly from the plasma pinch. Based on the preliminary experiences, the yttrium monitor was designed to automatically register neutron-induced yttrium activity. The MCNP geometrical model of PF-1000 and yttrium monitor were both used for calculation of the activation coefficient for yttrium. The yttrium monitor has been established as the permanent diagnostic for monitoring fusion reactions in the PF-1000 device.

  15. PREFACE: ARENA 2006—Acoustic and Radio EeV Neutrino detection Activities

    Science.gov (United States)

    Thompson, Lee

    2007-06-01

    The International Conference on Acoustic and Radio EeV Neutrino Activities, ARENA 2006 was jointly hosted by the Universities of Northumbria and Sheffield at the City of Newcastle Campus of the University of Northumbria in June 2006. ARENA 2006 was the latest in a series of meetings which have addressed, either separately or jointly, the use of radio and acoustic sensors for the detection of highly relativistic particles. Previous successful meetings have taken place in Los Angeles (RADHEP, 2000), Stanford (2003) and DESY Zeuthen (ARENA 2005). A total of 50 scientists from across Europe, the US and Japan attended the conference presenting status reports and results from a number of projects and initiatives spread as far afield as the Sweden and the South Pole. The talks presented at the meeting and the proceedings contained herein represent a `snapshot' of the status of the fields of acoustic and radio detection at the time of the conference. The three day meeting also included two invited talks by Dr Paula Chadwick and Dr Johannes Knapp who gave excellent summaries of the related astroparticle physics fields of high energy gamma ray detection and high energy cosmic ray detection respectively. As well as a full academic agenda there were social events including a Medieval themed conference banquet at Lumley Castle and a civic reception kindly provided by the Lord Mayor of Newcastle and hosted at the Mansion House. Thanks must go to the International Advisory Board members for their input and guidance, the Local Organising Committee for their hard work in bringing everything together and finally the delegates for the stimulating, enthusiastic and enjoyable spirit in which ARENA 2006 took place. Lee Thompson International Advisory Board G. Anton, ErlangenD. Besson, Kansas J. Blümer, KarlsruheA. Capone, Rome H. Falcke, BonnP. Gorham, Hawaii G. Gratta, StanfordF. Halzen, Madison J. Learned, HawaiiR. Nahnhauer, Zeuthen A. Rostovtzev, MoscowD. Saltzberg, Los Angeles L

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

    Science.gov (United States)

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

    2007-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-08-15

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

  18. Analysis of umayyad islamic silver coins (Dirhams) by using instrumental neutron activation analysis

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Islamic silver coins (Dirhams) running the period between 107 to 126 Hijri (726-743AD), which belong to the Umayyad Empire period, 41-132 hijri (661-750AD), were selected for analysis by using instrumentalneutron activation analysis techniques.During this period (105-126H),(724-743AD), the Caliph Hisham Eben Abdlemalek ruled the Umayyad Empire.Dirhams were irradiated in a reactor neutron activation facility.Levels of various elements viz.Cu, Ag and Au were estimated.It was found that the average silver concentration, the baseconstituent of the Dirham, was about 88wt%.Correlation between thecomposition of Dirhams and the historical implications was discussed.

  19. Ion Uptake Determination of Dendrochronologically-Dated Trees Using Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kenan Unlu; P.I. Kuniholm; D.K.H. Schwarz; N.O. Cetiner; J.J. Chiment

    2009-03-30

    Uptake of metal ions by plan roots is a function of the type and concentration of metal in the soil, the nutrient biochemistry of the plant, and the immediate environment of the root. Uptake of gold (Au) is known to be sensitive to soil pH for many species. Soil acidification due to acid precipitation following volcanic eruptions can dramatically increase Au uptake by trees. Identification of high Au content in tree rings in dendrochronologically-dated, overlapping sequences of trees allows the identification of temporally-conscribed, volcanically-influenced periods of environmental change. Ion uptake, specifically determination of trace amounts of gold, was performed for dendrochronologically-dated tree samples utilizing Neutron Activation Analysis (NAA) technique. The concentration of gold was correlated with known enviironmental changes, e.g. volcanic activities, during historic periods.

  20. Implementation of gamma-ray instrumentation for solid solar system bodies using neutron activation method

    Energy Technology Data Exchange (ETDEWEB)

    Litvak, M.L., E-mail: litvak@mx.iki.rssi.ru [Space Research Institute, RAS, Moscow 117997 (Russian Federation); Golovin, D.V. [Space Research Institute, RAS, Moscow 117997 (Russian Federation); Jun, I. [Jet Propulsion Laboratory, Pasadena, CA (United States); Kozyrev, A.S.; Mitrofanov, I.G.; Sanin, A.B. [Space Research Institute, RAS, Moscow 117997 (Russian Federation); Shvetsov, V.N.; Timoshenko, G.N.; Zontikov, A. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    2016-06-21

    In this paper we present the results of ground tests performed with a flight model and with industry prototypes of passive and active gamma ray spectrometers with the objective of understanding their capability to distinguish the elemental composition of planetary bodies in the solar system. The gamma instrumentation, which was developed for future space missions was used in the measurements at a special ground test facility where a simulant of planetary material was fabricated with a martian-like composition. In this study, a special attention was paid to the gamma lines from activation reaction products generated by a pulsed neutron generator. The instrumentation was able to detect and identify gamma lines attributed to O, Na, Mg, Al, Si, K, Ca and Fe.

  1. Embrittlement behaviour of different international low activation alloys after neutron irradiation

    Science.gov (United States)

    Schneider, H.-C.; Dafferner, B.; Aktaa, J.

    2001-05-01

    The embrittlement behaviour of ferritic/martensitic steels after irradiation in the Petten high flux reactor (HFR) was investigated by instrumented Charpy-V tests with subsize specimens. The main objective, apart from studying effects of particularly low doses, was a comparison of low activation alloys (LAA) from various countries with different Cr contents and different types and concentrations of minor alloying elements and impurities. In the present report, the results of another three materials (OPTIMAR, OPTIFER-IV, GA3X) obtained within the second phase of the MANITU programme (0.8 dpa, at 250-450°C) were analysed and assessed in comparison to the results of the first irradiation up to 0.8 dpa. The evaluation clearly showed a reduced embrittlement problem for the advanced reduced-activation alloys. Of the examined alloys, the GA3X steel shows the very best embrittlement behaviour after neutron irradiation.

  2. Magnetar-like Activity and Radio Emission Variability from the High Magnetic Field Pulsar PSR J1119-6127

    Science.gov (United States)

    Pearlman, Aaron B.; Majid, Walid A.; Horiuchi, Shinji; Kocz, Jonathon; Lippuner, Jonas; Prince, Thomas Allen

    2017-08-01

    We present results from a high frequency radio monitoring campaign of the high magnetic field pulsar PSR J1119-6127 with the Deep Space Network (DSN) 70 m antenna (DSS-43) in Canberra, Australia, following recently reported magnetar-like activity. Dramatic pulsed radio emission variability was observed over several months at S-band (2.3 GHz) and X-band (8.4 GHz) after an initial disappearance of radio pulsations. The S-band pulse profile evolved from a multiple-peaked structure into a single-peak over several weeks, which is extremely unusual for radio pulsars. We also observed significant differences between the polarized pulse profiles at both S-band and X-band. In addition, pulsed emission variability was observed on shorter timescales, of order tens of minutes, during individual observations.The spectral index from 2.3 GHz to 8.4 GHz varied between flux densities exceeding 0.49/0.27 Jy.Although PSR J1119-6127 is normally a rotation-powered pulsar, it is possible that the decay of the pulsar’s strong magnetic field, together with other magnetar-like mechanisms, may be responsible for the observed emission variability. We will discuss how these results could connect magnetars with high-B field pulsars.

  3. Verification of threshold activation detection (TAD) technique in prompt fission neutron detection using scintillators containing 19F

    Science.gov (United States)

    Sibczynski, P.; Kownacki, J.; Moszyński, M.; Iwanowska-Hanke, J.; Syntfeld-Każuch, A.; Gójska, A.; Gierlik, M.; Kaźmierczak, Ł.; Jakubowska, E.; Kędzierski, G.; Kujawiński, Ł.; Wojnarowicz, J.; Carrel, F.; Ledieu, M.; Lainé, F.

    2015-09-01

    In the present study ⌀ 5''× 3'' and ⌀ 2''× 2'' EJ-313 liquid fluorocarbon as well as ⌀ 2'' × 3'' BaF2 scintillators were exposed to neutrons from a 252Cf neutron source and a Sodern Genie 16GT deuterium-tritium (D+T) neutron generator. The scintillators responses to β- particles with maximum endpoint energy of 10.4 MeV from the n+19F reactions were studied. Response of a ⌀ 5'' × 3'' BC-408 plastic scintillator was also studied as a reference. The β- particles are the products of interaction of fast neutrons with 19F which is a component of the EJ-313 and BaF2 scintillators. The method of fast neutron detection via fluorine activation is already known as Threshold Activation Detection (TAD) and was proposed for photofission prompt neutron detection from fissionable and Special Nuclear Materials (SNM) in the field of Homeland Security and Border Monitoring. Measurements of the number of counts between 6.0 and 10.5 MeV with a 252Cf source showed that the relative neutron detection efficiency ratio, defined as epsilonBaF2 / epsilonEJ-313-5'', is 32.0% ± 2.3% and 44.6% ± 3.4% for front-on and side-on orientation of the BaF2, respectively. Moreover, the ⌀ 5'' EJ-313 and side-on oriented BaF2 were also exposed to neutrons from the D+T neutron generator, and the relative efficiency epsilonBaF2 / epsilonEJ-313-5'' was estimated to be 39.3%. Measurements of prompt photofission neutrons with the BaF2 detector by means of data acquisition after irradiation (out-of-beam) of nuclear material and between the beam pulses (beam-off) techniques were also conducted on the 9 MeV LINAC of the SAPHIR facility.

  4. Radio frequency ion source

    CERN Document Server

    Shen Guan Ren; Gao Fu; LiuNaiYi

    2001-01-01

    The study on Radio Frequency Ion Source is mainly introduced, which is used for CIAE 600kV ns Pulse Neutron Generator; and obtained result is also presented. The RF ion source consists of a diameter phi 25 mm, length 200 mm, coefficient of expansion =3.5 mA, beam current on target >=1.5 mA, beam spot =100 h.

  5. Determination of essential elements in commercial baby foods by INAA (Instrumental Neutron Activation Analysis)

    Energy Technology Data Exchange (ETDEWEB)

    Vallinoto, Priscila; Maihara, Vera A., E-mail: pvallinoto@ipen.br, E-mail: vmaihara@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    The World Health Organization recommends that infants be breast feed exclusively at least six months after birth. After this period, it is recommended to introduce complementary foods, in order to meet nutritional amounts, minerals and energy needs of children. Commercial food products intended for infants form an important part of the diet for many babies, so it is very important that such food contains sufficient amounts of minerals. Inadequate complementary feeding is a major cause of high rates of malnutrition in developing countries. In this study, essential elements: Ca, Co, Cr, Cs, Fe, K, Na and Zn levels were determined in seven different commercial food products samples by Instrumental Neutron Activation Analysis. The seven baby food samples were acquired in the markets of Sao Paulo city. After 8-hour irradiations in the IEA-R1 nuclear research reactor under a thermal neutron flux of 10{sup 12} n cm{sup -2} s{sup -1}, the essential elements were determined and the concentrations obtained were lower than the WHO requirements. For validation of the methodology, INCT MPH-2 Mixed Polish Herbs and NIST SRM 1577{sup b} Bovine Liver were analysed. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Kehler, P.

    1982-03-01

    Flow velocities in the downcomer at the PKL facility (in Erlangen, Germany) were measured by the Pulsed-Neutron Activation (PNA) techniques. This was the first time that a fully automated PNA system, incorporating a dedicated computer for on-line data reduction, was used for flow measurements. A prototype of a portable, pulsed, high-output neutron source, developed by the Sandia National Laboratories for the US Nuclear Regulatory Commission, was also successfully demonstrated during this test. The PNA system was the primary flow-measuring device used at the PKL, covering the whole range of velocities of interest. In this test series, the PKL simulated small-break accidents similar to the one that occurred at TMI. The flow velocities in the downcomer were, therefore, very low, ranging between 0.03 and 0.35 m/sec. Two additional flow-measuring methods were used over a smaller range of velocities. Wherever comparison was possible, the PNA-derived velocity values agreed well with the measurements performed by the two more conventional methods.

