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Sample records for neutron individual monitoring

  1. A CR-39 track dosemeter for routine individual neutron monitoring

    International Nuclear Information System (INIS)

    Luszik-Bhadra, M.; Alberts, W.G.; Dietz, E.; Guldbakke, S.; Matzke, M.; d'Errico, F.

    1994-01-01

    A personal neutron dosemeter for routine individual monitoring is proposed. It is based on a CR-39 track detector covered on three separate areas by converters with different boron contents and inserted into a commercial TLD albedo dosemeter capsule. The dose readings from three areas of the electrochemically etched CR-39 detector are combined to yield a dose equivalent response which is almost independent of the incident neutron energy in the range from thermal neutrons up to 20 MeV. In addition, the dose contributions of thermal, intermediate and fast neutrons can be determined separately. Unlike the TLD albedo dosemeter, which in general requires prior in-field calibration and whose use is then restricted to that field, this dosemeter can be used in neutron fields without any knowledge of the spectral distribution with the same calibration factor. The angular dependence of the dosemeter's response has been measured and compared with that of the directional dose equivalent H'(10). The lower limit of detection is 0.15 mSv. It is possible to obtain an independent, second dose reading from the same Cr-39 detector for neutron energies above 100 keV. The dosemeter has also been successfully tested for use in accident dosimetry applying chemical etching and an optical density reading of the CR-39 detector. (author)

  2. Brazilian two-component TLD albedo neutron individual monitoring system

    Energy Technology Data Exchange (ETDEWEB)

    Martins, M.M., E-mail: marcelo@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD), Av. Salvador Allende, s/n, CEP: 22780-160, Rio de Janeiro, RJ (Brazil); Mauricio, C.L.P., E-mail: claudia@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD), Av. Salvador Allende, s/n, CEP: 22780-160, Rio de Janeiro, RJ (Brazil); Fonseca, E.S. da, E-mail: evaldo@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD), Av. Salvador Allende, s/n, CEP: 22780-160, Rio de Janeiro, RJ (Brazil); Silva, A.X. da, E-mail: ademir@con.ufrj.b [Coordenacao dos Programas de Pos-Graduacao em Engenharia, COPPE/PEN Caixa Postal 68509, CEP: 21941-972, Rio de Janeiro, RJ (Brazil)

    2010-12-15

    Since 1983, Instituto de Radioprotecao e Dosimetria, Brazil, uses a TLD one-component albedo neutron monitor, which has a single different calibration factor specifically for each installation type. In order to improve its energy response, a two-component albedo monitor was developed, which measure the thermal neutron component besides the albedo one. The two-component monitor has been calibrated in reference neutron fields: thermal, five accelerator-produced monoenergetic beams (70, 144, 565, 1200 and 5000 keV) and five radionuclide sources ({sup 252}Cf, {sup 252}Cf(D{sub 2}O), {sup 241}Am-Be, {sup 241}Am-B and {sup 238}Pu-Be) at several distances. Since January 2008, mainly Brazilian workers who handle neutron sources at different distances and moderation, such as in well logging and calibration facilities are using it routinely.

  3. Development and characterization of two-component albedo based neutron individual monitoring system using thermoluminescent detectors

    International Nuclear Information System (INIS)

    Martins, Marcelo Marques

    2008-01-01

    A TLD-albedo based two-component neutron individual monitoring system was developed and characterized in this work. The monitor consists of a black plastic holder, an incident neutron boron loaded shield, a moderator polyethylene body (to increase its response), two pairs of TLD-600 and TLD-700 (one pair to each component) and an adjustable belt. This monitoring system was calibrated in thermal neutron fields and in 70 keV, 144 keV, 565 keV, 1.2 MeV and 5 MeV monoenergetic neutron fields. In addition, it was calibrated in 252C f(D 2 O), 252 Cf, 241 Am-B, 241 Am-Be and 238 Pu-Be source fields. For the latter, the lower detection levels are, respectively, 0.009 mSv, 0.06 mSv, 0.12 mSv, 0.09 mSv and 0.08 mSv. The participation in an international intercomparison sponsored by IAEA with simulated workplace fields validated the system. The monitoring system was successfully characterized in the ISO 21909 standard and in an IRD - the Brazilian Institute for Radioprotection and Dosimetry - technical regulation draft. Nowadays, the neutron individual system is in use by IRD for whole body individual monitoring of five institutions, which comprehend several activities. (author)

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  5. ASIC based neutron monitor

    International Nuclear Information System (INIS)

    Shastrakar, R.S.; Madavi, Vaishali; Chandratre, V.B.; Manna, A.; Jakati, R.K.; Kataria, S.K.; Gopalakrishnan, N.

    2005-01-01

    A Neutron monitor is designed and developed using the OCTPREM, ADAM ASIC and the triplex LCD devices developed by Electronics Division BARC. The Neutron monitor uses BF3 as detector. The Neutron monitor is subdivided into three modules front end pulse processing using the OCTPREM ASIC, H.V. Unit, and the counting display unit using ADAM ASIC. The monitor features low power design and portable. The unit demonstrates the success of the devices developed in Electronics Division BARC. (author)

  6. Individual monitoring

    International Nuclear Information System (INIS)

    2004-01-01

    This Practical Radiation Technical Manual is one of a series which has been designed to provide guidance on radiological protection for employers, Radiation Protection Officers, managers and other technically competent persons who have a responsibility to ensure the safety of employees working with ionizing radiation. The Manual may be used together with the appropriate IAEA Practical Radiation Safety Manual to provide adequate training, instruction or information on individual monitoring for all employees engaged in work with ionizing radiations. Sources of ionizing radiation have a large number of applications in the workplace. The exposures of the individual workers involved may need to be routinely monitored and records kept of their cumulative radiation doses. There are also occasions when it is necessary to retrospectively determine a dose which may have been received by a worker. This Manual explains the basic terminology associated with individual monitoring and describes the principal types of dosimeters and other related techniques and their application in the workplace. The Manual will be of most benefit if it forms part of more comprehensive training or is supplemented by the advice of a qualified expert in radiation protection. Most of the dosimeters and techniques described in this Manual can only be provided by qualified experts

  7. Development and characterization of two-component albedo based neutron individual monitoring system using thermoluminescent detectors; Desenvolvimento e caracterizacao de um sistema de monitoracao individual de neutrons tipo albedo de duas componentes usando detectores termoluminescentes

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Marcelo Marques

    2008-07-01

    A TLD-albedo based two-component neutron individual monitoring system was developed and characterized in this work. The monitor consists of a black plastic holder, an incident neutron boron loaded shield, a moderator polyethylene body (to increase its response), two pairs of TLD-600 and TLD-700 (one pair to each component) and an adjustable belt. This monitoring system was calibrated in thermal neutron fields and in 70 keV, 144 keV, 565 keV, 1.2 MeV and 5 MeV monoenergetic neutron fields. In addition, it was calibrated in {sup 252C}f(D{sub 2}O), {sup 252}Cf, {sup 241}Am-B, {sup 241}Am-Be and {sup 238}Pu-Be source fields. For the latter, the lower detection levels are, respectively, 0.009 mSv, 0.06 mSv, 0.12 mSv, 0.09 mSv and 0.08 mSv. The participation in an international intercomparison sponsored by IAEA with simulated workplace fields validated the system. The monitoring system was successfully characterized in the ISO 21909 standard and in an IRD - the Brazilian Institute for Radioprotection and Dosimetry - technical regulation draft. Nowadays, the neutron individual system is in use by IRD for whole body individual monitoring of five institutions, which comprehend several activities. (author)

  8. Compact neutron flux monitor

    International Nuclear Information System (INIS)

    Madhavi, V.; Phatak, P.R.; Bahadur, C.; Bayala, A.K.; Jakati, R.K.; Sathian, V.

    2003-01-01

    Full text: A compact size neutron flux monitor has been developed incorporating standard boards developed for smart radiation monitors. The sensitivity of the monitors is 0.4cps/nV. It has been tested up to 2075 nV flux with standard neutron sources. It shows convincing results even in high flux areas like 6m away from the accelerator in RMC (Parel) for 106/107 nV. These monitors have a focal and remote display, alarm function with potential free contacts for centralized control and additional provision of connectivity via RS485/Ethernet. This paper describes the construction, working and results of the above flux monitor

  9. Neutron monitoring for radiological protection

    International Nuclear Information System (INIS)

    Gibson, J.A.B.

    1985-01-01

    Neutron monitoring is a subject of increasing general interest and considerable attention is being paid to the development of improved techniques and methods for neutron monitoring. The Agency, therefore, considered it important to prepare a guide on the subject of neutron monitoring for radiation protection purposes. The present Manual is intended for those persons or authorities in Member States, particularly developing countries, who are responsible for the organization of neutron monitoring programmes and practical neutron monitoring. This Manual consequently, deals with topics such as neutron dosimetry, sources of neutrons and neutron detection as well as field instruments and operational systems used in this context

  10. Neutron flux monitor

    International Nuclear Information System (INIS)

    Oda, Naotaka.

    1993-01-01

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

  11. Neutron flux monitoring device

    International Nuclear Information System (INIS)

    Shimazu, Yoichiro.

    1995-01-01

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

  12. Proposal of requirements for performance in Brazil for systems of external individual monitoring for neutrons applying the TLD-albedo technique

    International Nuclear Information System (INIS)

    Martins, Marcelo M.; Mauricio, Claudia L.P.; Pereira, Walsan W.; Fonseca, Evaldo S. da; Silva, Ademir X.

    2009-01-01

    This work presents a criteria and conditions proposal for the regulations in Brazil of individual monitoring systems for neutrons applying the albedo technique with thermoluminescent detectors. Tests are proposed for the characterization performance of the system based on the Regulation ISO 21909 and on the experience of the authors

  13. Neutron detector cable monitoring

    International Nuclear Information System (INIS)

    Haller, P.

    1976-01-01

    In a neutron detector connected by a cable with a current amplifier for the signal based on (n,e)-processes, any change in the insulation resistance of the cable is monitored by means of an a-c voltage which is super-imposed on the offset voltage of the amplifier. The resistance-dependent a-c variable at the output of the amplifier, is used to make a limit indicator respond via a connected filter. The invention is of importance particularly for monitoring the internal core instrumentation of pressurized-water reactors

  14. Review on individual neutron dosimetry

    International Nuclear Information System (INIS)

    Portal, M.

    1983-01-01

    Up to now, nuclear energy workers in relation to neutron radiations were few. Fast development of nuclear energy lead us to study, for future, individual dosimetry techniques which are autonomous, more accurate and cheaper. The future dosemeter will be a couple: fast neutron dosemeter and slow neutron dosemeter. The different current studies concerning this ''composite'' dosemeter are described. In 1984-1985, operation of a ''non-homogeneous, composite'' dosemeter is foreseen; later on, an ''homogeneous composite'' dosemeter that is to say a dosemeter which needs same basis techniques [fr

  15. Personnel neutron monitoring developments at LLL

    International Nuclear Information System (INIS)

    Griffith, R.V.; Fisher, J.C.; Hankins, D.E.; Miller, D.E.

    1978-01-01

    Approximately 40 employees at LLL work in areas where personnel neutron monitoring is necessary. The dose rate in these areas is low, rarely exceeding 0.5 rem per year. However, the wide variety of neutron environments (dt neutron generators; a 3 MW pool type reactor; a 100 MeV electron Linac; and a number of vaults and glove boxes where alpha, n and spontaneous fission sources are stored) makes the neutron monitoring task difficult. As a result, we have been studying potential developments in personnel dosimetry and neutron field monitoring, particularly as they relate to proposed changes in the neutron quality factor and the implied reduction in allowable dose limits

  16. Neutronic analysis of JET external neutron monitor response

    Energy Technology Data Exchange (ETDEWEB)

    Snoj, Luka, E-mail: luka.snoj@ijs.si [Reactor Physics Division, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Lengar, Igor; Čufar, Aljaž [Reactor Physics Division, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Syme, Brian; Popovichev, Sergey [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, OX14 3DB, United Kingdom (United Kingdom); Batistoni, Paola [ENEA C. R. Frascati, via E. Fermi 45, 00044 Frascati, Roma (Italy); Conroy, Sean [VR Association, Uppsala University, Department of Physics and Astronomy, PO Box 516, SE-75120 Uppsala (Sweden)

    2016-11-01

    Highlights: • We model JET tokamak containing JET remote handling system. • We investigate effect of remote handling system on external neutron monitor response. • Remote handling system correction factors are calculated. • Integral correction factors are relatively small, i.e up to 8%. - Abstract: The power output of fusion devices is measured in terms of the neutron yield which relates directly to the fusion yield. JET made a transition from Carbon wall to ITER-Like Wall (Beryllium/Tungsten/Carbon) during 2010–11. Absolutely calibrated measurement of the neutron yield by JET neutron monitors was ensured by direct measurements using a calibrated {sup 252}Cf neutron source (NS) deployed by the in-vessel remote handling system (RHS) inside the JET vacuum vessel. Neutronic calculations were required in order to understand the neutron transport from the source in the vacuum vessel to the fission chamber detectors mounted outside the vessel on the transformer limbs of the tokamak. We developed a simplified computational model of JET and the JET RHS in Monte Carlo neutron transport code MCNP and analyzed the paths and structures through which neutrons reach the detectors and the effect of the JET RHS on the neutron monitor response. In addition we performed several sensitivity studies of the effect of substantial massive structures blocking the ports on the external neutron monitor response. As the simplified model provided a qualitative picture of the process only, some calculations were repeated using a more detailed full 3D model of the JET tokamak.

  17. Method and apparatus for neutron radiation monitoring

    International Nuclear Information System (INIS)

    Schwarzmann, A.

    1985-01-01

    A self-calibrated neutron radiation monitor includes a flux responsive element comprised of intrinsic silicon neutron detectors and self-calibration resistors in a single structure. As the resistance of the flux responsive element increases to the value of successive calibration resistors, known increments of flux have been encountered

  18. Bubble detectors in individual neutron dosimetry

    International Nuclear Information System (INIS)

    Spurny, F.; Votockova, I.

    1996-01-01

    Bubble detectors be able to fulfill requirements following from the ICRP 60 recommendations as far as individual neutron dosemeter is concerned. Particularly, the lowest limit of detection seems to be decreased down to about 10 μSv or even lower. At the moment there are two types of such detectors commercially available: bubble damage neutron detectors (BDNDs -Bubble Technology Industries, Chalk River) and superheated drop detectors (SDDs - Apfel Enterpr., New Haven). Both these types have been tested in our studies from the point of view of personal dosimetry. Particular attention is devoted their energetic dependences and their responses in the fields in which they should be wed to determine occupational exposures. (author)

  19. Monitor for reactor neutron detector

    International Nuclear Information System (INIS)

    Shirakami, Hisayuki; Shibata, Masatoshi

    1992-01-01

    The device of the present invention judges as to whether a neutron detector is normal or not while considering the change of indication value depending on the power change of a reactor core. That is, the device of the present invention comprises a standard value setting device for setting the standard value for calibrating the neutron detector and an abnormality judging device for comparing the standard value with a measured value of the neutron detector and judging the abnormality when the difference is greater than a predetermined value. The measured value upon initialization of each of the neutron detectors is determined as a quasi-standard value. An average value of the difference between the measured value and the quasi-standard value of a plurality of effective neutron detectors at a same level for the height of the reactor core is multiplied to a power rate based on the reactor core power at a position where the neutron detector is disposed upon calibration. The value obtained by adding the multiplied value and the quasi-standard value is determined as a standard value. The abnormality judging device compares the standard value with the measured value of the neutron detector and, if the difference is greater than a predetermined value, the neutron detector is determined as abnormal. As a result, judgement can be conducted more accurately than conventional cases. (I.S.)

  20. The Brazilian external individual monitoring scenario

    International Nuclear Information System (INIS)

    Mauricio, Claudia L.P.; Silva, Claudio R. da; Cunha, Paulo G. da

    2015-01-01

    In order to improve radiation protection it is necessary to have knowledge of the occupational radiation dose levels in all radiation facilities. This information comes from individual monitoring services, which are responsible for measuring and providing information about workers' radiation exposure. In 1981, the Comissao Nacional de Energia Nuclear (CNEN) of Brazil starts to develop a comprehensive system for regulation and storage of occupational radiation dose. This paper starts with an overview of the evolution of the Brazilian authorization and data storage system for external individual monitoring. It starts with a rule for authorization of all Brazilian photon individual monitoring services and the obligation for them to send the measured dose to CNEN. Up to now there is no regulation for neutron individual monitoring. The aim of this paper is to present the current scenario of the Brazilian external monitoring system, reinforcing its importance and remaining problems. The number of monitored workers greatly increases every year, having surpassed 150,000 people monitored. The stored data show that the mean annual occupational external dose is decreasing from 2.4 mSv in 1987 to about 0.6 mSv, in 2012, but there is still some not realistic very high dose measured (higher than 100 mSv), without investigation. About 80% of the annual dose values are lower than the monthly register level. As expected, the higher real photon doses are found in Nuclear Medicine, Industrial Radiology and Interventional Radiology. All recorded annual neutron dose values are lower than 20 mSv. (author)

  1. Development of a spherical neutron rem monitor

    International Nuclear Information System (INIS)

    Panchal, C.G.; Madhavi, V.; Bansode, P.Y.; Jakati, R.K.; Ghodgaonkar, M.D.; Desai, S.S.; Shaikh, A.M.; Sathian, V.

    2007-01-01

    A new neutron rem monitor based on spherical LINUS with the state of art electronic circuits has been designed in Electronics Division. This prototype instrument encompasses a spherical double polythene moderator to improve an isotropic response and a lead layer to extend its energy response compared to the conventional neutron rem monitors. A systematic testing and calibration of the energy and directional response of the prototype monitor have been carried out. Although the monitor is expected to perform satisfactorily upto an energy ∼ 55 MeV, at present its response has been tested upto 5 MeV. (author)

  2. Neutron detector with monitoring elements

    International Nuclear Information System (INIS)

    Haller, P.

    1976-01-01

    To check the reliable reading of a neutron detector the signal of which results from (n,e) processes and which is used for neutron flux supervision in the reactor core of pressurized-water reactors, a circuit is given which makes it possible to record the isolation resistivity of the cable connected to the input of the current amplifier and of the neutron detector, this resistivity determining, among others, the output signal. For supervision, the input offset voltage of the current amplifier is modulated by a low-frequency ac voltage and a filter is assigned to the output of an op amplifier, this filter feeding a limiting value recorder. (ORU) [de

  3. Embedded data acquisition system for neutron monitors

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  4. An automated neutron monitor maintenance system

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  5. Beam monitoring system for intense neutron source

    International Nuclear Information System (INIS)

    Tron, A.M.

    2001-01-01

    Monitoring system realizing novel principle of operation and allowing to register a two-dimensional beam current distribution within entire aperture (100...200 mm) of ion pipe for a time in nanosecond range has been designed and accomplished for beam control of the INR intense neutron source, for preventing thermo-mechanical damage of its first wall. Key unit of the system is monitor of two-dimensional beam current distribution, elements of which are high resistant to heating by the beam and to radiation off the source. The description of the system and monitor are presented. Implementation of the system for the future sources with more high intensities are discussed. (author)

  6. 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...

  7. On barometer correction for Dallas neutron monitor

    Science.gov (United States)

    Ahluwalia, H. S.; Beason, J. D.

    To verify the prediction of Ahluwalia and Singh (1973) that the frequency of 4 cpd at Dallas may be due to a lack of proper care in correcting the data for the local fluctuations of the atmospheric pressure, the barometer coefficient is redetermined for the Dallas neutron monitor by two independent methods. A barometer coefficient of -0.74 percent per mb is found, and when recorrected data are subjected to FFT, the frequency of 4 cpd does not appear above the noise level in the amplitude spectrum.

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  9. Monitoring of Bainite Transformation Using in Situ Neutron Scattering

    Directory of Open Access Journals (Sweden)

    Hikari Nishijima

    2016-01-01

    Full Text Available Bainite transformation behavior was monitored using simultaneous measurements of dilatometry and small angle neutron scattering (SANS. The volume fraction of bainitic ferrite was estimated from the SANS intensity, showing good agreement with the results of the dilatometry measurements. We propose a more advanced monitoring technique combining dilatometry, SANS and neutron diffraction.

  10. Personnel Neutron Monitoring at AB Atomenergi

    International Nuclear Information System (INIS)

    Hagsgaard, S.; Widell, C.O.

    1964-02-01

    The routine personnel monitoring of fast neutrons is carried out by the counting of tracks in a nuclear emulsion. The tracks are counted in a microscope on a projection screen. This is a very tedious job and is only done on irradiated films which are counted over 6 mm 2 . The irradiated films are selected according to the recorded dose on the gamma film. It is often difficult to tell how much the visible tracks have faded during a two-weeks period. Fortunately the fading does not often exceed 20 % for this period. If the dosimeter has been gamma-irradiated, it may be difficult to recognize the proton tracks. If the film is stored for some time before being developed, this gamma fog will to some extent fade away. For large neutron doses a foil activation dosimeter is used. This dosimeter consists of a cadmium-shielded phosphorus foil, a cadmium shielded gold foil and an unshielded gold foil. The phosphorus foil has to be counted shortly after exposure

  11. Monitoring of lithium plating by neutron reflectometry

    Science.gov (United States)

    Avdeev, M. V.; Rulev, A. A.; Bodnarchuk, V. I.; Ushakova, E. E.; Petrenko, V. I.; Gapon, I. V.; Tomchuk, O. V.; Matveev, V. A.; Pleshanov, N. K.; Kataev, E. Yu.; Yashina, L. V.; Itkis, D. M.

    2017-12-01

    The development of high-capacity rechargeable and safe metallic lithium negative electrodes for next-generation batteries requires an in-depth understanding of reasons for nonuniform lithium plating during lithium-metal battery charge. It drives the interest for the tools enabling efficient monitoring of electrochemical interfaces where lithium electrodeposition occurs. We report on a three-electrode electrochemical cell designed to track lithium electrodeposition from aprotic electrolytes by neutron reflectometry (NR) in the specular reflectivity mode. We performed a case study of Li plating from LiClO4 solution in propylene carbonate. The sensitivity was optimized by tuning the neutron scattering contrast for a given electrode material (Cu film) and the electrolyte, which was done employing a deuterated solvent. The analysis of the scattering length density (SLD) profiles derived from the modeling of the reflectivity data clearly demonstrated that the deposition of nm-thin Li layers above initially formed solid-electrolyte interphase (SEI) layer can be detected and their roughness, which is a characterizing parameter of electrodeposition nonuniformity, can be estimated. It makes NR a proper tool for further studies of "dendritic" lithium growth.

  12. Response of a neutron monitor area with TLDs pairs

    Energy Technology Data Exchange (ETDEWEB)

    Guzman G, K. A.; Borja H, C. G.; Valero L, C.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Gallego, E.; Lorente, A., E-mail: ing_karen_guzman@yahoo.com.mx [Universidad Politecnica de Madrid, Departamento de Ingenieria Nuclear, Jose Gutierrez Abascal 2, E-28006 Madrid (Spain)

    2011-10-15

    The response of a passive neutron monitor area has been calculated using the Monte Carlo code MCNP5. The response was the amount of n({sup 6}Li, T){alpha} reactions occurring in a TLD-600 located at the center of a cylindrical polyethylene moderator. Fluence, (n, a) and H*(10) responses were calculated for 47 monoenergetic neutron sources. The H*(10) relative response was compared with responses of commercially available neutron monitors being alike. Due to {sup 6}Li cross section (n, {alpha}) reactions are mainly produced by thermal neutrons, however TLD-600 is sensitive to gamma-rays; to eliminate the signal due to photons monitor area was built to hold 2 pairs of TLD-600 and 2 pairs of TLD-700, thus from the difference between TLD-600 and TLD-700 readouts the net signal due to neutrons is obtained. The monitor area was calibrated at the Universidad Politecnica de Madrid using a {sup 241}AmBe neutron source; net TLD readout was compared with the H*(10) measured with a Bert hold Lb-6411. Performance of the neutron monitor area was determined through two independent experiments, in both cases the H*(10) was statistically equal to H*(10) measured with a Bert hold Lb-6411. Neutron monitor area with TLDs pairs can be used in working areas with intense, mixed and pulsed radiation fields. (Author)

  13. Online monitoring of fast neutron (DT/DD) at Purnima neutron generator

    International Nuclear Information System (INIS)

    Bishnoi, S.; Patel, T.; Shukla, M.; Adhikari, P.S.; Sinha, A.

    2012-01-01

    A neutron generator (NG) at Purnima Labs, BARC has been developed for DT accelerator driven zero power subcritical (ADSS) system. Subcritical core of ADSS will be coupled to the NG for benchmarking experiments. Kinetic parameters of ADSS such as K-source, flux, power etc depends on this external neutron source strength injected to the core. However the neutron emission rate of NG does not remain stable throughout its operation. In view of this a reliable, precise and online monitoring of NG's neutron emission rate is required. An online neutron monitoring system based on associated particle method has been designed, developed and installed at NG. The monitoring unit consists of an ion implanted planar silicon detector, placed inside the drift tube of NG at an angle with respect to D + beam direction. A series of experiments were carried out with increasing neutron yield to optimize the position of detector such that it has sufficient counting statistics and minimum pileup. A complementary calibration procedure for validating these results based on activation technique was also carried out with standard Cu foil. The reaction rate monitored with online monitor and foil activation technique were compared, their variations with the predicted (theoretical) results were within 16%. This paper deals with the development and performance of online neutron monitoring system for DT and DD neutrons

  14. Individualized Behavioral Health Monitoring Tool

    Science.gov (United States)

    Mollicone, Daniel

    2015-01-01

    Behavioral health risks during long-duration space exploration missions are among the most difficult to predict, detect, and mitigate. Given the anticipated extended duration of future missions and their isolated, extreme, and confined environments, there is the possibility that behavior conditions and mental disorders will develop among astronaut crew. Pulsar Informatics, Inc., has developed a health monitoring tool that provides a means to detect and address behavioral disorders and mental conditions at an early stage. The tool integrates all available behavioral measures collected during a mission to identify possible health indicator warning signs within the context of quantitatively tracked mission stressors. It is unobtrusive and requires minimal crew time and effort to train and utilize. The monitoring tool can be deployed in space analog environments for validation testing and ultimate deployment in long-duration space exploration missions.

  15. Heliospheric Modulation Strength During The Neutron Monitor Era

    Science.gov (United States)

    Usoskin, I. G.; Alanko, K.; Mursula, K.; Kovaltsov, G. A.

    Using a stochastic simulation of a one-dimensional heliosphere we calculate galactic cosmic ray spectra at the Earth's orbit for different values of the heliospheric mod- ulation strength. Convoluting these spectra with the specific yield function of a neu- tron monitor, we obtain the expected neutron monitor count rates for different values of the modulation strength. Finally, inverting this relation, we calculate the modula- tion strength using the actually recorded neutron monitor count rates. We present the reconstructed annual heliospheric modulation strengths for the neutron monitor era (1953­2000) using several neutron monitors from different latitudes, covering a large range of geomagnetic rigidity cutoffs from polar to equatorial regions. The estimated modulation strengths are shown to be in good agreement with the corresponding esti- mates reported earlier for some years.

  16. Modeling delayed neutron monitoring systems for fast breeder reactors

    International Nuclear Information System (INIS)

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

    1983-10-01

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

  17. Core component vibration monitoring in BWRs using neutron noise

    International Nuclear Information System (INIS)

    Fry, D.N.; Robinson, J.C.; Kryter, R.C.; Cole, O.C.

    1975-01-01

    Neutron noise from in-core fission detectors in a BWR was investigated to determine its effectiveness as a monitor of mechanical vibrations of core components. In this study the general properties of BWR neutron noise were characterized, and a signal enhancement method was implemented to improve the measurement sensitivity. (auth)

  18. Individual monitoring: A tool for active ALARA

    International Nuclear Information System (INIS)

    Hoefert, M.

    1989-01-01

    The system of individual monitoring at CERN is presented. Following the substantial decrease of individual doses over the last decade, emphasis is now placed on monitoring rather than on dosimetric aspects. Future developments have to face a possible decrease of dose limits that are difficult to control in view of the lower detection limits for the detectors presently used. One possible solution to the problem is the increase in the wearing time for individual dosemeters. (author)

  19. Data analysis for neutron monitoring in an enrichment facility

    International Nuclear Information System (INIS)

    Markin, J.T.; Stewart, J.E.; Goldman, A.S.

    1982-01-01

    Area monitoring of neutron radiation to detect high-enriched uranium production is a potential strategy for inspector verification of operations in the cascade area of a centrifuge enrichment facility. This paper discusses the application of statistical filtering and hypothesis testing procedures to experimental data taken in an enrichment facility. The results demonstrate that these data analysis methods can enhance detection of facility misoperation by neutron monitoring

  20. Monitoring and dose recording for the individual

    International Nuclear Information System (INIS)

    1988-01-01

    This document specifies the conditions under which monitoring of individuals is required. For workers identified as Atomic Radiation Workers, determination of dose or exposure must be made. In circumstances where personal monitoring techniques are impractical, doses and exposures may be estimated by non-personal monitoring techniques. For workers not identified as Atomic Radiation Workers, licensees must be able to demonstrate that there is no reasonable potential for accumulating radiation doses or exposures in excess of regulatory limits. (L.L.)

  1. Pure commercial gold foils as neutron flux monitor: Neutron self-shielding assessment

    International Nuclear Information System (INIS)

    Haddad, Kh.; Haj-Hassan, H.; Helal, W.

    2007-01-01

    An assessment of pure commercial (99.9%) gold foils as neutron flux monitor was performed. A thin foils of pure commercial gold were prepared as an in-house reference material for neutron flux measurement. The assessed foils are available commercially and its cost is much less than the certified ones. Determination of the neutron self-shielding factors in these foils for both thermal and epithermal neutrons have been done experimentally. These foils show good results repeatability and good agreement with certified activation monitors. According to the well-known physical constants of the nuclide and its low cost comparing with certified foils, it can be used as an in-house reference monitor

  2. Ultra Wide Band RFID Neutron Tags for Nuclear Materials Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Nekoogar, F; Dowla, F; Wang, T

    2010-01-27

    Recent advancements in the ultra-wide band Radio Frequency Identification (RFID) technology and solid state pillar type neutron detectors have enabled us to move forward in combining both technologies for advanced neutron monitoring. The LLNL RFID tag is totally passive and will operate indefinitely without the need for batteries. The tag is compact, can be directly mounted on metal, and has high performance in dense and cluttered environments. The LLNL coin-sized pillar solid state neutron detector has achieved a thermal neutron detection efficiency of 20% and neutron/gamma discrimination of 1E5. These performance values are comparable to a fieldable {sup 3}He based detector. In this paper we will discuss features about the two technologies and some potential applications for the advanced safeguarding of nuclear materials.

  3. Ultra Wide Band RFID Neutron Tags for Nuclear Materials Monitoring

    International Nuclear Information System (INIS)

    Nekoogar, F.; Dowla, F.; Wang, T.

    2010-01-01

    Recent advancements in the ultra-wide band Radio Frequency Identification (RFID) technology and solid state pillar type neutron detectors have enabled us to move forward in combining both technologies for advanced neutron monitoring. The LLNL RFID tag is totally passive and will operate indefinitely without the need for batteries. The tag is compact, can be directly mounted on metal, and has high performance in dense and cluttered environments. The LLNL coin-sized pillar solid state neutron detector has achieved a thermal neutron detection efficiency of 20% and neutron/gamma discrimination of 1E5. These performance values are comparable to a fieldable 3 He based detector. In this paper we will discuss features about the two technologies and some potential applications for the advanced safeguarding of nuclear materials.

  4. Neutron flux profile monitor for use in a fission reactor

    Science.gov (United States)

    Kopp, Manfred K.; Valentine, Kenneth H.

    1983-01-01

    A neutron flux monitor is provided which consists of a plurality of fission counters arranged as spaced-apart point detectors along a delay line. As a fission event occurs in any one of the counters, two delayed current pulses are generated at the output of the delay line. The time separation of the pulses identifies the counter in which the particular fission event occured. Neutron flux profiles of reactor cores can be more accurately measured as a result.

  5. Neutron monitoring of plutonium at the ZPPR storage vault

    International Nuclear Information System (INIS)

    Caldwell, J.T.; Kuckertz, T.H.; Bieri, J.M.; France, S.W.; Goin, R.W.; Hastings, R.D.; Pratt, J.C.; Shunk, E.R.

    1981-12-01

    We investigated a method for monitoring a typical large storage vault for unauthorized removal of plutonium. The method is based on the assumption that the neutron field in a vault produced by a particular geometric configuration of bulk plutonium remains constant in time and space as long as the configuration is undisturbed. To observe such a neutron field, we installed an array of 25 neutron detectors in the ceiling of a plutonium storage vault at Argonne National Laboratory West. Each neutron detector provided an independent spatial measurement of the vault neutron field. Data collected by each detector were processed to determine whether statistically significant changes had occurred in the neutron field. Continuous observation experiments measured the long-term stability of the system. Removal experiments were performed in which known quantities of plutonium were removed from the vault. Both types of experiments demonstrated that the neutron monitoring system can detect removal or addition of bulk plutonium (11% 240 Pu) whose mass is as small as 0.04% of the total inventory

  6. Silicon detectors for the n-TOF neutron beams monitoring

    CERN Document Server

    Cosentino, L.; Barbagallo, M.; Colonna, N.; Damone, L.; Pappalardo, A.; Piscopo, M.; Finocchiaro, P.

    2015-01-01

    During 2014 the second experimental area EAR2 was completed at the n-TOF neutron beam facility at CERN. As the neutrons are produced via spallation, by means of a high-intensity 20 GeV pulsed proton beam impinging on a thick target, the resulting neutron beam covers an enormous energy range, from thermal to several GeV. In this paper we describe two beam diagnostic devices, designed and built at INFN-LNS, both exploiting silicon detectors coupled with neutron converter foils containing 6Li. The first one is based on four silicon pads and allows to monitor the neutron beam flux as a function of the neutron energy. The second one, based on position sensitive silicon detectors, is intended for the reconstruction of the beam profile, again as a function of the neutron energy. Several electronic setups have been explored in order to overcome the issues related to the gamma flash, namely a huge pulse present at the start of each neutron bunch which may blind the detectors for some time. The two devices have been ch...

  7. Current applications of vibration monitoring and neutron noise analysis

    International Nuclear Information System (INIS)

    Damiano, B.; Kryter, R.C.

    1990-02-01

    Monitoring programs using vibration monitoring or neutron noise analysis have demonstrated the ability to detect and, in some cases, diagnose the nature of reactor vessel internals structural degradation. Detection of compromised mechanical integrity of reactor vessel internal components in its early stages allows corrective action to be taken before weakening or damage occurs. In addition to the economic benefits early detection and correction can provide, they can also help maintain plant safety. Information on the condition of reactor vessel internal components gained from a monitoring program supplements in-service inspection results and may be useful in justifying plant license extension. This report, which was prepared under the Nuclear Plant Aging Research Program sponsored by the US Nuclear Regulatory Commission, discusses the application of vibration monitoring and neutron noise analysis for monitoring light-water reactor vessel internals. The report begins by describing the effects of structural integrity loss on internals vibration and how measurable parameters can be used to detect and track the progress of degradation. This is followed by a description and comparison of vibration monitoring and neutron noise analysis, two methods for monitoring the mechanical integrity of reactor vessel internals condition monitoring programs in the United States, Federal Republic of Germany, and France, three countries having substantial commitments to nuclear power. The last section presents guidelines for US utilities wishing to establish reactor internals condition monitoring programs. 20 refs., 5 figs., 4 tabs

  8. Application of neutron monitors in fuel fabrication and reprocessing installations

    International Nuclear Information System (INIS)

    Arnal, T.; Dumesnil, P.; Edeline, J.C.; Ganivet, M.

    Plutonium is detected and measured by means of its neutron emission: spontaneous fission of like isotopes and (α, n) reactions. Neutron emission intensity thus depends on the isotopic composition and the chemical nature of the Pu source. Waste containers are monitored by counting spontaneous fissions alone, which is made possible by the nonpoisson timing of the corresponding neutron events. The equipment comprises 24 3 He counters and can detect 10 mg( 240 Pu) in one minute in a 100 litre container. The door is monitored to detect small masses of plutonium in order to prevent the removal of this element. The door monitor comprises a variable number of 3 He counters placed around the doorway. An alarm rings if the number of counts per second exceeds a predetermined threshold value. A motion detector consisting of a Doppler radar limits the frequency of false alarms due to statistical fluctuations in the background. Sensitivity is on the order of several grams of Pu

  9. Ver reactor pressure vessel neutron exposure evaluation and monitoring

    International Nuclear Information System (INIS)

    Osmera, B.

    1992-01-01

    The surveillance neutron exposure monitoring system In VVER-440, V 213 series, consists of 54 Fe(n,p), 63 Cu(n,α and 93 Nb(n,n) detectors. The Fe detector is loaded for one year Cone fuel cycle) Irradiation only. The evaluation of the neutron monitor results including transformation to the critical locations of the reactor pressure vessel (RPV) can be based on the direct estimations of the neutron spectra and led factors (and other important space energy indices) in the mock-up experiments carried out. in the LR-0 experimental reactor, N.R.I. Rez. Because of high acceleration factor (about 11 for neutrons with energy above 0.5 MeV) the specimens are pulled out within five years of VVER-440 operation. After that the ex-vessel monitoring should be applied for RPV exposure determination. A recommended procedure (guide) for the RPV neutron exposure evaluation has been completed recently. All previous experimental data (the surveillance and ex-vessel monitors, I.R-0 mock-up measurements) have been revised arid reevaluated using the IRDF-90 (IAEA) cross section data. A brief review of this work is presented in the paper. Some comments relating to the RPV dosimetry of VVER-440, series 230, and VVER-1000 reactors are also done. (author)

  10. Neutron dosimetry. Environmental monitoring in a BWR type reactor

    International Nuclear Information System (INIS)

    Tavera D, L.; Camacho L, M.E.

    1991-01-01

    The measurements carried out on reactor dosimetry are applied mainly to the study on the effects of the radiation in 108 materials of the reactor; little is on the environmental dosimetry outside of the primary container of BWR reactors. In this work the application of a neutron spectrometer formed by plastic detectors of nuclear traces manufactured in the ININ, for the environmental monitoring in penetrations around the primary container of the unit I of the Laguna Verde central is presented. The neutron monitoring carries out with purposes of radiological protection, during the operational tests of the reactor. (Author)

  11. Characterization of a prototype neutron portal monitor detector

    Science.gov (United States)

    Nakhoul, Nabil

    The main objective of this thesis is to provide characterization measurements on a prototype neutron portal monitor (NPM) detector constructed at the University of Massachusetts Lowell. NPM detectors are deployed at all United States border crossings and shipping ports to stop the illicit transfer of weapons-grade plutonium (WGPu) into our country. This large prototype detector with its 0.93 square meter face area is based on thermal neutron capture in 6Li as an alternate technology to the current, very expensive, 3He-based NPM. A neutron detection efficiency of 27.5 % is measured with a 252Cf source which has a spontaneous fission neutron spectrum very similar to that of 240Pu in WGPu. Measurements with an intense 137Cs source establish the extreme insensitivity of the prototype NPM to gamma-ray backgrounds with only one additional count registered for 1.1 million incident gamma rays. This detector also has the ability to locate neutron sources to within an angle of a few degrees. Its sensitivity is further demonstrated by discovering in a few-second measurement the presence of a 2 curie PuBe neutron source even at a distance of 95.5 feet. This thesis also covers in considerable detail the design features that give rise to both a high intrinsic neutron detection efficiency and an extreme gamma-ray insensitivity.

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  13. 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.

  14. Indigenous development of diamond detectors for monitoring neutrons

    International Nuclear Information System (INIS)

    Singh, Arvind; Amit Kumar; Topkar, Anita; Pithawa, C.K.

    2013-01-01

    High purity synthetic chemically vapor deposited (CVD) diamond has several outstanding characteristics that make it as an important material for detector applications specifically for extreme environmental conditions like high temperature, high radiation, and highly corrosive environments. Diamond detectors are especially considered promising for monitoring fast neutrons produced by the D-T nuclear fusion reactions in next generation fusion facilities such as ITER. When fast neutrons interact with carbon, elastic, inelastic and (n,α) type reactions can occur. These reactions can be employed for the detection of fast neutrons using diamond. We have initiated the development of diamond detectors based on synthetic CVD substrates. In this paper, the first test of a polycrystalline CVD diamond detector with fast neutrons is reported. The test results demonstrate that this detector can be used for monitoring fast neutrons. The diamond detectors have been fabricated using 5 mm x 5 mm, 300 μm polycrystalline diamond substrates. Aluminum metallization has been used on both sides of the detector to provide electrical contacts. The performance of fabricated detectors was first evaluated using current and capacitance measurements. The leakage current was observed to be stable and about a few pAs for voltages up to 300V. The capacitance-voltage characteristics showed a constant capacitance which is as expected. To confirm the response of the detector to charged particles, the pulse height spectrum (PHS) was obtained using 238 Pu- 239 Pu dual α- source. The PHS showed a continuum without any peak due to polycrystalline nature of diamond film. The response of the detector to fast neutrons has been studied using the fast neutron facility at NXF, BARC. The PHS obtained for a neutron yield of 4 x 10 8 n/s is shown. The average counts per second (cps) measured for diamond detector for different neutron yields is shown. The plot shows linearity with coefficient of determination R

  15. Development of neutron personnel monitoring system based on CR-39 solid state nuclear track detector

    International Nuclear Information System (INIS)

    Massand, O.P.; Kundu, H.K.; Marathe, P.K.; Supe, S.J.

    1990-01-01

    Personnel neutron monitoring aims at providing a method to evaluate the magnitude of the detrimental effects on the personnel exposed to neutrons. Neutron monitoring is done for a small though growing number of personnel working with neutrons in a wide range of situations. Over the years, many solid state nuclear track detectors (SSNTD) have been tried for neutron personnel monitoring. CR-39 SSNTD is a proton sensitive polymer and offers a lot of promise for neutron personnel monitoring due to its high sensitivity and lower energy threshold for neutron detection. This report presents the mechanism of track formation in this polymer, the development of this neutron personnel monitoring system in our laboratory, its various characteristics and its promise as a routine personnel neutron monitor. (author). 1 tab., 7 figs

  16. A Transparent Detector for n_TOF Neutron Beam Monitoring

    CERN Document Server

    Andriamonje, S; Vlachoudis, V; Guerrero, C; Schillebeeckx, P; Losito, R; Sarmento, R; Calviani, M; Giganon, A; Gunsing, F; Berthoumieux, E; Siegler, P; Kadi, Y

    2011-01-01

    In order to obtain high precision cross-section measurements using the time-of-flight technique, it is important to know with good accuracy the neutron fluence at the measuring station. The detector dedicated to these measurements should be placed upstream of the detectors used for capture and fission cross-section measurements. The main requirement is to reduce the material of the detector as much as possible, in order to minimize the perturbation of the neutron beam and, especially, the background produced by the device itself. According to these considerations, a new neutron detector equipped with a small-mass device based on MicroMegas ``Micro-bulk{''} technology has been developed as a monitoring detector for the CERN n\\_TOF neutron beam. A description of the different characteristics of tins innovative concept of transparent detector for neutron beam monitoring is presented. The result obtained in the commissioning of the new spallation target of the n\\_TOF facility at CERN is shown, compared with simul...

  17. Extensive Air Showers Detected by Aragats Neutron Monitor

    International Nuclear Information System (INIS)

    Badalyan, A.; Chilingarian, A.; Hovsepyan, G.; Grigoryan, A.; Khanikyants, Y.; Manukyan, A.; Pokhsraryan, D.; Soghomonyan, S.

    2017-01-01

    Extensive Air Shower (EAS) duration as registered by the surface particle detectors does not exceed a few tens of nanosecond. However, Neutron monitors containing plenty of absorbing matter can respond to EAS core traversal during 1 ∼ms by registering secondary slow neutrons born by EAS hadrons in the soil, walls of buildings and in the matter of detector itself. Thus, the time distribution of the pulses from the proportional counters of the neutron monitor after EAS propagation extends to ∼l ms, ∼5 orders of magnitude larger than the EAS passing time. The Aragats Neutron Monitor (ArNM) has a special option for the EAS core detection. In general, the dead time of NM is ∼1 ms that provides the one-to-one relation of incident hadrons and detector counts. The pulses generated by the neutrons possibly entering the proportional chamber after the first one will be neglected. In ArNM, we use several “electronic” dead times, and with the shortest one, 400 ns, the detector counts all pulses that enter the proportional chambers. If ArNM one-second time series corresponding to the shortest dead time contain much more signals (a neutron burst) than with l-ms dead time, then we conclude that the EAS core hits the detector. We assume that he distribution of registered burst multiplicities is proportional to the energy of the primary particle. The primary cosmic ray energy spectrum was obtained by the frequency analysis through the counting frequencies of the multiplicities of different magnitudes and relating them to the integral energy spectrum measured by the MAKET array at the same place several years ago. (author)

  18. Measuring and monitoring KIPT Neutron Source Facility Reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Yan [Argonne National Lab. (ANL), Argonne, IL (United States); Gohar, Yousry [Argonne National Lab. (ANL), Argonne, IL (United States); Zhong, Zhaopeng [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-08-01

    Argonne National Laboratory (ANL) of USA and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on developing and constructing a neutron source facility at Kharkov, Ukraine. The facility consists of an accelerator-driven subcritical system. The accelerator has a 100 kW electron beam using 100 MeV electrons. The subcritical assembly has keff less than 0.98. To ensure the safe operation of this neutron source facility, the reactivity of the subcritical core has to be accurately determined and continuously monitored. A technique which combines the area-ratio method and the flux-to-current ratio method is purposed to determine the reactivity of the KIPT subcritical assembly at various conditions. In particular, the area-ratio method can determine the absolute reactivity of the subcritical assembly in units of dollars by performing pulsed-neutron experiments. It provides reference reactivities for the flux-to-current ratio method to track and monitor the reactivity deviations from the reference state while the facility is at other operation modes. Monte Carlo simulations are performed to simulate both methods using the numerical model of the KIPT subcritical assembly. It is found that the reactivities obtained from both the area-ratio method and the flux-to-current ratio method are spatially dependent on the neutron detector locations and types. Numerical simulations also suggest optimal neutron detector locations to minimize the spatial effects in the flux-to-current ratio method. The spatial correction factors are calculated using Monte Carlo methods for both measuring methods at the selected neutron detector locations. Monte Carlo simulations are also performed to verify the accuracy of the flux-to-current ratio method in monitoring the reactivity swing during a fuel burnup cycle.