  7. Characterization of airborne particulates in Bangkok urban area by neutron activation analysis.

    Science.gov (United States)

    Nouchpramool, S; Sumitra, T; Leenanuphunt, V

    1999-01-01

    Samples of airborne particulates were collected in a residential area and in an area near a busy highway in Bangkok during the period from January 1997 to May 1998. A stacked filter system was used for the former site and a Partisol 2000 was used for the latter site. Both 2.5 microns and 10-micron particulates were collected every week. The total suspended particulate matters were also collected at the latter site. The samples were analyzed by neutron activation analysis utilizing neutron flux from a 2-MW TRIGA MARK III research reactor. The elements most frequently detected in the airborne particulates were Al, As, Br, Ca, Ce, Cl, Co, Cr, Cs, Fe, I, K, La, Mg, Mn, Na, Rb, Sb, Sc, Sm, Th, Ti, V, and Zn. The enrichment factor and factor analysis were used to investigate trends, sources, and origin of the atmospheric aerosols. Anthropogenic elements in road dust, construction dust, motor vehicles emission, and other combustion components were identified. A comparative study of data between both sites was performed and it was found that the mass concentration in the area close to the highway was about three times higher than in the residential area.

  8. Rare earth elements in core marine sediments of coastal East Malaysia by instrumental neutron activation analysis.

    Science.gov (United States)

    Ashraf, Ahmadreza; Saion, Elias; Gharibshahi, Elham; Mohamed Kamari, Halimah; Chee Kong, Yap; Suhaimi Hamzah, Mohd; Suhaimi Elias, Md

    2016-01-01

    A study was carried out on the concentration of REEs (Dy, Sm, Eu,Yb, Lu, La and Ce) that are present in the core marine sediments of East Malaysia from three locations at South China Sea and one location each at Sulu Sea and Sulawesi Sea. The sediment samples were collected at a depth of between 49 and 109 m, dried, and crushed to powdery form. The entire core sediments prepared for Instrumental Neutron Activation Analysis (INAA) were weighted approximately 0.0500 g to 0.1000 g for short irradiation and 0.1500 g to 0.2000 g for long irradiation. The samples were irradiated with a thermal neutron flux of 4.0×10(12) cm(-2) s(-1) in a TRIGA Mark II research reactor operated at 750 kW. Blank samples and standard reference materials SL-1 were also irradiated for calibration and quality control purposes. It was found that the concentration of REEs varies in the range from 0.11 to 36.84 mg/kg. The chondrite-normalized REEs for different stations suggest that all the REEs are from similar origins. There was no significant REEs contamination as the enrichment factors normalized for Fe fall in the range of 0.42-2.82. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Neutron activation of natural zinc samples at kT = 25 keV

    CERN Document Server

    Reifarth, R; Heil, M; Käppeler, F; Plag, R; Sonnabend, K; Uberseder, E

    2013-01-01

    The neutron-capture cross sections of 64Zn, 68Zn, and 70Zn have been measured with the activation technique in a quasistellar neutron spectrum corresponding to a thermal energy of kT = 25 keV. By a series of repeated irradiations with different experimental conditions, an uncertainty of 3% could be achieved for the 64Zn(n,g)65Zn cross section and for the partial cross section 68Zn(n,g)69Zn-m feeding the isomeric state in 69Zn. For the partial cross sections 70Zn(n,g)71Zn-m and 70Zn(n,g)71Zn-g, which had not been measured so far, uncertainties of only 16% and 6% could be reached because of limited counting statistics and decay intensities. Compared to previous measurements on 64,68Zn, the uncertainties could be significantly improved, while the 70Zn cross section was found to be two times smaller than existing model calculations. From these results Maxwellian average cross sections were determined between 5 and 100 keV. Additionally, the beta-decay half-life of 71Zn-m could be determined with significantly imp...

  10. A Preliminary Assessment of Radiation and Air Activation for the Neutron Science Facility in RAON

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S. C.; Lee, C. W.; Lee, E. J.; Lee, Y. O. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, J. C. [Institute for Basic Science, Daejeon (Korea, Republic of)

    2015-05-15

    The works will stay in the DAQ room during an operation for about 1 month. In order to test the characteristics of the detector, the workers are also possible to access the TOF hall after a shutdown. Therefore, the shielding analysis of the NSF is required to meet the above purpose. In view of this, we performed the calculation of the shielding concrete thickness required for a target room by using MCNPX code with a neutron source obtained from Institute for Basic Science (IBS). In addition, the dose distribution and air activation for the entire space in NSF were evaluated using MCNPX and SP-FISPACT 2010 codes. We have performed the shielding calculation with the neutron source produced from the C(d,n) reactions. The concrete thickness was evaluated for all directions of the target room, and it was confirmed by performing the calculation of dose distribution to the entire space. However, the dose rate for the beam line was high. The radioactivity of radionuclides at TOF hall do not exceeded the air concentration and release limits.

  11. Instrumental Neutron Activation Analysis- INAA: environmental studies in Das Velhas Basin, Minas Gerais, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Rabelo V, M.A.; Andrade Q, M.T. [Researcher of National Council for Scientific and Technological Development, CNPq, Center University of the East of Minas Gerais State, UNILESTE-MG (Brazil); Araujo M, R. [CDTN (Brazil); Albernaz A, I. [SCA- CNRS/USR/059, Lyon (France); Oliveira, A.H. de [Federal University of Minas Gerais State (Brazil)]. e-mail: marvv@cdtn.br

    2006-07-01

    The Instrumental Neutron Activation Analysis - INAA was applied to determine concentrations of several elements in unpolluted areas and in the mining and farming region of the Das Velhas Basin, Minas Gerais State, Brazil. INAA was applied using the TRIGA Mark I IPR - R1 reactor at the Nuclear Technology Development Center of the National Committee of Nuclear Energy (CDTN/CNEN), in Belo Horizonte city, Minas Gerais State. At 100 kW of potency the flux of neutrons is 6.6 10{sup 11} n.cm{sup -2}.s{sup -1}. The samples analyzed were: water; sediment; gravel of gold mine and forage. The obtained results for the Das Velhas Basin in water and sediment samples - mining companies region - show a high level ({mu}g/g) of contamination with the analyzed elements, mainly in the sediment samples. During the period of floods, in farming region hundreds of kilometers away, contamination is found in fish and forage, reaching and harming both people and animals that live in the marginal region. (Author)

  12. Neutron activation analysis of ceramic tiles and its component and radon exhalation rate.

    Science.gov (United States)

    El-Shershaby, A; Sroor, A; Ahmed, F; Abdel-Haleem, A S; Abdel, Z

    2004-01-01

    The concentrations of 20 trace elements in several ceramics tiles and ceramic composites used in Egypt were elementally analyzed by neutron activation analysis(NAA) technique. The samples and standard were irradiated with reactor for 4 h (in the Second Research Egyptian Reactor(Et-RR-2)) with thermal neutron flux 5.9 x 10(13) n/(cm2 x s). The gamma-ray spectra obtained were measured for several times by means of the hyper pure germanium detection system(HPGe). Also a solid state nuclear track detector(SSNTD) CR-39, was used to measure the emanation rate of radon for these samples. The radium concentrations were found to vary from 0.39-3.59 ppm and the emanation rates were found to vary from (0.728-5.688) x 10(-4) kg/(m2 x s). The elemental analysis of the ceramic tiles and ceramic composites have a great importance in assigning the physical properties and in turn the quality of the material.

  13. Polymeric microspheres for radionuclide synovectomy containing neutron-activated holmium-166.

    Science.gov (United States)

    Mumper, R J; Mills, B J; Ryo, U Y; Jay, M

    1992-03-01

    Poly-L-lactic acid (PLA) microspheres containing neutron-activated 166Ho were investigated as potential agents for radionuclide synovectomy. Stable 165Ho, complexed to acetylacetone (AcAc), was incorporated into PLA spheres by the solvent evaporation technique. Spheres prepared with the optimal mean particle size of 7.2 microns (range 2-13 microns) containing 25.4% 165Ho-AcAc (9.1% 165Ho) were irradiated in a high neutron flux to produce 31.1-36.0 mCi 166Ho. In vitro human plasma studies showed that the irradiated spheres retained 99.0 +/- 0.01% of the 166Ho at 314 hr. In-vivo retention studies were conducted by administering irradiated PLA spheres with 257-591 microCi 166Ho into the joint space of normal rabbits (n = 6). Biodistribution analysis and gamma camera analysis showed 166Ho retention in the joint space after 120 hr of 97.7% +/- 0.8% and 98.2% +/- 2.4%, respectively, with no uptake by the lymph nodes. The ease with which the PLA spheres can be made in the optimal size range for later irradiation and their ability to retain the 166Ho make them attractive agents for radionuclide synovectomy.

  14. Throughput Maximization for Cognitive Radio Networks Using Active Cooperation and Superposition Coding

    KAUST Repository

    Hamza, Doha

    2015-02-13

    We propose a three-message superposition coding scheme in a cognitive radio relay network exploiting active cooperation between primary and secondary users. The primary user is motivated to cooperate by substantial benefits it can reap from this access scenario. Specifically, the time resource is split into three transmission phases: The first two phases are dedicated to primary communication, while the third phase is for the secondary’s transmission. We formulate two throughput maximization problems for the secondary network subject to primary user rate constraints and per-node power constraints with respect to the time durations of primary transmission and the transmit power of the primary and the secondary users. The first throughput maximization problem assumes a partial power constraint such that the secondary power dedicated to primary cooperation, i.e. for the first two communication phases, is fixed apriori. In the second throughput maximization problem, a total power constraint is assumed over the three phases of communication. The two problems are difficult to solve analytically when the relaying channel gains are strictly greater than each other and strictly greater than the direct link channel gain. However, mathematically tractable lowerbound and upperbound solutions can be attained for the two problems. For both problems, by only using the lowerbound solution, we demonstrate significant throughput gains for both the primary and the secondary users through this active cooperation scheme. We find that most of the throughput gains come from minimizing the second phase transmission time since the secondary nodes assist the primary communication during this phase. Finally, we demonstrate the superiority of our proposed scheme compared to a number of reference schemes that include best relay selection, dual-hop routing, and an interference channel model.

  15. Comparison of IUPAC k0 Values and Neutron Cross Sections to Determine a Self-consistent Set of Data for Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Firestone, Richard B; Revay, Zsolt

    2009-12-01

    Independent databases of nuclear constants for Neutron Activation Analysis (NAA) have been independently maintained by the physics and chemistry communities for many year. They contain thermal neturon cross sections s0, standardization values k0, and transition probabilities Pg. Chemistry databases tend to rely upon direct measurements of the nuclear constants k0 and Pg which are often published in chemistry journals while the physics databases typically include evaluated s0 and Pg data from a variety of experiments published mainly in physics journals. The IAEA/LBNL Evaluated Gamma-ray Activation File (EGAF) also contains prompt and delayed g-ray cross sections sg from Prompt Gamma-ray Activation Analysis (PGAA) measurements that can also be used to determine k0 and s0 values. As a result several independent databases of fundamental constants for NAA have evolved containing slightly different and sometimes discrepant results. An IAEA CRP for a Reference Database for Neutron Activation Analysis was established to compare these databases and investigate the possibilitiy of producing a self-consistent set of s0, k0, sg, and Pg values for NAA and other applications. Preliminary results of this IAEA CRP comparison are given in this paper.

  16. The Cosmic History of Hot Gas Cooling and Radio AGN Activity in Massive Early-Type Galaxies

    Science.gov (United States)

    Danielson, A. L. R.; Lehmer, B. D.; Alexander, D. M.; Brandt, W. M.; Luo, B.; Miller, N.; Xue, Y. Q.; Stott, J. P.

    2012-01-01

    We study the X-ray properties of 393 optically selected early-type galaxies (ETGs) over the redshift range of z approx equals 0.0-1.2 in the Chandra Deep Fields. To measure the average X-ray properties of the ETG population, we use X-ray stacking analyses with a subset of 158 passive ETGs (148 of which were individually undetected in X-ray). This ETG subset was constructed to span the redshift ranges of z = 0.1-1.2 in the approx equals 4 Ms CDF-S and approx equals 2 Ms CDF-N and z = 0.1-0.6 in the approx equals 250 ks E-CDF-S where the contribution from individually undetected AGNs is expected to be negligible in our stacking. We find that 55 of the ETGs are detected individually in the X-rays, and 12 of these galaxies have properties consistent with being passive hot-gas dominated systems (i.e., systems not dominated by an X-ray bright Active Galactic Nucleus; AGN). On the basis of our analyses, we find little evolution in the mean 0.5-2 keY to B-band luminosity ratio (L(sub x) /L(sub Beta) varies as [1 +z]) since z approx equals 1.2, implying that some heating mechanism prevents the gas from cooling in these systems. We consider that feedback from radio-mode AGN activity could be responsible for heating the gas. We select radio AGNs in the ETG population using their far-infrared/radio flux ratio. Our radio observations allow us to constrain the duty cycle history of radio AGN activity in our ETG sample. We estimate that if scaling relations between radio and mechanical power hold out to z approx equals 1.2 for the ETG population being studied here, the average mechanical power from AGN activity is a factor of approx equals1.4 -- 2.6 times larger than the average radiative cooling power from hot gas over the redshift range z approx equals 0-1.2. The excess of inferred AGN mechanical power from these ETGs is consistent with that found in the local Universe for similar types of galaxies.

  17. Activation of soil and chemical reagents exposed to the neutrons released by the JCO criticality accident in Tokai-mura.

    Science.gov (United States)

    Murata, Y; Muroyama, T; Kawabata, Y; Yamamoto, M; Komura, K

    2001-09-01

    Specific activities (Bq/g-element) of residual neutron-induced radionuclides by the JCO criticality accident were measured for soil, concrete block and chemical reagent samples collected in the JCO campus. Induced radionuclides such as 24Na, 46Sc, 54Mn, 59Fe, 60Co, 65Zn, 82Br, 122Sb, 134Cs and 140La were detected in the samples, depending on the ground distance from the accident point and the sampling date. Apparent thermal, epi-thermal and fast neutron fluences, which reached the sample at each point, were roughly estimated from the specific activities and cross sections of the target nuclides taken from a literature. The present data are believed to be important as validation data for a three-dimensional neutron transport model calculation.

  18. Use of Instrumental Neutron Activation Analysis to investigate the distribution of trace elements among subsamples of solid materials

    CERN Document Server

    DAgostino, Giancarlo; Giordani, Laura; Oddone, Massimo; Kipphardt, Heinrich; Richter, Silke

    2013-01-01

    The results of analytical measurements performed with solid-sampling techniques are affected by the distribution of the analytes within the matrix. The effect becomes significant in case of determination of trace elements in small subsamples. In this framework we propose a measurement model based on Instrumental Neutron Activation Analysis to determine the relative variability of the amount of an analyte among subsamples of a material. The measurement uncertainty is evaluated and includes the counting statistics, the full-energy gamma peak efficiency and the spatial gradient of the neutron flux at the irradiation position. The data we obtained in a neutron activation experiment and showing the relative variability of As, Au, Ir, Sb and W among subsamples of a highly pure Rh foil are also presented.

  19. Radio Journalism.

    Science.gov (United States)

    Bittner, John R.; Bittner, Denise A.

    This book, a how-to-do-it guide for the novice and the professional alike, deals with several aspects of radio journalism: producing documentaries, preparing and announcing radio news, ethics and responsibility, regulation of radio journalism, and careers. It traces the history and growth of radio news, shows its impact on the public, and…

  20. Activity and food choice of piscivorous perch ( Perca fluviatilis ) in a eutrophic shallow lake: a radio-telemetry study

    DEFF Research Database (Denmark)

    Jacobsen, Lene; Berg, Søren; Broberg, M.

    2002-01-01

    1. Radio transmitters were implanted in large perch (27-37 cm) in a shallow lake in Denmark. Between 6 and 13 perch were tracked every 3 h for 24-h periods twice (summer) or once a month (winter) from August 1997 to July 1998. Activity levels were recorded as minimum distance moved per hour. 2. N......+ planktivorous fish in lakes and has potential implications for pelagic food web structure and lake management by biomanipulation...

  1. The Photocatalytic Activity and Compact Layer Characteristics of TiO2 Films Prepared Using Radio Frequency Magnetron Sputtering

    OpenAIRE

    Chang, H. C.; Huang, H. H.; Wu, C. Y.; Hsu, R. Q.; C. Y. Hsu

    2014-01-01

    TiO2 compact layers are used in dye-sensitized solar cells (DSSCs) to prevent charge recombination between the electrolyte and the transparent conductive substrate (indium tin oxide, ITO; fluorine-doped tin oxide, FTO). Thin TiO2 compact layers are deposited onto ITO/glass by means of radio frequency (rf) magnetron sputtering, using deposition parameters that ensure greater photocatalytic activity and increased DSSC conversion efficiency. The photoinduced decomposition of methylene blue (MB) ...

  2. ANDI-03: a genetic algorithm tool for the analysis of activation detector data to unfold high-energy neutron spectra.

    Science.gov (United States)

    Mukherjee, Bhaskar

    2004-01-01

    The thresholds of (n,xn) reactions in various activation detectors are commonly used to unfold the neutron spectra covering a broad energy span, i.e. from thermal to several hundreds of MeV. The saturation activities of the daughter nuclides (i.e. reaction products) serve as the input data of specific spectra unfolding codes, such as SAND-II and LOUHI-83. However, most spectra unfolding codes, including the above, require an a priori (guess) spectrum to starting up the unfolding procedure of an unknown spectrum. The accuracy and exactness of the resulting spectrum primarily depends on the subjectively chosen guess spectrum. On the other hand, the Genetic Algorithm (GA)-based spectra unfolding technique ANDI-03 (Activation-detector Neutron DIfferentiation) presented in this report does not require a specific starting parameter. The GA is a robust problem-solving tool, which emulates the Darwinian Theory of Evolution prevailing in the realm of biological world and is ideally suited to optimise complex objective functions globally in a large multidimensional solution space. The activation data of the 27Al(n,alpha)24Na, 116In(n,gamma)116mIn, 12C(n,2n)11C and 209Bi(n,xn)(210-x)Bi reactions recorded at the high-energy neutron field of the ISIS Spallation source (Rutherford Appleton Laboratory, UK) was obtained from literature and by applying the ANDI-03 GA tool, these data were used to unfold the neutron spectra. The total neutron fluence derived from the neutron spectrum unfolded using GA technique (ANDI-03) agreed within +/-6.9% (at shield top level) and +/-27.2% (behind a 60 cm thick concrete shield) with the same unfolded with the SAND-II code.

  3. Grand Unification in Neutron Stars

    CERN Document Server

    Kaspi, Victoria M

    2010-01-01

    The last decade has shown us that the observational properties of neutron stars are remarkably diverse. From magnetars to rotating radio transients, from radio pulsars to `isolated neutron stars,' from central compact objects to millisecond pulsars, observational manifestations of neutron stars are surprisingly varied, with most properties totally unpredicted. The challenge is to establish an overarching physical theory of neutron stars and their birth properties that can explain this great diversity. Here I survey the disparate neutron stars classes, describe their properties, and highlight results made possible by the Chandra X-ray Observatory, in celebration of its tenth anniversary. Finally, I describe the current status of efforts at physical `grand unification' of this wealth of observational phenomena, and comment on possibilities for Chandra's next decade in this field.

  4. Grand unification of neutron stars.

    Science.gov (United States)

    Kaspi, Victoria M

    2010-04-20

    The last decade has shown us that the observational properties of neutron stars are remarkably diverse. From magnetars to rotating radio transients, from radio pulsars to isolated neutron stars, from central compact objects to millisecond pulsars, observational manifestations of neutron stars are surprisingly varied, with most properties totally unpredicted. The challenge is to establish an overarching physical theory of neutron stars and their birth properties that can explain this great diversity. Here I survey the disparate neutron stars classes, describe their properties, and highlight results made possible by the Chandra X-Ray Observatory, in celebration of its 10th anniversary. Finally, I describe the current status of efforts at physical "grand unification" of this wealth of observational phenomena, and comment on possibilities for Chandra's next decade in this field.

  5. Grand unification of neutron stars

    Science.gov (United States)

    Kaspi, Victoria M.

    2010-01-01

    The last decade has shown us that the observational properties of neutron stars are remarkably diverse. From magnetars to rotating radio transients, from radio pulsars to isolated neutron stars, from central compact objects to millisecond pulsars, observational manifestations of neutron stars are surprisingly varied, with most properties totally unpredicted. The challenge is to establish an overarching physical theory of neutron stars and their birth properties that can explain this great diversity. Here I survey the disparate neutron stars classes, describe their properties, and highlight results made possible by the Chandra X-Ray Observatory, in celebration of its 10th anniversary. Finally, I describe the current status of efforts at physical “grand unification” of this wealth of observational phenomena, and comment on possibilities for Chandra’s next decade in this field. PMID:20404205

  6. Investigation of therapeutic potentials of some selected medicinal plants using neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Abubakar, Sani; Isa, Nasiru Fage [Bayero University, Kano Nigeria (Nigeria); Usman, Ahmed Rufa’i [University of Malaya, Kuala Lumpur (Malaysia); Umaru Musa Yar’adua University, Katsina Nigeria (Nigeria); Khandaker, Mayeen Uddin [University of Malaya, Kuala Lumpur (Malaysia); Abubakar, Nuraddeen [Center for Energy Research and Training, Ahmadu Bello University, Zaria Nigeria (Nigeria)

    2015-04-24

    Series of attempts were made to investigate concentrations of trace elements and their therapeutic properties in various medicinal plants. In this study, samples of some commonly used plants were collected from Bauchi State, Nigeria. They includes leaves of azadirachta indica (neem), Moringa Oleifera (moringa), jatropha curcas (purgin Nut), guiera senegalensis (custard apple) and anogeissus leiocarpus (African birch). These samples were analyzed for their trace elements contents with both short and long irradiation protocols of Instrumental Neutron Activation Analysis (INAA) at Nigerian Research Reactor-1 (NIRR-1) of Ahmadu Bello University, Zaria, Nigeria. The level of trace elements found varies from one sample to another, with some reported at hundreds of mg/Kg dry weight. The results have been compared with the available literature data. The presence of these trace elements indicates promising potentials of these plants for relief of certain ailments.

  7. The optimization of gamma spectra processing in prompt gamma neutron activation analysis (PGNAA)

    Energy Technology Data Exchange (ETDEWEB)

    Pinault, Jean-Louis [IAEA Expert, 96 rue du Port David, 45370 Dry (France)], E-mail: jeanlouis_pinault@hotmail.fr; Solis, Jose [Instituto Peruano de Energia Nuclear, Av. Canada No. 1470, San Borja, Lima 41 (Peru)

    2009-04-15

    The uncertainty of the elemental analysis is one of the major factors governing the utility of on-line Prompt Gamma Neutron Activation Analysis (PGNAA) in the blending and sorting of bulk materials. In this paper, a general method applicable to Gamma spectra processing is presented and applied to PGNAA in mineral industry. Based on the Fourier transform of spectra and their de-correlation in the Fourier space (the improvement of the conditioning of the correlation matrix), processing of overlapping of characteristic peaks minimizes the propagation of random errors, which optimizes the accuracy and decreases the detection limits of elemental analyses. In comparison with classical methods based on the linear combinations of relevant regions of spectra the improvement may be considerable, especially when several elements are interfering. The method is applied to four case stories covering both borehole logging and on-line analysis on conveyor belt of raw materials.

  8. Application of neutron activation in hydrometallurgical process of lead chloride extraction from boulangerit

    Directory of Open Access Journals (Sweden)

    Zovko Emira

    2010-01-01

    Full Text Available In this work, a neutron activation analysis for the identification of radiochemical elements in the ore concentrate of zone Vareš, Bosnia and Hercegovina, has been applied. The possibility of dissolving ore concentrate from iron(III chloride was examined. To follow the dissolving lead (II sulphide yield from the ore concentrates, in addition to radioisotope labeling process, it is necessary to use a gravimetric analysis of the extracted lead(II chloride. Based on kinetic measurements of dissolving concentrate efficiency it was observed that the optimum dissolving time was about 2 to 3 h, and that the one-time procedure can dissolve about 72±5% of marked components.