  19. Experimental study on the performance of an epithermal neutron flux monitor for BNCT.

    Science.gov (United States)

    Guan, Xingcai; Manabe, Masanobu; Tamaki, Shingo; Liu, Shuangtong; Sato, Fuminobu; Murata, Isao; Wang, Tieshan

    2016-07-01

    The performance of an epithermal neutron (0.5eVflux monitor designed for boron neutron capture therapy (BNCT) was experimentally studied by using a prototype monitor in an appropriate neutron field at the intense deuterium-tritium neutron source facility OKTAVIAN of Osaka University, Japan. It was convinced from the experimental results that the developed monitor worked well and the epithermal neutron fluxes in BNCT neutron sources can be measured within 5% by the monitor. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. The development report of an intelligent neutron fluence integration monitor

    International Nuclear Information System (INIS)

    Jiang Zongbing; Wei Ying

    1996-10-01

    An intelligent neutron fluence integration monitor is introduced. It is used to measure the received neutron fluence of the monocrystalline silicon in reactor radiation channel. The significance of study and specifications of the instrument are briefly described. The emphasis is on the working principle, structure and characteristics of the instrument is intelligent due to use of monolithic microcomputer. It has many advantages proved in the actual practice, such as powerful function, high accuracy, diversity of application, high level automatization, easy to operate, high reliability, etc. After using this instrument the monocrystalline silicon radiation technology is improved and the efficiency of production is raised. (1 fig.)

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  2. New Calgary Neutron Monitor Data Acquisition System

    Science.gov (United States)

    Kouznetsov, A.; Unick, C.; Bland, C. J.; Knudsen, D. J.

    2017-12-01

    The purpose of the project is to supply the World Neutron Database (NMDB) with high-quality data in an online, real-time mode. To do so, we created, and run continuously, a new "real-time hardware" data acquisition system using a set of low-cost (less than $15) counters based on Cypress Programmable System on a Chip (PSoC) technology. The PSoC is flexible and has microcontroller and FPGA-like capabilities which have enabled us to build a multi-level solution with low-level multi-channel counters and a top-level data acquisition and storage system, capable of supplying the NMDB with a real-time data stream. The top-level data acquisition system queries twelve PSoCs in an asynchronous command mode, sending commands and waiting for replies from the PSoCs asynchronously. The PSOC units replace the preamplifier electronics on each counter. Recent test show the units to be stable with a variety of supply-voltage sources and capable of running without adjustment for extended periods.

  3. Portable system for periodical verification of area monitors for neutrons; Sistema portatil para verificacao periodica de monitores de area para neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Luciane de R.; Leite, Sandro Passos; Lopes, Ricardo Tadeu, E-mail: rluciane@ird.gov.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEN/COPPE/UFRJ), RJ (Brazil). Programa de Energia Nuclear; Patrao, Karla C. de Souza; Fonseca, Evaldo S. da; Pereira, Walsan W., E-mail: karla@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. Nacional de Metrologia das Radiacoes Ionizantes (LNMRI). Lab. de Neutrons

    2009-07-01

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

  4. MONITORING SHORT-TERM COSMIC-RAY SPECTRAL VARIATIONS USING NEUTRON MONITOR TIME-DELAY MEASUREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Ruffolo, D.; Sáiz, A.; Mangeard, P.-S.; Kamyan, N.; Muangha, P. [Department of Physics, Faculty of Science, Mahidol University, Bangkok 10400 (Thailand); Nutaro, T.; Rujiwarodom, M.; Tooprakai, P. [Thailand Center of Excellence in Physics, CHE, Ministry of Education, Bangkok 10400 (Thailand); Sumran, S.; Chaiwattana, C.; Gasiprong, N.; Channok, C.; Wuttiya, C. [Department of Physics, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani 34190 (Thailand); Asavapibhop, B. [Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Bieber, J. W.; Clem, J.; Evenson, P. [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Munakata, K., E-mail: david.ruf@mahidol.ac.th [Physics Department, Shinshu University, Matsumoto, Nagano 390-8621 (Japan)

    2016-01-20

    Neutron monitors (NMs) are ground-based detectors of cosmic-ray showers that are widely used for high-precision monitoring of changes in the Galactic cosmic-ray (GCR) flux due to solar storms and solar wind variations. In the present work, we show that a single neutron monitor station can also monitor short-term changes in the GCR spectrum, avoiding the systematic uncertainties in comparing data from different stations, by means of NM time-delay histograms. Using data for 2007–2014 from the Princess Sirindhorn Neutron Monitor, a station at Doi Inthanon, Thailand, with the world’s highest vertical geomagnetic cutoff rigidity of 16.8 GV, we have developed an analysis of time-delay histograms that removes the chance coincidences that can dominate conventional measures of multiplicity. We infer the “leader fraction” L of neutron counts that do not follow a previous neutron count in the same counter from the same atmospheric secondary, which is inversely related to the actual multiplicity and increases for increasing GCR spectral index. After correction for atmospheric pressure and water vapor, we find that L indicates substantial short-term GCR spectral hardening during some but not all Forbush decreases in GCR flux due to solar storms. Such spectral data from Doi Inthanon provide information about cosmic-ray energies beyond the Earth’s maximum geomagnetic cutoff, extending the reach of the worldwide NM network and opening a new avenue in the study of short-term GCR decreases.

  5. Criticality monitoring with digital systems and solid state neutron detectors

    International Nuclear Information System (INIS)

    Willhoite, S.B.

    1984-01-01

    A commercially available system for criticality monitoring combines the well established technology of digital radiation monitoring with state-of-the art detector systems capable of detecting criticality excursions of varying length and intensity with a high degree of confidence. The field microcomputer servicing the detector clusters contains hardware and software to acquire detector information in both the digital count rate and bit sensing modes supported by the criticality detectors. In both cases special criticality logic in the field microcomputer is used to determine the validity of the criticality event. The solid-state neutron detector consists of a 6 LiF wafer coupled to a diffused-junction charged particle detector. Alpha particles resulting from (n,α) interactions within the lithium wafer produce a pulsed signal corresponding to neutron intensity. Special detector circuitry causes the setting of a criticality bit recognizable by the microcomputer should neutron field intensities either exceed a hardware selectable frequency or saturate the detector resulting in a high current condition. These two modes of criticality sensing, in combination with the standard method of comparing an operator selectable alarm setpoint with the detector count rate, results in a criticality system capable of effective operation under the most demanding criticality monitoring conditions

  6. Individual monitoring and dosimetry: The Goiania experience

    International Nuclear Information System (INIS)

    Lipsztein, J.L.; Melo, D.R.; Oliveira, C.A.N.; Bertelli, L.

    2000-01-01

    Several people were contaminated with 137 Cs in an accident involving the stealing and breaching of a radiotherapy source in Goiania, Brazil. A drug known as Prussian Blue was administered to some contaminated individuals to enhance Cs elimination from the body. Individuals internally contaminated were monitored for the two first months, exclusively by in vitro bioassay, i.e., urine and faeces analysis. After that period of time a field whole-body counter was set up in Goiania and individuals started to be monitored in vivo, on a regular basis. The total internal committed doses and the effect of Prussian blue treatment have been evaluated. For adults, the biological half-time (T 2 ) under PB treatment was reduced to an average value around to 31% of the half-time after finished treatment. For adolescents (T 2 ) was reduced to an average value around to 54% and for children was reduced to an average value around to 57%. A weight dependent biokinetic study of 137 Cs retention in humans was conducted. Data from 10 girls and 7 boys, aged 1 to 10 y old, as well as from 10 adolescents: 4 females and 6 males, and from 30 adults: 15 females and 15 males, contaminated in the accident, were used in this study. A planned experiment with beagle dogs were carried out to furnish some further data for our study. Based on these data, a three terms exponential equation is suggested to describe the 137 Cs retention in the body, the first-term associated with a very short half-time, the second with a longer half-time and the third term with a very long half-time, of the order of 400 to 570 days and relating to a retention fraction of only 0.1%. A table of weight, age and sex specific half-times for the second term is suggested. (author)

  7. Shidaowan HTR Ex-Core Neutron Flux Monitoring Systems

    International Nuclear Information System (INIS)

    Artaud, Clark J.; Yang Shuping

    2014-01-01

    For the Huaneng Shandong Shidao Bay Nuclear Power Plant High Temperature Gas-Cooled Reactor Nuclear Power Plant Demonstration Project (HTR-PM) several neutron flux measurements are made outside the Reactor Pressure Vessel (RPV) performed by the Ex-core Neutron Flux Monitoring Systems (ENFMS). This paper will discuss the design of the ENFMS for the Shidaowan project. The unique design of this ENFMS includes a B-10 proportional counter for Source Range (SR) monitoring and a shared four-section guarded fission chamber detector assembly for both Intermediate Range (IR) and Power Range (PR) monitoring. The detectors hang from a suspension shielding device via wire rope. The IR channel ENFMS is completely qualified to survive Loss of Coolant Accidents (LOCA) and Main Steam Line Breaks (MSLB) per US NRC Reg Guide 1.97 Post Monitoring Requirements. The ENFMS will be qualified for Class 1E Safety-Related applications and also will undergo EMI / EMC testing per Reg Guide 1.180. Due to the long length of the HTR-PM core, the flux is measured at several axial positions. For the fission chamber based systems full advantage is taken of all the operating modes for fission chambers (pulse counting, mean square voltage (MSV), and linear current) to provide the Intermediate and Power Range signals. This paper describes the challenges in the development of the monitoring systems for the measurement of neutron flux within the ex core region. The selection of detector configuration and the associated signal processing will be discussed and compared with traditional PWR designs. The use of only analog signal processing techniques will also be elaborated on. (author)

  8. Optimization of neutron monitoring detector for LHD experiments

    International Nuclear Information System (INIS)

    Yamanishi, Hirokuni; Miyake, Hitoshi; Uda, Tatsuhiko; Tanahashi, Shugo; Saitou, Masasato; Handa, Hiroyuki

    2000-01-01

    There is a plan of D-D reaction experiments in the next phase of LHD (Large Helical Device) fusion plasma experiment. While the experiment, 2.45 MeV neutrons due to D-D reaction and gamma rays are generated. On the point of safety, radiation dose due to these radiation in working area or site boundary should be evaluated as accurate and precise as possible. In NIFS, the annual dose on the site boundary is limited as 0.05 mSv. Therefore, it is necessary to evaluate the dose precisely even for very small dose. However, the evaluation of neutron dose is much more difficult than that of gamma ray, because neutron dose conversion factor per unit fluence is considerably varied with neutron energy. (1) We evaluated the performance of now installing neutron detector in our radiation monitoring system which is consist of He-3 proportional counter with 25 mm thick polyethylene moderator. First of all, the characteristic of energy response for this detector was obtained by using Monte Carlo simulation code MCNP. The neutron fluence data at each place has been calculated by radiation transportation code DOT 3.5. The expected dose on each monitoring point was derived from radiation field data, and the detected dose was calculated from the data of radiation field and detector response. The coefficient which converts count to dose should be fixed not to underestimate the detected dose. As a result of the calculation, the overestimation of dose, the ratio of detected dose to expected dose, will be within three on the site boundary. (2) When one counter is applied for evaluating dose, the detected dose could be underestimated or much overestimated caused by change of neutron energy spectrum. In order to overcome this short point, optimization of pair counter which consist of two counters with each different thickness moderator was examined. We try to fit the energy response of this pair counter to the dose conversion factor. One of the two is fixed the counter with 2.5 cm thick

  9. Area monitor for neutrons with thin sheet of Au

    International Nuclear Information System (INIS)

    Valero L, C.; Guzman G, K. A.; Banuelos F, A.; Borja H, C. G.; Hernandez D, V. M.; Vega C, H. R.; Gallego, E.; Lorente, A.

    2011-11-01

    A passive area monitor for neutrons with an activation detector was designed and constructed to be used in sites where the radiation field is mixed, intense and pulsed, like happens in the radiotherapy rooms that use lineal accelerators of medical use or in enclosures with cyclotrons for PET, or where the field is mixed and intense as in the nuclear power plants. This equipment is useful for the exposition cases of the patients or workers that receive not counted radiation dose, generating harmful effects to the health, for what is necessary to take the pertinent measures for the radiological protection. The design of the area monitor was realized using the MCNP5 code, where was considered an activation detector and therefore thin sheets of Au-197 located in the moderator center were used. The moderator was designed as a polyethylene cylindrical to moderate the neutrons. The gold was used like detector for its high cross section and its physical and chemical characteristics. The response of the monitor is maxim for energies from 1 to 20 MeV, region where the flowing coefficients and dose are majors. Therefore, the designed and constructed monitor can be used in sites with high, mixed and pulsed radiation fields. (Author)

  10. Tritium contamination and monitoring at Frascati Neutron Generator

    Energy Technology Data Exchange (ETDEWEB)

    Lucci, F.; Sandri, S.; Ianni, A. [ENEA, Frascati (Italy). Dipartimento Ambiente; Vasselli, R. [ANPA, Roma (Italy); Pillon, M.; Bettinali, L. [ENEA, Frascati (Italy). Dipartimento Energia

    1994-11-01

    The Frascati Neutron Generator (FGN) is a specialised 300 keV, 3 mA direct electrostatic deuteron accelerator which produces about 5-10{sup 1}1 14 MeV neutrons per second by D-T reactions on a tritium-titanium fixed target. This paper concerns the tritium contamination control and monitoring aspects after some months of testing and a preliminary period of operation of the plant. The tritium monitoring system is composed of both on-line and off-line devices to control the tritium concentration in the atmosphere measured from different parts of the plant: vacuum exhaust clean up (VECU) system, stack, etc. The on-line devices are three flux monitors, that sample continuosly the air from up to eight different points in the plant. The passive sampling system is designed to select the chemical form of tritium and to collect respectively HTO and HT in two different cartridges filled with an appropriate drying material. The response of the on-line tritium monitor system are exposed and discussed: some measurements performed with atmosphere dehumidifying apparatus of this system are described and the relevant results are analysed.

  11. Tritium contamination and monitoring at Frascati Neutron Generator

    International Nuclear Information System (INIS)

    Lucci, F.; Sandri, S.; Ianni, A.; Pillon, M.; Bettinali, L.

    1994-11-01

    The Frascati Neutron Generator (FGN) is a specialised 300 keV, 3 mA direct electrostatic deuteron accelerator which produces about 5-10 1 1 14 MeV neutrons per second by D-T reactions on a tritium-titanium fixed target. This paper concerns the tritium contamination control and monitoring aspects after some months of testing and a preliminary period of operation of the plant. The tritium monitoring system is composed of both on-line and off-line devices to control the tritium concentration in the atmosphere measured from different parts of the plant: vacuum exhaust clean up (VECU) system, stack, etc. The on-line devices are three flux monitors, that sample continuosly the air from up to eight different points in the plant. The passive sampling system is designed to select the chemical form of tritium and to collect respectively HTO and HT in two different cartridges filled with an appropriate drying material. The response of the on-line tritium monitor system are exposed and discussed: some measurements performed with atmosphere dehumidifying apparatus of this system are described and the relevant results are analysed

  12. On the problem of monitoring the neutron parameters of the Fast Energy Amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Behringer, K.; Wydler, P

    1998-10-01

    The conceptual Fast Energy Amplifier, proposed by Rubbia et al. (1995), consists of a combination of a U-233/Th-232 fuelled fast-neutron subcritical facility with a proton accelerator. An intense beam of 1 GeV protons is injected into liquid lead at the core centre and drives the reactor by producing spallation neutrons. The burst of spallation neutrons produced by a single proton alters the basic neutron statistics which are well known for thermal neutrons in conventional nuclear reactors. A short assessment of standard neutron noise analysis methods is made with respect to monitoring neutron parameter data. (author) 18 refs., 14 figs., 3 tabs.

  13. Rhodium self-powered detector for monitoring neutron fluence, energy production, and isotopic composition of fuel

    International Nuclear Information System (INIS)

    Sokolov, A.P.; Pochivalin, G.P.; Shipovskikh, Yu.M.; Garusov, Yu.V.; Chernikov, O.G.; Shevchenko, V.G.

    1993-01-01

    The use of self-powered detectors (SPDs) with a rhodium emitter customarily involves monitoring of neutron fields in the core of a nuclear reactor. Since current in an SPD is generated primarily because of the neutron flux, which is responsible for the dynamics of particular nuclear transformations, including fission reactions of heavy isotopes, the detector signal can be attributed unambiguously to energy release at the location of the detector. Computation modeling performed with the KOMDPS package of programs of the current formation in a rhodium SPD along with the neutron-physical processes that occur in the reactor core makes it possible to take account of the effect of the principal factors characterizing the operating conditions and the design features of the fuel channel and the detector, reveal quantitative relations between the generated signal and individual physical parameters, and determine the metrological parameters of the detector. The formation and transport of changed particles in the sensitive part of the SPC is calculated by the Monte Carlo method. The emitter activation, neutron transport, and dynamics of the isotopic composition in the fuel channel containing the SPD are determined by solving the kinetic equation in the multigroup representation of the neutron spectrum, using the discrete ordinate method. In this work the authors consider the operation of a rhodium SPD in a bundle of 49 fuel channels of the RBMK-1000 reactor with a fuel enrichment of 2.4% from the time it is inserted into a fresh channel

  14. Experience with neutron flux monitoring systems qualified for post-accident monitoring

    International Nuclear Information System (INIS)

    Shugars, H.G.; Miller, J.F.

    1995-01-01

    In this paper we discuss the environmental requirements for excore neutron flux monitors that are qualified for use during and after postulated accidents in Pressurized Water Reactors (PWRs). We emphasize PWRs designed in the United States, which are similar to those used also in parts of Western Europe and Eastern Asia. We then discuss design features of the flux monitoring systems necessary to address the environmental, functional, and regulatory requirements, and the experience with these systems. (author). 9 refs, 2 figs

  15. Area monitor for neutrons with thin sheet of Au; Monitor de area para neutrones con laminilla de Au

    Energy Technology Data Exchange (ETDEWEB)

    Valero L, C.; Guzman G, K. A.; Banuelos F, A.; Borja H, C. G.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Gallego, E.; Lorente, A., E-mail: fermineutron@yahoo.com [Universidad Politecnica de Madrid, Departamento de Ingenieria Nuclear, C/ Jose Gutierrez Abascal 2, E-28006 Madrid (Spain)

    2011-11-15

    A passive area monitor for neutrons with an activation detector was designed and constructed to be used in sites where the radiation field is mixed, intense and pulsed, like happens in the radiotherapy rooms that use lineal accelerators of medical use or in enclosures with cyclotrons for PET, or where the field is mixed and intense as in the nuclear power plants. This equipment is useful for the exposition cases of the patients or workers that receive not counted radiation dose, generating harmful effects to the health, for what is necessary to take the pertinent measures for the radiological protection. The design of the area monitor was realized using the MCNP5 code, where was considered an activation detector and therefore thin sheets of Au-197 located in the moderator center were used. The moderator was designed as a polyethylene cylindrical to moderate the neutrons. The gold was used like detector for its high cross section and its physical and chemical characteristics. The response of the monitor is maxim for energies from 1 to 20 MeV, region where the flowing coefficients and dose are majors. Therefore, the designed and constructed monitor can be used in sites with high, mixed and pulsed radiation fields. (Author)

  16. The design of the electronic system on neutron beam monitor based on GEM

    International Nuclear Information System (INIS)

    Zuo Min; Zhuang Bao'an; Zhao Yubin; Chen Shaojia; Wang Na; Zhang Hongyu; Zhao Jingwei

    2012-01-01

    The Neutron Beam Monitor - a GEM based system used to monitor the neutron beams in real time - is introduced. The electronic parts are described in details, including the principles of the circuit, the system structure, the design of the Daughterboard and the logic and algorithm of the FPGA on the Monitor board. The test results are also given out in the final. (authors)

  17. The IAEA intercomparison for individual monitoring

    International Nuclear Information System (INIS)

    Griffith, R.V.; Boehm, J.; Herrman, D.; Strachotinsky, C.; Thompson, I.M.G.

    1990-01-01

    In 1985 the International Commission on Radiation Units and Measurements introduced a new set of operational quantities for radiation protection purposes through Report 39. The International Atomic Energy Agency has been concerned with the impact of possible adoption of these quantities by its 113 Member States. Thus the Agency implemented a Coordinated Research Programme on Intercomparison for Individual Monitoring in 1987. The first phase completed with a Research Coordination meeting of the participants in April, 1989. Photon exposures were provided at 11 energies over a range from 18 keV to 1.25 MeV at three standards laboratories in Austria, the GDR and the UK. Technical coordination was provided by the PTB, Braunschweig. Twenty one laboratories from 19 countries participated with film, TLD of various types, and combination dosemeters. Irradiations were performed on the IAEA 30 cm cubic, water-filled phantom that is in use throughout its network of 61 Secondary Standard Dosimetry Laboratories. Conversion coefficients for the IAEA phantom were calculated by the PTB and confirmed through measurements at ASMW in the GDR. Preliminary results indicated that the type of dosemeter (film or TLD) had little effect on the quality of results. The most important factor appears to be the specific techniques used for data interpretation. (author)

  18. Qualification of the monitor Pug-7N like dosimeter for neutrons; Habilitacion del monitor PUG-7N como dosimetro para neutrones

    Energy Technology Data Exchange (ETDEWEB)

    Benites R, J. L. [Centro Estatal de Cancerologia de Nayarit, Av. Enfermeria, Fracc. Fray Junipero Serra, 63000 Tepic, Nayarit (Mexico); Vega C, H. R.; Murillo O, R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Velazquez F, J. B., E-mail: jlbenitesr@prodigy.net.mx [Universidad Autonoma de Nayarit, Postgrado CBAP, Carretera Tepic Compostela Km. 9, Xalisco, Nayarit (Mexico)

    2011-10-15

    By means of an inter-comparison method, the monitor for neutrons Pug-7N was enabled like dosimeter for neutrons of two magnitudes: the environmental equivalent dose, H*(10), and the H equivalent dose. The monitor Pug-7N has a plastic detector of scintillation Pns-20 that can be used inside or outside of its polyethylene cylindrical moderator. This designed to detect the neutrons presence that is shown in ana logical form by means of a fast count. Although the instrument is useful to detect the neutrons presence its design it does not allow to estimate the dose. With the purpose of enabling it as dosimeter for neutrons, their response was compared with the response of the area monitor for neutrons Bert hold Lb 6411 and Eberline NRD model Asp-1. Under the same irradiation conditions the 3 instruments were exposed to a source of {sup 241}AmBe of 3.7E(9) Bq (100 mCi) of activity whose spectrum and dosimetric magnitudes were determined with a spectrometric system of Bonner spheres with scintillator of {sup 6}Lil(Eu) and the NSDUAZ code. Conversion factors of H*(10)/cpm and H/cpm were obtained for the two options of the monitor detector Pug-7N, with this procedure the monitor Pug-7N besides determining the presence of neutrons, it has been enabled for their use as dosimeter for neutrons. (Author)

  19. Vibration, neutron noise and acoustic monitoring in German LWRs

    International Nuclear Information System (INIS)

    Wach, D.

    1991-01-01

    In Germany monitoring methods for early failure detection and on-line diagnosis at primary circuit components have been developed and are successfully applied for assuring structural inegrity in all modern German LWRs. Vibration, noise signature and acoustic monitoring in frequency and/or time domain are performed with multi-sensor-systems distributed over the primary circuit. Advanced signal analysis methods, like correlation-, FFT-, pattern recognition techniques, are applied to calculate relevant features and signatures from stochastical signals. Deviations of actual signatures from reference signatures indicate incipient failure or malfunction developments and are used for on-line diagnoses. A detailed knowledge base about normal and abnormal feature behaviour is needed for correct interpretation. GRS was deeply involved in the basic method development for vibration, neutron noise and acoustic monitoring together with industry (mainly KWU) in the 70ies and has spent great efforts during the subsequent years, to collect operational experiences and to build up a comprehensive signature data bank for interpretation and diagnosis purposes in its laboratories. Recently new computer-based monitoring systems have been developed by GRS and installed in operating plants which allow more 'intelligent' data analysis and feature trending on-site as well as an optimal link to the experts and the signature data bank in the GRS diagnosis centre. The progress made by these new systems for vibration and loose parts monitoring in NPPs is briefly reviewed. (orig./HP)

  20. Uncertainty analysis in the task of individual monitoring data

    International Nuclear Information System (INIS)

    Molokanov, A.; Badjin, V.; Gasteva, G.; Antipin, E.

    2003-01-01

    Assessment of internal doses is an essential component of individual monitoring programmes for workers and consists of two stages: individual monitoring measurements and interpretation of the monitoring data in terms of annual intake and/or annual internal dose. The overall uncertainty in assessed dose is a combination of the uncertainties in these stages. An algorithm and a computer code were developed for estimating the uncertainties in these stages. An algorithm and a computer code were developed for estimating the uncertainty in the assessment of internal dose in the task of individual monitoring data interpretation. Two main influencing factors are analysed in this paper: the unknown time of the exposure and variability of bioassay measurements. The aim of this analysis is to show that the algorithm is applicable in designing an individual monitoring programme for workers so as to guarantee that the individual dose calculated from individual monitoring measurements does not exceed a required limit with a certain confidence probability. (author)

  1. Novel Scintillating Materials Based on Phenyl-Polysiloxane for Neutron Detection and Monitoring

    OpenAIRE

    Degerlier, M.; Carturan, S.; Gramegna, F.; Marchi, T.; Palma, M. Dalla; Cinausero, M.; Maggioni, G.; Quaranta, A.; Collazuol, G.; Bermudez, J.

    2013-01-01

    Neutron detectors are extensively used at many nuclear research facilities across Europe. Their application range covers many topics in basic and applied nuclear research: in nuclear structure and reaction dynamics (reaction reconstruction and decay studies); in nuclear astrophysics (neutron emission probabilities); in nuclear technology (nuclear data measurements and in-core/off-core monitors); in nuclear medicine (radiation monitors, dosimeters); in materials science (neutron imaging techni...

  2. Monitoring of plutonium contaminated solid waste streams. Chapter IV: Passive neutron assay

    International Nuclear Information System (INIS)

    Birkhoff, G.; Bondar, L.

    1978-01-01

    The fundamentals of the passive neutron technique for the non destructive assay of plutonium bearing materials are summarized. A reference monitor for the passive neutron assay of Pu contaminated solids is described in terms of instrumental design principles and performances. The theoretical model of this reference monitor with pertinent nuclear data and functions for the interpretation of experimental data is given

  3. SINUPERM N: a new digital neutron flux density monitoring system

    International Nuclear Information System (INIS)

    Flick, H.A.

    1993-01-01

    The new SINUPERM N System is developed for Neutron Monitoring in nuclear power plants. The development was started in 1989 (with the design specification) and will be finished in 1993 (with the qualification). The first built will be the nuclear power plant in Borselle (Netherlands). The design is based on a microprocessor system with a digital signal processor for calculations and signal filtering. The separation between analogue-input signals and digital processing enables for each detector type special input modules and standard output interfaces e.g. field - bus. The wide range of the Neutron Flux Density from 10 -2 cm -2 s -1 up to 10 8 cm -2 s -1 for the out-of-pile instrumentation and up to 10 14 cm -2 s -1 for the in-core-instrumentation will be covered by the SINUPERM N system. The requirements to be met by the SINUPERM N system are the IEEE 323, IEC 987 and the German standard KTA-3503 for safety systems. Other standards for instrumentation and control systems like IEC 801, IEC 1131 and IEC 68 for EMV, climatic and seismic requirements are also included in the hardware type test. The software requirement depends on the IEC 880 standard. (author). 3 figs

  4. High-Efficiency Thin-Film-Coated Semiconductor Neutron Detectors for Active Dosimetry Monitors

    International Nuclear Information System (INIS)

    Dunn, William L.; McGregor, Douglas

    2009-01-01

    To develop a compact high-detection-efficiency neutron dosimeter capable of discerning between thermal and fast neutron doses in real time. A need exists for portable neutron dosimeters that have greater than 10% thermal neutron detection efficiency and can provide direct readout in the field. To be of widespread use, these dosimeters should have low power requirements. It would be ideal if these dosimeters could differentiate thermal from fast neutrons, as this would allow characterization (at least to some degree) of the source of those neutrons. Such neutron dosimeters could be used either as personnel dosimeters or in area survey instruments. The project has been completed and the objectives of the project were met. Prototype perforated semiconductor neutron detectors have been developed and characterized. Individual detectors have been packaged in small, rugged, battery-powered containers that can be worn as active dosimeters and read in real time. Two prototype neutron dosimeters were constructed and tested.

  5. Monitoring neutrons from spent reactor fuel by bubble detectors

    CERN Document Server

    Tam, N C; Lakosi, L

    1999-01-01

    In order to eliminate the strong temperature-dependence of bubble detectors used for spent fuel assay, a simple way could be to keep them in the water pond but far from fuel assemblies before exposure for about 20 min, until the detectors warm up. Fast neutrons from fuel assemblies in the Paks Nuclear Power Plant, Hungary, were detected by BD-100R type detectors at 28 deg. C (in winter) and at 35 deg. C in summer). Calibration was performed by a standard sup 2 sup 5 sup 2 Cf source in borated water. Burnup monitoring inside fuel assemblies can be provided by smaller diameter detectors prepared from BD-100R type ones.

  6. Salient features, response and operation of Lead-Free Gulmarg Neutron Monitor

    International Nuclear Information System (INIS)

    Mufti, S.; Chatterjee, S.; Ishtiaq, P.M.; Darzi, M.A.; Mir, T.A.; Shah, G.N.

    2016-01-01

    Lead-Free Gulmarg Neutron Monitor (LFGNM) provides continuous ground level intensity measurements of atmospheric secondary neutrons produced in interactions of primary cosmic rays with the Earth's constituent atmosphere. We report the LFGNM detector salient features and simulation of its energy response for 10 −11 MeV to 10 4 MeV energy incident neutrons using the FLUKA Monte Carlo package. An empirical calibration of the LFGNM detector carried out with a Pu–Be neutron source for maximising its few MeV neutron counting sensitivity is also presented. As an illustration of its functionality a single representative transient solar modulation event recorded by LFGNM depicting Forbush decrease in integrated neutron data for which the geospace consequences are well known is also presented. Performance of LFGNM under actual observation conditions for effectively responding to transient solar modulation is seen to compare well with other world-wide conventional neutron monitors.

  7. Salient features, response and operation of Lead-Free Gulmarg Neutron Monitor

    Energy Technology Data Exchange (ETDEWEB)

    Mufti, S., E-mail: mufti.sabiuddin@gmail.com [Astrophysical Sciences Division, Nuclear Research Laboratory, Bhabha Atomic Research Centre, Srinagar - 190 006 (India); Chatterjee, S. [TLD Unit, Variable Energy Cyclotron Centre, Bhabha Atomic Research Centre, 1/AF-Bidhannagar, Kolkata - 700 064 (India); Ishtiaq, P.M.; Darzi, M.A.; Mir, T.A.; Shah, G.N. [Astrophysical Sciences Division, Nuclear Research Laboratory, Bhabha Atomic Research Centre, Srinagar - 190 006 (India)

    2016-03-21

    Lead-Free Gulmarg Neutron Monitor (LFGNM) provides continuous ground level intensity measurements of atmospheric secondary neutrons produced in interactions of primary cosmic rays with the Earth's constituent atmosphere. We report the LFGNM detector salient features and simulation of its energy response for 10{sup −11} MeV to 10{sup 4} MeV energy incident neutrons using the FLUKA Monte Carlo package. An empirical calibration of the LFGNM detector carried out with a Pu–Be neutron source for maximising its few MeV neutron counting sensitivity is also presented. As an illustration of its functionality a single representative transient solar modulation event recorded by LFGNM depicting Forbush decrease in integrated neutron data for which the geospace consequences are well known is also presented. Performance of LFGNM under actual observation conditions for effectively responding to transient solar modulation is seen to compare well with other world-wide conventional neutron monitors.

  8. Required accuracy and dose thresholds in individual monitoring

    DEFF Research Database (Denmark)

    Christensen, P.; Griffith, R.V.

    1994-01-01

    The paper follows the approach given in recent revisions of CEC and IAEA recommendations on requirements in individual monitoring for external radiations. The ICRP requirements on overall accuracy for individual monitoring, as given in ICRP Publication 35 (1982), form the basis for the specificat....... The paper discusses different definitions of the lower detectability of dosimetry systems for individual monitoring.......The paper follows the approach given in recent revisions of CEC and IAEA recommendations on requirements in individual monitoring for external radiations. The ICRP requirements on overall accuracy for individual monitoring, as given in ICRP Publication 35 (1982), form the basis...... the overall standard deviation of the dosimetry system by combining random and systematic uncertainties in quadrature, and procedures are also given for determining each individual uncertainty connected to the dose measurement. In particular, attention is paid to the evaluation of the combined uncertainty due...

  9. Quality Assurance in Individual Monitoring: 10 Years of Performance Monitoring of the TLD Based TNO Individual Monitoring Service (invited paper)

    International Nuclear Information System (INIS)

    Dijk, J.W.E. van

    1998-01-01

    The QA subscription forms the nucleus of the Quality Assurance (QA) programme of the TLD-based Individual Monitoring Service of TNO-CSD. This QA subscription is the subscription of a dummy customer to the service. As this customer is treated exactly like a normal customer, all aspects of the service are monitored by the QA subscription. An overview is given of 10 years of monitoring the performance of the service. Various improvements over the past decade have resulted in a standard deviation in a low dose measurement of 0.01 mSv and a relative standard deviation at higher doses of 5%. These figures represent the performance under routine circumstances and thus include variations due to variations in the natural background from place to place and, for example, due to transport. (author)

  10. Neutron dosimetry. Environmental monitoring in a BWR type reactor; Dosimetria de neutrones. Monitoreo ambiental en un reactor del tipo BWR

    Energy Technology Data Exchange (ETDEWEB)

    Tavera D, L.; Camacho L, M.E

    1991-01-15

    The measurements carried out on reactor dosimetry are applied mainly to the study on the effects of the radiation in 108 materials of the reactor; little is on the environmental dosimetry outside of the primary container of BWR reactors. In this work the application of a neutron spectrometer formed by plastic detectors of nuclear traces manufactured in the ININ, for the environmental monitoring in penetrations around the primary container of the unit I of the Laguna Verde central is presented. The neutron monitoring carries out with purposes of radiological protection, during the operational tests of the reactor. (Author)

  11. Qualification of the monitor Pug-7N like dosimeter for neutrons

    International Nuclear Information System (INIS)

    Benites R, J. L.; Vega C, H. R.; Murillo O, R.; Velazquez F, J. B.

    2011-10-01

    By means of an inter-comparison method, the monitor for neutrons Pug-7N was enabled like dosimeter for neutrons of two magnitudes: the environmental equivalent dose, H*(10), and the H equivalent dose. The monitor Pug-7N has a plastic detector of scintillation Pns-20 that can be used inside or outside of its polyethylene cylindrical moderator. This designed to detect the neutrons presence that is shown in ana logical form by means of a fast count. Although the instrument is useful to detect the neutrons presence its design it does not allow to estimate the dose. With the purpose of enabling it as dosimeter for neutrons, their response was compared with the response of the area monitor for neutrons Bert hold Lb 6411 and Eberline NRD model Asp-1. Under the same irradiation conditions the 3 instruments were exposed to a source of 241 AmBe of 3.7E(9) Bq (100 mCi) of activity whose spectrum and dosimetric magnitudes were determined with a spectrometric system of Bonner spheres with scintillator of 6 Lil(Eu) and the NSDUAZ code. Conversion factors of H*(10)/cpm and H/cpm were obtained for the two options of the monitor detector Pug-7N, with this procedure the monitor Pug-7N besides determining the presence of neutrons, it has been enabled for their use as dosimeter for neutrons. (Author)

  12. Design of a neutron poison monitor system (NPMS) of maximum sensitivity

    International Nuclear Information System (INIS)

    Piper, T.C.

    1989-01-01

    The development of a neutron poison monitoring system was first reported in 1958 and systems implemented by others have copied that design. The present work shows that the 1958 physical configuration does not yield maximum sensitivity [i.e. sensitivity = fractional change in neutron count rate for given fractional change in concentration]. The maximum sensitivity design being reported was configured by using neutron transport calculations to determine sensitivity versus configuration. Data from the new and the 1958 types are compared. 2 refs

  13. A neutron monitor for D-T neutron generator in the PGNAA-based online measurement system

    Science.gov (United States)

    Shan, Qing; Shengnan, Chu; Yongsheng, Ling; Pingkun, Cai; Wenbao, Jia

    2017-06-01

    A new type of neutron detector, which consists of polyethylene, an EJ200 plastic scintillator and fused silica, was proposed and optimized by the GEANT4 Monte Carlo simulation toolkit in our previous studies. The calculation method was also described for calculating the neutron flux in the preset condition. This paper reports the manufacturing of the prototype detector. Experiments are conducted to validate the feasibility of this detector. A D-T neutron generator and a 60Co gamma-ray source are used in the experiments. The designed detector and a He-3 proportional counter are simultaneously used to monitor the yield of the D-T neutron generator. A more universal calculation method is developed to enable the application of this detector to common conditions. The experimental results show that the performance of the designed detector is comparable to that of the He-3 proportional counter. The relative deviations between their normalized counts are less than 5%.

  14. Evaluation of the environmental equivalent dose rate using area monitors for neutrons in clinical linear accelerators

    International Nuclear Information System (INIS)

    Salgado, Ana Paula; Pereira, Walsan Wagner; Patrao, Karla C. de Souza; Fonseca, Evaldo S. da; Batista, Delano V.S.

    2009-01-01

    The Neutron Laboratory of the Radioprotection and Dosimetry Institute - IRD/CNEN, Rio de Janeiro, Brazil, initiated studies on the process of calibration of neutron area monitors and the results of the measurements performed at radiotherapy treatment rooms, containing clinical accelerators

  15. Neutron-activation method of monitoring of the environment

    International Nuclear Information System (INIS)

    Sattarov, G.S.; Muzafarov, A.M.; Komilov, J.M.; Kadirov, F.; Kist, A.A.

    2004-01-01

    Full text: Estimation of technogenic influences of the industrial enterprises on an environment, in particular, on ground and underground waters, was carried out by the fragmentary analysis of their element structure. In the report application of neutron-activation analysis (NAA) for monitoring an environment is considered. The total contents of elements was determined by NAA method with use of a reactor such as WWR-SM. Values of factors of correlation (K) are calculated with use of the computer, by special algorithm and reception of numerical values between 30 elements in the samples selected by a traditional technique from more than 600 points in area of activity GMZ-2. The developed technique has allowed to reveal elements indicators of technogenic (As, Ag, Sb, W, Au), mixed (Mo, Ba, Hg) and natural (Sc, Fe, Co, Ni, Rb, Cs, REE, Hf, Th, U) origins. Change of the total contents of elements in underground waters which were selected from observant chinks quarterly within three years is investigated. The technique of definition of forms of a presence of elements in underground and the sewage, based on electrodialysis division of ions with use nuclear (on a basis polyethyleneterephtalate film) filters with a diameter of pores of 0,16x0,2 micrometres is developed

  16. Development of an area monitor for neutrons using solid state nuclear track detector; Desenvolvimento de um monitor de area para neutrons utilizando detector solido de tracos nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Zahn, G.S.

    1994-12-31

    An area monitor for neutrons composed of the solid state nuclear track detector (SSNTD) Makrofol DE, together with a (n,{alpha}) converter, in the center of a 25 cm diameter polyethylene sphere, is developed. The optimal electrochemical etching conditions for the detection of thermal neutrons by the Makrofol DE using the BN converter are studied, leading to the choice of 55 min, at 30{sup 0} C, under a 44,2 kV.cm{sup -1} electric field with oscillation frequency of 2,0 khz. The response of this system to thermal neutrons, in the optimal conditions, is of 2,76(10)x 10{sup -3} tr/n. Changing from the BN converter to a 2,73(3)g compressed boric acid tablet this value lowers to 3,88(17)x 10{sup -4} tr/n. The performance of the whole monitor in the detection of fast neutrons is examined using the BN converter and neutrons from a {sup 241} Am Be source, with a response of 4,4(2)x 10{sup 3} tr.mSv{sup -1}.cm{sup -2} and operational limits between 7(3){mu}Sv and 5,6(2)mSv. The result of the monitoring of the control room of the IPEN Cyclotron accelerator are also presented as a final test for the viability of the practical use of the monitor. (author). 34 refs, 15 figs, 6 tabs, 1 app.

  17. Exploration of ion temperature profile measurements at JET using the upgraded neutron profile monitor

    International Nuclear Information System (INIS)

    Marocco, D.; Esposito, B.; Riva, M.

    2012-01-01

    The neutron profile monitor (NPM), routinely used at the Joint European Torus for neutron emissivity profile measurements, consists of two fan-shaped arrays of collimators and each line of sight (LOS) is equipped with a NE213 liquid organic scintillator for simultaneous measurements of the 2.5 MeV and 14 MeV neutrons. A digital system developed in ENEA has replaced the analog acquisition electronics and now enables the NPM to perform spatially resolved neutron spectrometry by providing neutron pulse height spectra (PHS) for each LOS. However, the NPM was not originally designed as a spectrometer and, therefore, lacks several key features, such as detailed measurements of the detector response functions and the presence of detector stability monitors. We present a proof of principle of ion temperature profile measurements derived from the NPM PHS in high plasma current discharges using simulated detector response functions.

  18. International conference on individual monitoring of ionising radiation

    International Nuclear Information System (INIS)

    Vanhavere, Filip

    2016-01-01

    This special issue of the journal Radiation Protection Dosimetry is dedicated to the Proceedings of the International Conference on Individual Monitoring of Ionising Radiation (IM2015), which is the fifth of a series of conferences dealing with individual monitoring. This conference series is initiated by EURADOS, the European Radiation Dosimetry Group, and is organised every 5 years. In 2015, the conference was jointly organised by the Belgian Nuclear Research Centre (SCK.CEN), AV Controlatom, and the Vrije Universiteit Brussel. It brought together scientists from regulatory authorities, individual monitoring services (IMS), research bodies, European networks and companies, for the purpose of facilitating the dissemination of knowledge, exchanging experiences and promoting new ideas in the field of individual monitoring. After the conference, 124 papers were submitted for publication in these peer-reviewed proceedings. From these, 103 were finally accepted for publication. The help of the numerous referees and the guest editors is very much appreciated. These proceedings provide a full image of the IM2015 conference. The high-level publications will be useful to improve the state of individual monitoring all over the world and aim to inspire many scientists to continue their work on a better monitoring of radiologically exposed workers

  19. Performance analysis of the TNO TLD individual monitoring service

    International Nuclear Information System (INIS)

    Dijk, J.W.E. van; Julius, H.W.

    1990-01-01

    The purpose of this study was to analyse the performance and to establish the lowest detectable occupational dose (LDOD) of the TNO TL dosemeter, in use for large scale routine individual monitoring since 1983. The TNO individual monitoring service uses three TLD reader systems and over 45000 TL dosemeters, designed to measure H s (0.07) and H p (10). Each reader system is normalised daily and each individual dosemeter is calibrated every ten readout cycles. The performance of the service is monitored by a double blind experimental set-up. A series of 10 routine dosemeters is issued every fortnight, mailed, exposed by staff not involved in the monitoring service, sent back and evaluated. The conclusion of this study is that the lowest detectable occupational dose is less than 0.04 mSv and that the integrated dose at the level of the annual dose limit is measured within 2%. (author)

  20. Implementation of standards for individual monitoring in Europe

    International Nuclear Information System (INIS)

    Fantuzzi, E.; Alves, J. G.; Ambrosi, P.; Janzekovic, H.; Vartiainen, E.

    2004-01-01

    A large number of standards are available for radiation protection and individual monitoring purposes. They are published by various organisations, international and national. Moreover, the increasing policy of 'Quality' applied to individual monitoring requires the implementation of standards on Quality Assurance (QA) both in technical and management aspects of a dosimetric service. Implementation of standards is not mandatory; therefore, varying degrees of implementation can be found in different European countries. However, for a number of good reasons, a degree of harmonisation within the European Union (EU) of the requirements and procedures for individual monitoring would be desirable. Harmonisation as applied to dosimetric services does not mean that they should all follow exactly the same procedures, but that they should aim to meet the same general requirements, and their results should be comparable. This article aims to compile information on the use of all standards applied within individual monitoring practices, be it on the calibration of dosemeters or on the QA procedures to be applied to the overall dose evaluation process. Both 'technical standards' and 'quality standards' will be discussed. A list of documents of relevance to subjects such as recommendations and requirements in the field of individual monitoring, whose application could help in the harmonisation of procedures, will also be given. As it is agreed that implementation of quality standards is a relevant framework within which harmonisation can be achieved, guidance on the implementation of quality standards in a dosimetric service is given. Accreditation and approval of dosimetric services will be of relevance in the process of harmonisation of individual monitoring within the EU. In this article, a discussion of various procedures and the meaning of both forms of recognition is also provided. Although most of the text applies to the monitoring of internal and external exposure to

  1. Design and fabrication of self-powered in-core neutron flux monitor assembly

    International Nuclear Information System (INIS)

    Chung, M.K.; Cho, S.W.; Kang, H.D.; Cho, K.K.; Cho, B.S.; Kang, S.S.