  9. Monte Carlo Calculation for Landmine Detection using Prompt Gamma Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seungil; Kim, Seong Bong; Yoo, Suk Jae [Plasma Technology Research Center, Gunsan (Korea, Republic of); Shin, Sung Gyun; Cho, Moohyun [POSTECH, Pohang (Korea, Republic of); Han, Seunghoon; Lim, Byeongok [Samsung Thales, Yongin (Korea, Republic of)

    2014-05-15

    Identification and demining of landmines are a very important issue for the safety of the people and the economic development. To solve the issue, several methods have been proposed in the past. In Korea, National Fusion Research Institute (NFRI) is developing a landmine detector using prompt gamma neutron activation analysis (PGNAA) as a part of the complex sensor-based landmine detection system. In this paper, the Monte Carlo calculation results for this system are presented. Monte Carlo calculation was carried out for the design of the landmine detector using PGNAA. To consider the soil effect, average soil composition is analyzed and applied to the calculation. This results has been used to determine the specification of the landmine detector.

  10. The accuracy of instrumental neutron activation analysis of kilogram-size inhomogeneous samples.

    Science.gov (United States)

    Blaauw, M; Lakmaker, O; van Aller, P

    1997-07-01

    The feasibility of quantitative instrumental neutron activation analysis (INAA) of samples in the kilogram range without internal standardization has been demonstrated by Overwater et al. (Anal. Chem. 1996, 68, 341). In their studies, however, they demonstrated only the agreement between the "corrected" γ ray spectrum of homogeneous large samples and that of small samples of the same material. In this paper, the k(0) calibration of the IRI facilities for large samples is described, and, this time in terms of (trace) element concentrations, some of Overwater's results for homogeneous materials are presented again, as well as results obtained from inhomogeneous materials and subsamples thereof. It is concluded that large-sample INAA can be as accurate as ordinary INAA, even when applied to inhomogeneous materials.

  11. Instrumental neutron activation analysis of an enriched 28Si single-crystal

    CERN Document Server

    DAgostino, G; Giordani, L; Mana, G; Oddone, M

    2013-01-01

    The determination of the Avogadro constant plays a key role in the redefinition of the kilogram in terms of a fundamental constant. The present experiment makes use of a silicon single-crystal highly enriched in 28Si that must have a total impurity mass fraction smaller than a few parts in 109. To verify this requirement, we previously developed a relative analytical method based on neutron activation for the elemental characterization of a sample of the precursor natural silicon crystal WASO 04. The method is now extended to fifty-nine elements and applied to a monoisotopic 28Si single-crystal that was grown to test the achievable enrichment. Since this crystal was likely contaminated, this measurement tested also the detection capabilities of the analysis. The results quantified contaminations by Ge, Ga, As, Tm, Lu, Ta, W and Ir and, for a number of the detectable elements, demonstrated that we can already reach the targeted 1 ng/g detection limit.

  12. Development of distinction method of production area of ginsengs by using a neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Youngjin; Chung, Yongsam; Sim, Chulmuu; Sun, Gwangmin; Lee, Yuna; Yoo, Sangho

    2011-01-15

    During the last 2 years of the project, we have tried to develop the technology to make a distinction of the production areas for Korean ginsengs cultivated in the various provinces in Korea and foreign countries. It will contribute to secure the health food safety for public and stability of its market. In this year, we collected ginseng samples cultivated in the northeastern province in Chinese mainland such as Liaoning province, Jilin province and Baekdu mountain within Jilin province. 10 ginseng samples were collected at each province. The elemental concentrations in the ginseng were analyzed by using a neutron activation analysis technique at the HANARO research reactor. The distinction of production area was made by using a statistical software. As a result, the Chinese Korean ginsengs were certainly differentiated from those cultivated in the famous province in Korea though there was a limitation that the number of our sample we analyzed is very small.

  13. Neutron Activation Analysis of the Rare Earth Elements (REE) - With Emphasis on Geological Materials

    Science.gov (United States)

    Stosch, Heinz-Günter

    2016-08-01

    Neutron activation analysis (NAA) has been the analytical method of choice for rare earth element (REE) analysis from the early 1960s through the 1980s. At that time, irradiation facilitieswere widely available and fairly easily accessible. The development of high-resolution gamma-ray detectors in the mid-1960s eliminated, formany applications, the need for chemical separation of the REE from the matrix material, making NAA a reliable and effective analytical tool. While not as precise as isotopedilution mass spectrometry, NAA was competitive by being sensitive for the analysis of about half of the rare earths (La, Ce, Nd, Sm, Eu, Tb, Yb, Lu). The development of inductively coupled plasma mass spectrometry since the 1980s, together with decommissioning of research reactors and the lack of installation of new ones in Europe and North America has led to the rapid decline of NAA.

  14. Neutron activation analysis of ceramic tiles and its component and radon exhalation rate

    Institute of Scientific and Technical Information of China (English)

    A. El-Shershaby; A. Sroor; F. Ahmed; A.S. Abdel-Haleem; Z. Abdel

    2004-01-01

    The concentrations of 20 trace elements in several ceramics tiles and ceramic composites used in Egypt were elementally analyzed by neutron activation analysis(NAA) technique. The samples and standard were irradiated with reactor for 4 h( in the Second The gamma-ray spectra obtained were measured for several times by means of the hyper pure germanium detection system( HPGe).Also a solid state nuclear track detector(SSNTD) CR-39, was used to measure the emanation rate of radon for these samples. The radium concentrations were found to vary from 0.39-3.59 ppm and the emanation rates were found to vary from (0.728-5.688) x 10-4The elemental analysis of the ceramic tiles and ceramic composites have a great importance in assigning the physical properties and in turn the quality of the material.

  15. Environmental variation of arsenic levels in human blood determined by neutron activation analysis

    DEFF Research Database (Denmark)

    Heydorn, Kaj

    1970-01-01

    Arsenic levels in blood plasma and red cells from patients with Blackfoot disease, a peripheral arteriosclerosis endemic to a small area in Taiwan, were studied in relation to healthy individuals from the same and other parts of Taiwan and compared with arsenic levels in a control group from...... Denmark. Arsenic was determined by neutron activation analysis with radiochemical separation and re-irradiation yield determination. The precision and accuracy of the results have been carefully evaluated in order to permit quantitative tests for the significance of the observed differences. The results...... from Taiwan followed a logarithmic normal distribution, and no difference was found between Blackfoot patients and their healthy family members. However, their overall arsenic levels were higher than the Taiwan average, presumably because of arsenic in their drinking water. Much lower levels were found...

  16. Determination of Mineral Contents in Unpolished Rice and Bean Samples by Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Moon, J. H.; Kim, S. H.; Baek, S. Y.; Chung, Y. S. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    As scientists have focused their researches on the health impacts caused by mineral nutrient deficiencies and hazardous elements, public concern regarding mineral intake from dietary food is rising. In this reason, the dietary habits of Koreans have been shifted from white rice to more nutrient rice like unpolished rice and rice mixed with beans. It is known that unpolished rice and beans contain more protein, vitamin and mineral contents than white rice and are more beneficial to human health, even though they sometimes cause indigestion or allergy. The objectives of this study were to determine the mineral contents in unpolished rice and bean samples by a neutron activation analysis (NAA) and to compare the level of mineral contents between the samples

  17. Microcomputer-based pneumatic controller for neutron activation analysis. [For analyzing uranium ore samples

    Energy Technology Data Exchange (ETDEWEB)

    Byrd, J.S.; Sand, R.J.

    1976-10-01

    A microcomputer-based pneumatic controller for neutron activation analysis was designed and built at the Savannah River Laboratory for analysis of large numbers of geologic samples for locating potential supplies of uranium ore for the National Uranium Resource Evaluation program. In this system, commercially available microcomputer logic modules are used to transport sample capsules through a network of pressurized air lines. The logic modules are interfaced to pneumatic valves, solenoids, and photo-optical detectors. The system operates from programs stored in firmware (permanent software). It also commands a minicomputer and a hard-wired pulse height analyzer for data collection and bookkeeping tasks. The advantage of the system is that major system changes can be implemented in the firmware with no hardware changes. This report describes the hardware, firmware, and software for the electronics system.

  18. Neutron activation analysis for assessing the concentrations of trace elements in laboratory detergents

    Energy Technology Data Exchange (ETDEWEB)

    Iskander, F.Y.

    1986-01-01

    Nondestructive instrumental neutron activation analysis was used to assess the concentration of 20 elements in the following laboratory detergents: Micro, Cavi-Clean liquid, RBS-35, Liqui-Nox, Treg-A-Zyme, Alcojet, Alconox, Alcotabs and Radiacwash: and a detergent additive: CaviClean additive. The upper detected limits or the concentration ranges for the detergents are (element concentration in ..mu..g/g): Ba, <20; Ce, <0.8; Cl, 27-10000; Co, <0.1; Cr, <1; Cs, <0.6; Eu, <0.009; Fe, <3-45; Hf, <0.07; Mn, <10; Ni, <5; Rb, <0.08-0.89; Sb, <0.006-1.8; Sc, <0.0003-0.008; Se, <0.05; Sr <30; Th, <0.6; U, <0.1; V, <10; Zn, <0.2-2.0. The concentrations of trace elements in the examined laboratory detergents are below those reported in the literature for household detergents.

  19. Chemical contents in Lygeum spartum L. using instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nedjimi, Bouzid [Djelfa Univ. (Algeria). Lab. of Exploration and Valorization of Steppe Ecosystem; Beladel, Brahim [Djelfa Univ. (Algeria)

    2015-09-01

    The present investigation was conducted to determine the chemical contents of Lygeum spartum L. (Poaceae). Samples were analyzed in order to determine essential (Ca, K, Na, Fe, Co) and some potentially toxic elements (Eu, Sb, Tb) using instrumental neutron activation analysis (INAA). In general chemical element contents were in substantial amounts to meet adult sheep requirements. Potential intake of Ca, K, Zn, Co and Fe by ruminant weighing 50 kg BW consuming 2.0 kg per day DM was sufficient to satisfy their requirements. However, only Na level was still insufficient to meet the requirements for grazing ruminants. Potential toxic elements in this species were within the safety baseline of all the assayed elements recommended by NRC. Na supplementation would seem to be necessary in this zone, for optimum productivity of grazing animals.

  20. Investigation of therapeutic potentials of some selected medicinal plants using neutron activation analysis

    Science.gov (United States)

    Abubakar, Sani; Usman, Ahmed Rufa'i.; Isa, Nasiru Fage; Khandaker, Mayeen Uddin; Abubakar, Nuraddeen

    2015-04-01

    Series of attempts were made to investigate concentrations of trace elements and their therapeutic properties in various medicinal plants. In this study, samples of some commonly used plants were collected from Bauchi State, Nigeria. They includes leaves of azadirachta indica (neem), Moringa Oleifera (moringa), jatropha curcas (purgin Nut), guiera senegalensis (custard apple) and anogeissus leiocarpus (African birch). These samples were analyzed for their trace elements contents with both short and long irradiation protocols of Instrumental Neutron Activation Analysis (INAA) at Nigerian Research Reactor-1 (NIRR-1) of Ahmadu Bello University, Zaria, Nigeria. The level of trace elements found varies from one sample to another, with some reported at hundreds of mg/Kg dry weight. The results have been compared with the available literature data. The presence of these trace elements indicates promising potentials of these plants for relief of certain ailments.

  1. Hybrid combination of multi-layer perceptron and neutron activation analysis in cement prediction

    Science.gov (United States)

    Eftekhari-Zadeh, E.; Feghhi, S. A. H.; Roshani, G. H.

    2017-02-01

    Determination of concentration of major elements such as Ca, Si, Al, and Fe in cement is very important for quality control during its production, correct classification according to the existing standards, and thus for appropriate use in the construction industry. For this purpose, neutron activation analysis is very suitable. In this preliminary theoretical work, the irradiation and consecutive measurement of the percentage of the constituent elements in different cement samples were done using MCNPX with γ-ray spectra as the output. Specific peaks of Ca, Si, Al, and Fe obtained from these spectra were used as input for artificial neural network (18 of them for training and 8 for testing) resulting in the determination of each element in the given sample. The mean absolute errors of the results are less than 0.4%, which is very promising for the future experimental work where the uncertainties are usually one order higher.

  2. Determination of Total Arsenic in Seaweed Products by Neutron Activation Analysis

    Directory of Open Access Journals (Sweden)

    N. Salim

    2013-04-01

    Full Text Available Seaweed products are widely consumed as food nowadays. Seaweeds are known to contain arsenic due to their capability to accumulate arsenic from the environment. Arsenic is a known toxic element which naturally occurs in the environment. Ingestion of high levels of arsenic will cause several adverse health effects. Arsenic in food occurs at trace concentrations which require sensitive and selective analysis methods to perform elemental analysis on. Validated neutron activation analysis was used to determine the arsenic contents in seaweed products namely catoni from domestic product and nori from foreign products. The total arsenic concentration in the samples analyzed ranges from 0.79 mg/kg to 30.14 mg/kg with mean concentration 14.39 mg/kg. The estimated exposure to arsenic contributed by the analyzed products is from 0.07% up to 8.54% of the established provisional tolerable daily intake (PTDI which is still far below the maximum tolerable level

  3. Multi-elemental profile of some Brazilian make-up products by instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Dalmazio, Ilza; Menezes, Maria Angela de B.C., E-mail: id@cdtn.b, E-mail: menezes@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico de Reator e Tecnicas Analiticas. Lab. de Ativacao Neutronica

    2011-07-01

    Recent works have shown that analysis in cosmetics and beauty products from the European and Asian markets indicate the presence of U, Th and rare earths besides other trace elements. Considering these previous findings and health issues, it would be valuable to obtain information on elements in cosmetics available in the Brazilian market. The purpose of this study was to acquire a multi-elemental profile of some Brazilian make-up products of diverse brands. Samples of eye shadow, liquid base, facial concealer, lipstick, and compact face powder were analyzed applying neutron activation analysis, k{sub 0}-standardization method at CDTN/CNEN, using the TRIGA Mark I IPR-R1 research reactor. Concentrations of more than 30 elements in samples are presented and it was found elements included in Brazilian National Health Surveillance Agency prohibitive list, rare earths, Th and U in a minimum of two cosmetic samples. (author)

  4. Multi-elemental profile of some Brazilian make-up products by instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Dalmazio, Ilza; Menezes, Maria Angela de B.C., E-mail: id@cdtn.b, E-mail: menezes@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico de Reator e Tecnicas Analiticas. Lab. de Ativacao Neutronica

    2011-07-01

    Recent works have shown that analysis in cosmetics and beauty products from the European and Asian markets indicate the presence of U, Th and rare earths besides other trace elements. Considering these previous findings and health issues, it would be valuable to obtain information on elements in cosmetics available in the Brazilian market. The purpose of this study was to acquire a multi-elemental profile of some Brazilian make-up products of diverse brands. Samples of eye shadow, liquid base, facial concealer, lipstick, and compact face powder were analyzed applying neutron activation analysis, k{sub 0}-standardization method at CDTN/CNEN, using the TRIGA Mark I IPR-R1 research reactor. Concentrations of more than 30 elements in samples are presented and it was found elements included in Brazilian National Health Surveillance Agency prohibitive list, rare earths, Th and U in a minimum of two cosmetic samples. (author)

  5. Development of Neutron Activation Analysis for Scientific Interpretation on Cultural Properties

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gyu Ho; Kim, Na Young; Ko, Min Chung; Kim, Min Ji; Cho, Su Mi; Kang, Ji Eun [Kongju National University, Gongju (Korea, Republic of)

    2010-05-15

    This research is tried to set up the application of neutron activation analysis and to evaluate the historical information about ceramics materials at production kilns for the standardized technology of NAA. This project is measured the 112 samples from Jijong-dong, Daejeon and 4 production kiln sites in Kyongsangdo by using NAA and XRF and classified as types and production site by PCA and applied of factor analysis, discruminant analysis and cluster analysis. As the results, we know that it is classified as pottery and roof tile as measured 11 elements and that it is not classified major and trace elements as the production kiln sites because raw materials is 2nd clay. At last, it is investigated the comparative evaluation of raw material as production kiln sites by cluster analysis as the basis of the data of NA

  6. Hybrid combination of multi-layer perceptron and neutron activation analysis in cement prediction

    Indian Academy of Sciences (India)

    E EFTEKHARI-ZADEH; S A H FEGHHI; G H ROSHANI

    2017-02-01

    Determination of concentration of major elements such as Ca, Si, Al, and Fe in cement is very important for quality control during its production, correct classification according to the existing standards, and thus for appropriate use in the construction industry. For this purpose, neutron activation analysis is verysuitable. In this preliminary theoretical work, the irradiation and consecutive measurement of the percentage of the constituent elements in different cement samples were done using MCNPX with γ -ray spectra as the output. Specific peaks of Ca, Si, Al, and Fe obtained from these spectra were used as input for artificial neural network (18 of them for training and 8 for testing) resulting in the determination of each element in the given sample. The mean absolute errors of the results are less than 0.4%, which is very promising for the future xperimental work where the uncertainties are usually one order higher.

  7. Elemental characterization of the Avogadro silicon crystal WASO 04 by neutron activation analysis

    CERN Document Server

    D'Agostino, Giancarlo; Giordani, Laura; Mana, Giovanni; Massa, Enrico; Oddone, Massimo; 10.1088/0026-1394/49/6/696

    2013-01-01

    Analytical measurements of the 28Si crystal used for the determination of the Avogadro constant are essential to prevent biased results or under-estimated uncertainties. A review of the existing data confirms the high-purity of silicon with respect to a large number of elements. In order to obtain a direct evidence of purity, we developed a relative analytical method based on neutron activation. As a preliminary test, this method was applied to a sample of the Avogadro crystal WASO 04. The investigation concerned twenty-nine elements. The mass fraction of Au was quantified to be 1.03(18) x 10-12. For the remaining twenty-eight elements, the mass fractions are below the detection limits, which range between 1 x 10-12 and 1 x 10-5.

  8. Application of instrumental neutron activation analysis for the examination of oil pigments

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Y.S.; Kim, S.H.; Sun, G.M.; Lim, J.M.; Moon, J.H.; Kim, Y.J. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lim, S.J.; Song, Y.N.; Kim, K. [National Museum of Contemporary Art, Gwacheon, Gyeonggi-do (Korea, Republic of)

    2011-07-01

    This study is to investigate the applicability of instrumental neutron activation analysis (INAA) as a non-destructive examination tool for the quantitative chemical composition analysis associated with authentication, restoration and conservation of art objects in the field of cultural heritage. The quantitative analysis of major, minor and trace elements in Rembrandt's {sup registered} oil pigments recently collected at the Korean market as one of the art objects was carried out using INAA facilities of the HANARO research reactor at the Korea Atomic Energy Research Institute in collaboration with the National Museum of Contemporary Art in Korea. Analytical quality control was implemented using NIST SRM 2709, certified reference materials and metal standards. The analytical results for seventeen characteristic elements of thirty-one measured elements were statistically treated to identify the characteristic correlations and patterns between color and source of oil pigment and similarity degree of constituents using a cluster and discriminate analysis. (orig.)

  9. Instrumental neutron activation analysis data for cloud-water particulate samples, Mount Bamboo, Taiwan

    Science.gov (United States)

    Lin, Neng-Huei; Sheu, Guey-Rong; Wetherbee, Gregory A.; Debey, Timothy M.

    2013-01-01

    Cloud water was sampled on Mount Bamboo in northern Taiwan during March 22-24, 2002. Cloud-water samples were filtered using 0.45-micron filters to remove particulate material from the water samples. Filtered particulates were analyzed by instrumental neutron activation analysis (INAA) at the U.S. Geological Survey National Reactor Facility in Denver, Colorado, in February 2012. INAA elemental composition data for the particulate materials are presented. These data complement analyses of the aqueous portion of the cloud-water samples, which were performed earlier by the Department of Atmospheric Sciences, National Central University, Taiwan. The data are intended for evaluation of atmospheric transport processes and air-pollution sources in Southeast Asia.

  10. Neutron activation analysis of cadmium bioremediation by yeast isolated from the fermentation of cachaca

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Frederico H.; Moreira, Luciana M.C.; Porto, Barbara A.A.; Menezes, Maria Angela B.C.; Amaral, Angela M.; Neves, Maria J. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)], e-mail: fhr@cdtn.br; Rosa, Carlos A. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)], e-mail: carlrosa@icb.ufmg.br

    2009-07-01

    The accumulation of heavy metal in urban environment is a final result of industrial waste discharges. The removal and recovery of heavy metals from contaminated water and wastewater is important in the protection of the environment and human health. There are several chemical technologies used to remove heavy metals. Most of these are ineffective or excessively expensive when the metal concentrations are less than 100 mgL{sup -1}. Biological treatment with bioremediation, is an innovative technology available for heavy metal polluted wastewaters. Brazil has a big production of yeast as a by-product of the fermentation of sugar cane for the production of ethanol or, for the production of artisanal cachaca, notedly in the state of Minas Gerais. Biological organisms remove metals through of two processes: bioaccumulation and biosorption. This research used neutron activation technique to determine the capacity of 10 isolated yeast of the fermentation for the withdrawal of cadmium. The efflux of ions K{sup +}, was also analyzed by the same technique after the incorporation of cadmium by cells. This work showed that the neutron activation analysis is a suitable technique to quantification the metal absorbed from liquid solution and that isolated strains of the fermentation of cachaca are more efficient in removing cadmium of the liquid solution that the laboratorial strain. The influences of the metals on the growth of the cells are also observed. The results obtained were compared with the yeast strain of laboratory, Saccharomyces cerevisiae W303-WT. The tolerance of cadmium to concentration of 100 mgL{sup -1} was evaluated. (author)

  11. Radio disappearance of the magnetar XTE J1810-197 and continued X-ray timing

    CERN Document Server

    Camilo, F; Halpern, J P; Alford, J A J; Cognard, I; Reynolds, J E; Johnston, S; Sarkissian, J; van Straten, W

    2016-01-01

    We report on timing, flux density, and polarimetric observations of the transient magnetar and 5.54 s radio pulsar XTE J1810-197 using the GBT, Nancay, and Parkes radio telescopes beginning in early 2006, until its sudden disappearance as a radio source in late 2008. Repeated observations through 2016 have not detected radio pulsations again. The torque on the neutron star, as inferred from its rotation frequency derivative f-dot, decreased in an unsteady manner by a factor of 3 in the first year of radio monitoring. In contrast, during its final year as a detectable radio source, the torque decreased steadily by only 9%. The period-averaged flux density, after decreasing by a factor of 20 during the first 10 months of radio monitoring, remained steady in the next 22 months, at an average of 0.7+/-0.3 mJy at 1.4 GHz, while still showing day-to-day fluctuations by factors of a few. There is evidence that during this last phase of radio activity the magnetar had a steep radio spectrum, in contrast to earlier be...

  12. Innovative high pressure gas MEM's based neutron detector for ICF and active SNM detection.

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Shawn Bryan; Derzon, Mark Steven; Renzi, Ronald F.; Chandler, Gordon Andrew

    2007-12-01

    An innovative helium3 high pressure gas detection system, made possible by utilizing Sandia's expertise in Micro-electrical Mechanical fluidic systems, is proposed which appears to have many beneficial performance characteristics with regards to making these neutron measurements in the high bremsstrahlung and electrical noise environments found in High Energy Density Physics experiments and especially on the very high noise environment generated on the fast pulsed power experiments performed here at Sandia. This same system may dramatically improve active WMD and contraband detection as well when employed with ultrafast (10-50 ns) pulsed neutron sources.

  13. Assessment of the associated particle prompt gamma neutron activation technique for total body nitrogen measurement in vivo

    Science.gov (United States)

    Total Body Nitrogen (TBN) can be used to estimate Total Body Protein (TBP), an important body composition component at the molecular level. A system using the associated particle technique in conjunction with prompt gamma neutron activation analysis has been developed for the measurement of TBN in ...

  14. Neutron activation analysis and numerical taxonomy of thin orange ceramics from the manufacturing site of Rio Carnero, Puebla, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Rattray, E. (Universidad Nacional Autonoma de Mexico, Mexico City (Mexico). Inst. de Investigaciones Antropologicas); Harbottle, G. (Brookhaven National Lab., Upton, NY (USA))

    1991-04-01

    Examples of different types of Thin Orange ceramics found at the recently-discovered manufacturing sites in the state of Puebla have been analyzed by neutron activation. A full multivariate numerical analysis indicates that this material is chemically identical with the well-known Thin Orange of Teotihuacan.'' 33 refs., 2 figs., 2 tabs.