    1980-01-01

    This is the final report on the prototypical fabrication of an in-core neutron flux monitor detector assembly for a specific power reactor conducted by KAERI from July 1, 1978 to December 31, 1979. It is well known that power reactors require a large number of in-core neutron flux detector for reactor regulation and the structures of detector assemblies are different from reactor to reactor. Therefore, from the nature of this project, it should be noted here that the target model of the prototypical farbrication of an in-core neutron flux monitor detector assembly is a VFD-2 System for Wolsung CANDU. It is concluded that fabrication of in-core neutron flux monitor detector assembly for CANDU reactor is technically feasible and will bring economical benefit as much as 50 % of the unit price if they are fabricated in Korea by using partially materials which are available from local market. (author)

  2. Development of a portable system to test area monitors for neutrons

    International Nuclear Information System (INIS)

    Souza, Luciane de Rezende

    2011-02-01

    The objective is to develop a portable system to test the reliability in terms of calibration of area monitors for neutrons. For the production of this system, thickness and location of the source within the system were simulated using the code of radiation transport MCNP5. The thicknesses were set for a 241 Am-Be source with an activity of 395 mCi, which will be in a polyethylene cylinder which will provide a ambient dose equivalent rate chosen through the points of calibration settings' used by the Laboratory of Neutrons (IRD / CNEN). The results obtained in this study show the feasibility of mounting the portable system as a tool to test the area monitors for neutrons, which will provide the user of neutron area monitors to check the instrument's response in the same field of operation, thus avoiding the use of an inadequate equipment. (author)

  3. Neutron intensity monitor with activation foil for p-Li neutron source for BNCT--Feasibility test of the concept.

    Science.gov (United States)

    Murata, Isao; Otani, Yuki; Sato, Fuminobu

    2015-12-01

    Proton-lithium (p-Li) reaction is being examined worldwide as a candidate nuclear production reaction for accelerator based neutron source (ABNS) for BNCT. In this reaction, the emitted neutron energy is not so high, below 1 MeV, and especially in backward angles the energy is as low as about 100 keV. The intensity measurement was thus known to be difficult so far. In the present study, a simple method was investigated to monitor the absolute neutron intensity of the p-Li neutron source by employing the foil activation method based on isomer production reactions in order to cover around several hundreds keV. As a result of numerical examination, it was found that (107)Ag, (115)In and (189)Os would be feasible. Their features found out are summarized as follows: (107)Ag: The most convenient foil, since the half life is short. (115)In: The accuracy is the best at 0°, though it cannot be used for backward angles. And (189)Os: Suitable nuclide which can be used in backward angles, though the gamma-ray energy is a little too low. These would be used for p-Li source monitoring depending on measuring purposes in real BNCT scenes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Application of pixel-cell detector technology for Advanced Neutron Beam Monitors

    Energy Technology Data Exchange (ETDEWEB)

    Kopp, Daniel M. [ORDELA, Inc., Oak Ridge, TN (United States)

    2011-01-11

    Application of Pixel-Cell Detector Technology for Advanced Neutron Beam Monitors Specifications of currently available neutron beam detectors limit their usefulness at intense neutron beams of large-scale national user facilities used for the advanced study of materials. A large number of neutron-scattering experiments require beam monitors to operate in an intense neutron beam flux of >10E+7 neutrons per second per square centimeter. For instance, a 4 cm x 4 cm intense beam flux of 6.25 x 10E+7 n/s/cm2 at the Spallation Neutron Source will put a flux of 1.00 x 10E+9 n/s at the beam monitor. Currently available beam monitors with a typical efficiency of 1 x 10E-4 will need to be replaced in less than two years of operation due to wire and gas degradation issues. There is also a need at some instruments for beam position information that are beyond the capabilities of currently available He-3 and BF3 neutron beam monitors. ORDELA, Inc.’s research under USDOE SBIR Grant (DE-FG02-07ER84844) studied the feasibility of using pixel-cell technology for developing a new generation of stable, long-life neutron beam monitors. The research effort has led to the development and commercialization of advanced neutron beam detectors that will directly benefit the Spallation Neutron Source and other intense neutron sources such as the High Flux Isotope Reactor. A prototypical Pixel-Cell Neutron Beam Monitor was designed and constructed during this research effort. This prototype beam monitor was exposed to an intense neutron beam at the HFIR SNS HB-2 test beam site. Initial measurements on efficiency, uniformity across the detector, and position resolution yielded excellent results. The development and test results have provided the required data to initiate the fabrication and commercialization of this next generation of neutron-detector systems. ORDELA, Inc. has (1) identified low-cost design and fabrication strategies, (2) developed and built pixel-cell detectors and

  5. Characterization of a diamond detector to be used as neutron yield monitor during the in-vessel calibration of JET neutron detectors in preparation of the DT experiment

    International Nuclear Information System (INIS)

    Pillon, Mario; Angelone, Maurizio; Batistoni, Paola; Loreti, Stefano; Milocco, Alberto

    2016-01-01

    Highlights: • A diamond detector has been characterized for use as neutron yield monitor of a portable 14 MeV neutron generator. • The system will be used for the 14 MeV calibration of JET neutron detector. • The results and the performances of the monitor are very satisfactory in term of accuracy and reliability. - Abstract: A new Deuterium-Tritium (DT) campaign is planned at JET. An accurate calibration for the 14 MeV neutron yield monitors is necessary. In order to perform the calibration a 14 MeV Neutron Generator with suitable intensity (∼10 8 n/s) will be used. Due to the intensity change during the Neutron Generator lifetime it would be necessary to monitor continuously the neutron emission intensity during the calibration using a compact detector attached to it. A high quality diamond detector has been chosen as one of the monitors. This detector has been fully characterized at the 14 MeV Frascati Neutron Generator facility. The characterization procedure and the resulting 14 MeV neutron response of the detector are described in this paper together with the obtained uncertainties.

  6. Experiences in troubleshooting of neutron rem monitor electronics and its subsequent calibration

    International Nuclear Information System (INIS)

    Maithani, Atul; Dash, Amit Kumar; Vijayasekaran, P.; Mathews, Geo; Ajoy, K.C.; Dhanasekaran, A.

    2014-01-01

    This paper deals with the troubleshooting of the signal processing and counting electronics of two no's of Neutron Rem monitors and its subsequent calibration. Electronics servicing with respect to detection of fault in the circuit board, replacement of faulty ICs, circuits (Analog and Digital) tracing and installation of new rechargeable battery pack was done. Electronic calibration using Test pulse generator was carried out for dose rate measurements, amplitude measurements and discriminator level setting. Serial communication settings were checked with both HyperTerminal and software for the monitors. Neutron Source calibration was also carried out for both the monitors. (author)

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

    International Nuclear Information System (INIS)

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

    1992-01-01

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

  8. Compendium of Neutron Beam Facilities for High Precision Nuclear Data Measurements. Annex: Individual Reports

    International Nuclear Information System (INIS)

    2014-07-01

    experts, together with the individual contributions describing the current status of their respective neutron beam facilities, highlighting major achievements and future developments in this field. The publication IAEA-TECDOC-1743 describes both the research reactor and accelerator based neutron beam facilities for nuclear data measurements, classifies them according to the type of neutron source (reactor or accelerator based), the neutron energy accessible to individual facilities or the measurement technique employed. In addition, the state of the art of experimental sample and target preparation, instrumentation, data acquisition and new research trends in the field are summarized. Each individual facility report is available on this CD-ROM which accompanies the publication

  9. Neutron-flux profile monitor for use in a fission reactor

    Science.gov (United States)

    Kopp, M.K.; Valentine, K.H.

    1981-09-15

    A neutron flux monitor is provided which consists of a plurality of fission counters arranged as spaced-apart point detectors along a delay line. As a fission event occurs in any one of the counters, two delayed current pulses are generated at the output of the delay line. The time separation of the pulses identifies the counter in which the particular fission event occurred. Neutron flux profiles of reactor cores can be more accurately measured as a result.

  10. Monitoring elastic strain and damage by neutron and synchrotron beams

    International Nuclear Information System (INIS)

    Withers, P.J.

    2001-01-01

    Large-scale neutron and synchrotron X-ray facilities have been providing important information for physicists and chemists for many decades. Increasingly, materials engineers are finding that they can also provide them with important information non-destructively. Highly penetrating neutron and X-ray synchrotron beams provide the materials engineer with a means of obtaining information about the state of stress and damage deep within materials. In this paper the principles underlying the elastic strain measurement and damage characterization techniques are introduced. (orig.)

  11. Monitoring individual and joint action outcomes in duet music performance

    DEFF Research Database (Denmark)

    Loehr, Janeen; Kourtis, Dimitrios; Vesper, Cordula

    2013-01-01

    We investigated whether people monitor the outcomes of their own and their partners’ individual actions as well as the outcome of their combined actions when performing joint actions together. Pairs of pianists memorized both parts of a piano duet. Each pianist then performed one part while...

  12. Monitoring Individual and Joint Action Outcomes in Duet Music Performance

    NARCIS (Netherlands)

    Loehr, J.D.; Kourtis, D.; Vesper, C.; Sebanz, N.; Knoblich, G.K.

    2013-01-01

    We investigated whether people monitor the outcomes of their own and their partners 'individual actions as well as the outcome of their combined actions when performing joint actions together. Pairs of pianists memorized both parts of a piano duet. Each pianist then performed one part while their

  13. Monitor units are not predictive of neutron dose for high-energy IMRT

    Directory of Open Access Journals (Sweden)

    Hälg Roger A

    2012-08-01

    Full Text Available Abstract Background Due to the substantial increase in beam-on time of high energy intensity-modulated radiotherapy (>10 MV techniques to deliver the same target dose compared to conventional treatment techniques, an increased dose of scatter radiation, including neutrons, is delivered to the patient. As a consequence, an increase in second malignancies may be expected in the future with the application of intensity-modulated radiotherapy. It is commonly assumed that the neutron dose equivalent scales with the number of monitor units. Methods Measurements of neutron dose equivalent were performed for an open and an intensity-modulated field at four positions: inside and outside of the treatment field at 0.2 cm and 15 cm depth, respectively. Results It was shown that the neutron dose equivalent, which a patient receives during an intensity-modulated radiotherapy treatment, does not scale with the ratio of applied monitor units relative to an open field irradiation. Outside the treatment volume at larger depth 35% less neutron dose equivalent is delivered than expected. Conclusions The predicted increase of second cancer induction rates from intensity-modulated treatment techniques can be overestimated when the neutron dose is simply scaled with monitor units.

  14. In core measurement and monitoring of reactor (neutron) radiation field

    International Nuclear Information System (INIS)

    Erben, O.

    1985-01-01

    A survey is presented of in core radiation detectors. The principles are described of activation detectors, fission chambers, self-powered neutron detectors and thermal sensors. Systems of in core measurement for WWER nuclear power plants, nuclear reactors of power plants operated by KWU, Babcock and Wilcox, Combustion Engineering and FRAMATOME are described. (E.S.)

  15. Individual Monitoring service for occupational exposure in Sudan

    International Nuclear Information System (INIS)

    Suliman, E.E.; Shaddad, I.; Medani, B.E.; Osman, M.Y.

    2005-01-01

    Full text: Individual Monitoring Service (IMS) is a dosimetry service provided by Radiation Protection Department (RPD) of Sudan Atomic Energy Commission (SAEC) to monitor about 400 occupational exposed workers all over the country. Measurements were done using thermoluminescence dosimeters (TLD). The calibration of the TLD system was performed on a phantom with application of suitable correction factors in the SSDL using Cs-137 and different qualities of x-ray energies. Personal dose equivalents Hp(10) and Hp(0.07) were evaluated by employing one individual dosimeter to be carried continuously by the occupational exposed person while at work. In this work the dose received by workers in x-ray diagnostic radiology, radiotherapy, nuclear medicine, research and industrial radiography were evaluated. Radiation doses for the years 1999, 2000, 2001, 2002 and 2003 were compared. From the results obtained, it was noticed that individual monitoring service had expanded over the last years. The average individual annual dose in different applications is less than 1 mSv/y except for the workers in industrial radiography, only 12 radiation workers (3.64 %) received doses exceeding 1 mSv and no individual approached the dose limit of 20 mSv recommended by the ICRP and set by Sudan's regulations. (author)

  16. Development of network communication function for digitalized neutron flux monitoring instrument

    International Nuclear Information System (INIS)

    Li Kai; Zhang Liangju; Chen Xiaojun; Li Baoxiang

    2002-01-01

    It is essential for a digitalized Neutron Flux Monitoring Instrument to communicate with other parts of Instrumentation and Control System in a network environment, and it is fairly different from the case of traditional analogue nuclear instrumentation. How to satisfy all the requirements of different network structure and communication protocol, which might be adopted in different target nuclear power plant, is a key issue in the design and development of a digitalized neutron flux monitoring instrument. The author describes the overall communication scheme, mainly discusses the design idea and the requirements of the communication interfaces and the implementation of the RS-485 interface as an example of the digitalized neutron flux monitoring instrument, which is under development in the institute

  17. Intercomparison of cosmic-ray neutron sensors and water balance monitoring in an urban environment

    Science.gov (United States)

    Schrön, Martin; Zacharias, Steffen; Womack, Gary; Köhli, Markus; Desilets, Darin; Oswald, Sascha E.; Bumberger, Jan; Mollenhauer, Hannes; Kögler, Simon; Remmler, Paul; Kasner, Mandy; Denk, Astrid; Dietrich, Peter

    2018-03-01

    Sensor-to-sensor variability is a source of error common to all geoscientific instruments that needs to be assessed before comparative and applied research can be performed with multiple sensors. Consistency among sensor systems is especially critical when subtle features of the surrounding terrain are to be identified. Cosmic-ray neutron sensors (CRNSs) are a recent technology used to monitor hectometre-scale environmental water storages, for which a rigorous comparison study of numerous co-located sensors has not yet been performed. In this work, nine stationary CRNS probes of type CRS1000 were installed in relative proximity on a grass patch surrounded by trees, buildings, and sealed areas. While the dynamics of the neutron count rates were found to be similar, offsets of a few percent from the absolute average neutron count rates were found. Technical adjustments of the individual detection parameters brought all instruments into good agreement. Furthermore, we found a critical integration time of 6 h above which all sensors showed consistent dynamics in the data and their RMSE fell below 1 % of gravimetric water content. The residual differences between the nine signals indicated local effects of the complex urban terrain on the scale of several metres. Mobile CRNS measurements and spatial simulations with the URANOS neutron transport code in the surrounding area (25 ha) have revealed substantial sub-footprint heterogeneity to which CRNS detectors are sensitive despite their large averaging volume. The sealed and constantly dry structures in the footprint furthermore damped the dynamics of the CRNS-derived soil moisture. We developed strategies to correct for the sealed-area effect based on theoretical insights about the spatial sensitivity of the sensor. This procedure not only led to reliable soil moisture estimation during dry-out periods, it further revealed a strong signal of intercepted water that emerged over the sealed surfaces during rain events. The

  18. Development of an area monitor for neutrons using solid state nuclear track detector

    International Nuclear Information System (INIS)

    Zahn, G.S.

    1994-01-01

    An area monitor for neutrons composed of the solid state nuclear track detector (SSNTD) Makrofol DE, together with a (n,α) converter, in the center of a 25 cm diameter polyethylene sphere, is developed. The optimal electrochemical etching conditions for the detection of thermal neutrons by the Makrofol DE using the BN converter are studied, leading to the choice of 55 min, at 30 0 C, under a 44,2 kV.cm -1 electric field with oscillation frequency of 2,0 khz. The response of this system to thermal neutrons, in the optimal conditions, is of 2,76(10)x 10 -3 tr/n. Changing from the BN converter to a 2,73(3)g compressed boric acid tablet this value lowers to 3,88(17)x 10 -4 tr/n. The performance of the whole monitor in the detection of fast neutrons is examined using the BN converter and neutrons from a 241 Am Be source, with a response of 4,4(2)x 10 3 tr.mSv -1 .cm -2 and operational limits between 7(3)μSv and 5,6(2)mSv. The result of the monitoring of the control room of the IPEN Cyclotron accelerator are also presented as a final test for the viability of the practical use of the monitor. (author). 34 refs, 15 figs, 6 tabs, 1 app

  19. Cosmic ray heliospheric transport study with neutron monitor data

    Science.gov (United States)

    Ahluwalia, H. S.; Ygbuhay, R. C.; Modzelewska, R.; Dorman, L. I.; Alania, M. V.

    2015-10-01

    Determining transport coefficients for galactic cosmic ray (GCR) propagation in the turbulent interplanetary magnetic field (IMF) poses a fundamental challenge in modeling cosmic ray modulation processes. GCR scattering in the solar wind involves wave-particle interaction, the waves being Alfven waves which propagate along the ambient field (B). Empirical values at 1 AU are determined for the components of the diffusion tensor for GCR propagation in the heliosphere using neutron monitor (NM) data. At high rigidities, particle density gradients and mean free paths at 1 AU in B can only be computed from the solar diurnal anisotropy (SDA) represented by a vector A (components Ar, Aϕ, and Aθ) in a heliospherical polar coordinate system. Long-term changes in SDA components of NMs (with long track record and the median rigidity of response Rm ~ 20 GV) are used to compute yearly values of the transport coefficients for 1963-2013. We confirm the previously reported result that the product of the parallel (to B) mean free path (λ||) and radial density gradient (Gr) computed from NM data exhibits a weak Schwabe cycle (11y) but strong Hale magnetic cycle (22y) dependence. Its value is most depressed in solar activity minima for positive (p) polarity intervals (solar magnetic field in the Northern Hemisphere points outward from the Sun) when GCRs drift from the polar regions toward the helioequatorial plane and out along the heliospheric current sheet (HCS), setting up a symmetric gradient Gθs pointing away from HCS. Gr drives all SDA components and λ|| Gr contributes to the diffusive component (Ad) of the ecliptic plane anisotropy (A). GCR transport is commonly discussed in terms of an isotropic hard sphere scattering (also known as billiard-ball scattering) in the solar wind plasma. We use it with a flat HCS model and the Ahluwalia-Dorman master equations to compute the coefficients α (=λ⊥/λ∥) and ωτ (a measure of turbulence in the solar wind) and transport

  20. The new Athens center on data processing from the neutron monitor network in real time

    Directory of Open Access Journals (Sweden)

    Mavromichalaki

    2005-11-01

    Full Text Available The ground-based neutron monitors (NMs record galactic and solar relativistic cosmic rays which can play a useful key role in space weather forecasting, as a result of their interaction with interplanetary disturbances. The Earth's-based neutron monitor network has been used in order to produce a real-time prediction of space weather phenomena. Therefore, the Athens Neutron Monitor Data Processing Center (ANMODAP takes advantage of this unique multi-directional device to solve problems concerning the diagnosis and forecasting of space weather. At this moment there has been a multi-sided use of neutron monitors. On the one hand, a preliminary alert for ground level enhancements (GLEs may be provided due to relativistic solar particles and can be registered around 20 to 30 min before the arrival of the main part of lower energy particles responsible for radiation hazard. To make a more reliable prognosis of these events, real time data from channels of lower energy particles and X-ray intensity from the GOES satellite are involved in the analysis. The other possibility is to search in real time for predictors of geomagnetic storms when they occur simultaneously with Forbush effects, using hourly, on-line accessible neutron monitor data from the worldwide network and applying a special method of processing. This chance of prognosis is only being elaborated and considered here as one of the possible uses of the Neutron Monitor Network for forecasting the arrival of interplanetary disturbance to the Earth. The achievements, the processes and the future results, are discussed in this work.

  1. The new Athens center on data processing from the neutron monitor network in real time

    Directory of Open Access Journals (Sweden)

    Mavromichalaki

    2005-11-01

    Full Text Available The ground-based neutron monitors (NMs record galactic and solar relativistic cosmic rays which can play a useful key role in space weather forecasting, as a result of their interaction with interplanetary disturbances. The Earth's-based neutron monitor network has been used in order to produce a real-time prediction of space weather phenomena. Therefore, the Athens Neutron Monitor Data Processing Center (ANMODAP takes advantage of this unique multi-directional device to solve problems concerning the diagnosis and forecasting of space weather. At this moment there has been a multi-sided use of neutron monitors. On the one hand, a preliminary alert for ground level enhancements (GLEs may be provided due to relativistic solar particles and can be registered around 20 to 30 min before the arrival of the main part of lower energy particles responsible for radiation hazard. To make a more reliable prognosis of these events, real time data from channels of lower energy particles and X-ray intensity from the GOES satellite are involved in the analysis. The other possibility is to search in real time for predictors of geomagnetic storms when they occur simultaneously with Forbush effects, using hourly, on-line accessible neutron monitor data from the worldwide network and applying a special method of processing. This chance of prognosis is only being elaborated and considered here as one of the possible uses of the Neutron Monitor Network for forecasting the arrival of interplanetary disturbance to the Earth. The achievements, the processes and the future results, are discussed in this work.

  2. GLE and Sub-GLE Redefinition in the Light of High-Altitude Polar Neutron Monitors

    Science.gov (United States)

    Poluianov, S. V.; Usoskin, I. G.; Mishev, A. L.; Shea, M. A.; Smart, D. F.

    2017-11-01

    The conventional definition of ground-level enhancement (GLE) events requires a detection of solar energetic particles (SEP) by at least two differently located neutron monitors. Some places are exceptionally well suitable for ground-based detection of SEP - high-elevation polar regions with negligible geomagnetic and reduced atmospheric energy/rigidity cutoffs. At present, there are two neutron-monitor stations in such locations on the Antarctic plateau: SOPO/SOPB (at Amundsen-Scott station, 2835 m elevation), and DOMC/DOMB (at Concordia station, 3233 m elevation). Since 2015, when the DOMC/DOMB station started continuous operation, a relatively weak SEP event that was not detected by sea-level neutron-monitor stations was registered by both SOPO/SOPB and DOMC/DOMB, and it was accordingly classified as a GLE. This would lead to a distortion of the homogeneity of the historic GLE list and the corresponding statistics. To address this issue, we propose to modify the GLE definition so that it maintains the homogeneity: A GLE event is registered when there are near-time coincident and statistically significant enhancements of the count rates of at least two differently located neutron monitors, including at least one neutron monitor near sea level and a corresponding enhancement in the proton flux measured by a space-borne instrument(s). Relatively weak SEP events registered only by high-altitude polar neutron monitors, but with no response from cosmic-ray stations at sea level, can be classified as sub-GLEs.

  3. Decadal trends in the diurnal variation of galactic cosmic rays observed using neutron monitor data

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Simon [Reading Univ. (United Kingdom). Dept. of Meteorology; Univ. College London, Dorking (United Kingdom). Mullard Space Science Lab.; Owens, Mathew; Lockwood, Mike [Reading Univ. (United Kingdom). Dept. of Meteorology; Owen, Chris [Univ. College London, Dorking (United Kingdom). Mullard Space Science Lab.

    2017-10-01

    The diurnal variation (DV) in galactic cosmic ray (GCR) flux is a widely observed phenomenon in neutron monitor data. The background variation considered primarily in this study is due to the balance between the convection of energetic particles away from the Sun and the inward diffusion of energetic particles along magnetic field lines. However, there are also times of enhanced DV following geomagnetic disturbances caused by coronal mass ejections or corotating interaction regions. In this study we investigate changes in the DV over four solar cycles using ground-based neutron monitors at different magnetic latitudes and longitudes at Earth. We divide all of the hourly neutron monitor data into magnetic polarity cycles to investigate cycle-to-cycle variations in the phase and amplitude of the DV. The results show, in general, a similarity between each of the A<0 cycles and A>0 cycles, but with a phase change between the two. To investigate this further, we split the neutron monitor data by solar magnetic polarity between times when the dominant polarity was either directed outward (positive) or inward (negative) at the northern solar pole. We find that the maxima and minima of the DV changes by, typically, 1-2 h between the two polarity states for all non-polar neutron monitors. This difference between cycles becomes even larger in amplitude and phase with the removal of periods with enhanced DV caused by solar wind transients. The time difference between polarity cycles is found to vary in a 22-year cycle for both the maximum and minimum times of the DV. The times of the maximum and minimum in the DV do not always vary in the same manner between A>0 and A<0 polarity cycles, suggesting a slight change in the anisotropy vector of GCRs arriving at Earth between polarity cycles. Polar neutron monitors show differences in phase between polarity cycles which have asymptotic directions at mid-to-high latitudes. All neutron monitors show changes in the amplitude of the

  4. An individual monitor of alpha atmospheric contamination (Monica α type)

    International Nuclear Information System (INIS)

    Charuau, J.; Pescayre, G.; Prigent, R.

    1984-01-01

    The development of an individual monitor of α atmospheric contamination must take into account the shape and size of the sampling head and the filter type. The monitor should: - draw in the aerosols up to an aerodynamic diameter (density 1) of 10 μm with a recovery efficiency near 100 %; - lead the biggest particles up to the sampling filter without any signicant loss on the walls; - after separation of natural radioactive aerosols (Rn and Th daughters) distribute the particles on the filter uniformly; - measure the α activity deposited with the best efficiency; - deliver a sound alarm as impulsion with frequencies varying with the volumic activity of the atmosphere [fr

  5. Calculation of neutron fluence to dose equivalent conversion coefficients using GEANT4; Calculo de coeficientes de fluencia de neutrons para equivalente de dose individual utilizando o GEANT4

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Rosane M.; Santos, Denison de S.; Queiroz Filho, Pedro P. de; Mauricio, CLaudia L.P.; Silva, Livia K. da; Pessanha, Paula R., E-mail: rosanemribeiro@oi.com.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2014-07-01

    Fluence to dose equivalent conversion coefficients provide the basis for the calculation of area and personal monitors. Recently, the ICRP has started a revision of these coefficients, including new Monte Carlo codes for benchmarking. So far, little information is available about neutron transport below 10 MeV in tissue-equivalent (TE) material performed with Monte Carlo GEANT4 code. The objective of this work is to calculate neutron fluence to personal dose equivalent conversion coefficients, H{sub p} (10)/Φ, with GEANT4 code. The incidence of monoenergetic neutrons was simulated as an expanded and aligned field, with energies ranging between thermal neutrons to 10 MeV on the ICRU slab of dimension 30 x 30 x 15 cm{sup 3}, composed of 76.2% of oxygen, 10.1% of hydrogen, 11.1% of carbon and 2.6% of nitrogen. For all incident energy, a cylindrical sensitive volume is placed at a depth of 10 mm, in the largest surface of the slab (30 x 30 cm{sup 2}). Physic process are included for neutrons, photons and charged particles, and calculations are made for neutrons and secondary particles which reach the sensitive volume. Results obtained are thus compared with values published in ICRP 74. Neutron fluence in the sensitive volume was calculated for benchmarking. The Monte Carlo GEANT4 code was found to be appropriate to calculate neutron doses at energies below 10 MeV correctly. (author)

  6. Study on in situ calibration for neutron flux monitor in the Large Helical Device based on Monte Carlo calculations.

    Science.gov (United States)

    Nakano, Y; Yamazaki, A; Watanabe, K; Uritani, A; Ogawa, K; Isobe, M

    2014-11-01

    Neutron monitoring is important to manage safety of fusion experiment facilities because neutrons are generated in fusion reactions. Monte Carlo simulations play an important role in evaluating the influence of neutron scattering from various structures and correcting differences between deuterium plasma experiments and in situ calibration experiments. We evaluated these influences based on differences between the both experiments at Large Helical Device using Monte Carlo simulation code MCNP5. A difference between the both experiments in absolute detection efficiency of the fission chamber between O-ports is estimated to be the biggest of all monitors. We additionally evaluated correction coefficients for some neutron monitors.

  7. New cathode design boron lined proportional counters for neutron area monitoring application

    International Nuclear Information System (INIS)

    Dighe, Priyamvada M.

    2007-01-01

    A new cathode design boron lined proportional counter of 26mm IDx100mm sensitive length SS304 cathode has been developed with boron-coated baffles separated by 3mm spacers inserted in the sensitive volume perpendicular to the axis. The baffles and the spacers were coated with indigenously available 27.7% enriched 10 B. The introduction of baffles enhanced the boron coated surface area by a factor of 2.8. Tests in 120nv thermal neutron flux show that the counter has 0.84cps/nv thermal neutron sensitivity, which shows enhancement in the sensitivity by a factor of 2.78 due to baffle structure. For comparison standard cylindrical cathode geometry counter coated with 92% enriched 10 B on its inner wall with a coating thickness of 0.8mg/cm 2 is developed with same outer dimensions for neutron area monitoring applications. The counter has 1cps/nv thermal neutron sensitivity. Comparative tests carried out on counters with and without baffle structure show that the baffles enhance the neutron sensitivity and in 2kR/h gamma background the effect of gamma pile up is similar on both the counters. The variation in cathode internal diameter due to baffle structure gives higher voltage plateau slope (2.8%/10V) as compared to conventional cylindrical geometry counter (1.2%/10V). The usability of boron lined counters for neutron area monitoring applications for the cylindrical geometry counter has been studied

  8. Development of detector for neutron monitor of wide energy range. Joint research

    CERN Document Server

    Kim, E; Nakamura, T; Rasolonjatovo, D R D; Shiomi, T; Tanaka, S; Yamaguchi, Y; Yoshizawa, M

    2002-01-01

    Radiation monitoring of neutrons in high-power proton accelerator facilities is very important for radiation safety management for workers and members of the public. In the present study, a neutron detector that can evaluate dose of neutrons in the energy range from thermal energy to 100MeV was developed using an organic liquid scintillator, a boron-loaded scintillator and a sup 6 Li glass scintillator. First, a method was developed to evaluate neutron doses above several MeV by a spectrum weight function (G-function) which is applied to the organic liquid scintillator, and the validity of the methods was confirmed by dose evaluation in some neutron fields. Second, the G-function was applied to the boron-loaded scintillator which detects thermal neutrons by sup 1 sup 0 B(n, alpha) sup 7 Li reaction, in order to expand the covering neutron energy range. The response function and the G-function of the scintillator were evaluated by experiment and calculation, and the characteristics of dose measurement were ana...

  9. Thermal–hydraulic analysis of a candidate design for ITER divertor neutron flux monitor (DNFM)

    International Nuclear Information System (INIS)

    Tanchuk, Victor; Alexandrov, Evgeny; Batyunin, Alexander; Kashchuk, Yuri; Korban, Svetlana; Lyublin, Boris; Obudovsky, Sergey; Senik, Konstantin

    2013-01-01

    The key role in direct measurement of the ITER fusion power is assigned to the neutron diagnostic system for measurement of total neutron flux of the D–D and D–T fusion reaction with the help of a neutron flux monitor located under the divertor dome. High plasma heat loads in this position implies stringent requirements for the detector design and its cooling system to ensure the required temperature operation regime of the neutron detector. The paper describes the neutron flux monitor design developed in close collaboration with IO ITER diagnostic division. Two numerical models (hydraulic and thermal) built up to simulate the water flow in the cooling system and the temperature state of detector components are also presented and discussed. The numerical investigations carried out on the developed models have shown that only good thermal contact between the shell of the detector blocks and water-cooled casing of the monitor (fit, brazing) will provide the required temperature operation regimes of the most temperature-sensitive IFC electrodes. The obtained high temperature of the detector supports makes necessary an auxiliary direct cooling of the supports or their redesign so as to provide their higher thermal conductivity

  10. Adequacy of individual monitoring of external exposure at the workplace

    International Nuclear Information System (INIS)

    Rannou, A.

    2006-01-01

    Individual monitoring of workers exposed to external radiations must fulfill technical, regulatory and organizational requirements. The external dosimetry should be adapted to the workplace. The relevant dosimetric techniques have to be chosen upon the workplace study that conditions both the categorization of exposed workers and classification of areas. Solutions exist which are satisfactory for the most situations. However, rational solutions still have to be found for a few specific situations. (author)

  11. Monitoring of neutron field parameters of pressure vessels of russian WWER in compliance with regulatory demands

    International Nuclear Information System (INIS)

    Borodkin, P.G.; Khrennikov, N.N.; Miroshnichenko, M.I.

    2015-01-01

    Results of finished calculational-experimental measurements which are performed on the number of Russian power units with WWER-440 and WWER-1000 are presented. The analysis of core power distribution of WWER-1000 and its influence on measurements and calculations of the integral through-vessel neutron leak-age are proposed. It is shown how to get improved estimation of parameters with reasonable uncertainty from actual reactor data (core operational parameters (from in-core monitoring system) and experimentally evaluated the integral leakage at the reactor vessel (neutron activation measurements). In the present paper discusses the results of such investigations and gives the conclusions on the necessity and sufficiency of monitoring of neutron field parameters on RPV [ru

  12. Solid state detectors for neutron radiation monitoring in fusion facilities

    International Nuclear Information System (INIS)

    Gómez-Ros, J.M.

    2014-01-01

    The purpose of this communication is to summarize the main solid state based detectors proposed for neutron diagnostic in fusion applications and their applicability under the required harsh conditions in terms of intense radiation, high temperature and available space restrictions. Activation systems, semiconductor based detectors, luminescent materials and Cerenkov fibre optics sensors (C-FOS) are the main devices that are described. - Highlights: • A state-of-the-art summary of solid state based detectors are described. • Conditions and restrictions for their applicability are described. • A list of the 38 more relevant references has been included

  13. Monitoring individual and joint action outcomes in duet music performance.

    Science.gov (United States)

    Loehr, Janeen D; Kourtis, Dimitrios; Vesper, Cordula; Sebanz, Natalie; Knoblich, Günther

    2013-07-01

    We investigated whether people monitor the outcomes of their own and their partners' individual actions as well as the outcome of their combined actions when performing joint actions together. Pairs of pianists memorized both parts of a piano duet. Each pianist then performed one part while their partner performed the other; EEG was recorded from both. Auditory outcomes (pitches) associated with keystrokes produced by the pianists were occasionally altered in a way that either did or did not affect the joint auditory outcome (i.e., the harmony of a chord produced by the two pianists' combined pitches). Altered auditory outcomes elicited a feedback-related negativity whether they occurred in the pianist's own part or the partner's part, and whether they affected individual or joint action outcomes. Altered auditory outcomes also elicited a P300 whose amplitude was larger when the alteration affected the joint outcome compared with individual outcomes and when the alteration affected the pianist's own part compared with the partner's part. Thus, musicians engaged in joint actions monitor their own and their partner's actions as well as their combined action outcomes, while at the same time maintaining a distinction between their own and others' actions and between individual and joint outcomes.

  14. The development of ex-core neutron flux monitoring system for integral reactor

    International Nuclear Information System (INIS)

    Lee, J. K.; Kwon, H. J.; Park, H. Y.; Koo, I. S.

    2004-12-01

    Due to the arrangement of major components within the reactor vessel, the integral reactor has relatively long distance between the core support barrel and the reactor vessel when compared with the currently operating plants. So, a neutron flux leakage at the ex-vessel represents a relatively low flux level which may generate some difficulties in obtaining a wide range of neutron flux information including the source range one. This fact may have an impact upon the design and fabrication of an ex-core neutron flux detector. Therefore, it is required to study neutron flux detectors that are suitable for the installation location and characteristics of an integral reactor. The physical constraints of an integral reactor should be considered when one designs and develops the ex-core neutron flux monitoring detectors and their systems. As a possible installation location of the integral reactor ex-core neutron flux detector assembly, two candidate locations are considered, that is, one is between the core support barrel and the reactor vessel and the other is within the Internal Shielding Tank(IST). And, for these locations, some factors such as the environmental requirements and geometrical restrictions are investigated In the case of considering the inside of the IST as a ex-core neutron flux detector installation position, an electrical insulation problem and a low neutron flux measurement problem arose and when considering the inside of the reactor vessel, a detector's sensitivity variation problem, an electrical insulation problem, a detector's insertion and withdrawal problem, and a high neutron flux measurement problem were encountered. Through a survey of the detector installation of the currently operating plants and detector manufacturer's products, the proposed structure and specifications of an ex-core neutron flux detector are suggested. And, the joint ownership strategy for a proposed detector model is also depicted. At the end, by studying the ex

  15. Development of Interactive Monitoring System for Neutron Scattering Instrument

    International Nuclear Information System (INIS)

    So, Ji Yong

    2015-01-01

    Neutron scattering instruments in HANARO research reactor have been contributed to various fields of basic science and material engineering. These instruments are open to publics and researchers can apply beam-time and do experiments with instrument scientists. In most cases, these instruments run for several weeks without stopping, and therefore instrument scientist wants to see the instrument status and receive information if the instruments have some problem. This is important for the safety. However, it is very hard to get instrument information outside of instruments. Access from external site is strongly forbidden in the institute due to the network safety, I developed another way to send instrument status information using commercial short messaging service(SMS). In this presentation, detailed features of this system will be shown. As a prototype, this system is being developed for the single instrument: Disk-chopper time-of-flight instruments (DC-TOF). I have successfully developed instruments and operate for several years. This information messaging system can be used for other neutron scattering instruments

  16. Quantitative monitoring of gas flooding in oil-bearing reservoirs using a pulsed neutron tool

    International Nuclear Information System (INIS)

    Ruhovets, N.; Wyatt, D.F. Jr.

    1991-01-01

    This paper reports on quantitative monitoring of gas flooding in oil bearing reservoirs which is unique in that saturations of three fluids (gas, oil and water) in the effective pore space have to be determined, while in most other applications saturation behind casing is determined only for two fluids: hydrocarbons and water. A new method has been developed to monitor gas flooding of oil reservoirs. The method is based on computing two porosities: true effective (base) porosity determined before gas flooding, and apparent effective (monitor) porosity determined after gas flooding. The base porosity is determined from open and/or cased hole porosity logs run before the flooding. When open hole logs are available, the cased hole porosity logs are calibrated against open hole log. The monitor porosity is determined from one of the cased hole porosity logs, such as a neutron log or count rate ratio curve from a pulsed neutron log run after the gas flooding. The base and monitor porosities provide determination of the hydrogen index of the reservoir fluid after the flooding. This hydrogen index is then used to determine saturation of the flood agent after flooding. Water saturation after flooding can be determined from the equation which relates neutron total cross section (Σm) to volumetric constituent cross sections, using Σm values from a monitor run (after flooding)

  17. Development of a new neutron monitor using a boron-loaded organic liquid scintillation detector

    CERN Document Server

    Rasolonjatovo, A H D; Kim, E; Nakamura, T; Nunomiya, T; Endo, A; Yamaguchi, Y; Yoshizawa, M

    2002-01-01

    A new type of neutron dose monitor was developed by using a 12.7 cm diameterx12.7 cm long boron-loaded organic liquid scintillation detector BC523A. This detector aims to have a response in the wide energy range of thermal energy to 100 MeV by using the H and C reactions to the fast neutrons of organic liquid and the sup 1 sup 0 B(n, alpha) reaction to thermalized neutrons in the liquid. The response functions of this detector were determined by the Monte Carlo simulation in the energy region from thermal energy to 100 MeV. Using these response functions, the spectrum-weighted dose function, G-function, to get the neutron dose from the light output spectrum of the detector was also determined by the unfolding technique. The calculated G-function was applied to determine the neutron dose in real neutron fields having energies ranging from thermal energy to several tens of MeV, where the light output spectra were measured with the BC523A detector. The thus-obtained ambient doses and effective doses show rather ...

  18. Decreased response monitoring in individuals with symptoms of trichotillomania.

    Science.gov (United States)

    Roberts, Kathryn; Stanley, Emily M; Franklin, Martin E; Simons, Robert F

    2014-07-01

    Trichotillomania (TTM) was long classified as an impulse-control disorder; however, the many characteristics it shares with obsessive-compulsive disorder (OCD) led to its recategorization in the DSM-V. The present study aimed to assess and inform the taxonomic placement of TTM through an examination of its neural correlates. While research has consistently associated OCD with enhanced response monitoring, the present study investigated whether a similar neural process is associated with TTM. Undergraduates reporting TTM symptoms and controls performed a modified version of the flanker task, and their event-related potentials were examined for between-group differences in error-related negativity (ERN). Results confirm that individuals who have symptoms of hair pulling have significantly smaller ERNs than the control group. Smaller ERNs reflect decreased levels of response monitoring and support the idea that TTM is distinct from OCD. Copyright © 2014 Society for Psychophysiological Research.

  19. Performance testing of the neutron flux monitors from 10keV to 1MeV developed for BNCT: A preliminary study.

    Science.gov (United States)

    Guan, Xingcai; Manabe, Masanobu; Tamaki, Shingo; Sato, Fuminobu; Murata, Isao; Wang, Tieshan

    2017-07-01

    The neutron flux monitors from 10keV to 1MeV designed for boron neutron capture therapy (BNCT) were experimentally tested with prototype monitors in an appropriate neutron field produced at the intense deuterium-tritium neutron source facility OKTAVIAN of Osaka University, Japan. The experimental test results and related analysis indicated that the performance of the monitors was good and the neutron fluxes from 10keV to 1MeV of practical BNCT neutron sources can be measured within 10% by the monitors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Use of Germanium as comparator and integral monitor of neutron flux in activation analysis

    International Nuclear Information System (INIS)

    Furnari, Juan C.; Cohen, Isaac M.; Arribere, Maria A.; Kestelman, Abraham J.

    1997-01-01

    The possibility of using germanium as monitor of the thermal and epithermal components of the neutron flux, and comparator in parametric activation analysis, is discussed. The advantages and drawbacks associated to the use of this element are commented on, and the comparison with zirconium, in terms of the determination relative error, is performed. The utilisation of germanium as integral flux monitor, including the fast component of the neutron spectrum, is also discussed. Data corresponding to measurements of k 0 factor for the most relevant gamma transitions from Ge-75 and Be-77 are presented, as well as the results of the reference material analysis, employing germanium as flux monitor and comparator in a simultaneous way. (author). 8 refs., 3 figs., 2 tabs

  1. A new start-up range neutron monitor

    International Nuclear Information System (INIS)

    Benson, M.R.; Sawyer, S.D.

    1984-01-01

    In the early 1960's General Electric began producing a line of radiation monitoring equipment known as Integrated Nuclear Measurement and Control (INMAC). Recent advances in technology, especially in the area of microprocessors, now allows improved performance in the same physical package size. This paper describes a new family of radiation monitoring equipment known as Nuclear Measurement Analysis and Control (NUMAC). In these instruments all essential logic and timing are implemented through the use of Microcomputer cards. In order to provide a high assurance of operability, an optional microprocessor controlled Self Test System may be incorporated. The Self Test System continuously checks operability of all safety related functions. Other design features include highly modularized construction, an enhanced operator interface and upwards compatibility with present and future General Electric instrumentation and control products. scheduled for the third quarter of 1984. This paper describes the requirements and design of the NUMAC line with emphasis on the Source Range Monitor

  2. Air pollution monitoring in Czech Republic by neutron activation analysis and other methods

    International Nuclear Information System (INIS)

    Kucear, J.; Faltejsek, J.; Starkova, B.

    1994-01-01

    High levels of air pollution occur in several areas of the Czech Republic due to both inland emissions sources (mainly coal-fired power plants) and those from other parts of Europe by local and long-range pollution processes, respectively. Therefore, regular air pollution monitoring is carried out both in the vicinity of large power plants in rural, locally unpolluted regions as well. Other emission sources (municipal waste incinerators, metallurgical plants, motor vehicles) are also examined to enable apportionment of individual emission sources types to the level of pollution in a particular area by receptor modelling. In this project, a study of elemental composition of airborne particulate matter in areas with high and low levels of pollution using instrumental neutron activation analysis (INAA) is proposed. Several elements, namely Cu, Cd, Ni, and Pb will be determined by atomic absorption spectrometry (AAS). Selected biological indicators of air pollution (mosses) will also be analyzed using INAA, radiochemical NAA (RNAA), and AAS. In addition, measurement of chemical composition of precipitation samples (selected elements, anions, cations, pH, and conductivity) will be carried out using AAS, INAA, RNAA, ion chromatography, and spectrophotometry. Quality assurance of the analyses will be pursued by concurrent analyses of suitable matrix-based reference materials and by participation in interlaboratory comparisons. (author). 17 refs, 1 tab

  3. Seven years of individual monitoring service in Cuba

    International Nuclear Information System (INIS)

    Cruz Suarez, R.; Diaz Bernal, E.D.; Lopez Bejerano, G.M.; Jova Sed, L.A.

    1996-01-01

    The Center for Radiation Protection and Hygiene (CPHR) has been carrying out from 1987 the individual monitoring of workers occupationally exposed to the ionizing radiations in the Republic of Cuba, excepting those that employ X-rays in diagnostic radiology. In this paper the results of the individual monitoring services during the period 1987-1993 are discussed. For all occupational practices the current system of dose limitation established in the country with 50 mSv as limit of annual dose is satisfied. The distribution in all occupational practices other than nuclear medicine and gamma-therapy is characterized by having more than 95% of the controlled personnel with an effective dose lower than 5 mSv. In the case of nuclear medicine and gamma-therapy more than 80% of the workers were below that dose value. For the practices evaluated in this paper the possibility of assuming the system of dose limitation recommended by ICRP is evident. The evaluations carried out for the introduction of operational quantities H p (0.07) and H p (10) in dose assessment procedure are presented. The expressions obtained during the characterization of the film badge dosemeter, in terms of operational quantities guarantees a deviation of response of the dosemeter with depending upon energies, lower than 20 %. (author)

  4. Education and training issues in individual monitoring of ionising radiation

    International Nuclear Information System (INIS)

    Dimitriou, P.; Kamenopoulou, V.

    2011-01-01

    The present article deals with the education and training (E and T) issues of individual monitoring (IM) of ionising radiation, based on the requirements provided by the Basic Safety Standards EURATOM Directive and the European Commission Technical Recommendations for IM of external radiation. The structure and the objectives of E and T programmes addressed to the staff of dosimetry services, in order to allow the recognition and ensure the continuity of expertise are discussed. The necessity for the establishment of a national strategy for building competence in IM through information, education, training and retraining programmes, addressed to the individually monitored personnel is underlined. The train the trainers' concept is recognised as being an important tool for optimising resources and transferring the skills necessary for building competence. The conditions under which an efficient train the trainers' approach can be established are discussed. Examples of curricula concerning the key persons involved in the provision of E and T in occupational radiation protection are also given. (authors)

  5. Individual Monitoring and Occupational Dose Record Management in China: History, Current Status and Perspectives.

    Science.gov (United States)

    Wang, Hong-Bo; Yu, Hai-Tao; Sun, Quan-Fu

    2016-06-03

    This review paper presents an overview of individual monitoring, as well as the national dose register and dose record management of radiation workers in China. Progress has recently been made on the individual monitoring of radiation workers. A critical analysis of current status and problems in individual monitoring is also presented and necessary future research on individual monitoring, such as the monitoring technology in the form of the ring dosimeters and eye lens dosimeters, is suggested.

  6. Investigation of neutron fluence using fluence monitors for irradiation test at WWR-K

    International Nuclear Information System (INIS)

    Romanova, N.K.; Takemoto, N.

    2013-01-01

    Irradiation test of a Si ingot is planned using WWR-K in Institute of Nuclear Physics Republic of Kazakhstan (INP RK) to develop an irradiation technology for Si semiconductor production by Neutron Transmutation Doping (NTD) method in the framework of an international cooperation between INP RK and Japan Atomic Energy Agency (JAEA), Japan. It is possible to irradiate the Si ingot of 6 inch in diameter at the K-23 irradiation channel in the WWR-K. The preliminary irradiation test using 4 Al ingots was performed to evaluate the actual neutronic irradiation field at the K-23 channel in the WWR-K. Each Al ingot has the same dimension as the Si ingot, and 15 fluence monitors are equipped in it. Iron wire and aluminum-cobalt wire are inserted into them, and it is possible to evaluate both fast and thermal neutron fluxes by measurement of these radiation activities after irradiation. This report described the results of the preliminary irradiation test and the neutronic calculations by Monte Carlo method in order to evaluate the neutronic irradiation field in the irradiation position for the silicon ingot at the channel in the WWR-K. (authors)

  7. Design and operation of a passive neutron monitor for assaying the TRU content of solid wastes

    International Nuclear Information System (INIS)

    Brodzinski, R.L.; Brown, D.P.; Rieck, H.G. Jr.; Rogers, L.A.

    1984-02-01

    A passive neutron monitor has been designed and built for determining the residual transuranic (TRU) and plutonium content of chopped leached fuel hulls and other solid wastes from spent Fast Flux Test Facility (FFTF) fuel. The system was designed to measure as little as 8 g of plutonium or 88 mg of TRU in a waste package as large as a 208-l drum which could be emitting up to 220,000 R/hr of gamma radiation. For practical purposes, maximum assay times were chosen to be 10,000 sec. The monitor consists of 96 10 BF 3 neutron sensitive proportional counting tubes each 5.08 cm in diameter and 183 cm in active length. Tables of neutron emission rates from both spontaneous fission and (α,n) reactions on oxygen are given for all contributing isotopes expected to be present in spent FFTF fuel. Tables of neutron yeilds from isotopic compositions predicted for various exposures and cooling times are also given. Methods of data reduction and sources, magnitude, and control of errors are discussed. Backgrounds and efficiencies have been measured and are reported. A section describing step-by-step operational procedures is included. Guidelines and procedures for quality control and troubleshooting are also given. 13 references, 15 figures, 4 tables

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

    Science.gov (United States)

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

    2015-02-01

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

  9. Dose record keeping: a multi purpose tool in individual monitoring

    International Nuclear Information System (INIS)

    Bermann, F.; Julius, H.W.