  15. Neutrons in active proton therapy. Parameterization of dose and dose equivalent

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Uwe; Haelg, Roger A. [Univ. of Zurich (Switzerland). Dept. of Physics; Radiotherapy Hirslanden AG, Aarau (Switzerland); Lomax, Tony [Paul Scherrer Institute, Villigen (Switzerland). Center for Proton Therapy

    2017-08-01

    One of the essential elements of an epidemiological study to decide if proton therapy may be associated with increased or decreased subsequent malignancies compared to photon therapy is an ability to estimate all doses to non-target tissues, including neutron dose. This work therefore aims to predict for patients using proton pencil beam scanning the spatially localized neutron doses and dose equivalents. The proton pencil beam of Gantry 1 at the Paul Scherrer Institute (PSI) was Monte Carlo simulated using GEANT. Based on the simulated neutron dose and neutron spectra an analytical mechanistic dose model was developed. The pencil beam algorithm used for treatment planning at PSI has been extended using the developed model in order to calculate the neutron component of the delivered dose distribution for each treated patient. The neutron dose was estimated for two patient example cases. The analytical neutron dose model represents the three-dimensional Monte Carlo simulated dose distribution up to 85 cm from the proton pencil beam with a satisfying precision. The root mean square error between Monte Carlo simulation and model is largest for 138 MeV protons and is 19% and 20% for dose and dose equivalent, respectively. The model was successfully integrated into the PSI treatment planning system. In average the neutron dose is increased by 10% or 65% when using 160 MeV or 177 MeV instead of 138 MeV. For the neutron dose equivalent the increase is 8% and 57%. The presented neutron dose calculations allow for estimates of dose that can be used in subsequent epidemiological studies or, should the need arise, to estimate the neutron dose at any point where a subsequent secondary tumour may occur. It was found that the neutron dose to the patient is heavily increased with proton energy.

  16. Discovery of an X-ray cavity near the radio lobes of Cygnus A indicating previous AGN activity

    CERN Document Server

    Chon, Gayoung; Krause, Martin; Truemper, Joachim

    2012-01-01

    Cygnus A harbours the nearest powerful radio jet of an Fanaroff-Riley (FR) class II radio galaxy in a galaxy cluster where the interaction of the jet with the intracluster medium (ICM) can be studied in detail. We use a large set of Chandra archival data, VLA and new LOFAR observations to shed new light on the interaction of the jets with the ICM. We identify an X-ray cavity in the distribution of the X-ray emitting plasma in the region south of the Cyg A nucleus which has lower pressure than the surrounding medium. The LOFAR and VLA radio observations show that the cavity is filled with synchrotron emitting plasma. The spectral age and the buoyancy time of the cavity indicates an age at least as large as the current Cyg A jets and not much larger than twice this time. We suggest that this cavity was created in a previous active phase of Cyg A when the energy output of the Active Galactic Nucleus (AGN) was about two orders of magnitude less than today.

  17. Parametric Evaluation of Active Neutron Interrogation for the Detection of Shielded Highly-Enriched Uranium in the Field

    Energy Technology Data Exchange (ETDEWEB)

    D. L. Chcihester; E. H. Seabury; S. J. Thompson; R. R. C. Clement

    2011-10-01

    Parametric studies using numerical simulations are being performed to assess the performance capabilities and limits of active neutron interrogation for detecting shielded highly enriched uranium (HEU). Varying the shield material, HEU mass, HEU depth inside the shield, and interrogating neutron source energy, the simulations account for both neutron and photon emission signatures from the HEU with resolution in both energy and time. The results are processed to represent different irradiation timing schemes and several different classes of radiation detectors, and evaluated using a statistical approach considering signal intensity over background. This paper describes the details of the modeling campaign and some preliminary results, weighing the strengths of alternative measurement approaches for the different irradiation scenarios.

  18. 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.

  19. Neutron Damage in Mechanically-Cooled High-Purity Germanium Detectors for Field-Portable Prompt Gamma Neutron Activation Analysis (PGNAA) Systems

    Energy Technology Data Exchange (ETDEWEB)

    E.H. Seabury; C.J. Wharton; A.J. Caffrey; J.B. McCabe; C. DeW. Van Siclen

    2013-10-01

    Prompt Gamma Neutron Activation (PGNAA) systems require the use of a gamma-ray spectrometer to record the gamma-ray spectrum of an object under test and allow the determination of the object’s composition. Field-portable systems, such as Idaho National Laboratory’s PINS system, have used standard liquid-nitrogen-cooled high-purity germanium (HPGe) detectors to perform this function. These detectors have performed very well in the past, but the requirement of liquid-nitrogen cooling limits their use to areas where liquid nitrogen is readily available or produced on-site. Also, having a relatively large volume of liquid nitrogen close to the detector can impact some assessments, possibly leading to a false detection of explosives or other nitrogen-containing chemical. Use of a mechanically-cooled HPGe detector is therefore very attractive for PGNAA applications where nitrogen detection is critical or where liquid-nitrogen logistics are problematic. Mechanically-cooled HPGe detectors constructed from p-type germanium, such as Ortec’s trans-SPEC, have been commercially available for several years. In order to assess whether these detectors would be suitable for use in a fielded PGNAA system, Idaho National Laboratory (INL) has been performing a number of tests of the resistance of mechanically-cooled HPGe detectors to neutron damage. These detectors have been standard commercially-available p-type HPGe detectors as well as prototype n-type HPGe detectors. These tests compare the performance of these different detector types as a function of crystal temperature and incident neutron fluence on the crystal.

  20. Low Frequency Radio Observations of X-ray Ghost Bubbles in Abell 2597: A History of Radio Activity in the Core

    CERN Document Server

    Clarke, T E; Blanton, E L; Neumann, D M; Kassim, N E

    2005-01-01

    A previous analysis of the Chandra X-ray image of the center of the cooling core cluster Abell 2597 showed two ``ghost holes'' in the X-ray emission to the west and northeast of the central radio galaxy PKS 2322-123. Previous radio observations did not detect any radio emission coming from the interior of the X-ray holes. We present new low frequency radio observations of Abell 2597. At 330 MHz, radio emission extends into the interior of the western ghost bubble, but not the northeast one. Our re-analysis of the archival Chandra data shows evidence for an X-ray tunnel (elongated region of reduced X-ray emission) extending from near the center of the cD out to the west ghost bubble. We also detect a smaller X-ray hole to the northeast of the center of the cD and closer than the outer ghost bubbles. Radio observations at 1.3 GHz show extensions to the west along the X-ray tunnel toward the west ghost bubble, to the northeast into the new X-ray hole, and to the northwest. All of these structures are much larger...

  1. Ultra-fast outflows in radio-loud active galactic nuclei

    CERN Document Server

    Tombesi, F; Mushotzky, R F; Ueda, Y; Cappi, M; Gofford, J; Reeves, J N; Guainazzi, M

    2014-01-01

    Recent X-ray observations show absorbing winds with velocities up to mildly-relativistic values of the order of ~0.1c in a limited sample of 6 broad-line radio galaxies. They are observed as blue-shifted Fe XXV-XXVI K-shell absorption lines, similarly to the ultra-fast outflows (UFOs) reported in Seyferts and quasars. In this work we extend the search for such Fe K absorption lines to a larger sample of 26 radio-loud AGNs observed with XMM-Newton and Suzaku. The sample is drawn from the Swift BAT 58-month catalog and blazars are excluded. X-ray bright FR II radio galaxies constitute the majority of the sources. Combining the results of this analysis with those in the literature we find that UFOs are detected in >27% of the sources. However, correcting for the number of spectra with insufficient signal-to-noise, we can estimate that the incidence of UFOs is this sample of radio-loud AGNs is likely in the range f=(50+/-20)%. A photo-ionization modeling of the absorption lines with XSTAR allows to estimate the d...

  2. A New Perspective of the Radio Bright Zone at The Galactic Center: Feedback from Nuclear Activities

    CERN Document Server

    Zhao, Jun-Hui; Goss, W M

    2015-01-01

    New observations of Sgr A have been carried out with the VLA using the broadband (2 GHz) continuum mode at 5.5 GHz, covering the central 30 pc region of the RBZ at the Galactic center. Using the MS-MFS algorithms in CASA, we have imaged Sgr A with a resolution of 1", achieving an rms 8 $\\mu$Jy/beam, and a dynamic range 100,000:1.The radio image is compared with X-ray, CN emission-line and Paschen-$\\alpha$ images obtained using Chandra, SMA and HST/NICMOS, respectively. We discuss several prominent radio features. The "Sgr A West Wings" extend 5 pc from the NW and SE tips of the ionized "Mini-spiral" in Sgr A West to positions located 2.9 and 2.4 arc min to the NW and SE of Sgr A*, respectively. The NW wing, along with several other prominent features, including the "NW Streamers", form an elongated radio lobe (NW lobe), oriented nearly perpendicular to the Galactic plane. This radio lobe, with a size of 14.4 pc x 7.3 pc, has a known X-ray counterpart. A row of three thermally emitting rings is observed in the...

  3. SU-E-T-557: Measuring Neutron Activation of Cardiac Devices Irradiated During Proton Therapy Using Indium Foils

    Energy Technology Data Exchange (ETDEWEB)

    Avery, S; Christodouleas, J; Delaney, K; Diffenderfer, E; Brown, K [University of Pennsylvania, Sicklerville, NJ (United States)

    2014-06-01

    Purpose: Measuring Neutron Activation of Cardiac devices Irradiated during Proton Therapy using Indium Foils Methods: The foils had dimensions of 25mm x 25mm x 1mm. After being activated, the foils were placed in a Canberra Industries well chamber utilizing a NaI(Tl) scintillation detector. The resulting gamma spectrum was acquired and analyzed using Genie 2000 spectroscopy software. One activation foil was placed over the upper, left chest of RANDO where a pacemaker would be. The rest of the foils were placed over the midline of the patient at different distances, providing a spatial distribution over the phantom. Using lasers and BBs to align the patient, 200 MU square fields were delivered to various treatment sites: the brain, the pancreas, and the prostate. Each field was shot at least a day apart, giving more than enough time for activity of the foil to decay (t1=2 = 54.12 min). Results: The net counts (minus background) of the three aforementioned peaks were used for our measurements. These counts were adjusted to account for detector efficiency, relative photon yields from decay, and the natural abundance of 115-In. The average neutron flux for the closed multi-leaf collimator irradiation was measured to be 1.62 x 106 - 0.18 x 106 cm2 s-1. An order of magnitude estimate of the flux for neutrons up to 1 keV from Diffenderfer et al. gives 3 x 106 cm2 s-1 which does agree on the order of magnitude. Conclusion: Lower energy neutrons have higher interaction cross-sections and are more likely to damage pacemakers. The thermal/slow neutron component may be enough to estimate the overall risk. The true test of the applicability of activation foils is whether or not measurements are capable of predicting cardiac device malfunction. For that, additional studies are needed to provide clinical evidence one way or the other.

  4. Neutron-induced 63Ni activity and microscopic observation of copper samples exposed to the Hiroshima atomic bomb

    Science.gov (United States)

    Shizuma, Kiyoshi; Endo, Satoru; Shinozaki, Kenji; Fukushima, Hiroshi

    2013-05-01

    Fast neutron activation data for 63Ni in copper samples exposed to the Hiroshima atomic bomb are important in evaluating neutron doses to the survivors. Up to until now, accelerator mass spectrometry and liquid scintillation counting methods have been applied in 63Ni measurements and data were accumulated within 1500 m from the hypocenter. The slope of the activation curve versus distance shows reasonable agreement with the calculation result, however, data near the hypocenter are scarce. In the present work, two copper samples obtained from the Atomic bomb dome (155 m from the hypocenter) and the Bank of Japan building (392 m) were utilized in 63Ni beta-ray measurement with a Si surface barrier detector. Additionally, microscopic observation of the metal surfaces was performed for the first time. Only upper limit of 63Ni production was obtained for copper sample of the Atomic bomb dome. The result of the 63Ni measurement for Bank of Japan building show reasonable agreement with the AMS measurement and to fast neutron activation calculations based on the Dosimetry System 2002 (DS02) neutrons.

  5. The panels for primary and secondary mirror reflectors and the Active Surface System for the new Sardinia Radio Telescope

    Science.gov (United States)

    Zacchiroli, G.; Fiocchi, F.; Maccaferri, G.; Morsiani, M.; Orfei, A.; Pernechele, C.; Pisanu, T.; Roda, J.; Vargiu, G.