    1993-01-01

    Proper recording of radiation doses is an essential part of the process of individual monitoring and shares in the same objective. A dose record keeping system is more than just a computer based data storage system and should rather be a Dose Registration and Information System (DRIS). Objectives of dose record keeping are given. As a result of the integration of member states of the European Communities, co-operation and exchange of personnel between countries will be increasing. This will probably require national dose registration systems and adequate data communication between them. These developments emphasize the necessity for international harmonization of dose record keeping systems and categorization of the data they contain. General characteristics and specific aspects of dose record keeping systems will be dealt with. Attention will also be given to some special applications of the recorded information, such as: the use of data for epidemiological studies and for QA purposes. (authors). 5 tabs., 4 refs

  10. Required accuracy and dose thresholds in individual monitoring

    DEFF Research Database (Denmark)

    Christensen, P.; Griffith, R.V.

    1994-01-01

    this uncertainty factor, a value of 21% can be evaluated for the allowable maximum overall standard deviation for dose measurements at dose levels near the annual dose limits increasing to 45% for dose levels at the lower end of the dose range required to be monitored. A method is described for evaluating...... the overall standard deviation of the dosimetry system by combining random and systematic uncertainties in quadrature, and procedures are also given for determining each individual uncertainty connected to the dose measurement. In particular, attention is paid to the evaluation of the combined uncertainty due...... to energy and angular dependencies of the dosemeter. In type testing of personal dosimetry systems, the estimated overall standard deviation of the dosimetry system is the main parameter to be tested. An important characteristic of a personal dosimetry system is its capability of measuring low doses...

  11. Calibration and monitoring of the GENEPI neutron source for the MUSE IV experiment

    Energy Technology Data Exchange (ETDEWEB)

    Vollaire, J.; Billebaud, A.; Brissot, R.; Le Brun, C.; Liatard, E. [Laboratoire de Physique Subatomique et de Cosmologie, INP2P3-CNRS/UJF/INPG, 53 av. des Martyrs, 38026 Grenoble Cedex (France)

    2003-07-01

    In order to characterize the neutron source produced by the GENEPI accelerator with the titanium tritium (TiT) target, an irradiation experiment was performed in January 2003 in the SC0 configuration of MASURCA, with all the rods inserted. During the irradiation, the LPSC acquisition system was used to monitor the number of pulses and the recoil particles produced by the reactions induced by the deuteron beam. (authors)

  12. TMI-2 source and intermediate range neutron flux monitors data report

    International Nuclear Information System (INIS)

    McCormick, R.D.

    1986-03-01

    This is a report on the preparation of data from the TMI-2 excore source and intermediate range neutron flux monitors for inclusion into the TMI Data Base. The sources of the as-recorded data are discussed as well as the process of transforming these data into digital form. The corrections to the as-recorded data are given and the data quality classification and uncertainty are established. The identifiers attached to each data set in the TMI Data Base are given

  13. Gadolinium-doped water cerenkov-based neutron and high energy gamma-ray detector and radiation portal monitoring system

    Science.gov (United States)

    Dazeley, Steven A; Svoboda, Robert C; Bernstein, Adam; Bowden, Nathaniel

    2013-02-12

    A water Cerenkov-based neutron and high energy gamma ray detector and radiation portal monitoring system using water doped with a Gadolinium (Gd)-based compound as the Cerenkov radiator. An optically opaque enclosure is provided surrounding a detection chamber filled with the Cerenkov radiator, and photomultipliers are optically connected to the detect Cerenkov radiation generated by the Cerenkov radiator from incident high energy gamma rays or gamma rays induced by neutron capture on the Gd of incident neutrons from a fission source. The PMT signals are then used to determine time correlations indicative of neutron multiplicity events characteristic of a fission source.

  14. Monte Carlo transport simulation for a long counter neutron detector employed as a cosmic rays induced neutron monitor at ground level

    Energy Technology Data Exchange (ETDEWEB)

    Pazianotto, Mauricio Tizziani; Carlson, Brett Vern [Instituto Tecnologico de Aeronautica (ITA), Sao Jose dos Campos, SP (Brazil); Federico, Claudio Antonio; Goncalez, Odair Lelis [Centro Tecnico Aeroespacial (CTA), Sao Jose dos Campos, SP (Brazil). Instituto de Estudos Avancados

    2011-07-01

    Full text: Great effort is required to understand better the cosmic radiation (CR) dose received by sensitive equipment, on-board computers and aircraft crew members at Brazil airspace, because there is a large area of South America and Brazil subject to the South Atlantic Anomaly (SAA). High energy neutrons are produced by interactions between primary cosmic ray and atmospheric atoms, and also undergo moderation resulting in a wider spectrum of energy ranging from thermal energies (0:025eV ) to energies of several hundreds of MeV. Measurements of the cosmic radiation dose on-board aircrafts need to be followed with an integral flow monitor on the ground level in order to register CR intensity variations during the measurements. The Long Counter (LC) neutron detector was designed as a directional neutron flux meter standard because it presents fairly constant response for energy under 10MeV. However we would like to use it as a ground based neutron monitor for cosmic ray induced neutron spectrum (CRINS) that presents an isotropic fluency and a wider spectrum of energy. The LC was modeled and tested using a Monte Carlo transport simulation for irradiations with known neutron sources ({sup 241}Am-Be and {sup 251}Cf) as a benchmark. Using this geometric model its efficiency was calculated to CRINS isotropic flux, introducing high energy neutron interactions models. The objective of this work is to present the model for simulation of the isotropic neutron source employing the MCNPX code (Monte Carlo N-Particle eXtended) and then access the LC efficiency to compare it with experimental results for cosmic ray neutrons measures on ground level. (author)

  15. Performance test of micro-fission chambers for in-vessel neutron monitoring of ITER

    International Nuclear Information System (INIS)

    Yamauchi, Michinori; Nishitani, Takeo; Ochiai, Kentaro; Morimoto, Yuichi; Hori, Jun-ichi; Ebisawa, Katsuyuki; Kasai, Satoshi

    2002-03-01

    A micro-fission chamber with 12 mg UO 2 and a dummy chamber without uranium were fabricated and the performance was tested. They are designed to be installed inside the vacuum vessel of the compact ITER (ITER-FEAT) for neutron monitoring. The vacuum leak rate of the dummy chamber with MI cable, resistances of chambers between central conductor and outer sheath, and mechanical strength up to 50G acceleration were confirmed to meet the design criteria. The gamma-ray sensitivity was measured for the dummy chamber with the 60 Co gamma-ray irradiation facility at JAERI Takasaki. The output signals for gamma-rays in Campbelling mode were estimated to be less than 0.1% of those by neutrons at the location behind the blanket module in ITER-FEAT. The detector response for 14 MeV neutrons was investigated with the FNS facility. Excellent linearity between count rates, square of Campbelling voltage and neutron fluxes was confirmed in the temperature range from 20degC (room) to 250degC. However, a positive dependence of 14 MeV neutron count rates on temperature was observed, which might be caused by the increase in the pulse height with temperature rise. Effects of a change of surrounding materials were evaluated by the sensitivity measurements of the micro-fission chamber inserted into the shielding blanket mock-up. The sensitivity was enhanced by slow-downed neutrons, which agreed with the calculation result by MCNP-4C code. As a result, it was concluded that the developed micro-fission chamber is applicable for ITER-FEAT. (author)

  16. Characterisation of CVD diamond detectors used for fast neutron flux monitoring

    CERN Document Server

    Foulon, F; Amosov, V N; Kaschuck, Y; Frunze, V; Tromson, D; Brambilla, A

    2002-01-01

    Natural diamond detectors (NDD) have been successfully used for fast neutron spectrometry on various fusion installations in plasma diagnostics. These detectors can work at high temperature, are radiation hard and exhibit a high energy resolution. However, the use of NDD is limited by the availability of IIa type diamonds exhibiting high electronic properties. With the recent advance in the growth of high quality chemically vapour deposited (CVD) diamond at LETI, CVD diamond appears to be a very promising material for plasma diagnostics. We present here for the first time results of the use of CVD diamond detectors for fast neutron flux monitoring on a neutron generator. The characteristics of CVD diamond detectors are compared with that of high quality NDD made by TRINITI. Pulse height spectra have been measured with CVD detectors and NDD under both 5.5 MeV alpha particles and 14.1 MeV neutrons. The quality of CVD diamond enables the recording of structured spectra allowing the distinction between the differ...

  17. Neutron spectrometry with Bonner spheres for area monitoring in particle accelerators

    International Nuclear Information System (INIS)

    Bedogni, R.

    2011-01-01

    Selecting the instruments to determine the operational quantities in the neutron fields produced by particle accelerators involves a combination of aspects, which is peculiar to these environments: the energy distribution of the neutron field, the continuous or pulsed time structure of the beam, the presence of other radiations to which the neutron instruments could have significant response and the large variability in the dose rate, which can be observed when moving from areas near the beam line to free-access areas. The use of spectrometric techniques in support of traditional instruments is highly recommended to improve the accuracy of dosimetric evaluations. The multi-sphere or Bonner Sphere Spectrometer (BSS) is certainly the most used device, due to characteristics such as the wide energy range, large variety of active and passive detectors suited for different workplaces, good photon discrimination and the simple signal management. Disadvantages are the poor energy resolution, weight and need to sequentially irradiate the spheres, leading to usually long measurement sessions. Moreover, complex unfolding analyses are needed to obtain the neutron spectra. This work is an overview of the BSS for area monitoring in particle accelerators. (authors)

  18. Theoretical study of physical characteristics of plutonium contaminated solid waste reference monitor for passive neutron measurements

    International Nuclear Information System (INIS)

    Souga, C.

    1983-01-01

    A three energy group theory is established to study physical characteristics of plutonium contaminated solid waste reference monitor for passive neutrons measurements. Spontaneous fission neutrons interaction with waste stream material and neutron leakage interaction with detector assembly are evaluated as a function of a set of physical and geometrical parameters (mass removal coefficient rho.Rsub(S)(g/cm 2 ); thickness of polyethylene moderator d(cm and energy E(eV)) using 1D ANISN-W transport code in S 8 P 3 and 100 groups approximations. Moreover this study allowed us to show the ''cross-over'': value of rho.Rsub(S) in proximity of which the dispersion around the mean effective escape probability is minimal and to evaluate the ''albedo effect'' which represents interaction between sample and detector assembly. The detection probability was evaluated as a function of different geometrical configurations of the detector in order to optimize its construction. Effective neutron escape probabilities calculated for three reference materials (polyethylene, iron and graphite) are in accordance with those given by experimental measures [fr

  19. Unattended mode monitoring of passive neutron coincidence detector systems using a commercial data logger

    International Nuclear Information System (INIS)

    Smith, B.G.R.; Outram, J.D.; Storey, M.

    1991-01-01

    A commercial Data Logger for unattended passive neutron coincidence data acquisition is described. This consists of an inexpensive commercial Data Logging equipment attached to a neutron coincidence electronics and a software package for data review. The Data Logger permits both the flexible configuration of a passive neutron coincidence measurement system for unattended mode monitoring and the storage of the measured Totals and Reals count rates. An additional feature of the Data Logger is a custom software package providing for the complete analysis of the stored data and yielding an assay of each item passing through the measurement cavity. The analysis includes an input for different isotopic compositions, the calculation of the multiplication corrected Reals rates, the inclusion of a calibration functions, and the determination of 240 Pu masses. The software package for data review displays the Totals and Reals count rates logged by the Data Logger as a function of time. In addition the custom software provides input files to the data review package to display the multiplication corrected Reals count rates and the measured 240 Pu masses as a function of time. Information on the Data Logger is presented along with the monitoring mode specifications. The analysis functions implemented are described as is the data review software. Results are presented for a specific application

  20. Calibration of neutrons monitors with moderators and application in the calibration factors of albedo dosemeters

    International Nuclear Information System (INIS)

    Schuch, L.A.

    1978-11-01

    The calibration factors and the reproducibility of an Albedo Dosimeter designed for personal neutron monitoring were determined. These factor were obtained simulating the dosimeter reading and the equivalent dose in the locality by a convenient combination of responses of the Bonner Sphere Spectrometer. The results obtained in the simulation were verified experimentally for different spectra employing the Am-Be, bare 252 Cf source and 253 Cf source with graphite sields of varying thickness. Different standards were used in the procedures necessary for the determination of the calibration factors. An Am-Be neutron source, standardized by the activation of a manganese sulphate bath was used as a primary standard. As a secondary standard, for the measurement of the neutron fluence, a De Pangher Long Counter was used and the scattering effects were determined using the shadow cone method. The other monitors such as the Rem-Counter and the Bonner Sphere Spectrometer were also calibrated with reference to the secondary standard with a view to comparing the results obtained with those furnished by the Albedo Dosimeter. (Author) [pt

  1. Cosmic Rays and Clouds, 1. Formation of Lead Mesoatoms In Neutron Monitor By Soft Negative Muons and Expected Atmospheric Electric Field Effect In The Cosmic Ray Neutron Component

    Science.gov (United States)

    Dorman, L. I.; Dorman, I. V.

    We extend our model (Dorman and Dorman, 1995) of cosmic ray atmospheric electric field effect on the case of neutron monitor. We take into account that about 0.07 of neu- tron monitor counting rate caused by negative soft muons captured by lead nucleons and formed mesoatoms with generation of several MeV energy neutrons from lead. In this case the neutron monitor or neutron supermonitor works as analyzer which de- tects muons of only one, negative sign. It is very important because the atmospheric electric field effect have opposite signs for positive and negative muons that main part of this effect in the muon telescope or in ionization chamber is compensated and we can observe only small part of total effect of one sign muons. On the basis of our gen- eral theory of cosmic ray meteorological effects with taking into account of negative soft muon acceleration and deceleration in the Earth atmosphere (in dependence of di- rection and intensity of electric field) we discuss the possibility of existing this effect in cosmic ray neutron component and made some rough estimations. REFERENCES: Dorman L.I. and Dorman I.V., 1995. "Cosmic-ray atmospheric electric field effects". Canadian J. of Physics, Vol. 73, pp. 440-443.

  2. Magnetic Field Monitoring in the SNS and LANL Neutron EDM Experiments

    Science.gov (United States)

    Aleksandrova, Alina; SNS nEDM Collaboration; LANL nEDM Collaboration

    2017-09-01

    The SNS neutron EDM experiment requires the ability to precisely control and monitor the magnetic field inside of the fiducial volume. However, it is not always practical (or even possible) to measure the field within the region of interest directly. To remedy this issue, we have designed a field monitoring system that will allow us to reconstruct the field inside of the fiducial volume using noninvasive measurements of the field components at discrete locations external to this volume. A prototype probe array (consisting of 12 single-axis fluxgate magnetometer sensors) was used to monitor the magnetic field within the fiducial volume of an in-house magnetic testing apparatus. In this talk, the design and results of this test will be presented, and the possible implementation of this field monitoring method may have in the room temperature LANL neutron EDM experiment will be discussed. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Award Number DE-SC-0014622.

  3. 10-decade wide-range neutron-monitoring system. Final test report

    Energy Technology Data Exchange (ETDEWEB)

    Green, W.K.

    1970-10-01

    The objective of Project Agreement 49 was to design, fabricate, test, and evaluate under actual nuclear reactor operating conditions, one prototype counting-Campbelling wide-range type thermal neutron flux measurement channel. This report describes the basic system designed for PA 49, and describes and presents the results of tests conducted on the system. Individual module descriptions and schematics are contained in the instruction manual which was issued with the system.

  4. Individual monitoring program for internal contamination by inhaled uranium

    International Nuclear Information System (INIS)

    Vazquez, C.; Chapel, M.L.; Saenz Gancedo, R.

    1988-01-01

    The metabolic behaviour of inhaled uranium is studied. Using a particular analytical method applied to the models and dose assessment methods recommended by ICRP, the organ committed equivalent dose and effective equivalent dose are calculated. The exact ALI and DAC are derived from there. In the paper, the influence that various parameters have on those results are considered for the specific case of a particular nuclear element fabrication factory. Different AMAD and solubility type of inhaled material are specially analyzed. The results show the paramount importance of some of these parameters on the secondary and derived dose limits. Relationships between the real intake, as a fraction of ALI, and the lung retention or urine excretion are shown for different cases and intake forms hypothesis. Minimum detectable intakes with the available experimental techniques are then established. The results shown in the papel are a useful tool to help on the decision on the type and frequency of the individual monitoring techniques to be established in different circumstances. (Author)

  5. Audit experience in external individual monitoring services accreditation in Brazil

    International Nuclear Information System (INIS)

    Martins, M.M.; Fonseca, E.S.; Pereira, W.W.; Ramos, M.M.O.; Salati, I.P.A.

    1998-01-01

    Brazilian Nuclear Energy Commission (CNEN) has been carrying out an accreditation program for the External Individual Monitoring Services (named SMIE) for about 45.000 workers involved with ionizing radiation. One of this steps of this accreditation program is the audit to each SMIE. The main audit objective is to verify and to check organizational documentation, system performance test, technical personnel ability and training, quality assurance system procedures and records, essential equipment and facilities and reliability of dose reports. In order to avoid a different audit for each SMIE, effort were made to obtain a standard process. Two aspects were considered the most relevant ones: human resources training and audit procedures. To achieve the first one, a practical and theoretical course taking into account auditing needs was elaborated. As well as experience in one of the technical related areas, an important condition to be member of an audit team is to obtain satisfactory approval in one of the offered courses. In order to accomplish the second point, a set of documents was implemented such as an audit checklist, audit report models, and procedures and recommendations to audit. Up to February 1998, 12 accreditation audits were performed. The main points of this program as well as an assessment of its difficulties and success are reported in this work

  6. External individual monitoring: experiments and simulations using Monte Carlo Method

    International Nuclear Information System (INIS)

    Guimaraes, Carla da Costa

    2005-01-01

    In this work, we have evaluated the possibility of applying the Monte Carlo simulation technique in photon dosimetry of external individual monitoring. The GEANT4 toolkit was employed to simulate experiments with radiation monitors containing TLD-100 and CaF 2 :NaCl thermoluminescent detectors. As a first step, X ray spectra were generated impinging electrons on a tungsten target. Then, the produced photon beam was filtered in a beryllium window and additional filters to obtain the radiation with desired qualities. This procedure, used to simulate radiation fields produced by a X ray tube, was validated by comparing characteristics such as half value layer, which was also experimentally measured, mean photon energy and the spectral resolution of simulated spectra with that of reference spectra established by international standards. In the construction of thermoluminescent dosimeter, two approaches for improvements have. been introduced. The first one was the inclusion of 6% of air in the composition of the CaF 2 :NaCl detector due to the difference between measured and calculated values of its density. Also, comparison between simulated and experimental results showed that the self-attenuation of emitted light in the readout process of the fluorite dosimeter must be taken into account. Then, in the second approach, the light attenuation coefficient of CaF 2 :NaCl compound estimated by simulation to be 2,20(25) mm -1 was introduced. Conversion coefficients C p from air kerma to personal dose equivalent were calculated using a slab water phantom with polymethyl-metacrilate (PMMA) walls, for reference narrow and wide X ray spectrum series [ISO 4037-1], and also for the wide spectra implanted and used in routine at Laboratorio de Dosimetria. Simulations of backscattered radiations by PMMA slab water phantom and slab phantom of ICRU tissue-equivalent material produced very similar results. Therefore, the PMMA slab water phantom that can be easily constructed with low

  7. Possible applications of neutron activation analysis at the RB reactor for the environmental monitoring

    International Nuclear Information System (INIS)

    Nikolic, D.; Pesic, M.; Milosevic, M.; Dasic, N.; Antic, D.; Kostic, Lj.; Ljubenov, V.

    2002-01-01

    This paper presents the possibilities of performing neutron activation analysis in Yugoslavia for the purpose of environmental pollution monitoring. Neutron activation analysis (NAA) is an established method for the determination of trace elements in a broad range of samples. It is non-destructive method used in a routine manner with gamma-ray spectrometry for various applications in biology, environmental toxicology, radiation assessment, mineral exploration, trace elements monitoring regarding human health studies. As a complex, powerful analytical tool, it might give results even when other analytical methods fail. NAA has been performed at the Nuclear Engineering Laboratory (NET), the VINCA Institute of Nuclear Sciences, for various applications in the reactor physics research. The samples are irradiated in the RB research reactor, which is the zero-power, bear, heavy water critical facility utilising three fuel element types. The reactor system is very flexible and allows for different core configurations, resulting in various neutron fields, with energy spectra ranging from thermal to fast (in the coupled fast-thermal system HERBE). There are several vertical and horizontal experimental channels available for sample's irradiation. The achievable thermal neutron flux is approximately 1 0 7 n/(cm 2 s) per 1 W of fission power. We believe the RB reactor could be successfully used for neutron activation analysis of trace elements in the environmental samples, comprising short-lived isotopes. Although the flux level and restricted irradiation time pose a certain limitation to NAA applications at the RB reactor, it can be compensated by the specific methodology advancement. That involves overcoming the main sources of error in the instrumental NAA evaluation methodology which utilises generally valid k 0 , and Q 0 factors. In particular, the computational accuracy of required nuclear parameters (e.g. neutron flux distribution, effective nuclear cross sections) can

  8. Monitoring of concrete structures by using the 14 MeV tagged neutron beams

    International Nuclear Information System (INIS)

    Sudac, D.; Nad, K.; Obhodas, J.; Valkovic, V.

    2013-01-01

    The maintenance and repair of reinforced concrete structures, especially those submerged in the sea-water require effective inspection and monitoring techniques for assessing the state of corrosion in the reinforcement material. An underwater inspection system was developed which is able to monitor the corrosion of the reinforcement. The system is composed of a remotely operating vehicle (ROV) equipped with the sealed tube neutron generator (NG). By rotating the NG and by using the associated alpha particle technique it is possible to measure the concrete cover thickness together with the reinforcing bar diameter. The possibility of estimating the carbon and chloride contents in the concrete was investigated. Iron plates of different thickness, covered by 6 cm thick concrete block, were successfully detected and the thickness of the concrete cover was estimated. In addition, reinforcing bar of one and 3 cm in diameter were identified and measured. All measurements could be performed without cleaning the concrete surface from fouling material. -- Highlights: • An underwater inspection system was developed which is able to monitor the state of reinforcement corrosion. • The system is composed of a remotely operating vehicle (ROV) equipped with the sealed tube neutron generator (NG). • All measurements could be performed without cleaning the concrete surface from fouling material

  9. Synopsis of moisture monitoring by neutron probe in the unsaturated zone at Area G

    Energy Technology Data Exchange (ETDEWEB)

    Vold, E.

    1997-12-31

    Moisture profiles from neutron probe data provide valuable information in site characterization and to supplement ground water monitoring efforts. The neutron probe precision error (reproducibility) is found to be about 0.2 vol% under in situ field conditions where the slope in moisture content with depth is varying slowly. This error is about 2 times larger near moisture spikes (e.g., at the vapor phase notch), due to the sensitivity of the probe response to vertical position errors on the order of 0.5 inches. Calibrations were performed to correct the downhole probe response to the volumetric moisture content determined on core samples. Calibration is sensitive to borehole diameter and casing type, requiring 3 separate calibration relations for the boreholes surveyed here. Power law fits were used for calibration in this study to assure moisture content results greater than zero. Findings in the boreholes reported here confirm the broad features seen previously in moisture profiles at Area G, a near-surface region with large moisture variability, a very dry region at greater depths, and a moisture spike at the vapor phase notch (VPN). This feature is located near the interface between the vitrified and vitrified stratigraphic units and near the base of the mesa. This report describes the in-field calibration methods used for the neutron moisture probe measurements and summarizes preliminary results of the monitoring program in the in-situ monitoring network at Area G. Reported results include three main areas: calibration studies, profiles from each of the vertical boreholes at Area G, and time-dependent variations in a select subset of boreholes. Results are reported here for the vertical borehole network. Results from the horizontal borehole network will be described when available.

  10. Synopsis of moisture monitoring by neutron probe in the unsaturated zone at Area G

    International Nuclear Information System (INIS)

    Vold, E.

    1997-01-01

    Moisture profiles from neutron probe data provide valuable information in site characterization and to supplement ground water monitoring efforts. The neutron probe precision error (reproducibility) is found to be about 0.2 vol% under in situ field conditions where the slope in moisture content with depth is varying slowly. This error is about 2 times larger near moisture spikes (e.g., at the vapor phase notch), due to the sensitivity of the probe response to vertical position errors on the order of 0.5 inches. Calibrations were performed to correct the downhole probe response to the volumetric moisture content determined on core samples. Calibration is sensitive to borehole diameter and casing type, requiring 3 separate calibration relations for the boreholes surveyed here. Power law fits were used for calibration in this study to assure moisture content results greater than zero. Findings in the boreholes reported here confirm the broad features seen previously in moisture profiles at Area G, a near-surface region with large moisture variability, a very dry region at greater depths, and a moisture spike at the vapor phase notch (VPN). This feature is located near the interface between the vitrified and vitrified stratigraphic units and near the base of the mesa. This report describes the in-field calibration methods used for the neutron moisture probe measurements and summarizes preliminary results of the monitoring program in the in-situ monitoring network at Area G. Reported results include three main areas: calibration studies, profiles from each of the vertical boreholes at Area G, and time-dependent variations in a select subset of boreholes. Results are reported here for the vertical borehole network. Results from the horizontal borehole network will be described when available

  11. Harmonisation (legal, dosimetric, quality aspects) of individual monitoring, and integration of monitoring for external and internal exposures (EURADOS working group)

    International Nuclear Information System (INIS)

    Lopez, M.A.; Currivan, L.; Falk, R.; Olko, P.; Wernli, C.; Castellani, C.M.; Dijk, J.W.E. van

    2003-01-01

    The EURADOS Working Group II on 'Harmonisation of individual monitoring' consists of experts from almost all EU Member States and Newly Associated States (NAS), involved in tasks related to the assessment of doses for internal and external radiation. The final objective is to achieve harmonisation in individual monitoring for occupational exposures. Sub-group 2 activities are focused on investigating how the results from personal dosemeters for external radiation and workplace monitoring and from monitoring for internal exposure can be combined into a complete and consistent system of individual monitoring. Three questionnaires were prepared, covering Individual monitoring of external radiation (Questionnaire 1), 'Internal exposure' (Questionnaire 2) and 'Natural sources of radiation at workplace' (Questionnaire 3). With the agreement of a 'contact-person' selected in each country, the distribution of the three EURADOS 2002 questionnaires was carried out by e-mail among the dosimetry facilities of 28 European countries. The preliminary results of these actions are presented here. (author)

  12. 10 CFR 20.1502 - Conditions requiring individual monitoring of external and internal occupational dose.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Conditions requiring individual monitoring of external and... PROTECTION AGAINST RADIATION Surveys and Monitoring § 20.1502 Conditions requiring individual monitoring of..., columns 1 and 2, of appendix B to §§ 20.1001-20.2402; (2) Minors likely to receive, in 1 year, a committed...

  13. Mini neutron monitor measurements at the Neumayer III station and on the German research vessel Polarstern

    Science.gov (United States)

    Heber, B.; Galsdorf, D.; Herbst, K.; Gieseler, J.; Labrenz, J.; Schwerdt, C.; Walter, M.; Benadé, G.; Fuchs, R.; Krüger, H.; Moraal, H.

    2015-08-01

    Neutron monitors (NMs) are ground-based devices to measure the variation of cosmic ray intensities, and although being reliable they have two disadvantages: their size as well as their weight. As consequence, [1] suggested the development of a portable, and thus much smaller and lighter, calibration neutron monitor that can be carried to any existing station around the world [see 2; 3]. But this mini neutron monitor, moreover, can also be installed as an autonomous station at any location that provides ’’office” conditions such as a) temperatures within the range of around 0 to less than 40 degree C as well as b) internet and c) power supply. However, the best location is when the material above the NM is minimized. In 2011 a mini Neutron Monitor was installed at the Neumayer III station in Antarctica as well as the German research vessel Polarstern, providing scientific data since January 2014 and October 2012, respectively. The Polarstern, which is in the possession of the Federal Republic of Germany represented by the Ministry of Education and Research and operated by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research and managed by the shipping company Laeisz, was specially designed for working in the polar seas and is currently one of the most sophisticated polar research vessels worldwide. It spends almost 310 days a year at sea usually being located in the waters of Antarctica between November and March while spending the northern summer months in Arctic waters. Therefore, the vessel scans the rigidity range below the atmospheric threshold and above 10 GV twice a year. In contrast to spacecraft measurements NM data are influenced by variations of the geomagnetic field as well as the atmospheric conditions. Thus, in order to interpret the data a detailed knowledge of the instrument sensitivity with geomagnetic latitude (rigidity) and atmospheric pressure is essential. In order to determine the atmospheric response data from the

  14. Rhodium self-powered neutron detector as a suitable on-line thermal neutron flux monitor in BNCT treatments

    International Nuclear Information System (INIS)

    Miller, Marcelo E.; Sztejnberg, Manuel L.; Gonzalez, Sara J.; Thorp, Silvia I.; Longhino, Juan M.; Estryk, Guillermo

    2011-01-01

    Purpose: A rhodium self-powered neutron detector (Rh SPND) has been specifically developed by the Comision Nacional de Energia Atomica (CNEA) of Argentina to measure locally and in real time thermal neutron fluxes in patients treated with boron neutron capture therapy (BNCT). In this work, the thermal and epithermal neutron response of the Rh SPND was evaluated by studying the detector response to two different reactor spectra. In addition, during clinical trials of the BNCT Project of the CNEA, on-line neutron flux measurements using the specially designed detector were assessed. Methods: The first calibration of the detector was done with the well-thermalized neutron spectrum of the CNEA RA-3 reactor thermal column. For this purpose, the reactor spectrum was approximated by a Maxwell-Boltzmann distribution in the thermal energy range. The second calibration was done at different positions along the central axis of a water-filled cylindrical phantom, placed in the mixed thermal-epithermal neutron beam of CNEA RA-6 reactor. In this latter case, the RA-6 neutron spectrum had been well characterized by both calculation and measurement, and it presented some marked differences with the ideal spectrum considered for SPND calibrations at RA-3. In addition, the RA-6 neutron spectrum varied with depth in the water phantom and thus the percentage of the epithermal contribution to the total neutron flux changed at each measurement location. Local (one point-position) and global (several points-positions) and thermal and mixed-field thermal neutron sensitivities were determined from these measurements. Thermal neutron flux was also measured during BNCT clinical trials within the irradiation fields incident on the patients. In order to achieve this, the detector was placed on patient's skin at dosimetric reference points for each one of the fields. System stability was adequate for this kind of measurement. Results: Local mixed-field thermal neutron sensitivities and global

  15. Rhodium self-powered neutron detector as a suitable on-line thermal neutron flux monitor in BNCT treatments.

    Science.gov (United States)

    Miller, Marcelo E; Sztejnberg, Manuel L; González, Sara J; Thorp, Silvia I; Longhino, Juan M; Estryk, Guillermo

    2011-12-01

    A rhodium self-powered neutron detector (Rh SPND) has been specifically developed by the Comisión Nacional de Energía Atómica (CNEA) of Argentina to measure locally and in real time thermal neutron fluxes in patients treated with boron neutron capture therapy (BNCT). In this work, the thermal and epithermal neutron response of the Rh SPND was evaluated by studying the detector response to two different reactor spectra. In addition, during clinical trials of the BNCT Project of the CNEA, on-line neutron flux measurements using the specially designed detector were assessed. The first calibration of the detector was done with the well-thermalized neutron spectrum of the CNEA RA-3 reactor thermal column. For this purpose, the reactor spectrum was approximated by a Maxwell-Boltzmann distribution in the thermal energy range. The second calibration was done at different positions along the central axis of a water-filled cylindrical phantom, placed in the mixed thermal-epithermal neutron beam of CNEA RA-6 reactor. In this latter case, the RA-6 neutron spectrum had been well characterized by both calculation and measurement, and it presented some marked differences with the ideal spectrum considered for SPND calibrations at RA-3. In addition, the RA-6 neutron spectrum varied with depth in the water phantom and thus the percentage of the epithermal contribution to the total neutron flux changed at each measurement location. Local (one point-position) and global (several points-positions) and thermal and mixed-field thermal neutron sensitivities were determined from these measurements. Thermal neutron flux was also measured during BNCT clinical trials within the irradiation fields incident on the patients. In order to achieve this, the detector was placed on patient's skin at dosimetric reference points for each one of the fields. System stability was adequate for this kind of measurement. Local mixed-field thermal neutron sensitivities and global thermal and mixed

  16. Footprint characteristics revised for field-scale soil moisture monitoring with cosmic-ray neutrons

    Science.gov (United States)

    Köhli, M.; Schrön, M.; Zreda, M.; Schmidt, U.; Dietrich, P.; Zacharias, S.

    2015-07-01

    Cosmic-ray neutron probes are widely used to monitor environmental water content near the surface. The method averages over tens of hectares and is unrivaled in serving representative data for agriculture and hydrological models at the hectometer scale. Recent experiments, however, indicate that the sensor response to environmental heterogeneity is not fully understood. Knowledge of the support volume is a prerequisite for the proper interpretation and validation of hydrogeophysical data. In a previous study, several physical simplifications have been introduced into a neutron transport model in order to derive the characteristics of the cosmic-ray probe's footprint. We utilize a refined source and energy spectrum for cosmic-ray neutrons and simulate their response to a variety of environmental conditions. Results indicate that the method is particularly sensitive to soil moisture in the first tens of meters around the probe, whereas the radial weights are changing dynamically with ambient water. The footprint radius ranges from 130 to 240 m depending on air humidity, soil moisture, and vegetation. The moisture-dependent penetration depth of 15 to 83 cm decreases exponentially with distance to the sensor. However, the footprint circle remains almost isotropic in complex terrain with nearby rivers, roads or hill slopes. Our findings suggest that a dynamically weighted average of point measurements is essential for accurate calibration and validation. The new insights will have important impact on signal interpretation, sensor installation, data interpolation from mobile surveys, and the choice of appropriate resolutions for data assimilation into hydrological models.

  17. Activation analysis of stainless steel flux monitors using 252Cf neutron sources

    International Nuclear Information System (INIS)

    Williams, J.G.; Newton, T.H. Jr.; Cogburn, C.O.

    1984-01-01

    Activation analysis was performed on stainless steel beads from a chain which is used in reactor pressure vessel surveillance experiments at the Arkansas Power and Light Company reactors. The beads allow monitoring of two fast and three thermal neutron induced reactions: 58 Ni(n,p) 58 Co, 54 Fe(n,p) 54 Mn, 58 Fe(n,γ) 59 Fe, 59 Co(n,γ) 60 Co and 50 Cr(n,γ) 51 Cr. The analysis was performed using 12 beads from various positions along 5 different batches of chain and standard materials in an H 2 O moderator tank using two intense californium sources which had a total neutron emission rate of 3.97 x 10 10 /s. Semiconductor gamma spectrometers were used to count the products of the above reactions in the specimens. The percentage by weight of the iron, chromium and cobalt in the beads were found to be 62.1%, 20.2% and 0.120%, respectively. The excellent uniformity found in the bead compositions demonstrates the reproducibility of the experimental techniques and enhances considerably the value of the beads as neutron flux montitors

  18. New measurement system for on line in core high-energy neutron flux monitoring in materials testing reactor conditions.

    Science.gov (United States)

    Geslot, B; Vermeeren, L; Filliatre, P; Lopez, A Legrand; Barbot, L; Jammes, C; Bréaud, S; Oriol, L; Villard, J-F

    2011-03-01

    Flux monitoring is of great interest for experimental studies in material testing reactors. Nowadays, only the thermal neutron flux can be monitored on line, e.g., using fission chambers or self-powered neutron detectors. In the framework of the Joint Instrumentation Laboratory between SCK-CEN and CEA, we have developed a fast neutron detector system (FNDS) capable of measuring on line the local high-energy neutron flux in fission reactor core and reflector locations. FNDS is based on fission chambers measurements in Campbelling mode. The system consists of two detectors, one detector being mainly sensitive to fast neutrons and the other one to thermal neutrons. On line data processing uses the CEA depletion code DARWIN in order to disentangle fast and thermal neutrons components, taking into account the isotopic evolution of the fissile deposit. The first results of FNDS experimental test in the BR2 reactor are presented in this paper. Several fission chambers have been irradiated up to a fluence of about 7 × 10(20) n∕cm(2). A good agreement (less than 10% discrepancy) was observed between FNDS fast flux estimation and reference flux measurement.

  19. Continuous monitoring of a mountain snowpack in the Austrian Alps by above-ground neutron sensing

    Science.gov (United States)

    Schattan, Paul; Baroni, Gabriele; Oswald, Sascha E.; Schöber, Johannes; Fey, Christine; Francke, Till; Huttenlau, Matthias; Achleitner, Stefan

    2017-04-01

    In alpine catchments the knowledge of the spatially and temporally heterogeneous dynamics of snow accumulation and depletion is crucial for modelling and managing water resources. While snow covered area can be retrieved operationally from remote sensing data, continuous measurements of other snow state variables like snow depth (SD) or snow water equivalent (SWE) remain challenging. Existing methods of retrieving both variables in alpine terrain face severe issues like a lack of spatial representativeness, labour-intensity or discontinuity in time. Recently, promising new measurement techniques combining a larger support with low maintenance cost like above-ground gamma-ray scintillators, GPS interferometric reflectometry or above-ground cosmic-ray neutron sensors (CRNS) have been suggested. While CRNS has proven its potential for monitoring soil moisture in a wide range of environments and applications, the empirical knowledge of using CRNS for snowpack monitoring is still very limited and restricted to shallow snowpacks with rather uniform evolution. The characteristics of an above-ground cosmic-ray neutron sensor (CRNS) were therefore evaluated for monitoring a mountain snowpack in the Austrian Alps (Kaunertal, Tyrol) during three winter seasons. The measurement campaign included a number of measurements during the period from 03/2014 to 06/2016: (i) neutron count measurements by CRNS, (ii) continuous point-scale SD and SWE measurements from an automatic weather station and (iii) 17 Terrestrial Laser Scanning (TLS) with simultaneous SD and SWE surveys. The highest accumulation in terms of SWE was found in 04/2014 with 600 mm. Neutron counts were compared to all available snow data. While previous studies suggested a signal saturation at around 100 mm of SWE, no complete signal saturation was found. A strong non-linear relation was found for both SD and SWE with best fits for spatially distributed TLS based snow data. Initially slightly different shapes were

  20. Novel Scintillating Materials Based on Phenyl-Polysiloxane for Neutron Detection and Monitoring

    Science.gov (United States)

    Degerlier, M.; Carturan, S.; Gramegna, F.; Marchi, T.; Palma, M. Dalla; Cinausero, M.; Maggioni, G.; Quaranta, A.; Collazuol, G.; Bermudez, J.

    Neutron detectors are extensively used at many nuclear research facilities across Europe. Their application range covers many topics in basic and applied nuclear research: in nuclear structure and reaction dynamics (reaction reconstruction and decay studies); in nuclear astrophysics (neutron emission probabilities); in nuclear technology (nuclear data measurements and in-core/off-core monitors); in nuclear medicine (radiation monitors, dosimeters); in materials science (neutron imaging techniques); in homeland security applications (fissile materials investigation and cargo inspection). Liquid scintillators, widely used at present, have however some drawbacks given by toxicity, flammability, volatility and sensitivity to oxygen that limit their duration and quality. Even plastic scintillators are not satisfactory because they have low radiation hardness and low thermal stability. Moreover organic solvents may affect their optical properties due to crazing. In order to overcome these problems, phenyl-polysiloxane based scintillators have been recently developed at Legnaro National Laboratory. This new solution showed very good chemical and thermal stability and high radiation hardness. The results on the different samples performance will be presented, paying special attention to a characterization comparison between synthesized phenyl containing polysiloxane resins where a Pt catalyst has been used and a scintillating material obtained by condensation reaction, where tin based compounds are used as catalysts. Different structural arrangements as a result of different substituents on the main chain have been investigated by High Resolution X-Ray Diffraction, while the effect of improved optical transmittance on the scintillation yield has been elucidated by a combination of excitation/fluorescence measurements and scintillation yield under exposure to alpha and γ-rays.

  1. Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering.

    Science.gov (United States)

    Morgan, Brian; Rinehart, Samantha J; Dadmun, Mark D

    2017-12-21

    We demonstrate a protocol to effectively monitor the gelation process of a high concentration solution of conjugated polymer both in the presence and absence of white light exposure. By instituting a controlled temperature ramp, the gelation of these materials can be precisely monitored as they proceed through this structural evolution, which effectively mirrors the conditions experienced during the solution deposition phase of organic electronic device fabrication. Using small angle neutron scattering (SANS) and ultra-small angle neutron scattering (USANS) along with appropriate fitting protocols we quantify the evolution of select structural parameters throughout this process. Thorough analysis indicates that continued light exposure throughout the gelation process significantly alters the structure of the ultimately formed gel. Specifically, the aggregation process of poly(3-hexylthiophene-2,5-diyl) (P3HT) nano-scale aggregates is negatively affected by the presence of illumination, ultimately resulting in the retardation of growth in conjugated polymer microstructures and the formation of smaller scale macro-aggregate clusters.

  2. In vivo monitoring of toxic metals: assessment of neutron activation and x-ray fluorescence techniques

    International Nuclear Information System (INIS)

    Ellis, K.J.

    1986-01-01

    To date, cadmium, lead, aluminum, and mercury have been measured in vivo in humans. The possibilities of monitoring other toxic metals have also been demonstrated, but no human studies have been performed. Neutron activation analysis appears to be most suitable for Cd and Al measurements, while x-ray fluorescence is ideally suited for measurement of lead in superficial bone. Filtered neutron beams and polarized x-ray sources are being developed which will improve in vivo detection limits. Even so, several of the current facilities are already suitable for use in epidemiological studies of selected populations with suspected long-term low-level ''environmental'' exposures. Evaluation and diagnosis of patients presenting with general clinical symptoms attributable to possible toxic metal exposure may be assisted by in vivo examination. Continued in vivo monitoring of industrial workers, especially follow-up measurements, will provide the first direct assessment of changes in body burden and a direct measure of the biological life-times of these metals in humans. 50 refs., 4 figs., 2 tabs

  3. The dielectric track and thermoluminescent detectors applied to neutron dosimetry in personnel monitoring

    International Nuclear Information System (INIS)

    Mebhah, D.

    1984-03-01

    The personnal dosimeter for neutron based on the detection of fission fragments from 237 Np and 232 Th by a polycarbonate 10 gm, and lithium fluorite 6 LIF/ 7 LIF, allow to cover an energy spectrum from 0.05 eV to 14 MeV with a easy neutron gamma discrimination. In criticality dosimetry, the energy spectrum of the incident neutrons can be defined by two components: the fast component by E b exp(-ae) with E between 0.1 and 14 MeV, a and b determined by a combination of 237 Np and 232 Th track detector responses, and the epithermal component in 1/E, the thermal component having a minor contribution to the total equivalent dose. We took into account the body influence on the detectors response by introducing effective cross section. The equivalent dose obtained by this dosimeter is 20% overestimated in low doses dosimetry. The interpretation of the detectors responses is based on the definition of a factor and a calibration parameter for each zone in which the spectrum is constant. The knowledge of this parameter for individual dosimeters allows to account for the variations of the conditions of calibration

  4. Use of an albedo neutron personnel dosimeter for X- and γ-ray monitoring

    International Nuclear Information System (INIS)

    Gorbics, S.G.; Nash, A.E.; Johnson, T.L.

    1981-01-01

    With a judicious choice of cadmium filter size and thickness, it is possible to use the information from the 7 LiF detectors used in an albedo neutron personnel dosimeter to determine an individual's X-and γ-ray exposure, thus eliminating the need for a separate dosimeter for this purpose. A filter area of 400 mm 2 and a thickness of 0.51 mm is shown to be optimum for a simple, plastic, dosimeter design using detectors held in dental-film size cards. (author)

  5. Monitoring of blood-10B concentration for boron neutron capture therapy using prompt gamma-ray analysis

    International Nuclear Information System (INIS)

    Raaijmakers, C.P.J.; Konijnenberg, M.W.; Dewit, L.; Mijnheer, B.J.; Haritz, D.; Huiskamp, R.; Philipp, K.; Siefert, A.; Stecher-Rasmussen, F.

    1995-01-01

    The aim of the present study was to monitor the blood- 10 B concentration of laboratory dogs receiving boron neutron capture therapy, in order to obtain optimal agreement between prescribed and actual dose. A prompt gamma-ray analysis system was developed for this purpose at the High Flux Reactor in Petten. The technique was compared with inductively coupled plasma-atomic emission spectrometry and showed good agreement. A substantial variation in 10 B clearance pattern after administration of borocaptate sodium was found between the different dogs. Consequently, the irradiation commencement was adjusted to the individually determined boron elimination curve. Mean blood- 10 B concentratios during irradiation of 25.8±2.2 μg/g (1 SD, n=18) and 49.3±5.3 μg/g (1 SD, n=17) were obtained for intended concentrations of 25 μg/g and 50 μg/g, respectively. These variations are a factor of two smaller than irradiations performed at a uniform post-infusion irradiation starting time. Such a careful bolld- 10 B monitoring procedure is a prerequisite for accurately obtaining such steep dose-response curves as observed during the dog study. (orig.)

  6. Monitoring the degradation of individual dietary fibres in pig models

    NARCIS (Netherlands)

    Jonathan, M.C.

    2013-01-01

    In this thesis, the degradation of dietary fibres in the gastrointestinal tract, especially in the large intestine, is monitored using in vitroand in vivostudies. First, an in vitromethod to simulate the conditions in the mouth, stomach and small intestine was adapted

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  8. Radiation portal monitor with 10B+ZnS(Ag) neutron detector performance for the detection of special nuclear materials

    International Nuclear Information System (INIS)

    Guzman G, K. A.; Gallego, E.; Lorente, A.; Ibanez F, S.; Vega C, H. R.; Gonzalez, J. A.; Mendez, R.