    In this paper we will describe the panels for the primary and secondary mirror reflectors and the active surface system that will be provided on the Sardinia Radio Telescope. The panels for the primary and secondary mirror have been designed to allow an operating frequency up to 100 GHz. The active surface system will be used to overcome the effect of gravity deformation on the antenna gain and to re-shape the primary mirror in a parabolic form, in order to avoid large phase error contribution on the gain for the highest frequencies placed in the primary focus.

  6. Elemental characterization of Mt. Sinabung volcanic ash, Indonesia by Neutron Activation Analysis

    Science.gov (United States)

    Kusmartini, I.; Syahfitri, W. Y. N.; Kurniawati, S.; Lestiani, D. D.; Santoso, M.

    2017-06-01

    Mount Sinabung is a volcano located in North Sumatera, Indonesia which has been recorded not erupted since 1600. However in 2013 it has been erupted and cause of black thick smog, rain sand and volcanic ash. Volcanic ash containing trace elements material that can be utilized in various applications but still has potential danger of heavy metals. In order to obtain an elemental composition data of volcanic ash, the characterization of volcanic ash were carried out using Neutron Activation Analysis. The volcanic ash was taken from Mt. Sinabung eruption. Samples were irradiated at the rabbit system in the reactor G.A Siwabessy facilities with neutron flux ˜ 1013 n.cm-2.s-1 and then counted using HPGe detector. Method validation was carried out by SRM NIST Coal Fly Ash 1633b and NIST 2711a Montana II Soil with recovery values were in the range of 96-108% and 95-106% respectively. The results showed that major elements; Al, Na, Ca and Fe, concentrations were 8.7, 1.05, 2.98 and 7.44 %, respectively, minor elements K, Mg, Mn, Ti, V and Zn were 0.87%, 0.78%, 0.18%, 0.62%, 197.13 ppm and 109.35 ppm, respectively, heavy metals; As, Cr, Co and Sb, contents were 4.48, 11.75, 17.13 and 0.35 ppm, respectively while rare earth elements such as Ce, Eu, La, Nd, Sm, Yb were 45.33, 1.22, 19.63, 20.34, 3.86, and 2.57 ppm respectively. The results of the elemental contents of volcanic ash that has been obtained can be used as the scientific based data for volcanic material utilization by considering the economic potential of elements contained and also the danger of the heavy metals content.

  7. Radio Emission from Globular Clusters

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Radio emission of globular clusters is studied by analyzing the VLA radio survey data of the NVSS and FIRST. We find that 13 clusters have radio sources within their half-mass radii of clusters. Sources detected previously in NGC 7078and NGC 6440 are identified. Pulsars in NGC 6121, NGC 6440 and NGC 7078cannot be detected because of the insufficient survey sensitivity and resolution.There may be a pulsar in the core of Terzan 1. The nature of the extended radio source near the core of NGC 6440 remains unclear. In the core of a globular cluster,there may be many neutron stars or an intermediate mass black hole, but this cannot be clarified with the current radio observations.

  8. Measurement of 232Th(n,2n)231Th reaction cross-sections at neutron energies of 14.1 MeV and 14.8 MeV using neutron activation method

    Institute of Scientific and Technical Information of China (English)

    兰长林; 解保林; 张凯; 彭猛; 方开洪

    2015-01-01

    In this study, the activation cross-sections were measured for 232Th(n,2n)231Th reactions at neutron ener-gies of 14.1 and 14.8 MeV, which were produced by a neutron generator through a T(d,n) 4He reaction. In-duced gamma-ray activities were measured using a low background gamma ray spectrometer equipped with a high resolution HPGe detector. In the cross-section calculations, corrections were made regarding the effects of gamma-ray attenuation, dead-time, fluctuation of the neutron flux, and low energy neutrons. The mea-sured cross-sections were compared with the literature data, evaluation data (ENDF-B/VII.1, JENDL-4.0 and CENDL-3.1), and the results of the model calculation (TALYS1.6).

  9. Development of a photonuclear activation file and measurement of delayed neutron spectra; Creation d'une bibliotheque d'activation photonucleaire et mesures de spectres d'emission de neutrons retardes

    Energy Technology Data Exchange (ETDEWEB)

    Giacri-Mauborgne, M.L

    2005-11-15

    This thesis work consists in two parts. The first part is the description of the creation of a photonuclear activation file which will be used to calculated photonuclear activation. To build this file we have used different data sources: evaluations but also calculations done using several cross sections codes (HMS-ALICE, GNASH, ABLA). This file contains photonuclear activation cross sections for more than 600 nuclides and fission fragments distributions for 30 actinides at tree different Bremsstrahlung energies and the delay neutron spectrum associated. These spectra are not in good agreement with experimental data. That is why we decided to launch measurement of delayed neutrons spectra from photofission. The second part of this thesis consists in demonstrating the possibility to do such measurements at the ELSA accelerator facility. To that purpose, we have developed the detection, the acquisition system and the analysis method of such spectra. These were tested for the measurement of the delayed neutron spectrum of uranium-238 after irradiation in a 2 MeV neutron flux. Finally, we have measured the delayed neutron spectrum of uranium-238 after irradiation in a 15 MeV Bremsstrahlung flux. We compare our results with experimental data. The experiment has allowed us to improve the value of {nu}{sub p}-bar with an absolute uncertainty below 7%, we propose {nu}{sub p}-bar = (3.03 {+-} 0.02) n/100 fissions, and to correct the Nikotin's parameters for the six group representation. Particularly, we have improved the data concerning the sixth group by taking into account results from different irradiation times.

  10. Internal exposure to neutron-activated {sup 56}Mn dioxide powder in Wistar rats. Pt. 1. Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Stepanenko, Valeriy; Kaprin, Andrey; Galkin, Vsevolod; Ivanov, Sergey; Kolyzhenkov, Timofey; Petukhov, Aleksey; Yaskova, Elena; Belukha, Irina; Khailov, Artem; Skvortsov, Valeriy; Ivannikov, Alexander; Akhmedova, Umukusum; Bogacheva, Viktoria [Medical Radiological Research Center (MRRC) named after A.F. Tsyb - National Medical Research Radiological Center of the Health Ministry of the Russian Federation, Obninsk, Kaluga Region (Russian Federation); Rakhypbekov, Tolebay; Dyussupov, Altay; Chaizhunusova, Nailya; Sayakenov, Nurlan; Uzbekov, Darkhan; Saimova, Aisulu; Shabdarbaeva, Dariya; Kairkhanova, Yankar [Semey State Medical University, Semey (Kazakhstan); Otani, Keiko; Endo, Satoru; Satoh, Kenichi; Kawano, Noriyuki; Fujimoto, Nariaki; Hoshi, Masaharu [Hiroshima University, Hiroshima (Japan); Shichijo, Kazuko; Nakashima, Masahiro; Takatsuji, Toshihiro [Nagasaki University, Nagasaki (Japan); Sakaguchi, Aya; Kato, Hiroaki; Onda, Yuichi [University of Tsukuba, Ibaraki (Japan); Toyoda, Shin [Okayama University of Science, Okayama (Japan); Sato, Hitoshi [Ibaraki Prefectural University of Health Science, Ibaraki (Japan); Skakov, Mazhin; Vurim, Alexandr; Gnyrya, Vyacheslav; Azimkhanov, Almas; Kolbayenkov, Alexander [National Nuclear Center of the Republic of Kazakhstan, Kurchatov (Kazakhstan); Zhumadilov, Kasym [Eurasian National University named after L.N. Gumilyov, Astana (Kazakhstan)

    2017-03-15

    There were two sources of ionizing irradiation after the atomic bombings of Hiroshima and Nagasaki: (1) initial gamma-neutron irradiation at the moment of detonation and (2) residual radioactivity. Residual radioactivity consisted of two components: radioactive fallout containing fission products, including radioactive fissile materials from nuclear device, and neutron-activated radioisotopes from materials on the ground. The dosimetry systems DS86 and DS02 were mainly devoted to the assessment of initial radiation exposure to neutrons and gamma rays, while only brief considerations were given for the estimation of doses caused by residual radiation exposure. Currently, estimation of internal exposure of atomic bomb survivors due to dispersed radioactivity and neutron-activated radioisotopes from materials on the ground is a matter of some interest, in Japan. The main neutron-activated radionuclides in soil dust were {sup 24}Na, {sup 28}Al, {sup 31}Si, {sup 32}P, {sup 38}Cl, {sup 42}K, {sup 45}Ca, {sup 46}Sc, {sup 56}Mn, {sup 59}Fe, {sup 60}Co, and {sup 134}Cs. The radionuclide {sup 56}Mn (T{sub 1/2} = 2.58 h) is known as one of the dominant beta- and gamma emitters during the first few hours after neutron irradiation of soil and other materials on ground, dispersed in the form of dust after a nuclear explosion in the atmosphere. To investigate the peculiarities of biological effects of internal exposure to {sup 56}Mn in comparison with external gamma irradiation, a dedicated experiment with Wistar rats exposed to neutron-activated {sup 56}Mn dioxide powder was performed recently by Shichijo and coworkers. The dosimetry required for this experiment is described here. Assessment of internal radiation doses was performed on the basis of measured {sup 56}Mn activity in the organs and tissues of the rats and of absorbed fractions of internal exposure to photons and electrons calculated with the MCNP-4C Monte Carlo using a mathematical rat phantom. The first results of

  11. Determination of Interesting Toxicological Elements in PM2.5 by Neutron and Photon Activation Analysis

    Directory of Open Access Journals (Sweden)

    Pasquale Avino

    2013-01-01

    Full Text Available Human activities introduce compounds increasing levels of many dangerous species for environment and population. In this way, trace elements in airborne particulate have a preeminent position due to toxic element presence affecting the biological systems. The main problem is the analytical determination of such species at ultratrace levels: a very specific methodology is necessary with regard to the accuracy and precision and contamination problems. Instrumental Neutron Activation Analysis and Instrumental Photon Activation Analysis assure these requirements. A retrospective element analysis in airborne particulate collected in the last 4 decades has been carried out for studying their trend. The samples were collected in urban location in order to determine only effects due to global aerosol circulation; semiannual samples have been used to characterize the summer/winter behavior of natural and artificial origin. The levels of natural origin element are higher than those in other countries owing to geological and meteorological factors peculiar to Central Italy. The levels of artificial elements are sometimes less than those in other countries, suggesting a less polluted general situation for Central Italy. However, for a few elements (e.g., Pb the levels measured are only slight lower than those proposed as air ambient standard.

  12. Measurement of reaction-in-flight neutrons using thulium activation at the National Ignition Facility

    Science.gov (United States)

    Grim, G. P.; Rundberg, R.; Fowler, M. M.; Hayes, A. C.; Jungman, G.; Boswell, M.; Klein, A.; Wilhelmy, J.; Tonchev, A.; Yeamans, C. B.

    2014-09-01

    We report on the first observation of tertiary reaction-in-flight (RIF) neutrons produced in compressed deuterium and tritium filled capsules using the National Ignition Facility at Lawrence Livermore National Laboratory, Livermore, CA. RIF neutrons are produced by third-order, out of equilibrium ("in-flight") fusion reactions, initiated by primary fusion products. The rate of RIF reactions is dependent upon the range of the elastically scattered fuel ions and therefore a diagnostic of Coulomb physics within the plasma. At plasma temperatures of ˜5 keV, the presence of neutrons with kinetic energies greater than 15 MeV is a unique signature for RIF neutron production. The reaction 169Tm(n,3n)167Tm has a threshold of 15.0 MeV, and a unique decay scheme making it a suitable diagnostic for observing RIF neutrons. RIF neutron production is quantified by the ratio of 167Tm/168Tm observed in a 169Tm foil, where the reaction 169Tm(n,2n)168Tm samples the primary neutron fluence. Averaged over 4 implosions1-4 at the NIF, the 167Tm/168Tm ratio is measured to be 1.5 +/- 0.3 x 10-5, leading to an average ratio of RIF to primary neutron ratio of 1.0 +/- 0.2 x 10-4. These ratios are consistent with the predictions for charged particle stopping in a quantum degenerate plasma.