    2016-10-01

    In homeland security, neutron detection is used to prevent the smuggling of special nuclear materials. Thermal neutrons are normally detected with 3 He proportional counters, in the radiation portal monitors, Rpms, however due to the 3 He shortage new procedures are being studied. In this work Monte Carlo methods, using the MCNP6 code, have been used to study the neutron detection features of a 10 B+ZnS(Ag) under real conditions inside of a Rpm. The performance for neutron detection was carried out for 252 Cf, 238 U and 239 Pu under different conditions. In order to mimic an actual situation occurring at border areas, a sample of SNM sited inside a vehicle was simulated and the Rpm with 10 B+ZnS(Ag) response was calculated. At 200 cm the 10 B+ZnS(Ag) on Rpm response is close to 2.5 cps-ng 252 Cf, when the 252 Cf neutron source is shielded with 0.5 cm-thick lead and 2.5 cm-thick polyethylene fulfilling the ANSI recommendations. Three different geometries of neutron detectors of 10 B+ZnS(Ag) in a neutron detection system in Rpm were modeled. Therefore, the 10 B+ZnS(Ag) detectors are an innovative and viable replacement for the 3 He detectors in the Rpm. (Author)

  9. A wide dynamic range BF{sub 3} neutron monitor with front-end electronics based on a logarithmic amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Ferrarini, M., E-mail: michele.ferrarini@polimi.i [Politecnico di Milano, Dipartimento Energia, via G. Ponzio 34/3, I-20133 Milano (Italy); Fondazione CNAO, via Caminadella 16, 20123 Milano (Italy); Varoli, V. [Politecnico di Milano, Dipartimento Energia, via G. Ponzio 34/3, I-20133 Milano (Italy); Favalli, A. [European Commission, Joint Research Centre, Institute for the Protection and Security of Citizen, TP 800, Via E. Fermi, 21027 Ispra (Vatican City State, Holy See) (Italy); Caresana, M. [Politecnico di Milano, Dipartimento Energia, via G. Ponzio 34/3, I-20133 Milano (Italy); Pedersen, B. [European Commission, Joint Research Centre, Institute for the Protection and Security of Citizen, TP 800, Via E. Fermi, 21027 Ispra (Italy)

    2010-02-01

    This paper describes a wide dynamic range neutron monitor based on a BF{sub 3} neutron detector. The detector is used in current mode, and front-end electronics based on a logarithmic amplifier are used in order to have a measurement capability ranging over many orders of magnitude. The system has been calibrated at the Polytechnic of Milan, CESNEF, with an AmBe neutron source, and has been tested in a pulsed field at the PUNITA facility at JRC, Ispra. The detector has achieved a dynamic range of over 6 orders of magnitude, being able to measure single neutron pulses and showing saturation-free response for a reaction rate up to 10{sup 6} s{sup -1}. It has also proved effective in measuring the PUNITA facility pulse integral fluence.

  10. Development of Web based system for individual internal monitoring programme

    International Nuclear Information System (INIS)

    Lima, Vanessa Rogeria de

    2007-01-01

    The purposes of the internal monitoring, in general, are to verify and document that each worker is protected adequately against risks from radionuclide intakes and the protection complies with legal requirements. Therefore, an overall radiation protection programme, starts with an assessment to identify work situations in which there is a risk of internal contamination of workers and to quantify the likely intake of radioactive material and the resulting committed effective dose. As a part of a continuous improvement of the monitoring programme for occupationally exposed workers at IPEN, it is being developed a Web based system to access the internal dosimetry database. The system was implemented using Hypertext Preprocessor, PHP, and a PostgreSQL database. This system will introduce a new paradigm in the routine of the internal dosimetry service, providing a fast access to the information among the measurement laboratories staff, dose evaluation group and the radiation protection supervisor. The database maintains information about worker identification, physical and chemical characteristics of the radionuclide, type of monitoring, measurement data and the dose. Moreover, this information will be readily available to provide support for regulatory compliance and quality control requirements. (author)

  11. CEC technical recommendations for monitoring the exposure of individuals to external radiation

    International Nuclear Information System (INIS)

    Marshall, T.O.; Christensen, P.; Julius, H.W.

    1989-01-01

    In 1975 the Commission of the European Communities (CEC) published ''Technical Recommendations for Monitoring the Exposure of Individuals to External Radiation'', EUR 5287. Since then, however, the objectives, concepts, and methods of individual monitoring have changed substantially. As a result the CEC has decided to revise this document. The paper highlights the major differences between the original document and the revised version. (author)

  12. Use of Neutron Beams for Materials Research Relevant to the Nuclear Energy Sector. Annex: Individual Reports

    International Nuclear Information System (INIS)

    2015-10-01

    Nuclear technologies such as fission and fusion reactors, including associated waste storage and disposal, rely on the availability of not only nuclear fuels but also advanced structural materials. In 2010–2013, the IAEA organized and implemented the Coordinated Research Project (CRP) on Development, Characterization and Testing of Materials of Relevance to Nuclear Energy Sector Using Neutron Beams. A total of 19 institutions from 18 Member States (Argentina, Australia, Brazil, China, Czech Republic, France, Germany, Hungary, Indonesia, Italy, Japan, Netherlands, Republic of Korea, Romania, Russian Federation (two institutions), South Africa, Switzerland and United States of America) cooperated with the main objective to address the use of various neutron beam techniques for characterization, testing and qualification of materials and components produced or under development for applications in the nuclear energy sector. This CRP aimed to bring stakeholders and end users of research reactors and accelerator based neutron sources together for the enhanced use of available facilities and development of new infrastructures for applied materials research. Work envisioned under this CRP was related to the optimization and validation of neutron beam techniques, including facility and instrument modifications/optimizations as well as improved data acquisition, processing and analysis systems. Particular emphasis was placed on variable environments during material characterization and testing as required by some applications such as intensive irradiation load, high temperature and high pressure conditions, and the presence of strong magnetic fields. Targeted neutron beam techniques were neutron diffraction, small angle neutron scattering and digital neutron radiography/tomography. The publication IAEA-TECDOC-1773 is a compilation of the main results and findings of the CRP, and this CD-ROM accompanying the publication contains 19 reports with additional relevant

  13. The STM32 microcontroller based pulse intensity registration system for the neutron monitor

    Directory of Open Access Journals (Sweden)

    Shepetov Alexander

    2017-01-01

    Full Text Available We present the outlines of a new microcontroller based data acquisition system which is aimed for reliable operation in a typical cosmic ray particle registration experiment. The system supports connection of up to 16 input signals and ensures the following operation functionality: (1 stable monitoring of the intensity of a digital pulse signal, or digitization of a continuous potential level with a low time resolution (typically, about 1 s–100 s; (2 registration of uninterruptable high-resolution (up to 5–10 μs time series of the input signal intensity; (3 synchronization of registered time series with both external (physical or local (program-based trigger signal; (4 possibility of an on-the-fly change of the whole configuration of informational system (both the combination and type of input signals, time resolution and sum duration of the time series measurements, trigger logic, etc. immediately in operation time through convenient communication by plain text messages in dialog mode. In particular, the considered system is applied now for a long-term, high precision measurement of the counting rate of neutron signals at the NM64 type neutron supermonitor of the Tien Shan mountain cosmic ray station, with a real-time representation of the whole collected dataset in a WWW database.

  14. Studies on monitoring of river water quality by neutron activation analysis of aquatic biota

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Masao; Tanizaki, Yoshiyuki; Shimokawa, Toshinari (Tokyo Metropolitan Isotope Research Center (Japan))

    1990-02-01

    In order to clarify the possibility of a new method to monitor the river water quality by neutron activation analysis of aquatic biota, the followings were investigated: (1) the species of fish, water plants and aquatic insects which we can collect easily in Tamagawa River basin, (2) problems in pre-treatment of biological samples, and (3) relationship between elemental concentrations in biological samples and in river water. We found that the biological species suitable for the analytical investigation are Carassius auratus langsdorfii (GINBUNA), Pseudorasbora parva (MOTSUGO), Potamageton orientalis Hagst. (AINOKOITOMO), Elodea nuttalli (Planch.) St. John (KOKANADAMO), Cheuma-topsyche brevilineata (Iwata) (KOGATASHIMATOBIKERA) and Hydropsyche orientalis Martynov (URUMASHIMATOBIKERA). Fish samples showed apparently different concentrations of elements in each part of their bodies. Simple washing of water plants and aquatic insects was found not to be enough to eliminate rock-oriented particles. Such elements as Ag, Mn and Zn showed relationships of their concentrations between in biological samples and in river water. (author).

  15. Study on ambient environmental monitoring using instrumental neutron activation analysis of airborne particulate matter

    International Nuclear Information System (INIS)

    Chung, Yong Sam; Moon, Jong Hwa; Chung, Young Ju; Cho, Seong Yeon; Kang, Sang Hun

    1997-01-01

    The aim of this research is to enhance the use of nuclear analytical techniques (NAT) for air pollution studies and to study the feasibility on the use of instrumental neutron activation analysis (INAA) as a routine monitoring tool to find out environmental pollution sources. For the collection of air particulates sample, the Gent stacked filter unit low volume sample and Nucleopore filters provided by IAEA for the coordination research program (CRP) were used. Trace elements in samples collected at two suburban residental sites, Taijon and Wonju city in the Republic of Korea, were analyzed by INAA. Variations of the elemental concentrations were measured monthly and the enrichment factors were calculated for the fine (<2μm EAD) and coarse size (2-10μm EAD) fractions, respectively. These results of the analyses are described to ensure emission source

  16. Testing baseline stability of some neutron monitors in Europe, Africa, and Asia

    Science.gov (United States)

    Ahluwalia, H. S.; Ygbuhay, R. C.

    2013-06-01

    For six decades, the global network of neutron monitors (NMs) has provided a continuous stream of very valuable data to the heliophysics community, leading to many insights into the myriad modes of charged particle transport in the tangled magnetic fields that permeate the 3D heliosphere. Earlier, Ahluwalia and Ygbuhay (2012) reported on the drifts in some high latitude NM counting rates in the American zone. We continue our enquiry by testing the stability of the counting rate baselines of some NMs operating in Europe, Africa, and Asia. The data from these detectors have been extremely valuable for the short-term time variation studies, but caution is advised in using the data for long-term studies from NMs with baselines that are drifting for cause(s) unknown.

  17. Monitoring individual traffic flows within the ATLAS TDAQ network

    CERN Document Server

    Sjoen, R; Ciobotaru, M; Batraneanu, S M; Leahu, L; Martin, B; Al-Shabibi, A

    2010-01-01

    The ATLAS data acquisition system consists of four different networks interconnecting up to 2000 processors using up to 200 edge switches and five multi-blade chassis devices. The architecture of the system has been described in [1] and its operational model in [2]. Classical, SNMP-based, network monitoring provides statistics on aggregate traffic, but for performance monitoring and troubleshooting purposes there was an imperative need to identify and quantify single traffic flows. sFlow [3] is an industry standard based on statistical sampling which attempts to provide a solution to this. Due to the size of the ATLAS network, the collection and analysis of the sFlow data from all devices generates a data handling problem of its own. This paper describes how this problem is addressed by making it possible to collect and store data either centrally or distributed according to need. The methods used to present the results in a relevant fashion for system analysts are discussed and we explore the possibilities a...

  18. Monitoring individual traffic flows within the ATLAS TDAQ network

    International Nuclear Information System (INIS)

    Sjoen, R; Batraneanu, S M; Leahu, L; Martin, B; Al-Shabibi, A; Stancu, S; Ciobotaru, M

    2010-01-01

    The ATLAS data acquisition system consists of four different networks interconnecting up to 2000 processors using up to 200 edge switches and five multi-blade chassis devices. The architecture of the system has been described in [1] and its operational model in [2]. Classical, SNMP-based, network monitoring provides statistics on aggregate traffic, but for performance monitoring and troubleshooting purposes there was an imperative need to identify and quantify single traffic flows. sFlow [3] is an industry standard based on statistical sampling which attempts to provide a solution to this. Due to the size of the ATLAS network, the collection and analysis of the sFlow data from all devices generates a data handling problem of its own. This paper describes how this problem is addressed by making it possible to collect and store data either centrally or distributed according to need. The methods used to present the results in a relevant fashion for system analysts are discussed and we explore the possibilities and limitations of this diagnostic tool, giving an example of its use in solving system problems that arise during the ATLAS data taking.

  19. Interior Vector Magnetic Field Monitoring for the SNS Neutron EDM Experiment

    Science.gov (United States)

    Nouri, Nima; Plaster, Brad

    2014-09-01

    A concept has been developed which provides for a real-time determination of the spatial dependence of the vector components of the magnetic field (and, hence, the ∂Bi / ∂xj field gradients) within the interior fiducial volume of the SNS neutron EDM experiment solely from exterior measurements at fixed discrete locations. This technique will be especially important during the operation of the experiment, when direct measurements of the field gradients present within the fiducial volume will not be physically possible. Our method, which is based on the solution to the Laplace Equation, is completely general and does not require the field to possess any type of symmetry. We describe the concept and our systematic approach for optimizing the locations of these exterior measurements. We also present results from prototyping studies of a field monitoring system deployed within a half-scale prototype of the experiment's magnetic field environment. A concept has been developed which provides for a real-time determination of the spatial dependence of the vector components of the magnetic field (and, hence, the ∂Bi / ∂xj field gradients) within the interior fiducial volume of the SNS neutron EDM experiment solely from exterior measurements at fixed discrete locations. This technique will be especially important during the operation of the experiment, when direct measurements of the field gradients present within the fiducial volume will not be physically possible. Our method, which is based on the solution to the Laplace Equation, is completely general and does not require the field to possess any type of symmetry. We describe the concept and our systematic approach for optimizing the locations of these exterior measurements. We also present results from prototyping studies of a field monitoring system deployed within a half-scale prototype of the experiment's magnetic field environment. This work was supported in part by the U.S. Department of Energy Office of

  20. Development of the national register of radiation workers: subsystem for individual monitoring of external exposure

    International Nuclear Information System (INIS)

    Yu Haitao; Niu Haowei; Sun Quanfu; Fu Yinghua; Fan Yaohua; Yue Baorong

    2010-01-01

    Objective: To develop a national registry and reporting system of individual monitoring for workers occupationally exposed to ionizing radiation. Methods: In accordance with the relevant law, regulations, standards and the current health supervision practice for radiation workers in China, to ensure more effective collection of information on individual monitoring from all levels of service providers across the country and an easy query and analysis of the collected information for both service providers and administrative institutions, the register consisted of an offline-system and a web-based information system. The off-line system consisted of 8 tables, which could easily make annual and period monitoring reports, and upload individual monitoring data in compressed and encrypted format. Web-based system consisted of 6 modules, could easily make S customized tabulations of monitoring data and show 2 trend figures. SSLVPN secure remote access was used in the system. Arranged by the Ministry of Health, training courses provided to all individual monitoring service providers and provincial administrative institutions. Results: A new and individual-based national register and reporting system of individual monitoring for workers occupationally exposed to ionizing radiation was successfully developed, and would be officially run soon. Conclusions: The establishment and running of the register would be great improvement on the national radiological health reports and produce a far-reaching impact on the individual monitoring in China. (authors)

  1. Use of in situ neutron diffraction to monitor high-temperature, solid/H2-gas reactions.

    Science.gov (United States)

    Tonus, Florent; Bahout, Mona; Henry, Paul F; Dutton, Siân E; Roisnel, Thierry; Battle, Peter D

    2009-05-14

    For the first time, the chemistry in H(2) gas of a perovskite-like material, Pr(2)Sr(2)CrNiO(8), has been monitored at temperatures up to approximately 700 degrees C, in situ, by neutron powder diffraction.

  2. New ICRU quantities for the environmental and individual monitoring. Standardization of individual dosemeters by using external beams of photon radiation

    International Nuclear Information System (INIS)

    Brosed, A.; Delgado, A.; Granados, C. E.

    1987-01-01

    The quantities introduced by ICRU for the radiological monitoring are commented, specially those implied in individual protection against external photons. A procedure is proposed in order to standardize the individual dosemeters by using the kerma in air references of CIEMAT-JEN. The reference radiation beams are described in connection with ISO standards. Provisional values are selected for the appropriate conversion and correction factors. (Author) 23 refs

  3. Method and apparatus for continuous monitoring and control of neutron absorption properties of chemical shim with temperature compensation

    International Nuclear Information System (INIS)

    Schukei, G.E.; Kowles, J.E.

    1975-01-01

    An apparatus is described to continuously monitor and control the neutron absorption properties of chemical shim used in regulating reactivity of a pressurized water nuclear reactor. Coolant-moderator fluid, containing soluble chemical shim with a neutron absorption property is continuously passed through a chamber having at least one neutron detector spaced from a neutron source of known strength. Utilizing the neutron absorptiometery principle, a signal relating to the concentration of the chemical shim in the coolant-moderator is derived. In addition, the temperature of the sample of coolant is obtained and a temperature compensation signal is generated. The signal related to chemical shim concentration is modified by the temperature compensation signal to correct for temperature related effects. The corrected signal is then applied to a readout and alarm device so that constant monitoring of the shim concentration may be accomplished; additionally, the signal may be applied to maintain the concentration of the chemical shim in the coolant-moderator at a desired level. (U.S.)

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

    OpenAIRE

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

    2013-01-01

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

  5. Method for detecting, screening and/or monitoring a cancer in an individual

    DEFF Research Database (Denmark)

    2003-01-01

    The invention relates to a method for screening and/or detecting and/or monitoring a cancer in an individual, said method comprising determining a first parameter represented by the concentration of TIMP-1 in at least one excreta, e.g. saliva, from the individual. The invention provides a method...... that without the need to use a blood sample is suitable for facilitating the early diagnosis of a cancer, monitoring the recurrence of a cancer, and/or monitoring the status of a cancer or the effect of cancer treatment in an individual....

  6. Simulations of the neutron energy-spectra at the Olympus Gate Environmental Monitoring Station due to historical Bevatron operations

    International Nuclear Information System (INIS)

    Donahue, R.J.; Thomas, R.H.; Zeman, G.H.

    2001-01-01

    Offsite neutron fluences resulting from Bevatron operations reached a maximum in 1959, prior to the addition of a permanent concrete roof shield, which was constructed in 1962. From the first operation of the Bevatron measurements of neutron fluence were made at locations around the perimeter of the Lawrence Berkeley National Laboratory (LBNL) campus. Since the late 1950's measurements made at several locations, and particularly at the site of what is now called the Olympus Gate Environmental Monitoring Station, have been routinely reported and published. Early measurements were used to establish the shape of the neutron-energy spectrum from which an energy-averaged fluence-to-dose equivalent conversion coefficient could be derived. This conversion coefficient was then applied to a measured total neutron fluence to obtain the appropriate dose equivalent quantity required by regulation. Recent work by Thomas et al. (2000) have compared the early conversion coefficients used in the sixties with those accepted today and suggest suggested that ''the dose equivalents reported in the late fifties and early sixties were conservative by factors between two and four. In any current review of the historical data, therefore it would be prudent to reduce the reported dose equivalents by at least a factor of two.'' However, that analysis was based on the ''state of the art'' neutron energy-spectra of the '60s. This paper provides a detailed knowledge of the neutron energy spectrum at the site boundary paper thus removing any uncertainty in the analysis of Thomas et al., which might be caused by the use of the early neutron energy-spectra. Detailed Monte Carlo analyses of the interactions of 6.2 GeV protons in thick, medium-A targets are described. In the computer simulations, neutrons produced were allowed to scatter in the atmosphere. Detailed neutron energy spectra were calculated at a distance and elevation corresponding to the location of the Olympus Gate EMS. Both older

  7. Using Cosmic-Ray Neutron Probes to Monitor Landscape Scale Soil Water Content in Mixed Land Use Agricultural Systems

    International Nuclear Information System (INIS)

    Franz, Trenton E.; Wahbi, Ammar; Weltin, Georg; Heng, Lee; Dercon, Gerd; Vreugdenhi, Mariette; Oismueller, Markus; Strauss, Peter; Desilets, Darin

    2016-01-01

    With an ever-increasing demand for natural resources and the societal need to understand and predict natural disasters such as flood, soil water content (SWC) observations remain a critical variable to monitor in order to optimally allocate resources, establish early warning systems, and improve weather forecasts. However, routine agricultural production practices of soil cultivation, planting, and harvest make the operation and maintenance of direct contact point sensors for long-term monitoring a challenging task. In this work, we used Cosmic-Ray Neutron Probe (CRNP) to monitor landscape average SWC in a mixed agricultural land use system in northeast Austria since December 2013.

  8. Continuous monitoring of snowpack dynamics in alpine terrain by aboveground neutron sensing

    Science.gov (United States)

    Schattan, Paul; Baroni, Gabriele; Oswald, Sascha E.; Schöber, Johannes; Fey, Christine; Kormann, Christoph; Huttenlau, Matthias; Achleitner, Stefan

    2017-05-01

    The characteristics of an aboveground cosmic-ray neutron sensor (CRNS) are evaluated for monitoring a mountain snowpack in the Austrian Alps from March 2014 to June 2016. Neutron counts were compared to continuous point-scale snow depth (SD) and snow-water-equivalent (SWE) measurements from an automatic weather station with a maximum SWE of 600 mm (April 2014). Several spatially distributed Terrestrial Laser Scanning (TLS)-based SD and SWE maps were additionally used. A strong nonlinear correlation is found for both SD and SWE. The representative footprint of the CRNS is in the range of 230-270 m. In contrast to previous studies suggesting signal saturation at around 100 mm of SWE, no complete signal saturation was observed. These results imply that CRNS could be transferred into an unprecedented method for continuous detection of spatially averaged SD and SWE for alpine snowpacks, though with sensitivity decreasing with increasing SWE. While initially different functions were found for accumulation and melting season conditions, this could be resolved by accounting for a limited measurement depth. This depth limit is in the range of 200 mm of SWE for dense snowpacks with high liquid water contents and associated snow density values around 450 kg m-3 and above. In contrast to prior studies with shallow snowpacks, interannual transferability of the results is very high regardless of presnowfall soil moisture conditions. This underlines the unexpectedly high potential of CRNS to close the gap between point-scale measurements, hydrological models, and remote sensing of the cryosphere in alpine terrain.

  9. Development of Neutron Energy Spectral Signatures for Passive Monitoring of Spent Nuclear Fuels in Dry Cask Storage

    Science.gov (United States)

    Harkness, Ira; Zhu, Ting; Liang, Yinong; Rauch, Eric; Enqvist, Andreas; Jordan, Kelly A.

    2018-01-01

    Demand for spent nuclear fuel dry casks as an interim storage solution has increased globally and the IAEA has expressed a need for robust safeguards and verification technologies for ensuring the continuity of knowledge and the integrity of radioactive materials inside spent fuel casks. Existing research has been focusing on "fingerprinting" casks based on count rate statistics to represent radiation emission signatures. The current research aims to expand to include neutron energy spectral information as part of the fuel characteristics. First, spent fuel composition data are taken from the Next Generation Safeguards Initiative Spent Fuel Libraries, representative for Westinghouse 17ˣ17 PWR assemblies. The ORIGEN-S code then calculates the spontaneous fission and (α,n) emissions for individual fuel rods, followed by detailed MCNP simulations of neutrons transported through the fuel assemblies. A comprehensive database of neutron energy spectral profiles is to be constructed, with different enrichment, burn-up, and cooling time conditions. The end goal is to utilize the computational spent fuel library, predictive algorithm, and a pressurized 4He scintillator to verify the spent fuel assemblies inside a cask. This work identifies neutron spectral signatures that correlate with the cooling time of spent fuel. Both the total and relative contributions from spontaneous fission and (α,n) change noticeably with respect to cooling time, due to the relatively short half-life (18 years) of the major neutron source 244Cm. Identification of this and other neutron spectral signatures allows the characterization of spent nuclear fuels in dry cask storage.

  10. Research and Development Program in Reactor Diagnostics and Monitoring with Neutron Noise Methods. Stages 14 and 15

    International Nuclear Information System (INIS)

    Pazsit, Imre; Wihlstrand, Gustav; Tambouratzis, Tatiana; Jonsson, Anders; Dahl, Berit

    2009-12-01

    This report constitutes Stages 14 and 15 of a long-term research and development program concerning the development of diagnostics and monitoring methods for nuclear reactors. Stage 14 was a full one-year project, whereas Stage 15 consisted of a half-year project. The program executed in Stages 14 and 15 consists of the following three parts: - Study of criticality, neutron kinetics and neutron noise in molten salt reactors (MSR) (Stages 14 and 15); - An overview and introduction to fuzzy logics (Stage 14), and an application to two-phase flow identification (Stage 15) - Preparations for and execution of an IAEA-ICTP workshop on Neutron fluctuations, reactor noise and their applications in nuclear reactors (Stage 14)

  11. Evaluation of the current fast neutron flux monitoring instrumentation applied to LFR demonstrator ALFRED. Capabilities and limitations

    International Nuclear Information System (INIS)

    Lepore, Luigi; Remetti, Romolo; Cappelli, Mauro

    2015-01-01

    Among Gen IV projects for future nuclear power plants, Lead Fast Reactors (LFR) seem to be a very interesting solution due to their benefits in terms of fuel cycle, coolant-safety and waste management. The novelty of the matter causes some open issues about coolant chemical aspect, structural aspects, monitoring instrumentation, etc. Particularly hard neutron flux spectra would make traditional neutron instrumentation unfit to all reactor conditions, i.e. source, intermediate, and power range. Identification of new models of nuclear instrumentation specialized for LFR neutron flux monitoring asks for an accurate evaluation of the environment the sensor will work in. In this study, thermal-hydraulics and chemical conditions for LFR core environment will be assumed, as the neutron flux will be studied extensively by means of the Monte Carlo transport code MCNPX. The core coolant’s high temperature drastically reduces the candidate instrumentation, because only some kind of fission chambers and Self Powered Neutron Detectors can be operated in such an environment. This work aims to evaluate the capabilities of the available instrumentation (usually designed for Sodium Fast Reactors, SFRs) when exposed to the neutron spectrum derived from ALFRED, a pool-type small-power LFR project to demonstrate the feasibility of this technology into the European framework. This paper shows that such instruments do follow the power evolution, but they are not completely suitable to detect the whole range of reactor power. Some improvements are then possible in order to increase the signal-to-noise ratio, by optimizing each instrument in the range of reactor power, such to get the best solution. Some new detector designs are here proposed, and the possibilities for prototyping and testing by means of a fast reactor investigated. (author)

  12. A microprocessor based area monitor system for neutron and gamma radiation

    International Nuclear Information System (INIS)

    Wilhelm, R.; Heusser, G.

    1980-01-01

    The conventional electronics of the area monitors at the MPI-Heidelberg accelerators have been replaced by a microprocessor system consisting of individual detector-microprocessors and a central microcomputer. The detector microprocessors convert the count rates of BF3 and GM counter tubes into dose rates and control three different radiation thresholds (failure, low and high level). Different warning signals are operated directly by the detector processors, whereas the dose rates are transferred to the central microcomputer. Here the data are processed for recording on tape and displaying on TV monitors. The detector as well as the central processors have been developed on the basis of a 16-bit microprocessor. In the control rooms the dose rates of the individual monitors are displayed and on an indicator board showing the different locations, the high radiation level and the state of the doors (open, locked, and closed, locked but open) are sianaled by different LED. If a high radiation threshold is surpassed, the doors adjacent to that area can be locked either by switches on the indicator board or automatically. Within the experimental area, the low and high radiation level is indicated by acoustic and light signals. The whole concept permits keeping the absorbed doses of the personnel as low as possible without affecting the flexibility of the experimental operations. The independence of the microprocessor driven area monitors guarantees a high reliability. Compared to conventional electronics the advantages of the system are its reliability and cost. (Author)

  13. Diagnostic assessment to estimate and minimize neutron dose rates received by occupationally exposed individuals at cyclotron facilities.

    Science.gov (United States)

    Reina, L C; Silva, A X; Suita, J C; Souza, M I S; Facure, A; Silva, J C P; Furlanetto, J A D; Rebello, W

    2010-03-01

    Since 2003, radiopharmaceuticals for medical diagnostic purposes have been produced at the Instituto de Engenharia Nuclear, in Brazil, using two cyclotron accelerators - CV-28 and RDS111. As a result of the ever increasing production, a diagnostic assessment to reduce neutron dose rates received by occupationally exposed individuals during irradiation processes has been developed. The purpose of this work is to present this assessment, which is currently being applied to both the Fluorine and Iodine targets of CV-28 and RDS111 cyclotron accelerators. Copyright 2009 Elsevier Ltd. All rights reserved.

  14. Rigidity spectrum of Forbush decrease calculated by neutron monitors data corrected and uncorrected for geomagnetic disturbances

    International Nuclear Information System (INIS)

    Alania, M V; Wawrzynczak, A; Sdobnov, V E; Kravtsova, M V

    2013-01-01

    Forbush decreases (Fd) of the galactic cosmic ray (GCR) intensity and geomagnetic storms are observed almost at the same time. Geomagnetic storm is a reason of significant disturbances of the magnetic cut off rigidity causing the distortion of the time profile of the Fd of the GCR intensity. We show some differences in the temporal changes of the rigidity spectra of Fd calculated by neutron monitors experimental data corrected and uncorrected for the changes of the geomagnetic cut off rigidity. Nevertheless, the general features of the temporal changes of the rigidity spectrum of Fd maintain as it was found in our previous investigations. Namely, at the beginning phase of Fd rigidity spectrum is relatively soft and gradually becomes hard up to reaching the minimum level of the GCR intensity; then the rigidity spectrum gradually becomes soft during the recovery phase of Fd. We also confirm that for the established temporal profiles of the rigidity spectrum of Fd a structural changes of the interplanetary magnetic field turbulence in the range of frequencies, 10 −-6 ÷10 −-5 Hz are responsible.

  15. Monitoring Landscape Scale Soil Water Content with Cosmic-Ray Neutron Sensors: Validation and Calibration

    International Nuclear Information System (INIS)

    Wahbi, Ammar; Avery, William A.; Dercon, Gerd; Heng, Lee; Weltin, Georg; Franz, Trenton E.; Strauss, Peter; Oismueller, Markus; Desilets, Darin

    2017-01-01

    Increasing populations growth combined with climate change are putting pressure on water resources and agricultural systems around the world. The need for effective water management strategies designed to maximize water use efficiency has made access to soil water content (SWC) information crucial to the global community. This work builds upon ongoing research that began in December 2013 in which a stationary Cosmic-Ray Neutron Sensor (CRNS) was used to monitor SWC within an agricultural system located in north central Austria. Past work at this study site at Petzenkirchen, Austria (100 km west of Vienna) has focused on the calibration and validation of the CRNS technology, and has shown the CRNS to reliably estimate SWC on a large scale (circle with radius of cca. 250 m) when compared to other methods of estimating SWC. This was determined via comparisons of insitu soil sampling, time domain reflectometry (TDR), and time domain transmissivity (TDT) of SWC with estimates of SWC determined from the CRNS. However, questions remain regarding the effective use of the CRNS technology.

  16. Real time processing of neutron monitor data using the edge editor algorithm

    Directory of Open Access Journals (Sweden)

    Mavromichalaki Helen

    2012-09-01

    Full Text Available The nucleonic component of the secondary cosmic rays is measured by the worldwide network of neutron monitors (NMs. In most cases, a NM station publishes the measured data in a real time basis in order to be available for instant use from the scientific community. The space weather centers and the online applications such as the ground level enhancement (GLE alert make use of the online data and are highly dependent on their quality. However, the primary data in some cases are distorted due to unpredictable instrument variations. For this reason, the real time primary data processing of the measured data of a station is necessary. The general operational principle of the correction algorithms is the comparison between the different channels of a NM, taking advantage of the fact that a station hosts a number of identical detectors. Median editor, Median editor plus and Super editor are some of the correction algorithms that are being used with satisfactory results. In this work an alternative algorithm is proposed and analyzed. The new algorithm uses a statistical approach to define the distribution of the measurements and introduces an error index which is used for the correction of the measurements that deviate from this distribution.

  17. Individual differences in episodic memory abilities predict successful prospective memory output monitoring.

    Science.gov (United States)

    Hunter Ball, B; Pitães, Margarida; Brewer, Gene A

    2018-02-07

    Output monitoring refers to memory for one's previously completed actions. In the context of prospective memory (PM) (e.g., remembering to take medication), failures of output monitoring can result in repetitions and omissions of planned actions (e.g., over- or under-medication). To be successful in output monitoring paradigms, participants must flexibly control attention to detect PM cues as well as engage controlled retrieval of previous actions whenever a particular cue is encountered. The current study examined individual differences in output monitoring abilities in a group of younger adults differing in attention control (AC) and episodic memory (EM) abilities. The results showed that AC ability uniquely predicted successful cue detection on the first presentation, whereas EM ability uniquely predicted successful output monitoring on the second presentation. The current study highlights the importance of examining external correlates of PM abilities and contributes to the growing body of research on individual differences in PM.

  18. A monitor for neutron flux measurements up to 20 MeV.

    Science.gov (United States)

    Ohrn, A; Blomgren, J; Park, H; Khurana, S; Nolte, R; Schmidt, D; Wilhelmsen, K

    2007-01-01

    A liquid scintillation detector aimed for neutron energy and fluence measurements in the energy region neutron fields. Careful measurements of the proton light output function and the response matrix have been performed allowing for the application of unfolding techniques using existing codes. The response matrix is used to characterise monoenergetic neutron fields produced by the T(d,n) at a low-energy deuteron accelerator installed at the Swedish Defense Research Agency (FOI).

  19. Multitaper spectral analysis of cosmic rays Sao Martinho da Serra's muon telescope and Newark's neutron monitor data

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marlos Rockenbach da; Alarcon, Walter Demetrio Gonzalez; Echer, Ezequiel; Lago, Alisson dal; Lucas, Aline de [National Institute for Space Research - INPE-MCT, Sao Jose dos Campos, SP (Brazil); Vieira, Luis Eduardo Antunes; Guarnieri, Fernando Luis [Universidade do Vale do Paraiba - UNIVAP, Sao Jose dos Campos, SP (Brazil); Schuch, Nelson Jorge [Southern Regional Space Research Center - CRSPE/INPE-MCT, Santa Maria, RS (Brazil); Munakata, Kazuoki, E-mail: marlos@dge.inpe.br, E-mail: gonzalez@dge.inpe.br, E-mail: eecher@dge.inpe.br, E-mail: dallago@dge.inpe.br, E-mail: delucas@dge.inpe.br, E-mail: levieira@univap.br, E-mail: guarnieri@univap.br, E-mail: njschuch@lacesm.ufsm.br, E-mail: kmuna00@gipac.shinshu-u.ac.jp [Physics Department, Shinshu University, Matsumoto (Japan)

    2007-07-01

    In this work we present an analysis on the correction efficiency of atmospheric effects on cosmic ray Sao Martinho da Serra's muon telescope and Newark's neutron monitor data. We use a Multitaper spectral analysis of cosmic rays time series to show the main periodicities present in the corrected and uncorrected data for the atmospheric effects. This kind of correction is very important when intends to study cosmic rays variations of extra-terrestrial origin. (author)

  20. Individual Self-monitoring &Peer-monitoring In One Classroom in Writing Activities: Who Is at Disadvantage?

    Directory of Open Access Journals (Sweden)

    Zohreh Zare Toofan

    2014-02-01

    Full Text Available Writing is an important experience through which we are able to share ideas, arouse feelings, persuade and convince other people (white & Arndt, 1991. It is important to view writing not solely as the product of an individual, but as a cognitive, social and cultural act. Writing is an act that takes place within a context, that accomplishes a particular purpose and that is appropriately shaped for its intended audience (Hamplyones & Condon, 1989. Here, the present research considers the significance effects of two important independent variables self-monitoring and peer-monitoring in writing activities on Iranian EFL learners. In this research it was supposed to study new effects of two Meta cognitive strategies self-monitoring and peer-monitoring on 173 male and female learners' writing activities whose age ranged between the age 16-27, and they had a composing description writing paragraph as pre & post test in the same conditions. Although many studies have been conducted on the effects of self-monitoring with a variety of students across a variety of settings (Amato-Zech, Hoff, & Doepke, 2006 Cooper et al., 2007, Dunlap, Dunlap, Koegel, & Koegel 1991. But goal of this study was to increase the participant’s on-task behavior in self & peer-monitoring (E. Johnson, 2007, Self &Peer-monitoring added. Although both of them were useful for providing challengeable students, and became useful for prosocial life, but self-monitoring helped them to become awareness of their weaknesses and strengths to increase positive way of the quality and quantity of their learning in written task, and peer-monitoring occurred when the students achieved recognition level to evaluate the other peers' behavior, and it was obviously understood that it needed more training time to arrive at the level of recognition of each others' behavior.

  1. Individual air pollution monitors. 2. Examination of some nonoccupational research and regulatory uses and needs

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, M.G.; Morris, S.C.

    1977-01-01

    Knowledge of the relationship between ambient air pollution levels measured at fixed monitoring stations and the actual exposure of the population is very limited. Indeed, there is rapidly growing evidence that fixed-station monitors do not provide adequate data for population exposure. This report examines available data for carbon monoxide (CO) and sulfur dioxide (SO/sub 2/) and presents a new analysis. Actual population exposure to CO appears to be consistently higher than expected from fixed-station data, while limited evidence suggests that exposures to SO/sub 2/ are lower. A reported general relationship between indoor and outdoor levels of SO/sub 2/ is not supported by the data. If air pollution represents a threat to public health, then more attention must be given to total population exposure to pollutants. A selective use of individual air pollution monitors that can be worn or carried appears to be required at some stage by any experimental design seeking to uncover the relation between air pollution exposure and health effects. Additionally, potential uses of individual monitoring in air pollution regulation are explored. Current status and research needs for individual air pollution monitors are examined and a first-order evaluation is given of the promise held by the candidate instrumentation technologies. A national program of support for the development of individual air pollution monitors is recommended.

  2. Neutron-photon mixed field dosimetry by TLD-700 glow curve analysis and its implementation in dose monitoring for Boron Neutron Capture Therapy (BNCT) treatments

    Energy Technology Data Exchange (ETDEWEB)

    Boggio, E. F.; Longhino, J. M. [Centro Atomico Bariloche, Departamento de Fisica de Reactores y Radiaciones / CNEA, Av. E. Bustillo Km 9.5, R8402AGP San Carlos de Bariloche (Argentina); Andres, P. A., E-mail: efboggio@cab.cnea.gov.ar [Centro Atomico Bariloche, Division Proteccion Radiologica / CNEA, Av. E. Bustillo Km 9.5, R8402AGP San Carlos de Bariloche (Argentina)

    2015-10-15

    BNCT is a cancerous cells selective, non-conventional radiotherapy modality to treat malignant tumors such as glioblastoma, melanoma and recurrent head and neck cancer. It consists of a two-step procedure: first, the patient is injected with a tumor localizing drug containing a non-radioactive isotope (Boron-10) with high slow neutron capture cross-section. In a second step, the patient is irradiated with neutrons, which are absorbed by the Boron-10 agent with the subsequently nuclear reaction B- 10(n,a)Li-7, thereby resulting in dose at cellular level due to the high-Let particles. The neutron fields suitable for BNCT are characterized by high neutron fluxes and low gamma dose. Determination of each component is not an easy task, especially when the volume of measurement is quite small or inaccessible for a miniature ionization chamber, for example. A method of measuring the photon and slow neutron dose(mainly by N-14 and B-10) from the glow curve (GC) analysis of a single {sup 7}LiF thermoluminescence detector is evaluated. This method was suggested by the group headed by Dr. Grazia Gambarini. The dosemeters used were TLD-600 ({sup 6}LiF:Mg,Ti with 95.6% {sup 6}Li) and TLD-700 ({sup 7}LiF:Mg,Ti with 99.9% {sup 7}LiF) from Harshaw. Photon dose measurement using the GC analysis method with TLD-700 in mixed fields requires the relation of the two main peaks of a TLD-600 GC shape obtained from an exposition to the same neutron field, and a photon calibrated GC with TLD-700. The requirements for slow neutron dose measurements are similar. In order to properly apply the GC analysis method at the Ra-6 Research Reactor BNCT facility, measurements were carried out in a standard water phantom, fully characterized on the BNCT beam by conventional techniques (activation detectors and paired ionization chambers technique). Next, the method was implemented in whole body dose monitoring of a patient undergoing a BNCT treatment, using a Bo MAb (Bottle Manikin Absorption) phantom

  3. Measurement of Neutron Field Characteristics at Nuclear-Physics Instalations for Personal Radiation Monitoring

    CERN Document Server

    Alekseev, A G; Britvich, G I; Kosyanenko, E V; Pikalov, V A; Gomonov, I P

    2003-01-01

    n this work the observed data of neutron spectra on Rostov NEP, Kursk NEP and Smolensk NEP and on the reactor IRT MIPHI are submitted. For measurement of neutron spectra two types of spectrometer were used: SHANS (IHEP design ) and SDN-MS01 (FEI design). The comparison of the data measurements per-formed by those spectrometers above one-type cells on the reactor RBMK is submitted. On the basis of the 1-st horizontal experimental channel HEC-1 of the IRT reactor 4 reference fields of neutrons are investigated. It is shown, that spectra of neutrons of reference fields can be used for imitation of neutron spectra for conditions of NEP with VVER and RBMK type reactors.

  4. Growth of mesoporous silica nanoparticles monitored by time-resolved small-angle neutron scattering.

    Science.gov (United States)

    Hollamby, Martin J; Borisova, Dimitriya; Brown, Paul; Eastoe, Julian; Grillo, Isabelle; Shchukin, Dmitry

    2012-03-06

    Since the first development of surfactant-templated mesoporous silicas, the underlying mechanisms behind the formation of their structures have been under debate. Here, for the first time, time-resolved small-angle neutron scattering (tr-SANS) is applied to study the complete formation of mesoporous silica nanoparticles. A distinct advantage of this technique is the ability to detect contributions from the whole system, enabling the visualization not only of particle genesis and growth but also the concurrent changes to the coexistent micelle population. In addition, using contrast-matching tr-SANS, it is possible to highlight the individual contributions from the silica and surfactant. An analysis of the data agrees well with the previously proposed "current bun" model describing particle growth: Condensing silica oligomers adsorb to micelles, reducing intermicellar repulsion and resulting in aggregation to form initial particle nuclei. From this point, the growth occurs in a cooperative manner, with condensing silica filling the gaps between further aggregating micelles. The mechanistic results are discussed with respect to different reaction conditions by changing either the concentration of the silica precursor or the temperature. In doing so the importance of in situ techniques is highlighted, in particular, tr-SANS, for mechanism elucidation in the broad field of materials science.

  5. First assessment of individual monitoring of medical workers occupationally exposed to ionizing radiation in Burkina Faso

    International Nuclear Information System (INIS)

    Yakoro, A.; Nobila Ouédraogo, Salimata Traoré

    2010-01-01

    This paper reports the results of monitoring of medical workers occupationally exposed to ionizing radiation as a consequence of exposure to X-rays, from 2007 to 2010, in Burkina Faso. The radiation exposure monitoring was made with thermoluminescent dosimeters (TLD-100) type 0110 and the reader used was Harshaw 4500. The medical establishments. subscribers were provided with personal dosimeters (measuring Hp (10) and Hp (0.07)) and dosimeters for background and workplace exposure (H*10) measurement. The dosimeters have been worn for periods of 2 months each. The number of establishments subscribed and workers monitored has gradually increased from 4 radiology establishments with 13 workers monitored at September 2007 to 23 subscribers with 121 workers monitored at the end of April 2010. 13 establishments were still working without monitoring. From September 2007 to April 2010, no individual annual dose limit has really been reached. 88.16% of the 2 months dose values of personal dosimeters were below 0.1mSv, the detection limit and 96.61% of Hp (10) bimonthly values were below 3.33mSv. The workplace exposure monitoring values were often low (varying from 0.00mSv to 40.45mSv). 87.08% of the values of H*(10) were below 3.33mSv, the upper limit of Hp (10) for a period of 2 months. Low values of individual dose have also been recorded despite of high values of workplace monitoring. This allowed to state that the workers monitored were not exposed to a major risk. Nevertheless, 13 TLD have been lost and 3 damaged by subscribers (out of 1504 TLD provided). 26 times (out of 240), background measurement and workplace exposure monitoring dosimeters have been placed at the improper location. Therefore, sensitization of the establishments using ionizing radiation should be reinforced and the national regulations should impose radiation monitoring (author)

  6. Cognitive Abilities, Monitoring Confidence, and Control Thresholds Explain Individual Differences in Heuristics and Biases

    Science.gov (United States)

    Jackson, Simon A.; Kleitman, Sabina; Howie, Pauline; Stankov, Lazar

    2016-01-01

    In this paper, we investigate whether individual differences in performance on heuristic and biases tasks can be explained by cognitive abilities, monitoring confidence, and control thresholds. Current theories explain individual differences in these tasks by the ability to detect errors and override automatic but biased judgments, and deliberative cognitive abilities that help to construct the correct response. Here we retain cognitive abilities but disentangle error detection, proposing that lower monitoring confidence and higher control thresholds promote error checking. Participants (N = 250) completed tasks assessing their fluid reasoning abilities, stable monitoring confidence levels, and the control threshold they impose on their decisions. They also completed seven typical heuristic and biases tasks such as the cognitive reflection test and Resistance to Framing. Using structural equation modeling, we found that individuals with higher reasoning abilities, lower monitoring confidence, and higher control threshold performed significantly and, at times, substantially better on the heuristic and biases tasks. Individuals with higher control thresholds also showed lower preferences for risky alternatives in a gambling task. Furthermore, residual correlations among the heuristic and biases tasks were reduced to null, indicating that cognitive abilities, monitoring confidence, and control thresholds accounted for their shared variance. Implications include the proposal that the capacity to detect errors does not differ between individuals. Rather, individuals might adopt varied strategies that promote error checking to different degrees, regardless of whether they have made a mistake or not. The results support growing evidence that decision-making involves cognitive abilities that construct actions and monitoring and control processes that manage their initiation. PMID:27790170

  7. Cognitive abilities, monitoring, and control explain individual differences in heuristics and biases

    Directory of Open Access Journals (Sweden)

    Simon Anthony Jackson

    2016-10-01

    Full Text Available In this paper, we investigate whether individual differences in performance on heuristic and biases tasks can be explained by cognitive abilities, monitoring confidence and control thresholds. Current theories explain individual differences in these tasks by the ability to detect errors and override automatic but biased judgements, and deliberative cognitive abilities that help to construct the correct response. Here we retain cognitive abilities but disentangle error detection, proposing that lower monitoring confidence and higher control thresholds promote error checking. Participants (N = 250 completed tasks assessing their fluid reasoning abilities, stable monitoring confidence levels, and the control threshold they impose on their decisions. They also completed seven typical heuristic and biases tasks such as the cognitive reflection test and resistance to framing. Using structural equation modelling, we found that individuals with higher reasoning abilities, lower monitoring confidence and higher control threshold performed significantly and, at times, substantially better on the heuristic and biases tasks. Individuals with higher control thresholds also showed lower preferences for risky alternatives in a gambling task. Furthermore, residual correlations among the heuristic and biases tasks were reduced to null, indicating that cognitive abilities, monitoring confidence and control thresholds accounted for their shared variance. Implications include the proposal that the capacity to detect errors does not differ between individuals. Rather, individuals might adopt varied strategies that promote error checking to different degrees, regardless of whether they have made a mistake or not. The results support growing evidence that decision making involves cognitive abilities that construct actions and monitoring and control processes that manage their initiation.

  8. Cognitive Abilities, Monitoring Confidence, and Control Thresholds Explain Individual Differences in Heuristics and Biases.

    Science.gov (United States)

    Jackson, Simon A; Kleitman, Sabina; Howie, Pauline; Stankov, Lazar

    2016-01-01

    In this paper, we investigate whether individual differences in performance on heuristic and biases tasks can be explained by cognitive abilities, monitoring confidence, and control thresholds. Current theories explain individual differences in these tasks by the ability to detect errors and override automatic but biased judgments, and deliberative cognitive abilities that help to construct the correct response. Here we retain cognitive abilities but disentangle error detection, proposing that lower monitoring confidence and higher control thresholds promote error checking. Participants ( N = 250) completed tasks assessing their fluid reasoning abilities, stable monitoring confidence levels, and the control threshold they impose on their decisions. They also completed seven typical heuristic and biases tasks such as the cognitive reflection test and Resistance to Framing. Using structural equation modeling, we found that individuals with higher reasoning abilities, lower monitoring confidence, and higher control threshold performed significantly and, at times, substantially better on the heuristic and biases tasks. Individuals with higher control thresholds also showed lower preferences for risky alternatives in a gambling task. Furthermore, residual correlations among the heuristic and biases tasks were reduced to null, indicating that cognitive abilities, monitoring confidence, and control thresholds accounted for their shared variance. Implications include the proposal that the capacity to detect errors does not differ between individuals. Rather, individuals might adopt varied strategies that promote error checking to different degrees, regardless of whether they have made a mistake or not. The results support growing evidence that decision-making involves cognitive abilities that construct actions and monitoring and control processes that manage their initiation.

  9. Monitoring of individual doses and its information management system for CAEP's employees

    International Nuclear Information System (INIS)

    Wei Xiye; Lei Jiarong; Yuan Yonggang; Zhao Lin; Zhao Minzhi; Cui Gaoxian

    2007-01-01

    Employees' individual dose is very important to radiation workers, this paper introduces the monitoring of individual doses for the employees of CAEP in brief. A mass of employees' individual dose information records needed for being disposed, the data management software IDDMS for individual dose was developed. This paper describes the database structure, main modules, statistic and printing functions in this program. Based on much experience of many years in data management of individual dose, this program is developed using the object-oriented language Visual Foxpro 6.0. Meanwhile, it had been tested for several months. The results show that this software can be used directly for daily management of individual dose, and report forms of individual dose can also be printed easily for the related superior department. (authors)

  10. Evaluation of performance of electronic dosimeters for individual monitoring: tests in laboratory

    International Nuclear Information System (INIS)

    Garzon, W.J.; Khoury, H.J.; Barros, V.S.M. de; Medeiros, R.B.

    2015-01-01

    Electronic dosimeters based on direct ion storage technology are being widely used in many countries for individual monitoring in many applications of ionizing radiation. However, their use as routine dosimeter has been established in a few countries due to lack of accreditation or intercomparison programs. The objective of this study is to evaluate the performance of two direct íon storage dosimeters model available in the international market: the Miriom-Instadose-1 and RADOS DIS-1 to be eventually accepted for individual monitoring in Brazil. (author)

  11. Harmonisation and dosimetric quality assurance in individual monitoring for external radiation

    DEFF Research Database (Denmark)

    Bartlett, D.T.; Ambrosi, P.; Back, C.

    2001-01-01

    The current situation amongst Member States is that there are widely differing national requirements for dosimetric services and for dosemeter performance. It is clear that with the free movement of workers within the European Union (EU) and the requirements for individual dosimetry given...... of individual monitoring using personal dosemeters and assisting movement towards harmonised procedures. An outline of the work of the action group is given and the term 'harmonisation' is discussed....

  12. Cognitive Abilities, Monitoring Confidence, and Control Thresholds Explain Individual Differences in Heuristics and Biases

    OpenAIRE

    Jackson, Simon A.; Kleitman, Sabina; Howie, Pauline; Stankov, Lazar

    2016-01-01

    In this paper, we investigate whether individual differences in performance on heuristic and biases tasks can be explained by cognitive abilities, monitoring confidence, and control thresholds. Current theories explain individual differences in these tasks by the ability to detect errors and override automatic but biased judgments, and deliberative cognitive abilities that help to construct the correct response. Here we retain cognitive abilities but disentangle error detection, proposing tha...

  13. Cognitive abilities, monitoring, and control explain individual differences in heuristics and biases

    OpenAIRE

    Simon Anthony Jackson; Sabina Kleitman; Pauline Howie; Lazar Stankov

    2016-01-01

    In this paper, we investigate whether individual differences in performance on heuristic and biases tasks can be explained by cognitive abilities, monitoring confidence and control thresholds. Current theories explain individual differences in these tasks by the ability to detect errors and override automatic but biased judgements, and deliberative cognitive abilities that help to construct the correct response. Here we retain cognitive abilities but disentangle error detection, proposing tha...

  14. Scintillating-Glass-Fiber neutron sensors, their application and performance for plutonium detection and monitoring

    International Nuclear Information System (INIS)

    Seymour, R.S.; Richardson, B.; Morichi, M.; Bliss, M.; Craig, R.A.; Sunberg, D.S.

    1998-01-01

    Most neutron detection sensors presently employ 3 He gas-filled detectors. Despite their excellent performance and widespread use, there are significant limitations to this technology. A significant alternative neutron sensor utilizing neutron-active material incorporated into a glass scintillator is presented that offers novel commercial sensors not possible or practical with gas tube technology. The scintillating optical fiber permits sensors with a multitude of sizes ranging from devices of a single fiber of 150μm to sensors with tens of thousands of fibers with areas as large as 5m 2 depending on the neutron flux to be measured. A second significant advantage is the use of high-speed electronics that allow a greater dynamic range, not possible with gas detectors. These sensors are flexible, conformable and less sensitive to vibration that optimizes the source-to-detector geometry and provides robust performance in field applications. The glass-fibers are sensitive to both gamma rays and neutrons. However the coincidence electronics are optimized for neutron to gamma ray discrimination allowing very sensitive measurements with a low false-alarm rate. Applications include SNM surveillance, material control and accountability (MC and A), safeguard inspections, Pu health physics / bioassay and environmental characterization. (author)

  15. Basis and algorithms applied in modern neutron flux monitoring equipment for WWER. Some results of its operation

    International Nuclear Information System (INIS)

    Alpatov, A. M.; Kamyshan, A. N.; Louzhnov, A. M.; Sokolov, I. V.

    2007-01-01

    The report presents the principle of operation and description of equipment complex for monitoring, control and protection by power, period, reactivity and local parameters of the core of WWER type reactor. The use in NFME of programmed computing means permitted on basis of signals from ex-core neutron detectors of working range, distributed over IC channel height, to realize operative non-inertia monitoring of mean axial power distribution shape in the core and its main characteristics (axial offset and axial non-uniformity coefficient). With regard for this and due to the use of information on position of control banks and on coolant temperature in the reactor vessel downcomer the equipment for power correction, eliminating the influence of the above factors on resulting signal and permitting to increase significantly the accuracy of power monitoring, was designed(Authors)

  16. Individual Differences in Search and Monitoring for Color Targets in Dynamic Visual Displays.

    Science.gov (United States)

    Muhl-Richardson, Alex; Godwin, Hayward J; Garner, Matthew; Hadwin, Julie A; Liversedge, Simon P; Donnelly, Nick

    2018-02-01

    Many real-world tasks now involve monitoring visual representations of data that change dynamically over time. Monitoring dynamically changing displays for the onset of targets can be done in two ways: detecting targets directly, post-onset, or predicting their onset from the prior state of distractors. In the present study, participants' eye movements were measured as they monitored arrays of 108 colored squares whose colors changed systematically over time. Across three experiments, the data show that participants detected the onset of targets both directly and predictively. Experiments 1 and 2 showed that predictive detection was only possible when supported by sequential color changes that followed a scale ordered in color space. Experiment 3 included measures of individual differences in working memory capacity (WMC) and anxious affect and a manipulation of target prevalence in the search task. It found that predictive monitoring for targets, and decisions about target onsets, were influenced by interactions between individual differences in verbal and spatial WMC and intolerance of uncertainty, a characteristic that reflects worry about uncertain future events. The results have implications for the selection of individuals tasked with monitoring dynamic visual displays for target onsets. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  17. Individual monitoring of external exposure in terms of personal dose equivalent, Hp(d)

    International Nuclear Information System (INIS)

    Fantuzzi, E.

    2001-01-01

    The institute for Radiation Protection of ENEA - Bologna has organised a one day-workshop on the subject: Individual monitoring of external exposure in terms of personal dose equivalent, H p (d). The aim of the workshop was the discussion of the new implications and modifications to be expected in the routine individual monitoring of external radiation, due to the issue of the Decree 241/00 (G.U. 31/8/2000) in charge since 01/01/2001. The decree set up in Italian law the standards contained in the European Directive EURATOM 96/29-Basic Standards for the Protection of Health of Workers and the General Public against Dangers arising from Ionizing Radiation. Among others, the definition of the operational quantities for external radiation for personal and environmental monitoring, H p (d) e H * (d) respectively as defined by ICRU (International Commission for Radiation Units and Measurements), requires to update the methods of measurements and calibration of the personal dosemeters and environmental monitors. This report collects the papers presented at the workshop dealing with the Personal Dose Equivalent, H p (d), the conversion coefficients, H p (d)/K a e H p (d)/ , obtained through Monte Carlo calculations published by ICRU and ICRP (International Commission for Radiation Protection), the new calibration procedures and the practical implication in the routine of individual monitoring in terms of H p (d). Eventually, in the last chapter, the answers to Frequently Asked Questions (FAQ) are briefly reported [it

  18. Radiological protection. Technical recommendations for monitoring the exposure of individuals to external radiation

    International Nuclear Information System (INIS)

    1975-01-01

    Advice is given on the assessment of personal doses received by each worker. The objectives of individual monitoring programs and the requirements which personal dosemeters should satisfy are given. The paper is mainly concerned with assessment of doses due to photon and electron radiations

  19. Antipsychotic Use and Metabolic Monitoring in Individuals with Developmental Disabilities Served in a Medicaid Medical Home

    Science.gov (United States)

    Ruiz, Lisa M.; Damron, Mackenzie; Jones, Kyle B.; Weedon, Dean; Carbone, Paul S.; Bakian, Amanda V.; Bilder, Deborah A.

    2016-01-01

    This study describes antipsychotic use and metabolic monitoring rates among individuals with developmental disabilities enrolled in a subspecialty medical home (N = 826). Four hundred ninety-nine participants (60.4%) were taking antipsychotics, which was associated with male gender (p = 0.01), intellectual disability with and without autism…

  20. Aircrew exposure onboard a Czech airlines aircraft, individual monitoring of aircrew

    Energy Technology Data Exchange (ETDEWEB)

    Ploc, O.; Spurny, F.; Turek, K. [Nuclear Physics Institute AS CR, Dept. of Radiation Dosimetry, Prague (Czech Republic); Ploc, O. [Czech Technical Univ., Dept. of Dosimetry and Application of Ionizing Radiation, Prague (Czech Republic)

    2006-07-01

    The contribution presents new results related to the aircraft crew exposure onboard aircraft of Czech air companies. First the results of long term monitoring onboard of an aircraft of Czech Airlines are presented. The monitoring has been performed in the period May - December 2005, more than 500 individual flights have been followed. M.D.U.-Liulin Si-diode based spectrometer was used, together with thermoluminescent and track detectors. Total effective dose was about 12 mSv, the results obtained with dosimeters mentioned are analyzed and compared with the results of calculation performed with C.A.R.I. and E.P.C.A.R.D. codes. Individual monitoring of air crew members has been started in the Czech Republic since 1998 year. The results obtained during few last years are presented, general tendencies of aircraft crew onboard exposure of Czech air companies are outlined. (authors)

  1. Dynamic monitoring of weight data at the pen vs at the individual level

    DEFF Research Database (Denmark)

    Jensen, Dan; Toft, Nils; Kristensen, A. R. K.

    recorded weight data from finisher pigs. Data are collected at insertion and at the exit of the first pigs in the pen, and in few pens, the weight is recorded weekly. Dynamic linear models are fitted on the weight data, at the pig level (univariate), at the double pen level using averaged weight...... (univariate) and using individual pig values as parameters in a hierarchical (multivariate) model including section, double pen, and individual level. Variance components of the different models are estimated using the Expectation Maximization algorithm. The difference of information obtained...... at the individual vs pen level is thereafter assessed. Whereas weight data is usually monitored after a batch is being sent to the slaughter house, this method provides weekly updating of the data. Perspectives of application include dynamic monitoring of weight data in relation to events such as diarrhoea, tail...

  2. Dynamic monitoring of weight data at the pen vs at the individual level

    DEFF Research Database (Denmark)

    Jensen, Dan Børge; Toft, Nils; Kristensen, Anders Ringgaard

    recorded weight data from finisher pigs. Data are collected at insertion and at the exit of the first pigs in the pen, and in few pens, the weight is recorded weekly. Dynamic linear models are fitted on the weight data, at the pig level (univariate), at the double pen level using averaged weight...... (univariate) and using individual pig values as parameters in a hierarchical (multivariate) model including section, double pen, and individual level. Variance components of the different models are estimated using the Expectation Maximization algorithm. The difference of information obtained...... at the individual vs. pen level is thereafter assessed. Whereas weight data is usually monitored after a batch is being sent to the slaughter house, this method provides with weekly updating of the data. Perspectives of application include dynamic monitoring of weight data in relation to events such as diarrhoea...

  3. Monitoring and assessment of individual doses of occupationally exposed workers due to intake of radionuclides

    International Nuclear Information System (INIS)

    Alexander, O. A.

    2014-04-01

    Monitoring and estimation of individual intakes of radionuclides can be complex. Doses of intakes cannot be measured directly, however must be assessed from the monitoring data of the individual. The individual monitoring data includes whole body counting, excretion analysis (urine or faecal). In the estimation of these data requires that the assessor makes assumptions about the exposure scenario, including the pattern and mode of radionuclide intake. Also physicochemical characteristics of the material involved and the period of time between exposure and measurement. This project report seeks to provide some underlying guidance on monitoring programmes and data interpretation using case study. In this present study the committed effective dose (CED) 1.20mSv exceeded the recording level (i.e. 1mSv) however it was below the investigation level (i.e. 2mSv). The present study recommends that as an essential part in internal dosimetry, specialists be capable of recognizing conditions warranting follow-up bioassay and dose evaluation. Personnel should be familiar with the relevant internal dosimetry literature and the recommendations of national and international scientific organizations with regard to internal dose. (au)

  4. Neutron generator control system

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  5. Using Cosmic-Ray Neutron Probes to Monitor Landscape Scale Soil Water Content in Mixed Land Use Agricultural Systems

    Directory of Open Access Journals (Sweden)

    Trenton E. Franz

    2016-01-01

    Full Text Available With an ever-increasing demand for natural resources and the societal need to understand and predict natural disasters, soil water content (SWC observations remain a critical variable to monitor in order to optimally allocate resources, establish early warning systems, and improve weather forecasts. However, routine agricultural production practices of soil cultivation, planting, and harvest make the operation and maintenance of direct contact point sensors for long-term monitoring challenging. In this work, we explore the use of the newly established Cosmic-Ray Neutron Probe (CRNP and method to monitor landscape average SWC in a mixed agricultural land use system in northeast Austria. The calibrated CRNP landscape SWC values compare well against an independent in situ SWC probe network (MAE = 0.0286 m3/m3 given the challenge of continuous in situ monitoring from probes across a heterogeneous agricultural landscape. The ability of the CRNP to provide real-time and accurate landscape SWC measurements makes it an ideal method for establishing long-term monitoring sites in agricultural ecosystems to aid in agricultural water and nutrient management decisions at the small tract of land scale as well as aiding in management decisions at larger scales.

  6. Neutron-Detection Based Monitoring of Void Effects in Boiling Water Reactors

    Science.gov (United States)

    Loberg, John; Österlund, Michael; Bejmer, Klaes-Håkan; Blomgren, Jan

    2009-08-01

    The ratio between the thermal and fast neutron flux in a BWR (Boiling Water Reactor) depends on the void fraction. The density of the steam-water mixture present in the core determines the efficiency of the moderation of fast neutrons born in fission, and therefore the void fraction could be determined by means of a simultaneous measurement of the thermal and fast neutron fluxes. Such measurement could also be used to investigate channel bow of the nuclear fuel bundles surrounding the detector because of sensitivity of the thermal flux to geometry changes. Calculations have been performed with lattice codes to study the behavior of the void fraction correlation to the ratio of the thermal and fast neutron flux. The results prove the correlation to be nearly linear and robust. The rate of change of the correlation is insensitive to standard reactor operating parameters such as control rods and burnable absorbers; the sensitivity of the ratio to void fraction changes primarily depends on the geometry of the fuel bundles.

  7. Trace elements monitored with neutron activation analysis durig neurodegeneration in brains of mutant mice

    Czech Academy of Sciences Publication Activity Database

    Kranda, Karel; Kučera, Jan; Bäurle, J.

    2006-01-01

    Roč. 269, č. 3 (2006), s. 555-559 ISSN 0236-5731 Institutional research plan: CEZ:AV0Z10480505 Keywords : trace elements * neutron activation analysis * brain neurodegeneration * mutant mice Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 0.509, year: 2006

  8. Method and device for monitoring vibration of incore neutron detector guide tube

    International Nuclear Information System (INIS)

    Enomoto, Mitsuhiro; Naito, Norio; Oda, Akira.

    1978-01-01

    Purpose: To easily detect the vibration of an incore neutron detector guide tube and to prevent the occurrence of such accidents that the guide tube comes into contact with the fuel channel box arranged around the periphery thereof to break the channel box. Method: A neutron detector guide tube is disposed within a channel box, and the neutron detector is arranged at the center of the guide tube. Now, when the guide tube vibrates at an inherent number of vibration and a predetermined amplitude, the guide tube moves in the radial direction by the predetermined amplitude part to come into contact with the channel box. Upon this occasion, the detector similarity vibrates, and the output signal is varied by the predetermined neutron flux variation part. This output signal is sent to a comparator through an analyser, and compared with the output signal produced from a device wherein the result analysed at normal time, and the output signal is sent to an alarm device and an indicator, respectively. (Aizawa, K.)

  9. Comparisons between direct ion storage and thermoluminescence dosimetry individual monitoring systems, and internet reporting

    International Nuclear Information System (INIS)

    Kiuru, A.; Kahilainen, J.; Hyvoenen, H.; Vartiainen, E.

    2001-01-01

    A new electronic direct ion storage (DIS) dosemeter allows accumulated personal dose equivalent H p (d) at depths of 10 mm and 0.07 mm to be monitored in a few seconds by inserting the dosemeter into a local reader without deleting the accumulated dose. The DIS system meets general requirements on individual monitoring of hospital personnel using ionising radiation. It differs greatly from off-line thermoluminescence dosimetry systems and offers many additional benefits. The non-volatile reading takes only 5 s, is taken as often as needed, and the data are collected into a dose database, where background radiation is subtracted. Individual personnel doses are reported in Intranet as well as on the Internet at regular intervals to the National Regulatory Authorities. (author)

  10. Within-Individual Hematocrit Variations and Self-Monitoring of Blood Glucose

    OpenAIRE

    Topping, Kaila A.; Cembrowski, George S.

    2013-01-01

    Many self-monitoring of blood glucose (SMBG) systems have generated artefactually increased glucose results in low-hematocrit patients (e.g., intensive care unit and renal failure patients); conversely, these devices could produce artefactually decreased glucose results in high-hematocrit patients (e.g., neonates). The introduction of hematocrit-independent SMBG systems permits more accurate testing in anemic or polycythemic individuals. In this issue of Journal of Diabetes Science and Techno...

  11. Photoneutrons from a beryllium reflector: a potential source of problems with Zr-Au flux monitors ink0standardization based neutron activation analysis.

    Science.gov (United States)

    Koster-Ammerlaan, M J J; Bode, P; Winkelman, A J M

    The assumption that the shape of the epithermal neutron spectrum can be described, in any research reactor, by the 1/ E 1+α function is a fundamental starting point of the k 0 standardization. This assumption may be questioned from a reactor physics viewpoint. The type of moderator, the existence of neutron reflectors, the additional production of (γ, n ) neutrons and resonance capture by construction materials may be different for each reactor, with consequences for the shape of the neutron spectrum. This dependency may explain that various practitioners reported contradicting experiences with the use of Zr-Au flux monitors for the determination of the α-parameter. An objective view on the influence of the design of the reactor and irradiation facility on the shape of the neutron spectrum can be obtained by modeling. This has been applied in the Reactor Institute Delft for reactor configurations in which the irradiation facilities face the fuel elements with the presence of beryllium reflector elements. The Monte Carlo calculations indicate a distortion of the 1/ E 1+α relationship at the higher energy edge of the epithermal neutron spectrum. This distortion is attributed to the formation and thermalisation of both photoneutrons and ( n , 2 n ) produced fast neutrons in the beryllium, and has a direct impact on the resonance activation of 95 Zr, other than represented by the 1/ E 1+α function. The obtained relationship between neutron flux and neutron energy was also used for estimating the f -value and compared with the value obtained by the Delft Cr-Mo-Au flux monitor.

  12. Monitoring Chandra Observations of the Quasi-persistent Neutron Star X-Ray Transient MXB 1659-29 in Quiescence: The Cooling Curve of the Heated Neutron Star Crust

    NARCIS (Netherlands)

    Wijnands, R.A.D.; Homan, J.; Miller, J.M.; Lewin, W.H.G.

    2004-01-01

    We have observed the quasi-persistent neutron star X-ray transient and eclipsing binary MXB 1659-29 in quiescence on three occasions with Chandra. The purpose of our observations was to monitor the quiescent behavior of the source after its last prolonged (~2.5 yr) outburst that ended in 2001

  13. Neutron detector

    Science.gov (United States)

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

    2011-04-05

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

  14. Neutron monitoring systems including gamma thermometers and methods of calibrating nuclear instruments using gamma thermometers

    Science.gov (United States)

    Moen, Stephan Craig; Meyers, Craig Glenn; Petzen, John Alexander; Foard, Adam Muhling

    2012-08-07

    A method of calibrating a nuclear instrument using a gamma thermometer may include: measuring, in the instrument, local neutron flux; generating, from the instrument, a first signal proportional to the neutron flux; measuring, in the gamma thermometer, local gamma flux; generating, from the gamma thermometer, a second signal proportional to the gamma flux; compensating the second signal; and calibrating a gain of the instrument based on the compensated second signal. Compensating the second signal may include: calculating selected yield fractions for specific groups of delayed gamma sources; calculating time constants for the specific groups; calculating a third signal that corresponds to delayed local gamma flux based on the selected yield fractions and time constants; and calculating the compensated second signal by subtracting the third signal from the second signal. The specific groups may have decay time constants greater than 5.times.10.sup.-1 seconds and less than 5.times.10.sup.5 seconds.

  15. Can individualized weight monitoring using the HeartPhone algorithm improve sensitivity for clinical deterioration of heart failure?

    LENUS (Irish Health Repository)

    Ledwidge, Mark T

    2013-04-01

    Previous studies have demonstrated poor sensitivity of guideline weight monitoring in predicting clinical deterioration of heart failure (HF). This study aimed to evaluate patterns of remotely transmitted daily weights in a high-risk HF population and also to compare guideline weight monitoring and an individualized weight monitoring algorithm.

  16. Probabilistic n/γ discrimination with robustness against outliers for use in neutron profile monitors

    Science.gov (United States)

    Uchida, Y.; Takada, E.; Fujisaki, A.; Kikuchi, T.; Ogawa, K.; Isobe, M.

    2017-08-01

    A method to stochastically discriminate neutron and γ-ray signals measured with a stilbene organic scintillator is proposed. Each pulse signal was stochastically categorized into two groups: neutron and γ-ray. In previous work, the Expectation Maximization (EM) algorithm was used with the assumption that the measured data followed a Gaussian mixture distribution. It was shown that probabilistic discrimination between these groups is possible. Moreover, by setting the initial parameters for the Gaussian mixture distribution with a k-means algorithm, the possibility of automatic discrimination was demonstrated. In this study, the Student's t-mixture distribution was used as a probabilistic distribution with the EM algorithm to improve the robustness against the effect of outliers caused by pileup of the signals. To validate the proposed method, the figures of merit (FOMs) were compared for the EM algorithm assuming a t-mixture distribution and a Gaussian mixture distribution. The t-mixture distribution resulted in an improvement of the FOMs compared with the Gaussian mixture distribution. The proposed data processing technique is a promising tool not only for neutron and γ-ray discrimination in fusion experiments but also in other fields, for example, homeland security, cancer therapy with high energy particles, nuclear reactor decommissioning, pattern recognition, and so on.

  17. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1993-12-31

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

  18. Radiation portal monitor with {sup 10}B+ZnS(Ag) neutron detector performance for the detection of special nuclear materials

    Energy Technology Data Exchange (ETDEWEB)

    Guzman G, K. A.; Gallego, E.; Lorente, A.; Ibanez F, S. [Universidad Politecnica de Madrid, Departamento de Ingenieria Energetica, ETSI Industriales, C. Jose Gutierrez Abascal 2, 28006 Madrid (Spain); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Gonzalez, J. A. [Universidad Politecnica de Madrid, Laboratorio de Ingenieria Nuclear, ETSI Caminos, Canales y Puertos, C. Prof. Aranguren 3, 28040 Madrid (Spain); Mendez, R., E-mail: ingkarenguzman@gmail.com [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Laboratorio de Patrones Neutronicos, Av. Complutense 40, 28040 Madrid (Spain)

    2016-10-15

    In homeland security, neutron detection is used to prevent the smuggling of special nuclear materials. Thermal neutrons are normally detected with {sup 3}He proportional counters, in the radiation portal monitors, Rpms, however due to the {sup 3}He shortage new procedures are being studied. In this work Monte Carlo methods, using the MCNP6 code, have been used to study the neutron detection features of a {sup 10}B+ZnS(Ag) under real conditions inside of a Rpm. The performance for neutron detection was carried out for {sup 252}Cf, {sup 238}U and {sup 239}Pu under different conditions. In order to mimic an actual situation occurring at border areas, a sample of SNM sited inside a vehicle was simulated and the Rpm with {sup 10}B+ZnS(Ag) response was calculated. At 200 cm the {sup 10}B+ZnS(Ag) on Rpm response is close to 2.5 cps-ng {sup 252}Cf, when the {sup 252}Cf neutron source is shielded with 0.5 cm-thick lead and 2.5 cm-thick polyethylene fulfilling the ANSI recommendations. Three different geometries of neutron detectors of {sup 10}B+ZnS(Ag) in a neutron detection system in Rpm were modeled. Therefore, the {sup 10}B+ZnS(Ag) detectors are an innovative and viable replacement for the {sup 3}He detectors in the Rpm. (Author)

  19. Criteria for calculation of effective dose from the individual monitoring; Criterios para calculo de dose efetiva a partir da monitoracao individual

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-11-15

    This Regulation refers to the requirements of the Regulation CNEN-NN.3.01. 'Basic Act of Radiological Protection', as expressed in the section 5.9, and its application to the effective dose calculation for individual occupationally exposed. from the internal and external individual monitoring data

  20. Individual differences in error monitoring in healthy adults: psychological symptoms and antisocial personality characteristics.

    Science.gov (United States)

    Chang, Wen-Pin; Davies, Patricia L; Gavin, William J

    2010-10-01

    Recent studies have investigated the relationship between psychological symptoms and personality traits and error monitoring measured by error-related negativity (ERN) and error positivity (Pe) event-related potential (ERP) components, yet there remains a paucity of studies examining the collective simultaneous effects of psychological symptoms and personality traits on error monitoring. This present study, therefore, examined whether measures of hyperactivity-impulsivity, depression, anxiety and antisocial personality characteristics could collectively account for significant interindividual variability of both ERN and Pe amplitudes, in 29 healthy adults with no known disorders, ages 18-30 years. The bivariate zero-order correlation analyses found that only the anxiety measure was significantly related to both ERN and Pe amplitudes. However, multiple regression analyses that included all four characteristic measures while controlling for number of segments in the ERP average revealed that both depression and antisocial personality characteristics were significant predictors for the ERN amplitudes whereas antisocial personality was the only significant predictor for the Pe amplitude. These findings suggest that psychological symptoms and personality traits are associated with individual variations in error monitoring in healthy adults, and future studies should consider these variables when comparing group difference in error monitoring between adults with and without disabilities. © 2010 The Authors. European Journal of Neuroscience © 2010 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

  1. Ambulatory Blood Pressure Monitoring in Individuals with HIV: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Kent, Shia T; Bromfield, Samantha G; Burkholder, Greer A; Falzon, Louise; Oparil, Suzanne; Overton, Edgar T; Mugavero, Michael J; Schwartz, Joseph E; Shimbo, Daichi; Muntner, Paul

    2016-01-01

    Abnormal diurnal blood pressure (BP) rhythms may contribute to the high cardiovascular disease risk in HIV-positive (HIV+) individuals. To synthesize the current literature on ambulatory BP monitoring (ABPM) in HIV+ individuals, a systematic literature review and meta-analysis were performed. Medical databases were searched through November 11, 2015 for studies that reported ABPM results in HIV+ individuals. Data were extracted by 2 reviewers and pooled differences between HIV+ and HIV-negative (HIV-) individuals in clinic BP and ABPM measures were calculated using random-effects inverse variance weighted models. Of 597 abstracts reviewed, 8 studies with HIV+ cohorts met the inclusion criteria. The 420 HIV+ and 714 HIV- individuals in 7 studies with HIV- comparison groups were pooled for analyses. The pooled absolute nocturnal systolic and diastolic BP declines were 3.16% (95% confidence interval [CI]: 1.13%, 5.20%) and 2.92% (95% CI: 1.64%, 4.19%) less, respectively, in HIV+ versus HIV- individuals. The pooled odds ratio for non-dipping systolic BP (nocturnal systolic BP decline HIV+ versus HIV- individuals was 2.72 (95% CI: 1.92, 3.85). Differences in mean clinic, 24-hour, daytime, or nighttime BP were not statistically significant. I2 and heterogeneity chi-squared statistics indicated the presence of high heterogeneity for all outcomes except percent DBP dipping and non-dipping SBP pattern. An abnormal diurnal BP pattern may be more common among HIV+ versus HIV- individuals. However, results were heterogeneous for most BP measures, suggesting more research in this area is needed.

  2. Results from the audit process in the Brazilian accreditation program for external individual monitoring services

    International Nuclear Information System (INIS)

    Barbosa, R.A.; Mauricio, C.L.P.; Cunha, P.G. da; Mota, H.C.

    1998-01-01

    In 1997 the Committee for Evaluation of the External Individual Monitoring Services from the Instituto de Radioprotecao e Dosimetria, in Brazil, starded the audit process within the Accreditation Program for 13 Brazilian Services, which are responsible for occupational dose monitoring of more than 45,000 workers. As the audit objective had been check also the Services procedures, a group of dosimeters were irraiated with gamma ray of 6 0 C o. During the audit proccess, the results from the dosimeters, which were previously irradiated at the national Laboratory for Ioninising Radiation Metrology in Rio de Janeiro, Brazil, have been evaluated in he trumpet curves following the rule for which 90% of the points, at least, should be between the curves. This work shows the results from the SMIEs under audit and analyses the necessity of radiation quelities others than 6 0 C o

  3. Implementation of an accreditation program for individual monitoring services in Brazil

    International Nuclear Information System (INIS)

    Salati, I.P.A.; Barbosa, R.A.; Cunha, P.G.; Martins, M.M.; Mauricio, C.L.P.; Mota, H.C.; Ramos, M.M.O.

    1998-01-01

    Although Brazilian regulations for External Individual monitoring services (SMIE) have been established since 1981, they were not sufficient to make these services meet the requirements of quality assurance programs appointed by national and international recommendations of the services operating in Brazil. This services are responsible for the monitoring of more than 45.000 workers throughout this country. In 1992, a working group (named CASMIE) was created at IRD/CNEN aiming to the development of technical standards and to propose new procedures of SIMIEs accreditation by CNEN. The new procedures were implemented in the period of 1995 to 1997 and now they are in routine. A clear improvement is SMIEs working conditions can now be noticed. This program could be suitable for other countries which do not have an established accreditation procedure yet. In this work, the relevant aspects of this process and a summary of the technical documents developed by CASMIE are presented

  4. Monitoring of peri-operative fluid administration by individualized goal-directed therapy

    DEFF Research Database (Denmark)

    Bundgaard-Nielsen, M; Holte, Kathrine; Secher, N H

    2007-01-01

    (n = 725) found a reduced hospital stay. Post-operative nausea and vomiting (PONV) and ileus were reduced in three studies and complications were reduced in four studies. Of the monitors that may be applied for goal-directed therapy, only oesophageal Doppler has been tested adequately; however...... referenced from these papers. Furthermore, methods applied in these studies and other monitors with a potential for goal-directed therapy are described. RESULTS: Nine studies were identified pertaining to fluid optimization during the intra- and post-operative period with goal-directed therapy. Seven studies......BACKGROUND: In order to avoid peri-operative hypovolaemia or fluid overload, goal-directed therapy with individual maximization of flow-related haemodynamic parameters has been introduced. The objectives of this review are to update research in the area, evaluate the effects on outcome and assess...

  5. Comparing infants' use of featural and spatiotemporal information when individuating objects in an event monitoring design

    DEFF Research Database (Denmark)

    Krøjgaard, Peter

    , to what extent infants rely on spatiotemporal or featural object information when individuating objects is currently under debate. Hitherto, infants' use of spatiotemporal and featural object information has only been compared directly using the rather cognitively demanding event mapping design....... The results obtained using this design reveal that infants are more successful using spatiotemporal object information than when using featural information. However, recent studies using the less cognitively demanding event monitoring design have revealed that even younger infants are capable of object...... in the present series of experiments in which infants' use of spatiotemporal and featural information is compared directly using the less demanding event monitoring design. The results are discussed in relation to existing empirical evidence....

  6. Proceedings of a seminar on the potential for LMFBR boiling detection by acoustic/neutronic monitoring, Argonne, Illinois, April 8--9, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Carey, W.M.; Albrecht, R.W.

    1976-06-01

    A seminar involving ten technical presentations by principal investigators was held to assess the current scope of ERDA-sponsored programs to determine the feasibility of sodium-boiling detection in LMFBRs and to establish areas in need of additional research and development. The consensus was that (1) feasibility of boiling detection by acoustic, neutronic, and acoustic/neutronic monitors has been demonstrated in U.S. and European programs; (2) additional research and development is needed in areas of reactor noise, cavitation, and the effects of noncondensible gases on sound source levels and transmission; (3) the role of acoustic/neutronic monitors from the standpoint of reactor surveillance rather than reactor safety is a viable approach to be adapted; and, in particular (4) a need exists for an operational LMFBR demonstration system. Each paper has been separately abstracted and indexed. (DG)

  7. Complementary system for monitoring and control of neutron flux during a fuel outage and during reactor start up stage

    International Nuclear Information System (INIS)

    Lichkov, R.

    2000-01-01

    The present work is an example for that, how with modern technical instruments is possible to compensate disadvantage and to increase technical resources of the old systems, without a change of given system totally with new one. The system detail design and implementation was possible mostly, due to the international conferences and courses organised by IAEA and technical information provided by the agency. The designed system plays a role of complementary system to the in-situ operational systems for monitoring and control of the reactor core neutron flux, allowing its measurement and control during a fuel outage and during reactor start up stage. Additionally, the system recalculates the reactivity in beta units and according to its value the reactor criticality fixed up reactivity is defined. (author)

  8. Effectiveness of individual counselling and activity monitors to promote physical activity among university students.

    Science.gov (United States)

    Maselli, Marco; Gobbi, Erica; Carraro, Attilio

    2017-12-01

    Physical activity (PA) promotion among university students is important to contribute to a lifelong healthy lifestyle. Nevertheless, research in the field is still limited in quantity, quality and generalizability. This study aimed at evaluating the effectiveness of two individual-based strategies for promoting PA among university students in such university contexts where course-based interventions are difficult to implement. Thirty-three university students were recruited by means of face-to-face interviews and randomly assigned to three groups. The first group attended individual counselling sessions (based on the Social-Cognitive theory and the Transtheoretical model of behaviour change) via videoconferencing calls, the second used wearable PA monitors designed to motivate to PA, and the third served as control. Interventions lasted 12 weeks. Measures of weekly PA (self-reported by questionnaires and recorded by ActiGraph-GT3X+ monitors) and the stage of change of participants were collected at baseline (t0), immediately after the 12-week intervention (t1), and after a 3-month follow-up (t2). Students in the individual counselling group increased self-reported energy expenditure between t0 and t1 and maintained this improvement at t2; on the contrary, there was no increase in ActiGraph measures of PA. Progression through stages of changes was observed in the same group at t1, followed by some relapses at t2. No significant differences were found neither in the group of students who used the PA monitors nor in the control group. Although measures of self-reported PA and stage of change suggest the effectiveness of the counselling intervention, the results obtained with accelerometers are contrasting, probably due to the fact that some types of PA participants engaged in could not be recorder by accelerometers. Further studies are needed to determine the efficacy of individual counselling to promote PA in university students. The autonomous use of PA monitors had

  9. Development of in vitro techniques for individual monitoring of 32P

    International Nuclear Information System (INIS)

    Almeida, A.P.F.; Sousa, W.O.; Dantas, A.L.A.; Dantas, B.M.

    2016-01-01

    The 32 P is used in the form of liquid unsealed sources in medical facilities, research and teaching, representing a risk of internal exposure in routine activities and in case of accidental incorporation. The evaluation of 32 P incorporation can be accomplished through in vitro bioanalysis of urine. This paper aims to provide a methodology to analyze 32 P in biological samples, applicable to internal individual monitoring using liquid scintillation technique. The minimum detectable activity of the system was determined and the sensitivity of the technique was evaluated, based on the detected minimum effective dose. (author)

  10. Individual Radiation Protection Monitoring in the Marshall Islands. Utrok Atoll (2010-2012)

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, T. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kehl, S. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Martinelli, R. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hickman, R. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hickman, D. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tumey, S. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brown, T. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Langston, R. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tamblin, M. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tibon, S. [Utrok Whole Body Counting Facility, Majuro Atoll (Republic of the Marshall Islands); Chee, L. [Utrok Whole Body Counting Facility, Majuro Atoll (Republic of the Marshall Islands); Aisek, Jr., A. [Utrok Whole Body Counting Facility, Majuro Atoll (Republic of the Marshall Islands); DeDrum, Z. [Utrok Whole Body Counting Facility, Majuro Atoll (Republic of the Marshall Islands); Mettao, M. [Utrok Whole Body Counting Facility, Majuro Atoll (Republic of the Marshall Islands); Henson, J. [Utrok Whole Body Counting Facility, Majuro Atoll (Republic of the Marshall Islands)

    2014-12-15

    As a hard copy supplement to the Marshall Islands Program website (https://marshallislands.llnl.gov), this document provides an overview of the individual radiological surveillance monitoring program established in support of residents of Utrōk Atoll and nonresident citizens of the Utrōk Atoll population group, along with full disclosure of verified measurement data (2010-2012). The Utrōk Atoll Whole Body Counting Facility has been temporarily stationed on Majuro Atoll and, in cooperation with the Utrōk Atoll Local Government, serves as a national radiological facility open to the general public.

  11. [Study on monitoring index of individual exposure dose of volatile organic compounds in environment].

    Science.gov (United States)

    Feng, Baohai; Cui, Jiusi; Hao, Shoujin

    2003-11-01

    In order to study the monitoring index of individual exposure dose of volatile organic compounds (VOCs) in environment, the thermal desorption capillary gas chromatographic (TD-GC) analysis was used to examine the VOCs level in air and the expired breath of female workers. Headspace solid phase micro-extraction gas chromatography (SPME-GC) was applied to determine the blood concentration of VOCs in female workers. The results from epidemiological study showed clearly that concentration of 10 subtypes of VOCs in blood, environmental air and expired breath from exposure group were higher than those from control group. The findings from the study suggested that the blood concentration of VOCs was sensitive and specific and this index might be one of good indexes in assessment of individual exposure dose of VOCs.

  12. Within-Individual Hematocrit Variations and Self-Monitoring of Blood Glucose

    Science.gov (United States)

    Topping, Kaila A.; Cembrowski, George S.

    2013-01-01

    Many self-monitoring of blood glucose (SMBG) systems have generated artefactually increased glucose results in low-hematocrit patients (e.g., intensive care unit and renal failure patients); conversely, these devices could produce artefactually decreased glucose results in high-hematocrit patients (e.g., neonates). The introduction of hematocrit-independent SMBG systems permits more accurate testing in anemic or polycythemic individuals. In this issue of Journal of Diabetes Science and Technology, Ramljak and coauthors have created glucose bias graphs for 19 common SMBG devices and declared certain systems to be optimally accurate because of insensitivity to hematocrit variation over a broad hematocrit range. Luckily, the average within-individual variation of hematocrit is low (between 2.9 and 3.3%). As such, a larger spectrum of SMBG devices can be regarded as optimally hematocrit independent. PMID:23439177

  13. Research and Development Program in Reactor Diagnostics and Monitoring with Neutron Noise Methods. Stage 10. Final Report

    International Nuclear Information System (INIS)

    Demaziere, C.; Pazsit, I.; Sunde, S.; Wright, J.

    2004-12-01

    This report constitutes Stage 10 of a long-term research and development program concerning the development of diagnostics and monitoring methods for nuclear reactors. The program executed in Stage 10 consists of three parts and the work performed in each part is summarized below. A so-called 2-D 2-group neutron noise simulator was previously developed at the Department of Reactor Physics. This simulator is able to calculate the space-dependence of the neutron noise induced by localised or spatially-distributed absorbers of variable strength or by vibrating absorbers. These calculations are performed in the 2-group diffusion approximation and can treat an arbitrary heterogeneous 2-D system. The goal of the present investigation is to use the simulator for unfolding purposes, i.e. to reconstruct the noise source from the detector readings. This task is particularly challenging since the number of detectors available in a commercial PWR can be very low. In this study, five detectors are assumed to be present and evenly distributed in the core. Furthermore, only localised absorbers of variable strength are considered as perturbations. Numerical simulations were first carried out to verify that the space-dependent local and global components of the neutron noise were overwhelmingly large compared to the point-kinetic term of the neutron noise whose spatial structure does not depend on the position of the perturbation. The significance of the space-dependent global component is that its relaxation length is large enough, so that several neutron detectors can monitor it. Therefore, the neutron noise induced at the position of the detectors is itself a function of the position of the perturbation. Unfolding procedures could thus be considered. Prior to performing any unfolding, the type of the noise source has to be determined, since the algorithms developed in this report are based on the assumption of an absorber of variable strength. Such a noise source can also be

  14. Individual internal monitoring of workers of Fabrica de Combustivel Nuclear - FCN

    International Nuclear Information System (INIS)

    Castro, Marcelo X.

    2005-01-01

    In nuclear fuel fabrication facilities, workers are exposed to different compounds of enriched uranium. Due to the high cost of the individual monitoring programme for internal dose assessment in the routine monitoring programmes, usually only one type of measurement is assigned. In complex situations like the one described in this paper, where several parameters can compromise the accuracy of the bioassay interpretation it is need to have a combination of techniques to evaluate the internal dose. According to ICRP 78 (1997), the general order of preference in terms of accuracy of interpretation is: body activity measurement, excreta analysis and personal air sampling. A group of fifteen workers from controlled area of the fuel fabrication facility was selected to evaluate the internal dose using all different available techniques during a certain period. The workers were monitored for determination of uranium content in the daily urinary excretion, faecal excretion, chest counting and personal air sampling (PAS). The results have shown that at least two types of sensitivity techniques must be used, since there are some sources of uncertainties on the bioassay interpretation, like mixture of uranium compounds intake and different routes of intake. The combination of urine and faeces analysis has shown be the more appropriate methodology for assessing internal dose in this situation. (author)

  15. Systemic Case Formulation, Individualized Process Monitoring, and State Dynamics in a Case of Dissociative Identity Disorder.

    Directory of Open Access Journals (Sweden)

    Guenter Karl Schiepek

    2016-10-01

    Full Text Available Objective. The aim of this case report is to demonstrate the feasibility of a systemic procedure (synergetic process management including modeling of the idiographic psychological system and continuous high-frequency monitoring of change dynamics in a case of dissociative identity disorder. The psychotherapy was realized in a day treatment center with a female client diagnosed with borderline personality disorder (BPD and dissociative identity disorder. Methods. A three hour long co-creative session at the beginning of the treatment period allowed for modeling the systemic network of the client’s dynamics of cognitions, emotions, and behavior. The components (variables of this idiographic system model (ISM were used to create items for an individualized process questionnaire for the client. The questionnaire was administered daily through an internet-based monitoring tool (Synergetic Navigation System, SNS, to capture the client’s individual change process continuously throughout the therapy and after-care period. The resulting time series were reflected by therapist and client in therapeutic feedback sessions. Results. For the client it was important to see how the personality states dominating her daily life were represented by her idiographic system model and how the transitions between each state could be explained and understood by the activating and inhibiting relations between the cognitive-emotional components of that system. Continuous monitoring of her cognitions, emotions, and behavior via SNS allowed for identification of important triggers, dynamic patterns, and psychological mechanisms behind seemingly erratic state fluctuations. These insights enabled a change in management of the dynamics and an intensified trauma-focused therapy. Conclusion. By making use of the systemic case formulation technique and subsequent daily online monitoring, client and therapist continuously refer to detailed visualizations of the mental and

  16. Systemic Case Formulation, Individualized Process Monitoring, and State Dynamics in a Case of Dissociative Identity Disorder.