  13. Design of Stopper of Prompt Gamma Neutron Activation Analysis Facility at China Advanced Research Reactor

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The PGNAA facility consists of the filtered collimated neutron beam, the shielding of the whole facility, the control system, the detecting equipment and the data acquisition and analysis system. The neutron beam is filtered by a mono-crystalline bismuth filter,

  14. A NEW PERSPECTIVE OF THE RADIO BRIGHT ZONE AT THE GALACTIC CENTER: FEEDBACK FROM NUCLEAR ACTIVITIES

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jun-Hui [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Morris, Mark R. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095 (United States); Goss, W. M., E-mail: jzhao@cfa.harvard.edu [NRAO, P.O. Box O, Socorro, NM 87801 (United States)

    2016-02-01

    New observations of Sgr A have been carried out with the Jansky VLA in the B and C arrays using the broadband (2 GHz) continuum mode at 5.5 GHz. The field of view covers the central 13′ (30 pc) region of the radio-bright zone at the Galactic center. Using the multi-scale and multi-frequency-synthesis (MS-MFS) algorithms in CASA, we have imaged Sgr A with a resolution of 1″, achieving an rms noise of 8 μJy beam{sup −1}, and a dynamic range of 100,000:1. Both previously known and newly identified radio features in this region are revealed, including numerous filamentary sources. The radio continuum image is compared with Chandra X-ray images, with a CN emission-line image obtained with the Submillimeter Array and with detailed Paschen-α images obtained with Hubble Space Telescope/NICMOS. We discuss several prominent features in the radio image. The “Sgr A west Wings” extend 2′ (5 pc) from the NW and SE tips of the Sgr A west H ii region (the “Mini-spiral”) to positions located 2.9 and 2.4 arcmin to the northwest and southeast of Sgr A*, respectively. The NW wing, along with several other prominent features, including the previously identified “NW Streamers,” form an elongated radio lobe (NW lobe), oriented nearly perpendicular to the Galactic plane. This radio lobe, with a size of 6.′3 × 3.′2 (14.4 pc × 7.3 pc), has a known X-ray counterpart. In the outer region of the NW lobe, a row of three thermally emitting rings is observed. A field containing numerous amorphous radio blobs extends for a distance of ∼2 arcmin beyond the tip of the SE wing; these newly recognized features coincide with the SE X-ray lobe. Most of the amorphous radio blobs in the NW and SE lobes have Paschen-α counterparts. We propose that they have been produced by shock interaction of ambient gas concentrations with a collimated nuclear wind or an outflow that originated from within the circumnuclear disk (CND). We also discuss the possibility that the ionized

  15. A New Perspective of the Radio Bright Zone at The Galactic Center: Feedback from Nuclear Activities

    Science.gov (United States)

    Zhao, Jun-Hui; Morris, Mark R.; Goss, W. M.

    2016-02-01

    New observations of Sgr A have been carried out with the Jansky VLA in the B and C arrays using the broadband (2 GHz) continuum mode at 5.5 GHz. The field of view covers the central 13‧ (30 pc) region of the radio-bright zone at the Galactic center. Using the multi-scale and multi-frequency-synthesis (MS-MFS) algorithms in CASA, we have imaged Sgr A with a resolution of 1″, achieving an rms noise of 8 μJy beam-1, and a dynamic range of 100,000:1. Both previously known and newly identified radio features in this region are revealed, including numerous filamentary sources. The radio continuum image is compared with Chandra X-ray images, with a CN emission-line image obtained with the Submillimeter Array and with detailed Paschen-α images obtained with Hubble Space Telescope/NICMOS. We discuss several prominent features in the radio image. The “Sgr A west Wings” extend 2‧ (5 pc) from the NW and SE tips of the Sgr A west H ii region (the “Mini-spiral”) to positions located 2.9 and 2.4 arcmin to the northwest and southeast of Sgr A*, respectively. The NW wing, along with several other prominent features, including the previously identified “NW Streamers,” form an elongated radio lobe (NW lobe), oriented nearly perpendicular to the Galactic plane. This radio lobe, with a size of 6.‧3 × 3.‧2 (14.4 pc × 7.3 pc), has a known X-ray counterpart. In the outer region of the NW lobe, a row of three thermally emitting rings is observed. A field containing numerous amorphous radio blobs extends for a distance of ˜2 arcmin beyond the tip of the SE wing; these newly recognized features coincide with the SE X-ray lobe. Most of the amorphous radio blobs in the NW and SE lobes have Paschen-α counterparts. We propose that they have been produced by shock interaction of ambient gas concentrations with a collimated nuclear wind or an outflow that originated from within the circumnuclear disk (CND). We also discuss the possibility that the ionized wind or

  16. The radio/gamma-ray connection in Active Galactic Nuclei in the era of the Fermi Large Area Telescope

    CERN Document Server

    Ackermann, M; Allafort, A; Angelakis, E; Axelsson, M; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bouvier, A; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Buehler, R; Buson, S; Caliandro, G A; Cameron, R A; Cannon, A; Caraveo, P A; Casandjian, J M; Cavazzuti, E; Cecchi, C; Charles, E; Chekhtman, A; Cheung, C C; Ciprini, S; Claus, R; Cohen-Tanugi, J; Cutini, S; de Palma, F; Dermer, C D; Silva, E do Couto e; Drell, P S; Dubois, R; Dumora, D; Escande, L; Favuzzi, C; Fegan, S J; Focke, W B; Fortin, P; Frailis, M; Fuhrmann, L; Fukazawa, Y; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Giglietto, N; Giommi, P; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grandi, P; Grenier, I A; Guiriec, S; Hadasch, D; Hayashida, M; Hays, E; Healey, S E; J, G; Johnson, A S; Kamae, T; Katagiri, H; Kataoka, J; Kn, J; Kuss, M; Lande, J; Lee, S -H; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Makeev, A; Max-Moerbeck, W; Mazziotta, M N; McEnery, J E; Mehault, J; Michelson, P F; Mizuno, T; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Naumann-Godo, M; Nishino, S; Nolan, P L; Norris, J P; Nuss, E; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ormes, J F; Ozaki, M; Paneque, D; Pavlidou, V; Pelassa, V; Pepe, M; Pesce-Rollins, M; Pierbattista, M; Piron, F; Porter, T A; Rain, S; Razzano, M; Readhead, A; Reimer, A; Reimer, O; Richards, J L; Romani, R W; Sadrozinski, H F -W; Scargle, J D; Sgr, C; Siskind, E J; Smith, P D; Spandre, G; Spinelli, P; Strickman, M S; Suson, D J; Takahashi, H; Tanaka, T; Taylor, G B; Thayer, J G; Thayer, J B; Thompson, D J; Torres, D F; Tosti, G; Tramacere, A; Troja, E; Vandenbroucke, J; Vianello, G; Vitale, V; Waite, A P; Wang, P; Winer, B L; Wood, K S; Yang, Z; Ziegler, M

    2011-01-01

    We present a detailed statistical analysis of the correlation between radio and gamma-ray emission of the Active Galactic Nuclei (AGN) detected by Fermi during its first year of operation, with the largest datasets ever used for this purpose. We use both archival interferometric 8.4 GHz data (from the VLA and ATCA, for the full sample of 599 sources) and concurrent single-dish 15 GHz measurements from the Owens Valley Radio Observatory (OVRO, for a sub sample of 199 objects). Our unprecedentedly large sample permits us to assess with high accuracy the statistical significance of the correlation, using a surrogate-data method designed to simultaneously account for common-distance bias and the effect of a limited dynamical range in the observed quantities. We find that the statistical significance of a positive correlation between the cm radio and the broad band (E>100 MeV) gamma-ray energy flux is very high for the whole AGN sample, with a probability <1e-7 for the correlation appearing by chance. Using the...

  17. The effects of impurity composition and concentration in reactor structure material on neutron activation inventory in pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Gil Yong; Kim, Soon Young [RADCORE, Daejeon (Korea, Republic of); Lee, Jae Min [TUV Rheinland Korea, Seoul (Korea, Republic of); Kim, Yong Soo [Hanyang University, Seoul (Korea, Republic of)

    2016-06-15

    The neutron activation inventories in reactor vessel and its internals, and bio-shield of a PWR nuclear power plant were calculated to evaluate the effect of impurity elements contained in the structural materials on the activation inventory. Carbon steel is, in this work, used as the reactor vessel material, stainless steel as the reactor vessel internals, and ordinary concrete as the bio-shield. For stainless steel and carbon steel, one kind of impurity concentration was employed, and for ordinary concrete five kinds were employed in this study using MCNP5 and FISPACT for the calculation of neutron flux and activation inventory, respectively. As the results, specific activities for the cases with impurity elements were calculated to be more than twice than those for the cases without impurity elements in stainless and carbon steel. Especially, the specific activity for the concrete material with impurity elements was calculated to be 30 times higher than that without impurity. Neutron induced reactions and activation inventories in each material were also investigated, and it is noted that major radioactive nuclide in steel material is Co-60 from cobalt impurity element, and, in concrete material, Co-60 and Eu-152 from cobalt and europium impurity elements, respectively. The results of this study can be used for nuclear decommissioning plan during activation inventory assessment and regulation, and it is expected to be used as a reference in the design phase of nuclear power plant, considering the decommissioning of nuclear power plants or nuclear facilities.

  18. Essential and toxic element determination in edible mushrooms by neutron activation analysis; Determinacao de elementos essenciais e toxicos em cogumelos comestiveis por analise por ativacao com neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Patricia Landim da Costa

    2008-07-01

    In this study concentrations of As, Br, Co, Cr, Cs, Fe, K, Na, Rb, Se and Zn were determined in edible mushrooms acquired from commercial establishments in the city of Sao Paulo and directly from Mogi das Cruzes, Suzano, Juquitiba and Mirandopolis producers. The analytical technique used for determining these elements in edible mushrooms was Instrumental Neutron Activation Analysis (INAA). Species of the Agaricus, Lentinus and Pleurotus genera were acquired during the period from November, 2006 to March, 2007. About 150 to 200 mg of freeze-dried mushrooms were irradiated in a neutron flux of 1012 cm{sup -2} s{sup -1} for 8 hours in the IEA-R1 nuclear research reactor at IPEN-CNEN-SP. In order to evaluate the precision and accuracy of the methodology, four reference materials: INCT-MPH-2 Mixed Polish Herbs and INCT-TL-1 Tea Leaves, NIST SRM 1577b Bovine Liver, and the material Mushroom from IAEA were analyzed. Results showed some variation in the element concentrations among the different genera. In some samples, arsenic was found but in low concentrations. Arsenic is probably derived from the contamination from pesticides used in the cultivation, in their the substrates where mushrooms uptake their nutrients. Although there are element concentration variations, mushrooms can still be considered a very rich nutritional source, mainly because of their low concentrations of Na, and due to the good source of K, Fe and Zn. (author)

  19. Determination os essential elements in diet and light foods using neutron activation analysis; Determinacao de elementos essenciais em alimentos diet e light por analise por ativacao com neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Gerson Hideo [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Quimica]. E-mail: gehideo@gmail.com; Maihara, Vera Akiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Lab. de Analise por Ativacao Neutronica]. E-mail: vmaihara@ipen.br

    2007-07-01

    The object of this study was to determine essential elements on the diet and light foods and their normal similar through the neutron activation analysis (NAA) and to compare their results. Samples of sweetning, cappuccino, gelatine and chocolate collected at the Sao Paulo commerce were irradiated by a period of 8 hours, under a 10{sup 12} n cm{sub -2} s{sub -1} thermal neutron flux at the IEA-R1 research reactor - IPEN/CNEN-SP, Brazil, together with reference materials and elementary standards, for the determination the concentrations of Br, Ca, Cr, Co, K, Na, Fe, Se and Zn. The obtained results shown that the diet gelatine samples presented concentrations higher for determined elements related to the light and normal gelatines samples. Compared with cappucino samples there was not differences among the concentrations of the determined elements, excepted the element Cr for the cappuccino light. For the chocolate light they presents higher values related to the normal type. The sweetening did not present differences among the samples. (author)

  20. Study of the neutronic activation of the stainless steel in a nuclear reactor; Estudios de la activacion neutronica del acero inoxidable en un reactor nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Lazaro Roche, I.; Rodenas Diago, J.; Marques, J. G.

    2013-07-01

    During operation of a nuclear reactor, various components can be activated by neutron reactions. The activity thus generated produces a dose that is a potential risk to workers and environment. Was simulated using the MCNP and CINDER'90 such activation codes on a piece of steel and the values obtained compared with experimental measurements. The equivalence of both methods is verified to calculate neutron activation and evolution of the dose rate with the cooling time.