    Science.gov (United States)

    Schiepek, Günter K; Stöger-Schmidinger, Barbara; Aichhorn, Wolfgang; Schöller, Helmut; Aas, Benjamin

    2016-01-01

    Objective: The aim of this case report is to demonstrate the feasibility of a systemic procedure (synergetic process management) including modeling of the idiographic psychological system and continuous high-frequency monitoring of change dynamics in a case of dissociative identity disorder. The psychotherapy was realized in a day treatment center with a female client diagnosed with borderline personality disorder (BPD) and dissociative identity disorder. Methods: A three hour long co-creative session at the beginning of the treatment period allowed for modeling the systemic network of the client's dynamics of cognitions, emotions, and behavior. The components (variables) of this idiographic system model (ISM) were used to create items for an individualized process questionnaire for the client. The questionnaire was administered daily through an internet-based monitoring tool (Synergetic Navigation System, SNS), to capture the client's individual change process continuously throughout the therapy and after-care period. The resulting time series were reflected by therapist and client in therapeutic feedback sessions. Results: For the client it was important to see how the personality states dominating her daily life were represented by her idiographic system model and how the transitions between each state could be explained and understood by the activating and inhibiting relations between the cognitive-emotional components of that system. Continuous monitoring of her cognitions, emotions, and behavior via SNS allowed for identification of important triggers, dynamic patterns, and psychological mechanisms behind seemingly erratic state fluctuations. These insights enabled a change in management of the dynamics and an intensified trauma-focused therapy. Conclusion: By making use of the systemic case formulation technique and subsequent daily online monitoring, client and therapist continuously refer to detailed visualizations of the mental and behavioral network and

  17. Interpretation of the results from individual monitoring of workers at the Nuclear Fuel Fabrication Facility, Brazil

    International Nuclear Information System (INIS)

    Castro, Marcelo Xavier de

    2005-01-01

    In nuclear fuel fabrication facilities, workers are exposed to different compounds of enriched uranium. Although in this kind of facility the main route of intake is inhalation, ingestion may occur in some situations, and also a mixture of both. The interpretation of the bioassay data is very complex, since it is necessary taking into account all the different parameters, which is a big challenge. Due to the high cost of the individual monitoring programme for internal dose assessment in the routine monitoring programmes, usually only one type of measurement is assigned. In complex situations like the one described in this study, where several parameters can compromise the accuracy of the bioassay interpretation it is need to have a combination of techniques to evaluate the internal dose. According to ICRP 78 (1997), the general order of preference of measurement methodologies in terms of accuracy of interpretation is: body activity measurement, excreta analysis and personal air sampling. Results of monitoring of working environment may provide information that assists in the interpretation on particle size, chemical form, solubility and date of intake. A group of fifteen workers from controlled area of the studied nuclear fuel fabrication facility was selected to evaluate the internal dose using all different available techniques during a certain period. The workers were monitored for determination of uranium content in the daily urinary and faecal excretion (collected over a period of 3 consecutive days), chest counting and personal air sampling. The results have shown that at least two types of sensitivity techniques must be used, since there are some sources of uncertainties on the bioassay interpretation, like mixture of uranium compounds intake and different routes of intake. The combination of urine and faeces analysis has shown to be the more appropriate methodology for assessing internal dose in this situation. The chest counting methodology has not shown

  18. Monte Carlo Simulations Comparing the Response of a Novel Hemispherical Tepc to Existing Spherical and Cylindrical Tepcs for Neutron Monitoring and Dosimetry.

    Science.gov (United States)

    Broughton, David P; Waker, Anthony J

    2017-05-01

    Neutron dosimetry in reactor fields is currently mainly conducted with unwieldy flux monitors. Tissue Equivalent Proportional Counters (TEPCs) have been shown to have the potential to improve the accuracy of neutron dosimetry in these fields, and Multi-Element Tissue Equivalent Proportional Counters (METEPCs) could reduce the size of instrumentation required to do so. Complexity of current METEPC designs has inhibited their use beyond research. This work proposes a novel hemispherical counter with a wireless anode ball in place of the traditional anode wire as a possible solution for simplifying manufacturing. The hemispherical METEPC element was analyzed as a single TEPC to first demonstrate the potential of this new design by evaluating its performance relative to the reference spherical TEPC design and a single element from a cylindrical METEPC. Energy deposition simulations were conducted using the Monte Carlo code PHITS for both monoenergetic 2.5 MeV neutrons and the neutron energy spectrum of Cf-D2O moderated. In these neutron fields, the hemispherical counter appears to be a good alternative to the reference spherical geometry, performing slightly better than the cylindrical counter, which tends to underrespond to H*(10) for the lower neutron energies of the Cf-D2O moderated field. These computational results are promising, and if follow-up experimental work demonstrates the hemispherical counter works as anticipated, it will be ready to be incorporated into an METEPC design.

  19. Environmental monitoring near urban lead refineries by photon and neutron activation analysis

    International Nuclear Information System (INIS)

    Paciga, J.J.; Chattopadhyay, A.; Jervis, R.E.

    1974-01-01

    Photon activation has been used in conjunction with neutron activation for multielement determinations in airborne particulates, soil, and hair samples collected near two secondary lead refineries in Metropolitan Toronto. Particle size distributions of suspended particulates collected with a high volume Andersen sampler are reported for Al, Sb, As, Br, Cl, Mn, Na, Pb, Ti and V. Increases in the concentrations of Pb, As and Sb associated with particles >3.3 μm diameter on certain days near the refineries has resulted in localized contamination as reflected in higher concentrations of these elements in soil. To assess Pb accumulation in local residents compared with control groups, approximately 250 hair samples were analyzed for Pb by photon activation analysis. Children living close to the refineries, especially boys, exhibit the most elevated levels: up to 20 times urban control values in some cases

  20. Monitoring thylakoid ultrastructural changes in vivo using small-angle neutron scattering.

    Science.gov (United States)

    Unnep, Renáta; Nagy, Gergely; Markó, Márton; Garab, Győző

    2014-08-01

    The light reactions of oxygenic photosynthesis take place in the thylakoid membranes, flattened vesicles, which contain the two photosystems and also embed the cytochrome b6f complex and the ATP synthase. In general, the thylakoid membranes are assembled into multilamellar membrane systems, which warrant an optimal light capturing efficiency. In nature, they show astounding variations, primarily due to large variations in their protein composition, which is controlled by multilevel regulatory mechanisms during long-term acclimation and short-term adaptation processes and also influenced by biotic or abiotic stresses - indicating a substantial degree of flexibility in the membrane ultrastructure. The better understanding of the dynamic features of this membrane system requires the use of non-invasive techniques, such as small angle neutron scattering (SANS), which is capable of providing accurate, statistically and spatially averaged information on the repeat distances of periodically organized thylakoid membranes under physiologically relevant conditions with time resolutions of seconds and minutes. In this review, after a short section on the basic properties of neutrons, we outline the fundamental principles of SANS measurements, its strengths and weaknesses in comparison to complementary structure investigation techniques. Then we overview recent results on isolated plant thylakoid membranes, and on living cyanobacterial and algal cells as well as on whole leaves. Special attention is paid to light-induced reversible ultrastructural changes in vivo, which, in cyanobacterial and diatom cells, were uncovered with the aid of SANS measurements; we also discuss the role of membrane reorganizations in light adaptation and photoprotection mechanisms. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  1. Assessment of individual organ doses in a realistic human phantom from neutron and gamma stimulated spectroscopy of the breast and liver.

    Science.gov (United States)

    Belley, Matthew D; Segars, William Paul; Kapadia, Anuj J

    2014-06-01

    Understanding the radiation dose to a patient is essential when considering the use of an ionizing diagnostic imaging test for clinical diagnosis and screening. Using Monte Carlo simulations, the authors estimated the three-dimensional organ-dose distribution from neutron and gamma irradiation of the male liver, female liver, and female breasts for neutron- and gamma-stimulated spectroscopic imaging. Monte Carlo simulations were developed using the Geant4 GATE application and a voxelized XCAT human phantom. A male and a female whole body XCAT phantom was voxelized into 256 × 256 × 600 voxels (3.125 × 3.125 × 3.125 mm(3)). A monoenergetic rectangular beam of 5.0 MeV neutrons or 7.0 MeV photons was made incident on a 2 cm thick slice of the phantom. The beam was rotated at eight different angles around the phantom ranging from 0° to 180°. Absorbed dose was calculated for each individual organ in the body and dose volume histograms were computed to analyze the absolute and relative doses in each organ. The neutron irradiations of the liver showed the highest organ dose absorption in the liver, with appreciably lower doses in other proximal organs. The dose distribution within the irradiated slice exhibited substantial attenuation with increasing depth along the beam path, attenuating to ~15% of the maximum value at the beam exit side. The gamma irradiation of the liver imparted the highest organ dose to the stomach wall. The dose distribution from the gammas showed a region of dose buildup at the beam entrance, followed by a relatively uniform dose distribution to all of the deep tissue structures, attenuating to ~75% of the maximum value at the beam exit side. For the breast scans, both the neutron and gamma irradiation registered maximum organ doses in the breasts, with all other organs receiving less than 1% of the breast dose. Effective doses ranged from 0.22 to 0.37 mSv for the neutron scans and 41 to 66 mSv for the gamma scans. Neutron and gamma

  2. Morphometric and immunocytochemical analysis of melanoma samples for individual optimization of therapy for boron neutron capture (BNCT)

    International Nuclear Information System (INIS)

    Carpano, M; Dagrosa, A; Brandizzi, D; Nievas, S; Olivera, M S; Perona, M; Rodriguez, C; Cabrini, R; Juvenal, G; Pisarev, M

    2012-01-01

    an average maximum concentration of 21.47 ± 5.4, with individual values between 19.92 and 25.91 ppm of 10B at 2 h post injection. Tumor-to-blood and tumor-to-distal skin ratios were 7.09 and 3.66 respectively. Normal tissue temperature correlated with body core temperature with average values of 37 o C. Histological studies showed a wide area of tumor viability with small foci of necrosis. Tumors with large areas of viability showed a higher boron uptake. The immunohistochemical studies showed a high number of Ki67 positive tumor cells and the presence of vasculature in the peripheral zone with blood vessels of big diameter in tumors which showed a higher boron uptake. Conclusion: These findings seem to indicate a direct correlation between BPA uptake, viability, proliferative state and vascularisation of tumors. The determination of indirect indicators of the boron concentration in tumor will allow us to adjust the dose of neutrons for the optimization of individual therapy (author)

  3. A method for the monitoring of metal recrystallization based on the in-situ measurement of the elastic energy release using neutron diffraction

    International Nuclear Information System (INIS)

    Christien, F.; Le Gall, R.; Telling, M. T. F.; Knight, K. S.

    2015-01-01

    A method is proposed for the monitoring of metal recrystallization using neutron diffraction that is based on the measurement of stored energy. Experiments were performed using deformed metal specimens heated in-situ while mounted at the sample position of the High Resolution Powder Diffractometer, HRPD (ISIS Facility), UK. Monitoring the breadth of the resulting Bragg lines during heating not only allows the time-dependence (or temperature-dependence) of the stored energy to be determined but also the recrystallized fraction. The analysis method presented here was developed using pure nickel (Ni270) specimens with different deformation levels from 0.29 to 0.94. In situ temperature ramping as well as isothermal annealing was undertaken. The method developed in this work allows accurate and quantitative monitoring of the recrystallization process. The results from neutron diffraction are satisfactorily compared to data obtained from calorimetry and hardness measurements

  4. A method for the monitoring of metal recrystallization based on the in-situ measurement of the elastic energy release using neutron diffraction.

    Science.gov (United States)

    Christien, F; Telling, M T F; Knight, K S; Le Gall, R

    2015-05-01

    A method is proposed for the monitoring of metal recrystallization using neutron diffraction that is based on the measurement of stored energy. Experiments were performed using deformed metal specimens heated in-situ while mounted at the sample position of the High Resolution Powder Diffractometer, HRPD (ISIS Facility), UK. Monitoring the breadth of the resulting Bragg lines during heating not only allows the time-dependence (or temperature-dependence) of the stored energy to be determined but also the recrystallized fraction. The analysis method presented here was developed using pure nickel (Ni270) specimens with different deformation levels from 0.29 to 0.94. In situ temperature ramping as well as isothermal annealing was undertaken. The method developed in this work allows accurate and quantitative monitoring of the recrystallization process. The results from neutron diffraction are satisfactorily compared to data obtained from calorimetry and hardness measurements.

  5. Neutron Scattering

    International Nuclear Information System (INIS)

    Fayer, Michael J.; Gee, Glendon W.

    2005-01-01

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

  6. Individual differences in conflict-monitoring: testing means and covariance hypothesis about the Simon and the Eriksen Flanker task

    NARCIS (Netherlands)

    Keye, D.; Wilhelm, O.; Oberauer, K.; van Ravenzwaaij, D.

    2009-01-01

    Conflict and context slow-down have been proposed as indicators of a conflict-monitoring system that initiates cognitive control to resolve conflicts in information processing. We investigated individual differences in conflict-monitoring and their associations with working memory (WM) and

  7. The role of the National Metrology laboratory for the improvement for the improvement of the individual monitoring in brazil

    International Nuclear Information System (INIS)

    Barbosa, R.A.; Baptista, L.A.M.M.; Silva, T.A. da

    1998-01-01

    Since 1980, the National Laboratory for ionising Radiation Metrology- LNMRI/IRD from Brazil has given support and performed quality control tests in the services that provide individual monitoring of external radiation in the country. Although the LNMRI/IRD has promoted intercomparisons and performance tests in all Brazilian individual monitoring systems, results showed that improvements in the their quality were too small, mainly due to a lack of a national policy and legal requirements for quality control them. In 1996, the Committee for Evaluation of External Individual Monitoring Services established a national policy for accreditation of individual monitoring services. In the new policy, the role of the LNMRI/IRD is mainly to verify the compliance of any individual monitoring system to the minimum accuracy requirements for the photon dose equivalent evaluation. Additionally, the LNMRI/IRD may verify any specific type-test to verify the results stated by the service itself. A new quality control program for all accredited services is also to be maintained by the LNMRI/IRD . This work shows and discusses the results of the role of the LNMRI/IRD under the old and the new accreditation policy for the systems used for the individual monitoring of photon beams

  8. POSSIBILITIES OF TEACHERS FOR MONITORING, DETECTING AND RECORDING OF INDIVIDUAL CHARACTERISTICS OF STUDENTS IN EARLY SCHOOL AGE

    Directory of Open Access Journals (Sweden)

    Tatjana Koteva-mojsovska

    2015-06-01

    Full Text Available The monitoring and recording of the individual characteristics of children are very important for the development of quality education. Also the views of the teachers about the differences in the development, the potentials and the affinities of the children in the early school period are especially important. The quality education process in the modern school should be adapted to the individual potentials of the children. The children are individuals with their own integrity and characteristics. (Johnston and Halocha, 2010. They have individual pace and develop individual approaches in the learning process. This individual pace in the development of the children requires the teachers to regularly monitor and record the individual characteristics and differences of the children, monitoring the children’s interests, planning instruction which will adapt to the different learning approaches and the different pace of progress of the students.Setting out from this paradigm, this paper, which is based on a realized research, aims to offer findings about the treatment of the individual characteristics of the early school-age children in our country. According to this, we carried out a research in four primary schools in Skopje, which showed us that the teachers lack the appropriate conditions and possibilities to monitor and record the individual characteristics and the specific differences of the students in the early school period. 

  9. Prescription Monitoring Program Trends Among Individuals Arrested in Maine for Trafficking Prescription Drugs in 2014.

    Science.gov (United States)

    McCall, Kenneth; Nichols, Stephanie D; Holt, Christina; Ochs, Leslie; Cattabriga, Gary; Tu, Chunhao

    2016-06-01

    To evaluate controlled substance prescribing trends available in the Maine Prescription Monitoring Program (PMP) among individuals arrested for prescription drug "trafficking." The demographic characteristics of the individuals who had matching prescription records in the PMP within 90 days of the arrest were identified. A population-based, retrospective cohort study using data from the Maine Diversion Alert Program (DAP) and the Maine PMP. The study population consisted of persons arrested for trafficking prescription drugs in Maine during the 2014 calendar year from January 1 to December 31. There were 594 trafficking arrests reported by the Maine DAP in 2014. The study population consisted of the 235 persons (40%) with arrests involving controlled prescription medications. The mean age of these persons was 33 years (range 18-77 yrs), and 156 (66%) were male. Arrests involved 154 prescription opioids (65%), seven stimulants (3%), seven benzodiazepines (3%), and 77 unspecified controlled prescription drugs (33%). A minority of individuals (n=57, 24%) had a prescription record in the PMP that matched the substance involved in the arrest. Only one person with matching PMP and arrest records utilized ≥ 5 prescribers, while none used ≥ 5 pharmacies within 90 days before the arrest. Payment methods for matching prescriptions were commercial insurance (n=28, 49%), Medicaid (n=19, 33%), Medicare (n=5, 9%), and cash (n=5, 9%). The majority (76%) of persons arrested for prescription drug trafficking did not have PMP records and did not directly obtain the diverted medication from a licensed pharmacy. Traditional red flags, like cash payment and using multiple prescribers or pharmacies, were uncommon. Therefore, arrest records for diversion and PMPs are distinct and complementary tools for identifying individuals at risk for substance misuse. © 2016 Pharmacotherapy Publications, Inc.

  10. Routine individual monitoring of aircrew: Czech experience and results since 1998

    International Nuclear Information System (INIS)

    Spurny, F.; Ploc, O.

    2005-01-01

    Full text: International Commission on Radiological Protection (ICRP) recommended in its Publication 60 that the radiation exposure due to the cosmic component at high altitudes be taken into account when appropriate as part of occupational exposure to the radiation. Air crew members have become in such a way another group of workers for whom the exposure to ionizing radiation is one of important occupational hazard. The recommendation mentioned was incorporated to the Czech regulation already at 1997, the studies how to perform individual dosimetry of Czech companies aircrew has started immediately after. The contribution describes first the preliminary studies with the goal to elaborate optimal procedure for the aircrew routine individual dosimetry. It was decided to perform individual monitoring through the calculation based on the information on the flights realized during a period and the list of aircrew members participated in them. As a transport code CARI was chosen, since the beginning the version 6 has been used. The information on the flight schedules and the participation of aircrew in is received from the air company. In the Czech Republic, three companies are concerned with. The procedure was proposed to the Czech authorities and it received their accreditation. Routine individual dosimetry has started since 1998. It is regularly checked and innovated. Main results for the period 1998 - 2003 are as follows: both relative frequencies as well as average annual effective dosis vary with the company and with the year, without any evident general tendency; the average values of E are between 1.5 and 2 mSv, closely to the higher value; this average value is slightly higher for charter type air-companies. Further more detailed analysis will be presented, as well as future possible modifications of the procedure. (author)

  11. Eurados self-sustained programme of intercomparisons for individual monitoring services

    International Nuclear Information System (INIS)

    Grimbergen, T. W. M.; Figel, M.; Romero, A. M.; Stadtmann, H.; McWhan, A. F.

    2011-01-01

    Within EURADOS working group 2, a system for self-sustained intercomparisons for individual monitoring services for external radiation was developed. With the intercomparison results, the participants can show compliance within their quality management system, compare their results with those from other participants and develop plans for improvement of their system. The costs of the exercises are covered by the participants fees. In this programme, the first intercomparison exercise for whole-body dosemeters has been executed in 2008 with 62 participating dosimetry systems from participants across Europe. In general, film systems show the largest deviations, although the results of some participants indicate that it is possible to achieve results with a film system with similar quality as for thermoluminescence dosimetry (TLD) systems. A second intercomparison has been organised for extremity dosemeters in 2009. For 2010 it is planned to organise a second intercomparison for whole-body dosemeters. (authors)

  12. An RF powering system with adaptive impedance matching for individual health monitoring applications.

    Science.gov (United States)

    Zemin Liu; Yu-Pin Hsu; Hella, Mona M

    2016-08-01

    This paper presents a high-efficiency RF powering system, suitable for individual health monitoring applications. The system is composed of an antenna, an impedance matching network, and a two-stage full-wave RF-DC rectifier. A novel tuning mechanism is proposed to automatically adjust the impedance of the matching network. This mechanism can effectively improve the power efficiency of the system by 47% compared to the case without tuning. For the adaptive impedance, only a 5-bits binary weighted capacitor bank is required in the matching network. The complete system, designed in a standard 0.13μm CMOS technology, converts a -6dBm 915MHz RF signal to a 1.7V DC voltage with an output current of 85μA. The simulated maximum power efficiency of the complete RF harvester is 66%.

  13. FMC-based Neutron and Gamma Radiation Monitoring Module for xTCA Applications

    CERN Document Server

    Kozak, T; Napieralski, A

    2012-01-01

    The machines used in High Energy Physics (HEP) experiments, such as accelerators or tokamaks, are sources of gamma and neutron radiation fields. The radiation has a negative influence on electronics and can lead to the incorrect functioning of complex control and diagnostic system designed for HEP machines. Therefore, in most cases the electronic equipments is installed in radiation-safe areas, but in some cases this rule is omitted to decrease costs of the project. The European X-ray Free Electron Laser (E-XFEL), being under construction at DESY research center, is a good example. The E-XFEL uses single tunnel and part of the electronic system will be installed next to main beam pipe and exposed to radiation. The modern Advanced/Micro Telecommunications Computing Architecture (ATCA/μTCA) standards are foreseen as a base for control and diagnostic system for this new project. These flexible standards provide high reliability, availability and usability for the system which can be decreased by negative influe...

  14. Integrated Sensor Networks for Monitoring the Health and Well-Being of Vulnerable Individuals

    Science.gov (United States)

    Heatley, D. J. T.; Kalawsky, R. S.; Neild, I.; Bowman, P. A.

    The inescapable fact that people are living longer today than ever before means that the number of elderly people needing care or medical treatment has never been higher. In response to this there is a growing trend to place the elderly and infirm in residential homes or in sheltered accommodation, where they live in a protective environment while retaining some independence. Current healthcare systems in residential, sheltered, and community settings generally operate on a reactive basis rather than a pre-emptive basis [1]. This means that the people being cared for (the 'clients') are often already clinically ill and in need of medical attention, sometimes urgently, by the time the healthcare system engages, whereupon the treatment and recovery regime can be protracted and costly [2]. Unfortunately, a significant majority of our ageing population do not have the benefit of this level of healthcare [3], despite the evidence that our ageing population are regarded to be at an increased risk of falls [4], malnutrition [5], and failure to take prescribed medication [6]. It is this self-neglect that is of great concern. A far better scheme for all parties is one that continuously monitors clients who, although in fine health at that time, are considered to be at risk and likely to need attention at a time in the future, particularly if they are elderly and live alone. By continually monitoring certain behavioural characteristics of an individual, it is feasible to ascertain their well-being or detect when things deviate from the norm.

  15. Program of individual monitoring of the internal contamination and their implementation in the Republic the Cuba

    International Nuclear Information System (INIS)

    Lopez Bejerano, Gladys M.; Capote Ferrera, Eduardo; Fernandez Gomez, Isis M.; Acosta Rodriguez, Nancy; Carrazana Gonzalez, Jorge A.; Cruz Suarez, Rodolfo

    2008-01-01

    Full text: In different Cuban institutions linked fundamentally to the medical practice of nuclear medicine and the investigations, it is worked with sources open of ionizing radiations, that which makes indispensable the existence of a system of radiological surveillance that includes the control radiological individual of the received doses as a result of the occupational, such exhibition that is guaranteed that the exhibition of the Hard-working Exposed Occupationally, stay inside the recommended limits, in the International Basic Norms of Protection against the Ionizing radiations and safe-deposit of the Sources of Radiation (NBIS) and in turn adopted in the Norma Cuban. From the year 1986 in the Center of Protection and Hygiene of the Radiations is carried out in way centralized this control; but with the inconvenience of not being able to carry out the same one to workers from the domestic interior when not being feasible the transfer of these toward its headquarters, reason why the doses were ignored received in an important number of these. In and of itself the Laboratory of Internal Contamination of this institution in these years has developed managed works to define firstly, for each institution, the program of monitoring of the internal contamination of its workers using for it the methodology recommended by the OIEA where the potential doses are evaluated that for incorporation these they receive and whose results suggested the introduction of a program of individual monitoring as behavior to continue in most of the institutions. In correspondence with it was designed and established a program that included the study of feasibility of the existent equipment in the institutions to carry out the monitoring of the internal contamination using technical of measuring in vivo and in vitro, as it corresponds, their calibration, the establishment of procedures that respond to the requirements of a System of Quality for the Norma ISO/IEC 17025 and

  16. Use of Germanium as comparator and integral monitor of neutron flux in activation analysis; Utilizacion del germanio como comparador y monitor integral de flujo neutronico en analisis por activacion

    Energy Technology Data Exchange (ETDEWEB)

    Furnari, Juan C.; Cohen, Isaac M. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Centro Atomico Ezeiza; Arribere, Maria A.; Kestelman, Abraham J. [Comision Nacional de Energia Atomica, San Carlos de Bariloche (Argentina). Centro Atomico Bariloche

    1997-10-01

    The possibility of using germanium as monitor of the thermal and epithermal components of the neutron flux, and comparator in parametric activation analysis, is discussed. The advantages and drawbacks associated to the use of this element are commented on, and the comparison with zirconium, in terms of the determination relative error, is performed. The utilisation of germanium as integral flux monitor, including the fast component of the neutron spectrum, is also discussed. Data corresponding to measurements of k{sub 0} factor for the most relevant gamma transitions from Ge-75 and Be-77 are presented, as well as the results of the reference material analysis, employing germanium as flux monitor and comparator in a simultaneous way. (author). 8 refs., 3 figs., 2 tabs.

  17. Research and development program in reactor diagnostics and monitoring with neutron noise methods. Stage 7. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Pazsit, I.; Demaziere, C.; Arzhanov, V. [Chalmers Univ. of Technology, Goeteborg (Sweden). Department of Reactor Physics; Garis, N.S. [Swedish Nuclear Power Inspectorate, Stockholm (Sweden)

    2001-08-01

    This report constitutes stage 7 of a long-term research and development program concerning the development of diagnostics and monitoring methods for nuclear reactors. A proposal for the continuation of this program in stage 8 is also given at the end of the report. In stage 6, the basic principles of a 3-D fully coupled neutronic/thermal-hydraulic simulator in the frequency domain were presented. The neutronic model relied on the two-group diffusion approximation, whereas the thermal-hydraulic algorithms relied on the so called 'lumped' model. The key element of this simulator was that only the static data were required which could be obtained from the Studsvik Scandpower CASMO-4/TABLES-3/ SIMULATE-3 code package. The simulator was developed with this underlying idea, which means that the calculation of the static fluxes and the eigenvalue were avoided. Depending on what kind of spatial discretization scheme which is used in the noise simulator to calculate the 'leakage' noise, it is not granted that the system remains critical by using the group constants supplied by SIMULATE. Nevertheless, when the system is critical, the balance equations should be fulfilled in all nodes with respect to the discretization scheme used. In concrete terms, the calculation of the static fluxes and eigenvalue can be avoided if the system is brought back to criticality by modifying the cross-sections so that the balance equations are always fulfilled with the chosen spatial discretization scheme. This approach was used in this study with the finite difference scheme. As pointed out in stage 6, the finite difference scheme is relatively inefficient compared to finite elements or nodal methods, but on the other hand it is rather easy to implement. These two more sophisticated schemes are planned to be investigated at a later stage, but for the time being the simulator relying on the finite difference scheme was improved as much as possible so that a 2-D entirely

  18. Monitoring and forecasting of radiation hazard from great solar energetic particle events by using on-line one-min neutron monitor and satellite data.

    Science.gov (United States)

    Dorman, Lev I

    2007-01-01

    The method of automatically determining the start of great solar energetic particle (SEP) events are described on the basis of cosmic ray (CR) one-min observations by neutron monitors in real-time scale. It is shown that the probabilities of false alarms and missed triggers are negligible. After the start of SEP event, it is automatically determined by the method of coupling functions the SEP energy spectrum and flux for each minute of observations. By solving the inverse problem during few first minutes of SEP event, diffusion coefficient in the interplanetary space, source function on the Sun, and time of ejection of SEP into solar wind are determined. For extending obtained results into small energy range we use also available from Internet the satellite one-min CR data. This make possible to give forecast of space-time variation of SEP for more than 2 days and estimate expected radiation dose for satellite and aircrafts. With each new minute of observations, the quality of forecast increased, and after approximately 30 min became near 100%.

  19. Standard Test Method for Use of 2N2222A Silicon Bipolar Transistors as Neutron Spectrum Sensors and Displacement Damage Monitors

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the use of 2N2222A silicon bipolar transistors as dosimetry sensors in the determination of neutron energy spectra, and as silicon 1-MeV(Si) equivalent displacement damage fluence monitors. 1.2 The neutron displacement damage is especially valuable as a neutron spectrum sensor in the range 0.1 to 2.0 MeV when fission foils are not available. It has been applied in the fluence range between 2 × 10 12 n/cm2 and 1 × 1014 n/cm2 and should be useful up to 1015 n/cm2. This test method details the steps for the acquisition and use of silicon 1-MeV equivalent fluence information (in a manner similar to the use of activation foil data) for the determination of neutron spectra. 1.3 In addition, this sensor can provide important confirmation of neutron spectra determined with other sensors, and yields a direct measurement of the silicon 1-MeV fluence by the transfer technique. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in ...

  20. Characterization of thermal neutron fields for calibration of neutron monitors in accordance with great equivalent dose environment H⁎(10); Caracterização de campos de nêutrons térmicos para a calibração de monitores de nêutrons em termos da grandeza equivalente de dose ambiente H⁎(10)

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Larissa P. S. da; Silva, Felipe S.; Fonseca, Evaldo S.; Patrao, Karla C.S.; Pereira, Walsan W. [Instituto de Radioproteção e Dosimetria (LNMRI/IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Laboratório Nacional de Metrologia das Radiações Ionizantes; Astuto, Achilles, E-mail: larissapaizante@poli.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    The Laboratório Brasileiro de Nêutrons do Instituto de Radioproteção e Dosimetria (IRD/CNEN) has developed and built a thermal neutron flux facility to provide neutron fluence for dosimeters (Astuto, 2014). This fluency is obtained by four 16 Ci sources {sup 241}AmBe (α, n) positioned around the channel positioned in the center of the Thermal Flow Unit (UFT). The UFT was built with blocks of paraffin with graphite addition and graphite blocks of high purity to obtain a central field with a homogeneous thermal neutron fluence for calibration purposes with the following measurements: 1.2 x 1.2 x 1.2 m{sup 3}. The objective of this work is to characterize several points, in the thermal energy range, in terms of the equivalent ambient dose quantity H⁎(10) for calibration and irradiation of monitors neutrons.

  1. Low-level gamma and neutron monitoring based on use of proportional counter filled with 3He in polythene moderator: study of the responses to gamma and neutrons.

    Science.gov (United States)

    Pszona, S; Bantsar, A; Tulik, P; Wincel, K; Zaręba, B

    2014-10-01

    It has been shown that a proportional counter filled with (3)He placed centrally inside a polythene sphere opens a new possibility for measuring gamma photons and neutrons in the separate pulse-height windows. The responses to gamma and neutrons (in terms of ambient dose equivalent) of the detector assembly consisting of 203-mm polythene sphere with centrally positioned 40-mm diameter (3)He proportional counter have been studied. The response to secondary gammas from capture process in hydrogen has also been studied. The rather preliminary studies indicate that the proposed measuring system has very promising features as an ambient dose equivalent device for mixed gamma-neutron fields. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Super Phenix. Monitoring of structures subject to irradiation. Neutron dosimetry measurement and calculation program

    International Nuclear Information System (INIS)

    Cabrillat, J.C.; Arnaud, G.; Calamand, D.; Manent, G.; Tavassoli, A.A.

    1984-09-01

    For the Super Phenix reactor, the evolution, versus the irradiation of the mechanical properties of the core diagrid steel is the object of studies and is particularly monitored. The specimens irradiated, now in PHENIX and will be later irradiated in SUPER PHENIX as soon as the first operating cycles. An important dosimetry program coupling calculation and measurement, is parallely carried out. This paper presents the reasons, the definition of the structure, of the development and of materials used in this program of dosimetry, as also the first results of a calculation-measurement comparison [fr

  3. Development of monitoring method of spatial neutron distribution in neutrons-gamma rays mixed field using imaging plate for NCT--depression of the field.

    Science.gov (United States)

    Tanaka, Kenichi; Endo, Satoru; Hoshi, Masaharu; Takada, Jun

    2011-12-01

    The degree of depression in the neutron field caused by neutron absorption in the materials of an imaging plate (IP) was investigated using MCNP-4C. Consequently, the IP doped with Gd, which reproduced the distribution of (157)Gd(n,γ)(158)Gd reaction rate in the previous study, depresses the relative distribution by about 50%. The depression for the IP in which Gd is replaced with similar amount of B atoms was estimated to be about 10%. The signal intensity for this IP is estimated to be at a similar level with that for Gd-doped IP. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Interactions of Endoglucanases with Amorphous Cellulose Films Resolved by Neutron Reflectometry and Quartz Crystal Microbalance with Dissipation Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Gang [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Datta, Supratim [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Liu, Zelin [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States). Dept. of Chemistry; Wang, Chao [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States). Dept. of Chemistry; Murton, Jaclyn K. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brown, Page A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jablin, Michael S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dubey, Manish [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Majewski, Jaroslaw [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Halbert, Candice E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Browning, James F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Esker, Alan R. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States). Dept. of Chemistry; Watson, Brian J. [Univ. of Maryland, College Park, MD (United States). Dept. of Cell Biology and Molecular Genetics; Zhang, Haito [Univ. of Maryland, College Park, MD (United States). Dept. of Cell Biology and Molecular Genetics; Hutcheson, Steven W. [Univ. of Maryland, College Park, MD (United States). Dept. of Cell Biology and Molecular Genetics; Huber, Dale L. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sale, Kenneth L. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Simmons, Blake A. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kent, Michael S. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2012-05-03

    A study of the interaction of four endoglucanases with amorphous cellulose films by neutron reflectometry (NR) and quartz crystal microbalance with dissipation monitoring (QCM-D) is reported. The endoglucanases include a mesophilic fungal endoglucanase (Cel45A from H. insolens), a processive endoglucanase from a marine bacterium (Cel5H from S. degradans), and two from thermophilic bacteria (Cel9A from A. acidocaldarius and Cel5A from T. maritima). The use of amorphous cellulose is motivated by the promise of ionic liquid pretreatment as a second generation technology that disrupts the native crystalline structure of cellulose. The endoglucanases displayed highly diverse behavior. Cel45A and Cel5H, which possess carbohydrate-binding modules (CBMs), penetrated and digested within the bulk of the films to a far greater extent than Cel9A and Cel5A, which lack CBMs. While both Cel45A and Cel5H were active within the bulk of the films, striking differences were observed. With Cel45A, substantial film expansion and interfacial broadening were observed, whereas for Cel5H the film thickness decreased with little interfacial broadening. Lastly, these results are consistent with Cel45A digesting within the interior of cellulose chains as a classic endoglucanase, and Cel5H digesting predominantly at chain ends consistent with its designation as a processive endoglucanase.

  5. Incident spectrum determination for time-of-flight neutron powder diffraction data analysis

    International Nuclear Information System (INIS)

    Hodges, J. P.

    1998-01-01

    Accurate characterization of the incident neutron spectrum is an important requirement for precise Rietveld analysis of time-of-flight powder neutron diffraction data. Without an accurate incident spectrum the calculated model for the measured relative intensities of individual Bragg reflections will possess systematic errors. We describe a method for obtaining an accurate numerical incident spectrum using data from a transmitted beam monitor

  6. A Compact Monitoring System for Recording X-Rays, Gamma Rays and Neutrons Generated By Atmospheric Lightning Discharges and Other Natural Phenomena

    Science.gov (United States)

    Martin, I. M.; Alves, M. A.

    2009-12-01

    The generation of X-rays, gamma-rays and neutrons by atmospheric lightning discharges has been predicted by different researchers several decades ago. But only within the last 25 years the first experimental evidences of events relating the generation of these radiations with lightning have been made; since then there is a continuing effort to collect more information about this type of phenomenon. In this study we describe a compact monitoring system to detect simultaneously X-rays, gamma-rays and neutrons using rather inexpensive off-the-shelf commercial detectors (Micro Roengten Radiation Monitor, 8-inch gamma tube coupled to a 3x3 inch sodium iodide [Nai(Tl)] crystal, Ludlum He-3 neutron detector) and accompanying computer interfaces. The system is extremely portable and can be powered with small automotive batteries, if necessary. Measurements are performed at ground-level. Preliminary measurements have already yielded positive results, e.g., changes in the neutron flux related to a lightning discharge and varying weather conditions have been observed in the city of Sao Jose dos Campos, Brazil (23° 11‧ 11″S, 45° 52‧ 43″ W, 600 m above sea level). This a pilot study, in the near future a larger number of these compact monitoring system will be installed in different location in order to increase the area coverage. Although the main objective of the study is to detect high-energy events produced by lightning discharges, the monitoring system will also be able to detect changes in the radiation background produced by other natural phenomena.

  7. Research and Development Program in Reactor Diagnostics and Monitoring with Neutron Noise Methods, Stage 18

    International Nuclear Information System (INIS)

    Pazsit, Imre; Nam, Tran Hoai; Dykin, Victor; Jonsson, Anders

    2013-01-01

    This report constitutes Stage 18 of a long-term research and development program concerning the development of diagnostics and monitoring methods for nuclear reactors. The objective of the research program is to contribute to the strategic research goal of competence and research capacity by building up competence within the Department of Nuclear Engineering at Chalmers University of Technology, regarding reactor physics, reactor dynamics and noise diagnostics. The purpose is also to contribute to the research goal of giving a basis for SSM's supervision by developing methods for identification and localization of perturbations in reactor cores. Results up to Stage 17 were reported in SKI and SSM reports, as listed in the report's summary

  8. Self-Monitoring Using Continuous Glucose Monitors with Real-Time Feedback Improves Exercise Adherence in Individuals with Impaired Blood Glucose: A Pilot Study.

    Science.gov (United States)

    Bailey, Kaitlyn J; Little, Jonathan P; Jung, Mary E

    2016-03-01

    Exercise helps individuals with prediabetes or type 2 diabetes (T2D) manage their blood glucose (BG); however, exercise adherence in this population is dismal. In this pilot study we tested the efficacy of a self-monitoring group-based intervention using continuous glucose monitors (CGMs) at increasing exercise adherence in individuals with impaired BG. Thirteen participants with prediabetes or T2D were randomized to an 8-week standard care exercise program (CON condition) (n = 7) or self-monitoring exercise intervention (SM condition) (n = 6). Participants in the SM condition were taught how to self-monitor their exercise and BG, to goal set, and to use CGM to observe how exercise influences BG. We hypothesized that compared with the CON condition, using a real-time CGM would facilitate self-monitoring behavior, resulting in increased exercise adherence. Repeated-measures analysis of variance revealed significant Condition × Time interactions for self-monitoring (P self-efficacy to self-monitor (P = 0.01), such that the SM condition showed greater increases in these outcomes immediately after the program and at the 1-month follow-up compared with the CON condition. The SM condition had higher program attendance rates (P = 0.03), and a greater proportion of participants reregistered for additional exercise programs (P = 0.048) compared with the CON condition. Participants in both conditions experienced improvements in health-related quality of life, waist circumference, and fitness (P values self-monitoring and exercise behavior in individuals living with prediabetes or T2D.

  9. Interleukin-6 dynamics as a basis for an early-warning monitor for sepsis and inflammation in individual pigs.

    Science.gov (United States)

    Tambuyzer, Tim; De Waele, Tine; Chiers, Koen; Berckmans, Daniel; Goddeeris, Bruno M; Aerts, Jean-Marie

    2014-06-01

    Static interleukin-6 (IL-6) levels of pigs contain considerable individual differences, which obstruct the practical use of IL-6 for disease monitoring purposes. It was hypothesised that interleukin-6 (IL-6) dynamics could be used to quantify these individual differences and carries critical information of the individual pig infection status. Time series of IL-6 responses in 25 pigs were analysed before and after infection by Actinobacillus pleuropneumoniae. The results indicated that amplitude increases of IL-6 fluctuations of individual pigs rather than static IL-6 values should be used as indicator of the infection state. This study shows the added value for IL-6 time series analyses of individual pigs. These results are a first step towards the development of objective individualised methods for monitoring and early detection of sepsis and inflammation processes in pigs by integrating animal response dynamics. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Individual monitoring conducted by the Health Protection Agency in the London polonium-210 incident

    International Nuclear Information System (INIS)

    Bailey, Michael; Birchall, Alan; Etherington, George; Wilkins, Bernard; Bishop, Louise; Fraser, Graham; Gross, Roger; Maguire, Helen; Evans, Barry; Shaw, Karen

    2008-01-01

    Mr. Alexander Litvinenko died on 23 November 2006, having allegedly been poisoned with polonium- 210 ( 210 Po) a few weeks earlier. The police investigation identified a number of contaminated locations, including parts of several hotels, restaurants, offices and transport. An extensive programme of individual monitoring of potentially exposed persons was rapidly initiated, based on urine sampling. Methods used for low-level measurement of 210 Po in environmental samples were adapted. The Health Protection Agency set a Reporting Level of 30 mBq d -1 , results above which indicated likely intake of 210 Po from the incident. At each location, risk assessments were undertaken to identify persons with significant risk of contamination with 210 Po. These individuals were invited to provide samples, not only to enable a direct assessment to be made of their own exposures, but also to inform decisions on whether others connected with the location should provide samples, or whether they could be reassured. Urine samples from 753 people were processed: about 500 during the first month. Of these, 139 measurements were above the Reporting Level, assessed doses for 36 were in the range ≥ 1 mSv and <6 mSv, and 17 were ≥ 6 mSv, with the highest at about 100 mSv. Many of the hotel guests were overseas visitors. An Overseas Advice Team was set up to encourage authorities abroad to adopt similar strategies. Overall, 664 persons from 52 countries and territories were identified. For 176, results of urine measurements were provided to the Overseas Advice Team, of which 13 were above the Reporting Level. Assessed doses for eight of these were <1 mSv, and the other five were in the range ≥ 1 mSv and <6 mSv. (author)

  11. Monitoring differential synthesis of RNA in individual cells by capillary electrophoresis.

    Science.gov (United States)

    Han, Futian; Lillard, Sheri J

    2002-03-01

    A capillary electrophoresis (CE)-based technique is reported here to monitor differential RNA synthesis in individual Chinese hamster ovary cells at distinct stages of the cell proliferation cycle. Cell synchronization was achieved by the shake-off method, in which mitotic (M) cells were dislodged, and cells at G(1), S, and G(2) phases were harvested 2.5, 10, and 13 h, respectively, after synchronizing the mitotic cells. Thirty-two cells (eight from each phase) were analyzed by injecting each cell into the capillary, lysing it with dilute surfactant, separating the RNA by capillary electrophoresis, and detecting the peaks with laser-induced fluorescence. The results from single cells show that the total amount of RNA increased at each successive stage (from G(1) to M), while the relative synthetic rates of different RNA fractions varied with progression through the cycle. There was a threefold increase in the synthetic rate of total RNA from S to G(2), compared with G(1) to S. In addition, differential accumulation of specific RNA fractions was observed, with the low-molecular-mass fraction exhibiting a much higher synthetic rate from G(2) to M, relative to the rates of the larger ribosomal RNA (rRNA) fractions. Comparison of the large rRNA fractions with one another reveals that at S phase more 28S rRNA was accumulated than 18S rRNA, and at G(1) and M phases, the synthetic rate of 28S rRNA was slowed compared with that of 18S. Minimal sample preparation, combined with the separation power of CE and single-cell detection sensitivity of laser-induced fluorescence, results in a simple method for assessing differential accumulation of RNA from distinct individual cells.

  12. Individuality and stability in male songs of cao vit gibbons (Nomascus nasutus with potential to monitor population dynamics.

    Directory of Open Access Journals (Sweden)

    Jun-Juan Feng

    Full Text Available Vocal individuality and stability has been used to conduct population surveys, monitor population dynamics, and detect dispersal patterns in avian studies. To our knowledge, it has never been used in these kinds of studies among primates. The cao vit gibbon is a critically endangered species with only one small population living in a karst forest along China-Vietnam border. Due to the difficult karst terrain, an international border, long life history, and similarity in male morphology, detailed monitoring of population dynamics and dispersal patterns are not possible using traditional observation methods. In this paper, we test individuality and stability in male songs of cao vit gibbons. We then discuss the possibility of using vocal individuality for population surveys and monitoring population dynamics and dispersal patterns. Significant individuality of vocalization was detected in all 9 males, and the correct rate of individual identification yielded by discriminant function analysis using a subset of variables was satisfactory (>90%. Vocal stability over 2-6 years was also documented in 4 males. Several characters of cao vit gibbons allowed long-term population monitoring using vocal recordings in both China and Vietnam: 1 regular loud calls, 2 strong individuality and stability in male songs, 3 stable territories, and 4 long male tenure. During the course of this research, we also observed one male replacement (confirmed by vocal analysis. This time- and labor-saving method might be the most effective way to detect dispersal patterns in this transboundary population.

  13. Estimating individual radioactive contamination by selective interpretation of radiotoxicological monitoring results

    International Nuclear Information System (INIS)

    Piechowski, J.; Menoux, B.

    1995-01-01

    The interpretation methods used for estimating individual doses from measurement results contain some difficulties with regard to the adaptation of the metabolic models to situations encountered in practice. In essence, these difficulties concern the definition of the right parameters of the cases encountered. Moreover apart from characterised incidents, they are very often related to a lack of knowledge of the contamination routes and the chronology of the episodes. As a consequence, we were led to contemplate how the interpretation of monitoring data could be simplified by considering separately the results specific to the routes of entry and those relating to systemic contamination, i.e. after the radionuclides have been transferred to the blood. The study first develops an approach to the interpretation of the systemic contamination measurement results. Using the systemic contamination results and the appropriate retention and excretion functions, the values of the activity absorbed daily from the routes of entry to the blood are calculated. A day-to-day follow-up of absorbed activity is thus made possible, providing easy-to-consult results in real time. Some applications of the method are proposed for acute tritium and uranium contamination cases, and for chronic tritium, uranium and iodine contaminations. The conditions and constraints affecting the validity of the approach proposed are discussed. (authors). 10 refs., 5 figs., 3 tabs

  14. Neutron physics

    International Nuclear Information System (INIS)

    Beckurts, K.H.; Wirtz, K.

    1974-01-01

    This textbook consists of four sections which deal with the following subjects: 1. Production of neutrons and their interactions with the nuclei; neutron sources; neutron detectors; cross-section measurements. 2. Theory of neutron interactions with macroscopic media; neutron slowing down; space distribution of moderated neutrons; neutron thermalization; neutron scattering. 3. Radioactive probe measurements of thermal neutron fluxes; activation by means of epithermal neutrons; threshold detectors of fast neutrons; neutron calibration. 4. Neutron energy; slowing down kernels; neutron age; diffusion length and absorption of neutrons

  15. Evaluation of area monitor response for neutrons in radiation field generated by a 15 MV clinic accelerator; Avaliacao da resposta dos monitores de area para neutrons em campo de radiacao gerado por um acelerador clinico de 15 MV

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, Ana Paula

    2011-07-01

    The clinical importance and usage of linear accelerators in cancer treatment increased significantly in the last years. Coupled with this growth came the concern about the use of accelerators with energies over to 10 MeV which produce therapeutic beam contaminated with neutrons generated when high-energy photons interact with high-atomic-number materials such as tungsten and lead present in the accelerator itself. At these facilities, measurements of the ambient dose equivalent for neutrons present difficulties owing to the existence of a mixed radiation field and possible electromagnetic interference near the accelerator. The Neutron Laboratory of the IRD - Brazilian Institute for Radioprotection and Dosimetry, aiming to evaluate the survey meters performance at these facilities, initiated studies of instrumentation response in the presence of different neutron spectra. Neutrons sources with average energies ranging from 0.55 to 4.2 MeV, four different survey meters and one ionization chamber to obtain the ratio between the dose due to neutrons and gamma radiation were used in this work. The evaluation of these measurements, performed in a 15 MV linear accelerator room is presented. This work presents results that demonstrate the complexity and care needed to make neutrons measurements in radiotherapy treatment rooms containing high energy clinical accelerators. (author)

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

    International Nuclear Information System (INIS)

    Wentzeis, Luis M.; Calvo, Maria D.

    2009-01-01

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

  17. Research and Development Program in Reactor Diagnostics and Monitoring with Neutron Noise Methods, Stage 16

    International Nuclear Information System (INIS)

    Pazsit, Imre; Dykin, Victor; Jonsson, Anders; Demaziere, Christophe

    2010-12-01

    This report gives an account of the work performed by the Dept. of Nuclear Engineering, Chalmers Univ. of Technology, in the frame of a research contract with the Swedish Radiation Safety Authority (SSM), contract No. SSM 2009/2093. The present report is based on work performed by Imre Pazsit, Victor Dykin, Anders Jonsson and Christophe Demaziere, with Imre Pazsit being the project leader. This report describes the results obtained during Stage 16 of a long-term research and development program concerning the development of diagnostics and monitoring methods for nuclear reactors. The long-term goals are elaborated in more detail in e.g. the Final Reports of Stage 1 and 2 (SKI Report 95:14 and 96:50, Pazsit et al. 1995, 1996). Results up to Stage 15 were reported in (Pazsit et al. 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2003a, 2003b; Demaziere et al, 2004; Sunde et al, 2006; Pazsit et al. 2008, 2009). A brief proposal for the continuation of this program in Stage 17 is also given at the end of the report. The program executed in Stage 16 consists of four parts as follows: - An overview of the present status of experience with BWR stability; - An investigation of the significance of the properties of the noise source for BWR instability; - Study of the dynamics of molten salt systems: construction of the adjoint and calculating the space dependent noise induced by propagating perturbations in the fuel; - A specific study of some novel methods of analysis of non-linear and non-stationary processes

  18. Properties of neutron sources

    International Nuclear Information System (INIS)

    1987-03-01

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

  19. Comparison of different PADC materials and etching conditions for fast neutron dosimetry

    International Nuclear Information System (INIS)

    Assenmacher, F.; Boschung, M.; Hohmann, E.; Mayer, S.

    2016-01-01

    Etched-track polyallyl diglycol carbonate (PADC) dosemeters have been in use at the Paul Scherrer Institute since 1998 in neutron dosimetry for individual monitoring. In the last years, the availability of PADC materials from different manufacturers has grown, and different etching conditions were proposed, with the intention to improve the quality and overall performance of PADC in individual neutron monitoring. The goal of the present study was to compare the performance of different PADC materials and to investigate the influence of different etching conditions on sensitivity to fast neutrons and lower detection limit. The comparison covers six different PADC materials and eight different etching conditions. (authors)

  20. Semiconductor neutron detector

    Science.gov (United States)

    Ianakiev, Kiril D [Los Alamos, NM; Littlewood, Peter B [Cambridge, GB; Blagoev, Krastan B [Arlington, VA; Swinhoe, Martyn T [Los Alamos, NM; Smith, James L [Los Alamos, NM; Sullivan, Clair J [Los Alamos, NM; Alexandrov, Boian S [Los Alamos, NM; Lashley, Jason Charles [Santa Fe, NM

    2011-03-08

    A neutron detector has a compound of lithium in a single crystal form as a neutron sensor element. The lithium compound, containing improved charge transport properties, is either lithium niobate or lithium tantalate. The sensor element is in direct contact with a monitor that detects an electric current. A signal proportional to the electric current is produced and is calibrated to indicate the neutrons sensed. The neutron detector is particularly useful for detecting neutrons in a radiation environment. Such radiation environment may, e.g. include gamma radiation and noise.

  1. Evaluation of area monitor response for neutrons in radiation field generated by a 15 MV clinic accelerator

    International Nuclear Information System (INIS)

    Salgado, Ana Paula

    2011-01-01

    The clinical importance and usage of linear accelerators in cancer treatment increased significantly in the last years. Coupled with this growth came the concern about the use of accelerators with energies over to 10 MeV which produce therapeutic beam contaminated with neutrons generated when high-energy photons interact with high-atomic-number materials such as tungsten and lead present in the accelerator itself. At these facilities, measurements of the ambient dose equivalent for neutrons present difficulties owing to the existence of a mixed radiation field and possible electromagnetic interference near the accelerator. The Neutron Laboratory of the IRD - Brazilian Institute for Radioprotection and Dosimetry, aiming to evaluate the survey meters performance at these facilities, initiated studies of instrumentation response in the presence of different neutron spectra. Neutrons sources with average energies ranging from 0.55 to 4.2 MeV, four different survey meters and one ionization chamber to obtain the ratio between the dose due to neutrons and gamma radiation were used in this work. The evaluation of these measurements, performed in a 15 MV linear accelerator room is presented. This work presents results that demonstrate the complexity and care needed to make neutrons measurements in radiotherapy treatment rooms containing high energy clinical accelerators. (author)

  2. New ICRU quantities for the environmental and individual monitoring. Standardization of individual dosemeters by using external beams of photon radiation; Nuevas magnitudes ICRU para la vigilancia radiologica ambiental e individual. Calibracion de dosimetros personales usando haces externos de fotones

    Energy Technology Data Exchange (ETDEWEB)

    Brosed, A.; Delgado, A.; Granados, C. E.

    1987-07-01

    The quantities introduced by ICRU for the radiological monitoring are commented, specially those implied in individual protection against external photons. A procedure is proposed in order to standardize the individual dosemeters by using the kerma in air references of CIEMAT-JEN. The reference radiation beams are described in connection with ISO standards. Provisional values are selected for the appropriate conversion and correction factors. (Author) 23 refs.

  3. Neutron monitors and muon detectors for solar modulation studies: Interstellar flux, yield function, and assessment of critical parameters in count rate calculations

    Science.gov (United States)

    Maurin, D.; Cheminet, A.; Derome, L.; Ghelfi, A.; Hubert, G.

    2015-01-01

    Particles count rates at given Earth location and altitude result from the convolution of (i) the interstellar (IS) cosmic-ray fluxes outside the solar cavity, (ii) the time-dependent modulation of IS into Top-of-Atmosphere (TOA) fluxes, (iii) the rigidity cut-off (or geomagnetic transmission function) and grammage at the counter location, (iv) the atmosphere response to incoming TOA cosmic rays (shower development), and (v) the counter response to the various particles/energies in the shower. Count rates from neutron monitors or muon counters are therefore a proxy to solar activity. In this paper, we review all ingredients, discuss how their uncertainties impact count rate calculations, and how they translate into variation/uncertainties on the level of solar modulation ϕ (in the simple Force-Field approximation). The main uncertainty for neutron monitors is related to the yield function. However, many other effects have a significant impact, at the 5-10% level on ϕ values. We find no clear ranking of the dominant effects, as some depend on the station position and/or the weather and/or the season. An abacus to translate any variation of count rates (for neutron and μ detectors) to a variation of the solar modulation ϕ is provided.

  4. Application of low-cost Gallium Arsenide light-emitting-diodes as kerma dosemeter and fluence monitor for high-energy neutrons.

    Science.gov (United States)

    Mukherjee, B; Simrock, S; Khachan, J; Rybka, D; Romaniuk, R

    2007-01-01

    Displacement damage (DD) caused by fast neutrons in unbiased Gallium Arsenide (GaAs) light emitting diodes (LED) resulted in a reduction of the light output. On the other hand, a similar type of LED irradiated with gamma rays from a (60)Co source up to a dose level in excess of 1.0 kGy (1.0 x 10(5) rad) was found to show no significant drop of the light emission. This phenomenon was used to develop a low cost passive fluence monitor and kinetic energy released per unit mass dosemeter for accelerator-produced neutrons. These LED-dosemeters were used to assess the integrated fluence of photoneutrons, which were contaminated with a strong bremsstrahlung gamma-background generated by the 730 MeV superconducting electron linac driving the free electron laser in Hamburg (FLASH) at Deutsches Elektronen-Synchrotron. The applications of GaAs LED as a routine neutron fluence monitor and DD precursor for the electronic components located in high-energy accelerator environment are highlighted.

  5. The IVOG feeding station: a tool for monitoring the individual feed intake of group-housed weanling pigs

    NARCIS (Netherlands)

    Bruininx, E.M.A.M.; Peet-Schwering, van der C.M.C.; Schrama, J.W.; Vesseur, P.C.; Everts, H.; Beynen, A.C.

    2001-01-01

    Three batches of weanling pigs (total n=310 pigs) were used in a 34-day experiment to validate the use of an IVOG? feeding station as a tool for monitoring individual feed intake of group-housed weanling pigs. An IVOG? feeding station for weanling pigs consists of a single-space dry feeder placed on

  6. The Role of Self-Monitoring in Assessing Individual Students' Quantity and Quality of Comments in Large-Class Discussion

    Science.gov (United States)

    Carstens, B. A.; Wright, J. M.; Coles, J. T.; McCleary, L. N.; Williams, R. L.

    2013-01-01

    This study developed a reliable and valid self-monitoring procedure for student use in recording and rating the quality of their individual comments in large college classes. Students used daily record cards immediately to record and rate each comment they made each day. However, a limit was set on the amount of credit students could claim for…

  7. Individual Self-Monitoring & Peer-Monitoring in One Classroom in Writing Activities: Who Is at Disadvantage?

    Science.gov (United States)

    Toofan, Zohreh Zare

    2014-01-01

    Writing is an important experience through which we are able to share ideas, arouse feelings, persuade and convince other people (white & Arndt, 1991). It is important to view writing not solely as the product of an individual, but as a cognitive, social and cultural act. Writing is an act that takes place within a context, that accomplishes a…

  8. Research and Development Program in Reactor Diagnostics and Monitoring with Neutron Noise Methods. Stage 11 and 12. Final report

    International Nuclear Information System (INIS)

    Sunde, C.; Pazsit, I.; Demaziere, C.; Dahl, O.; Mileshina, L.

    2006-06-01

    This report describes the results obtained during Stage 11 and 12 of a long-term research and development program concerning the development of diagnostics and monitoring methods for nuclear reactors. The long-term goals are elaborated in more detail in e.g. the Final Reports of stage 1 and 2 (SKI Report 95:14 and 96:50). Higher order eigenfunctions and eigenvalues of the diffusion equation, describing a static core, have lost their significance when doing calculations in realistic systems, since there are usually made by nodal methods or other direct numerical techniques. However, there are situations when knowledge of the higher order modes is still useful. Such case is the separation of the global and regional flux oscillations in the case of BWR instability. Another case is the investigation of the stability properties of large inhomogeneous cores, which is usually quantified with the so-called eigenvalue separation, ES=1/k 1 - 1/k 0 where k 0 and k 1 , are the fundamental and first higher order eigenvalues, respectively. Numerical codes used for ICMF calculations usually do not have the option of calculating the higher order eigenvalues and eigenfunctions. In idealised systems, these can be calculated with semi-analytical methods. In order to get insight into the characteristics of the higher order eigenmodes of the neutron flux and the adjoint, these were calculated in a reflected homogeneous system with two-group theory. The adjoint eigenmodes are necessary if an orthogonality property needs to be used, such as the separation of the modes from a flux shape which is a sum of several eigenmodes. At the same time, the so-called numerical noise simulator, developed at the Dept., was extended such that it became suitable for the calculation of the higher order eigenmodes, both direct and adjoint ones. This simulator can treat real inhomogeneous cores, with an input deck compatible with that of SIMULATE. The simulator was used to calculate the eigenfunctions and

  9. Research and Development Program in Reactor Diagnostics and Monitoring with Neutron Noise Methods. Stage 11 and 12. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sunde, C.; Pazsit, I.; Demaziere, C.; Dahl, O.; Mileshina, L. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Nuclear Engineering

    2006-06-15

    This report describes the results obtained during Stage 11 and 12 of a long-term research and development program concerning the development of diagnostics and monitoring methods for nuclear reactors. The long-term goals are elaborated in more detail in e.g. the Final Reports of stage 1 and 2 (SKI Report 95:14 and 96:50). Higher order eigenfunctions and eigenvalues of the diffusion equation, describing a static core, have lost their significance when doing calculations in realistic systems, since there are usually made by nodal methods or other direct numerical techniques. However, there are situations when knowledge of the higher order modes is still useful. Such case is the separation of the global and regional flux oscillations in the case of BWR instability. Another case is the investigation of the stability properties of large inhomogeneous cores, which is usually quantified with the so-called eigenvalue separation, ES=1/k{sub 1} - 1/k{sub 0} where k{sub 0} and k{sub 1}, are the fundamental and first higher order eigenvalues, respectively. Numerical codes used for ICMF calculations usually do not have the option of calculating the higher order eigenvalues and eigenfunctions. In idealised systems, these can be calculated with semi-analytical methods. In order to get insight into the characteristics of the higher order eigenmodes of the neutron flux and the adjoint, these were calculated in a reflected homogeneous system with two-group theory. The adjoint eigenmodes are necessary if an orthogonality property needs to be used, such as the separation of the modes from a flux shape which is a sum of several eigenmodes. At the same time, the so-called numerical noise simulator, developed at the Dept., was extended such that it became suitable for the calculation of the higher order eigenmodes, both direct and adjoint ones. This simulator can treat real inhomogeneous cores, with an input deck compatible with that of SIMULATE. The simulator was used to calculate the

  10. Research and Development Program in Reactor Diagnostics and Monitoring with Neutron Noise Methods. Stage 8. Final report

    International Nuclear Information System (INIS)

    Pazsit, I.; Demaziere, C.; Arzhanov, V.

    2003-01-01

    This report constitutes Stage 8 of a long-term research and development program concerning the development of diagnostics and monitoring methods for nuclear reactors. A brief proposal for the continuation of this program in stage 9 is also given at the end of the report. The program executed in Stage 8 consists of three parts and the work performed in each part is summarized below. In Stage 7, an anomaly localisation algorithm was presented and applied to the Forsmark-1 channel instability event. This investigation was carried out with a set of static data that were typical of a generic BWR model, since no data except the Local Power Range Monitors (LPRMs) time signals recorded during the instability event were made accessible to us at that time. In the present Stage, these static data were obtained from Vattenfall Fuel AB, who used the SIMULATE-3 code. The first Section of this report is thus devoted to this anomaly localisation but this time with a relevant set of data, both regarding the static core conditions and regarding the LPRMs time signals. The noise source pointed out by the localisation algorithm was once again found to be very close to an unseated fuel assembly discovered during the fuel outage following the instability event. The localisation procedure relies in fact on the prior calculation of the reactor transfer function, carried out via the neutron noise simulator first presented in Stage 6 and later improved in Stage 7. The neutron noise simulator was also improved in this Stage. More precisely, a 2-D 2- group static core simulator was developed in order to calculate the static flux and the associated eigenvalue with a spatial discretization scheme compatible with the one in use in the neutron noise simulator, i.e. finite differences. It has generally been assumed that the Decay Ratio (DR), a parameter characterizing the stability of BWRs, is a space-independent parameter of the reactor, i.e. it is independent of which LPRM is used in the core to

  11. SU-E-T-249: Neutron Model Upgrade for Radiotherapy Patients Monitoring Using a New Online Detector

    Energy Technology Data Exchange (ETDEWEB)

    Irazola, L; Sanchez Doblado, F. [Departamento de Fisiologia Medica y Biofisica, Universidad de Sevilla (Spain); Servicio de Radiofisica, Hospital Universitario Virgen Macarena, Sevilla (Spain); Lorenzoli, M; Pola, A. [Politecnico di Milano, Departimento di Ingegneria Nuclear, Milano (Italy); Terron, J.A. [Servicio de Radiofisica, Hospital Universitario Virgen Macarena, Sevilla (Spain); Bedogni, R. [Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare (INFN) (Italy); Sanchez Nieto, B. [Instituto de Fisica, Pontificia Universidad Catolica de Chile, Santiago (Chile); Romero-Exposito, M. [Departamento de Fisica, Universitat Autonoma de Barcelona (Spain)

    2014-06-01

    Purpose: The purpose of this work is to improve the existing methodology to estimate neutron equivalent dose in organs during radiotherapy treatments, based on a Static Random Access Memory neutron detector (SRAMnd) [1]. This is possible thanks to the introduction of a new digital detector with improved characteristics, which is able to measure online the neutron fluence rate in the presence of an intense photon background [2]. Its reduced size, allows the direct estimation of doses in specific points inside an anthropomorphic phantom (NORMA) without using passive detectors as TLD or CR-39. This versatility will allow not only to improve the existing models (generic abdomen and H and N [1]) but to generate more specific ones for any technique. Methods: The new Thermal Neutron Rate Detector (TNRD), based on a diode device sensitized to thermal neutrons, have been inserted in 16 points of the phantom. These points are distributed to infer doses to specific organs. Simultaneous measurements of these devices and a reference one, located in front of the gantry, have been performed for the mentioned generic treatments, in order to improve the existing model. Results: These new devices have shown more precise since they agree better with Monte Carlo simulations. The comparison of the thermal neutron fluence, measured with TNRD, and the existing models, converted from events to fluence, shows an average improvement of (3.90±3.37) % for H and N and (12.61±9.43) % for abdomen, normalized to the maximum value. Conclusion: This work indicates the potential of these new devices for more precise neutron equivalent dose estimation in organs, as a consequence of radiotherapy treatments. The simplicity of the process makes possible to establish more specific models that will provide a better dose estimation. References[1] Phys Med Biol 2012; 57:6167–6191.[2] A new active thermal neutron detector. Radiat. Prot. Dosim. (in press)

  12. Feasibility study of the water Cherenkov detector as a D-T fusion power monitor in the system using neutron activation of flowing water. First experimental phase

    International Nuclear Information System (INIS)

    Verzilov, Yury M.; Ochiai, Kentaro; Nishitani, Takeo

    2003-09-01

    The technique of monitoring D-T neutrons using water flow is based on the reaction of the 16 O(n, p) 16 N. In order to significantly improve the D-T neutron monitoring system in the ITER reactor in comparison with the system that uses a γ-ray scintillation detector, a new approach was proposed. The basic idea of this approach is to utilize the Cherenkov light, produced by energetic β-particles from 16 N in water near the first wall of the fusion reactor, and then deliver the light by the optical fiber to the remote light detector. The proof of the principle experiment is divided into two phases. The main idea of the first experimental phase is to examine Cherenkov light measurements using a remotely located water and light detector. During the second phase the water radiator will be placed next to the neutron source, then the Cherenkov light will be transferred by an optical fiber to the remotely located light detector. For the purpose of the first experimental phase, a water Cherenkov detector was installed in the shielded measurement room. A closed water loop, with circulating water, was used to transport 16 N from the D-T source to the Cherenkov detector. The experiment was carried out at FNS/JAERI, with the accelerator set to a direct current mode, the source neutron yield around 2 x 10 11 n/s, and the water flowage approximately 2 m/s. The registered Cherenkov signal was identified as the light produced by β-particles from 16 N using the time decay and the energy spectra data. According to the present study, the water Cherenkov detector is very effective for measurements of the 16 N activity, due to high counting efficiency, absence of the scintillation detector and simplicity of the method. (author)

  13. Development of in vitro techniques for individual monitoring of {sup 32}P; Desenvolvimento de tecnicas in vitro para monitoracao individual de {sup 32}P

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, A.P.F.; Sousa, W.O.; Dantas, A.L.A.; Dantas, B.M., E-mail: adantas@ird.gov.br, E-mail: wander@ird.gov.br, E-mail: bmdantas@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Divisao de Dosimetria

    2016-07-01

    The {sup 32}P is used in the form of liquid unsealed sources in medical facilities, research and teaching, representing a risk of internal exposure in routine activities and in case of accidental incorporation. The evaluation of {sup 32}P incorporation can be accomplished through in vitro bioanalysis of urine. This paper aims to provide a methodology to analyze {sup 32}P in biological samples, applicable to internal individual monitoring using liquid scintillation technique. The minimum detectable activity of the system was determined and the sensitivity of the technique was evaluated, based on the detected minimum effective dose. (author)

  14. Intense fusion neutron sources

    Science.gov (United States)

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

    2010-04-01

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

  15. Fast neutron imaging device and method

    Science.gov (United States)

    Popov, Vladimir; Degtiarenko, Pavel; Musatov, Igor V.

    2014-02-11

    A fast neutron imaging apparatus and method of constructing fast neutron radiography images, the apparatus including a neutron source and a detector that provides event-by-event acquisition of position and energy deposition, and optionally timing and pulse shape for each individual neutron event detected by the detector. The method for constructing fast neutron radiography images utilizes the apparatus of the invention.

  16. Development of a Wireless Sensor Network for Individual Monitoring of Panels in a Photovoltaic Plant

    Directory of Open Access Journals (Sweden)

    Miguel J. Prieto

    2014-01-01

    Full Text Available With photovoltaic (PV systems proliferating in the last few years due to the high prices of fossil fuels and pollution issues, among others, it is extremely important to monitor the efficiency of these plants and optimize the energy production process. This will also result in improvements related to the maintenance and security of the installation. In order to do so, the main parameters in the plant must be continuously monitored so that the appropriate actions can be carried out. This monitoring should not only be carried out at a global level, but also at panel-level, so that a better understanding of what is actually happening in the PV plant can be obtained. This paper presents a system based on a wireless sensor network (WSN that includes all the components required for such monitoring as well as a power supply obtaining the energy required by the sensors from the photovoltaic panels. The system proposed succeeds in identifying all the nodes in the network and provides real-time monitoring while tracking efficiency, features, failures and weaknesses from a single cell up to the whole infrastructure. Thus, the decision-making process is simplified, which contributes to reducing failures, wastes and, consequently, costs.

  17. Development of a wireless sensor network for individual monitoring of panels in a photovoltaic plant.

    Science.gov (United States)

    Prieto, Miguel J; Pernía, Alberto M; Nuño, Fernando; Díaz, Juan; Villegas, Pedro J

    2014-01-30

    With photovoltaic (PV) systems proliferating in the last few years due to the high prices of fossil fuels and pollution issues, among others, it is extremely important to monitor the efficiency of these plants and optimize the energy production process. This will also result in improvements related to the maintenance and security of the installation. In order to do so, the main parameters in the plant must be continuously monitored so that the appropriate actions can be carried out. This monitoring should not only be carried out at a global level, but also at panel-level, so that a better understanding of what is actually happening in the PV plant can be obtained. This paper presents a system based on a wireless sensor network (WSN) that includes all the components required for such monitoring as well as a power supply obtaining the energy required by the sensors from the photovoltaic panels. The system proposed succeeds in identifying all the nodes in the network and provides real-time monitoring while tracking efficiency, features, failures and weaknesses from a single cell up to the whole infrastructure. Thus, the decision-making process is simplified, which contributes to reducing failures, wastes and, consequently, costs.

  18. Organic liquid scintillation detectors for on-the-fly neutron/gamma alarming and radionuclide identification in a pedestrian radiation portal monitor

    Energy Technology Data Exchange (ETDEWEB)

    Paff, Marc Gerrit; Ruch, Marc L; Poitrasson-Riviere, Alexis; Sagadevan, Athena; Clarke, Shaun D; Pozzi, Sara

    2015-07-21

    We present new experimental results from a radiation portal monitor based on the use of organic liquid scintillators. The system was tested as part of a {sup 3}He-free radiation portal monitor testing campaign at the European Commission’s Joint Research Centre in Ispra, Italy, in February 2014. The radiation portal monitor was subjected to a wide range of test conditions described in ANSI N42.35, including a variety of gamma-ray sources and a 20,000 n/s {sup 252}Cf source. A false alarm test tested whether radiation portal monitors ever alarmed in the presence of only natural background. The University of Michigan Detection for Nuclear Nonproliferation Group’s system triggered zero false alarms in 2739 trials. It consistently alarmed on a variety of gamma-ray sources travelling at 1.2 m/s at a 70 cm source to detector distance. The neutron source was detected at speeds up to 3 m/s and in configurations with up to 8 cm of high density polyethylene shielding. The success of on-the-fly radionuclide identification varied with the gamma-ray source measured as well as with which of two radionuclide identification methods was used. Both methods used a least squares comparison between the measured pulse height distributions to library spectra to pick the best match. The methods varied in how the pulse height distributions were modified prior to the least squares comparison. Correct identification rates were as high as 100% for highly enriched uranium, but as low as 50% for {sup 241}Am. Both radionuclide identification algorithms produced mixed results, but the concept of using liquid scintillation detectors for gamma-ray and neutron alarming in radiation portal monitor was validated.

  19. Monitoring of peri-operative fluid administration by individualized goal-directed therapy

    DEFF Research Database (Denmark)

    Bundgaard-Nielsen, M; Holte, Kathrine; Secher, N H

    2007-01-01

    (n = 725) found a reduced hospital stay. Post-operative nausea and vomiting (PONV) and ileus were reduced in three studies and complications were reduced in four studies. Of the monitors that may be applied for goal-directed therapy, only oesophageal Doppler has been tested adequately; however......, several other options exist. CONCLUSION: Goal-directed therapy with the maximization of flow-related haemodynamic variables reduces hospital stay, PONV and complications, and facilitates faster gastrointestinal functional recovery. So far, oesophageal Doppler is recommended, but other monitors...

  20. Error-Monitoring in Response to Social Stimuli in Individuals with Higher-Functioning Autism Spectrum Disorder

    Science.gov (United States)

    McMahon, Camilla M.; Henderson, Heather A.

    2014-01-01

    Error-monitoring, or the ability to recognize one's mistakes and implement behavioral changes to prevent further mistakes, may be impaired in individuals with Autism Spectrum Disorder (ASD). Children and adolescents (ages 9-19) with ASD (n = 42) and typical development (n = 42) completed two face processing tasks that required discrimination of either the gender or affect of standardized face stimuli. Post-error slowing and the difference in Error-Related Negativity amplitude between correct and incorrect responses (ERNdiff) were used to index error-monitoring ability. Overall, ERNdiff increased with age. On the Gender Task, individuals with ASD had a smaller ERNdiff than individuals with typical development; however, on the Affect Task, there were no significant diagnostic group differences on ERNdiff. Individuals with ASD may have ERN amplitudes similar to those observed in individuals with typical development in more social contexts compared to less social contexts due to greater consequences for errors, more effortful processing, and/or reduced processing efficiency in these contexts. Across all participants, more post-error slowing on the Affect Task was associated with better social cognitive skills. PMID:25066088

  1. Monitoring of trace-levels of herbicides in the Cachoeira River in Bahia State, Brazil, by neutron activation analysis

    International Nuclear Information System (INIS)

    Severo, Maria Isabel; Oliveira, Eduardo; Caribe, Ana Cristina; Revel, Gilles; Oliveira, Arno Heeren

    1995-01-01

    A systematic study was undertaken in order to find out which of the most relevant elements can be determined in water normal conditions by non-destructive neutron activation and a suitable mono standard method. Standardized water from Cachoeira river and croustaceous samples were brought to dryness by freeze-drying and irradiated in quartz at a neutron flux of 10 14 cm -2 s -1 . Trace element contents in quartz ampoules from different origins were determined separately. The following elements were preliminarily identified: Cr, Co, Cu, Br, Sb, Cs, Ce, Nb, Au, Pa, Zn, La, Sm. (author). 10 refs., 2 tabs

  2. The neutron 'thunder' accompanying the extensive air shower

    OpenAIRE

    Erlykin, A. D.

    2007-01-01

    Simulations show that neutrons are the most abundant component among extensive air shower hadrons. However, multiple neutrons which appear with long delays in neutron monitors nearby the EAS core ('neutron thunder') are mostly not the neutrons of the shower, but have a secondary origin. The bulk of them is produced by high energy EAS hadrons hitting the monitors. The delays are due to the termalization and diffusion of neutrons in the moderator and reflector of the monitor accompanied by the ...

  3. Prototype Neutron Energy Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Stephen Mitchell, Sanjoy Mukhopadhyay, Richard Maurer, Ronald Wolff

    2010-06-16

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

  4. Using Data to Individualize a Multicomponent, Technology-Based Self-Monitoring Intervention

    Science.gov (United States)

    Bruhn, Allison Leigh; Vogelgesang, Kari; Fernando, Josephine; Lugo, Wilbeth

    2016-01-01

    Technology in schools is abundant as is the call for evidence-based interventions for students who need additional support to be successful. One promising use of technology is for self-monitoring interventions aimed at improving classroom behavior. In this study, two middle school students with disabilities used a multicomponent, self-monitoring…

  5. The effect of parental monitoring on trajectories of disordered eating attitudes and behaviors among adolescents: An individual growth curve analysis.

    Science.gov (United States)

    Martinson, Laura E; Esposito-Smythers, Christianne; Blalock, Dan V

    2016-12-01

    The primary aim of the present study was to examine whether parental monitoring, as reported by adolescents and their parents, predicts more or less favorable trajectories of disordered eating behavior and attitudes over the course of one year in a sample of adolescent males and females. An additional aim was to explore whether these trajectories vary when study analyses are limited to females. Participants included 87 adolescents (mean age = 15.5 ± 1.4) in mental health treatment and their parents. Self-report measures included the Parental Monitoring Questionnaire, completed at baseline, and the Eating Attitudes Test-Dieting Subscale, completed at baseline as well as 6-month and 12-month follow-ups. Individual growth curve (IGC) analyses were used to examine change in disordered eating behavior and attitudes. Adolescents who reported lower parental monitoring showed trajectories characterized by increases in disordered eating attitudes and behaviors. The same pattern emerged when using parent report of monitoring, though only a trend was evident. When analyses were restricted to females, the main effect of parental and adolescent report of monitoring on disordered eating were equally strong. Results may suggest that parents who are less knowledgeable about their adolescents' daily lives, may be less aware of potential disordered eating attitudes and behaviors, and thus less likely to intervene. Findings could be used to inform family-based interventions for this population. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Comparison of neutron and gamma irradiation effects on KU1 fused silica monitored by electron paramagnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Bravo, D. [Department Fisica de Materiales, Universidad Autonoma de Madrid, E-28049 Madrid (Spain)], E-mail: david.bravo@uam.es; Lagomacini, J.C. [Department Fisica de Materiales, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Leon, M.; Martin, P. [Materiales para Fusion, CIEMAT, Avda. Complutense 22, E-28040 Madrid (Spain); Martin, A. [Department Fisica e Instalaciones, ETS Arquitectura UPM, E-28040 Madrid (Spain); Lopez, F.J. [Department Fisica de Materiales, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Ibarra, A. [Materiales para Fusion, CIEMAT, Avda. Complutense 22, E-28040 Madrid (Spain)

    2009-06-15

    Electron paramagnetic resonance (EPR) studies have been carried out on KU1 fused silica irradiated with neutrons at fluences 10{sup 21} and 10{sup 22} n/m{sup 2}, and gamma-ray doses up to 12 MGy. The effects of post-irradiation thermal annealing treatments, up to 850 deg. C, have also been investigated. Paramagnetic oxygen-related defects (POR and NBOHC) and E'-type defects have been identified and their concentration has been measured as a function of neutron fluence, gamma dose and post-irradiation annealing temperature. It is found that neutrons at the highest fluence generate a much higher concentration of defects (mainly E' and POR, both at concentrations about 5 x 10{sup 18} spins/cm{sup 3}) than gamma irradiations at the highest dose (mainly E' at a concentration about 4 x 10{sup 17} spins/cm{sup 3}). Moreover, for gamma-irradiated samples a lower treatment temperature (about 400 deg. C) is required to annihilate most of the observed defects than for neutron-irradiated ones (about 600 deg. C)

  7. A new monitor set for the determination of neutron flux parameters in short-time k0-NAA

    Czech Academy of Sciences Publication Activity Database

    Kubešová, Marie; Kučera, Jan; Fikrle, Marek

    2011-01-01

    Roč. 656, č. 1 (2011), s. 61-64 ISSN 0168-9002 R&D Projects: GA ČR GA202/09/0363 Institutional research plan: CEZ:AV0Z10480505 Keywords : Short-time activation analysis * ko standartizacion * neutron flux parameters Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.207, year: 2011

  8. Neutron personnel dosimetry

    International Nuclear Information System (INIS)

    Griffith, R.V.

    1981-01-01

    The current state-of-the-art in neutron personnel dosimetry is reviewed. Topics covered include dosimetry needs and alternatives, current dosimetry approaches, personnel monitoring devices, calibration strategies, and future developments

  9. Atlas of neutron resonances

    CERN Document Server

    Mughabghab, Said

    2018-01-01

    Atlas of Neutron Resonances: Resonance Properties and Thermal Cross Sections Z= 1-60, Sixth Edition, contains an extensive list of detailed individual neutron resonance parameters for Z=1-60, as well as thermal cross sections, capture resonance integrals, average resonance parameters and a short survey of the physics of thermal and resonance neutrons. The long introduction contains: nuclear physics formulas aimed at neutron physicists; topics of special interest such as valence neutron capture, nuclear level density parameters, and s-, p-, and d-wave neutron strength functions; and various comparisons of measured quantities with the predictions of nuclear models, such as the optical model. As in the last edition, additional features have been added to appeal to a wider spectrum of users. These include: spin-dependent scattering lengths that are of interest to solid-state physicists, nuclear physicists and neutron evaluators; calculated and measured Maxwellian average 5-keV and 30-keV capture cross sections o...

  10. Monitoring and assessment of individual doses of occupationally exposed workers due to external radiation

    International Nuclear Information System (INIS)

    Kitaw, S. T.

    2015-05-01

    Exposure to external radiation occurs in many occupations. Any exposure to ionizing radiation has the tendency to change the biochemical make-up of the human body which may result in biological health effects of ionizing radiation. This study reviews the monitoring and assessment of external radiation doses in industrial radiography using thermoluminescence and direct reading dosimeters. Poor handling procedures such as inadequate engineering control of equipment, safety culture, management, and inadequate assessment and monitoring of doses are the causes of most of the reported cases of exposure to external radiation in industrial radiography. Occupational exposure data in industrial radiography from UNSCEAR report 2008 was discussed and recommendations were made to regulatory authorities, operating organizations and radiographers. (au)

  11. Modernization in-core monitoring system, of WWER-1000 reactors (W-320) by fuel assemblies with individual characteristics using

    International Nuclear Information System (INIS)

    Mitin, V. I.; Semchenkov, J. M.; Kalinushkin, A. E.

    2007-01-01

    The present report covers object, conception, engineering solution of construction of modern system of high-powered reactor in-core control, including WWER-1000 (V-320) reactors. It is known that ICMS main task is on-line monitoring distribution of power release field and its functioning independently of design programs to avoid common reason error. It is shown in what way field of power release recovery has been carrying on; rest on the signals of in-core neutron and temperature sensors. On the base of the obtained and refined information there have being automatically generated signals of preventive and emergency protection on local parameters (linear power to the maximum intensive fuel elements, reserve to heat exchange crisis, 'picking factor'). There have represented technology on sensors and processing methods of SPND and TC signals, ICIS composition and structure, program hard ware, system and applied software. Structure, composition and the taken decisions allow combining class 1E and class B and C tasks in accordance with international norms of separation and safety classes' realization. At present ICIS-M is a system, providing implementation of control, safety, information and diagnostic functions, which allow securing actual increase of quality, reliability and safety in operation of nuclear fuel and NPP units. And at the same time it reduces human factor negative influence to core work thermo technical eliability in the operational process (Authors)

  12. Individualized guidance and telephone monitoring in a self-supervised home-based physiotherapeutic program in Parkinson

    Directory of Open Access Journals (Sweden)

    Ihana Thaís Guerra de Oliveira Gondim

    Full Text Available Abstract Introduction: Home therapeutic exercises have been a target of interest in the treatment of the Parkinson's disease (PD. The way that the physical therapist guides and monitors these exercises can impact the success of therapy. Objective: To evaluate the effects of individualized orientation and monitoring by telephone in a self-supervised home therapeutic exercise program on signs and symptoms of PD and quality of life (QoL. Methods: Single-blind randomized clinical trials with 28 people with PD (Hoehn and Yahr 1 to 3. Patients were randomized into two groups: experimental and control. The experimental group had a meeting with individualized guidance about physiotherapy exercises present in a manual, received the manual to guide their activities at home and obtained subsequent weekly monitoring by telephone. The control group received the usual cares by the service. Both were orientated to carry out exercises three times a week during 12 weeks. Was evaluated: (1 activities of daily living (ADL and motor examination sections of the Unified Parkinson's Disease Rating Scale (UPDRS and QoL by the Parkinson Disease Questionnaire 39 (PDQ-39. The analysis between groups was performed by the Mann-Whitney test and intragroup through the Wilcoxon (p < 0.05. Results: Significant improvement in ADL (p= 0.001 and motor examination (p= 0.0008 of the UPDRS, PDQ-39 total (p = 0.027 and dimensions mobility (p = 0.027, emotional well-being (p= 0.021 and bodily discomfort (p = 0.027 in the experimental group compared to the control group. Conclusion: The individualized guidance and weekly monitoring by telephone in a self-supervised home therapeutic exercises program promoted positive effects on ADL, motor examination and QoL of people in early stages of PD.

  13. Individual recognition of territorial peregrine falcons Falco peregrinus: a key for long-term monitoring programmes.

    Directory of Open Access Journals (Sweden)

    ZUBEROGOITIA, I., ENRIQUE MARTÍNEZ, J., ZABALA, J.

    2013-01-01

    including the shape, length and size of the moustache and the dark marks that extend from the nape to the cheek and neck; design, size, density and distribution of the spots on the breast, throat, neck and cheek; and the colour of the breast and neck. From 1997 to 2013 we identified 83 males and 96 females in 35 territories. We found phenotypic variation among individuals when the combination of the possible subgroups of identification characters was considered, which constitutes an opportunity to recognise individual hawks without marking them with artificial tags.

  14. Individualized treatment of multidrug-resistant tuberculosis using therapeutic drug monitoring

    Directory of Open Access Journals (Sweden)

    Mathieu S Bolhuis

    2016-01-01

    Conclusion: TDM is highly valuable to individualize and optimize treatment of complex MDR-TB patients. TDM is routinely applied in Tuberculosis Center Beatrixoord, and high success rates for treatment of MDR-TB patients have been achieved. DBS and LSS make implementation of TDM feasible, even in low- and middle-income countries.

  15. Therapeutic drug monitoring for the individualization of docetaxel dosing: a randomized pharmacokinetic study

    NARCIS (Netherlands)

    Engels, Frederike K.; Loos, Walter J.; van der Bol, Jessica M.; de Bruijn, Peter; Mathijssen, Ron H. J.; Verweij, Jaap; Mathot, Ron A. A.

    2011-01-01

    Docetaxel pharmacokinetic (PK) parameters, notably clearance and exposure (AUC), are characterized by large interindividual variability. The purpose of this study was to evaluate the effect of PK-guided [area under the plasma concentration versus time curve (AUC) targeted], individualized docetaxel

  16. Harmonisation and dosimetric quality assurance in individual monitoring for external radiation

    DEFF Research Database (Denmark)

    Bartlett, D.T.; Ambrosi, P.; Back, C.

    2001-01-01

    The current situation amongst Member States is that there are widely differing national requirements for dosimetric services and for dosemeter performance. It is clear that with the free movement of workers within the European Union (EU) and the requirements for individual dosimetry given in Coun...

  17. Systematic processing of the external individual monitoring data obtained by photographic film and capacitor dosemeters

    International Nuclear Information System (INIS)

    Krueger, F.; Shtuk, D.

    1983-01-01

    Individual radiation load measurements have been carried out both with photographic film and capacitor type dosemeters (CD). Systematic statistics methods were applied for the obtained data processing. The CD data were shown to exceed those measured with the film dosemeters. Specific features of the CD application are revealed that should be taken into account in practice [ru

  18. Individual Monitoring of Vocal Effort with Relative Fundamental Frequency: Relationships with Aerodynamics and Listener Perception

    Science.gov (United States)

    Lien, Yu-An S.; Michener, Carolyn M.; Eadie, Tanya L.; Stepp, Cara E.

    2015-01-01

    Purpose: The acoustic measure relative fundamental frequency (RFF) was investigated as a potential objective measure to track variations in vocal effort within and across individuals. Method: Twelve speakers with healthy voices created purposeful modulations in their vocal effort during speech tasks. RFF and an aerodynamic measure of vocal effort,…

  19. Routine individual monitoring of aircraft crew exposure; Czech experience and results 1998-2008

    Czech Academy of Sciences Publication Activity Database

    Malušek, Alexandr; Ploc, Ondřej; Kovář, Ivan; Brabcová, Kateřina; Spurný, František

    2011-01-01

    Roč. 144, 1-4 (2011), s. 684-687 ISSN 0144-8420 R&D Projects: GA ČR GA205/09/0171 Grant - others:Evropské společenství ILSRA(XE) FIGM-CT2000-00068 $c; JSPS(JP) P09753 Institutional research plan: CEZ:AV0Z10480505 Keywords : aircraft * crew exposure * monitoring Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.822, year: 2011

  20. Research and development program in reactor diagnostics and monitoring with neutron noise methods. Stage 6. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Pazsit, I.; Demaziere, C.; Avdic, S.; Dahl, B. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Reactor Physics

    2000-07-15

    The program executed in Stage 6 consists of three parts and the work performed in each part is summarized below. In Stage 5 experimental and numerical investigations were made of the applicability of using the gradient of the static flux to locate a neutron source in a water tank. The measurements were made with a recently developed very small optical fibre detector, and the supporting calculations done with the Monte Carlo code MCNP. In the present Stage, the work was extended to the investigation of the true neutron current. Based on the same thin fibre detector, a detector capable of measuring the neutron current was constructed. This was achieved by covering one side of the detector with a cadmium cladding. With this detector, laboratory measurements were carried out the same way as with the gradient detector in the previous stage. A neutron source located in a water tank was used and the flux and the current measured in points with varying distance from the source. The direction of the neutron current vector indicates the direction of the source from the measurement point, and the ratio of the absolute value of the current to the flux can be used to estimate the distance to the source. For the latter, values of the same ratio as a function of the source-detector distance must be available from theory or calculations. We have used earlier MCNP calculations of the gradient/flux ratio for this purpose. The results show that it is possible to measure the true neutron current with the detector construction and, by comparing them to MCNP calculations, to determine the distance to the source and thereby also determine the position of the source. In the previous stage, we have developed a numerical finite-difference code which can be used to calculate the dynamic adjoint (i.e. the transfer function) in a heterogeneous 1-D reactor system and in two-group diffusion theory. The purpose in this Stage was to extend the calculations to 2-D and 3-D cases. This was achieved

  1. The Change of the Seebeck Coefficient Due to Neutron Irradiation and Thermal Fatigue of Nuclear Reactor Pressure Vessel Steel and its Application to the Monitoring of Material Degradation

    International Nuclear Information System (INIS)

    Niffenegger, M.; Reichlin, K.; Kalkhof, D.

    2002-05-01

    The monitoring of material degradation, that might be caused by neutron irradiation and thermal fatigue, is an important topic in lifetime extension of nuclear power plants. We therefore investigated the application of the Seebeck effect for determining material degradation of common reactor pressure vessel steel. The Seebeck coefficient (SC) of several irradiated Charpy specimens made from Japanese JRQ-steel were measured. The specimens suffered a fluence from 0 up to 4.5 x 10 19 neutrons per cm 2 with energies higher than 1 MeV. The measured changes of the SC within this range were about 500 nV, increasing continuously in the range under investigation. Some indications of saturation appeared at fluencies larger than 4.55 x 10 19 neutrons per cm 2 . We obtained a linear dependency between the SC and the temperature shift ΔT 41 of the Charpy-Energy- Temperature curve which is widely used to characterize material embrittlement. Similar measurements were performed on specimens made from the widely used austenitic steel X6CrNiTi18-10 (according to DIN 1.4541) that were fatigued by applying a cyclic strain amplitude of 0.28%. For this kind of fatigue the observed change of SC was somewhat smaller than for the irradiated specimens. Further investigations were made to quantify the size of the gage volume in which the thermoelectric power is generated. It appeared that the information gathered from a Thermo Electric Power (TEP) measurement is very local. To overcome this problem we propose a novel TEP-method using a Thermoelectric Scanning Microscope (TSM). We finally conclude that the change of the SC has a potential for monitoring of material degradation due to neutron irradiation and thermal fatigue, but it has to be taken into account that several influencing parameters could contribute to the TEP in either an additional or extinguishing manner. A disadvantage of the method is the requirement of a clean surface without any oxide layer. A part of this disadvantage can

  2. Fibromyalgia Symptom Reduction by Online Behavioral Self-monitoring, Longitudinal Single Subject Analysis and Automated Delivery of Individualized Guidance.

    Science.gov (United States)

    Collinge, William; Yarnold, Paul; Soltysik, Robert

    2013-09-01

    Fibromyalgia (FM) is a complex chronic pain condition that is difficult to treat. The prevailing approach is an integration of pharmacological, psycho-educational, and behavioral strategies. Information technology offers great potential for FM sufferers to systemically monitor symptoms as well as potential impacts of various management strategies. This study aimed to evaluate effects of a web-based, self-monitoring and symptom management system (SMARTLog) that analyzes personal self-monitoring data and delivers data-based feedback over time. Subjects were self-referred, anonymous, and recruited via publicity on FM advocacy websites. Standardized instruments assessed health status, self-efficacy, and locus of control at baseline and monthly during participation. Subjects were encouraged to complete the SMARTLog several times weekly. Within-subject, univariate, and multivariate analyses were used to derive classification trees for each user associating specific behavior variables with symptom levels over time. Moderate use (3 times weekly x 3 months) increased likelihood of clinically significant improvements in pain, memory, gastrointestinal problems, depression, fatigue, and concentration; heavy use (4.5 times weekly x five months) produced the above plus improvement in stiffness and sleep difficulties. Individualized, web-based behavioral self-monitoring with personally-tailored feedback can enable FM sufferers to significantly reduce symptom levels over time.

  3. Self-monitoring of blood pressure in hypertension: A systematic review and individual patient data meta-analysis.

    Science.gov (United States)

    Tucker, Katherine L; Sheppard, James P; Stevens, Richard; Bosworth, Hayden B; Bove, Alfred; Bray, Emma P; Earle, Kenneth; George, Johnson; Godwin, Marshall; Green, Beverly B; Hebert, Paul; Hobbs, F D Richard; Kantola, Ilkka; Kerry, Sally M; Leiva, Alfonso; Magid, David J; Mant, Jonathan; Margolis, Karen L; McKinstry, Brian; McLaughlin, Mary Ann; Omboni, Stefano; Ogedegbe, Olugbenga; Parati, Gianfranco; Qamar, Nashat; Tabaei, Bahman P; Varis, Juha; Verberk, Willem J; Wakefield, Bonnie J; McManus, Richard J

    2017-09-01

    Self-monitoring of blood pressure (BP) appears to reduce BP in hypertension but important questions remain regarding effective implementation and which groups may benefit most. This individual patient data (IPD) meta-analysis was performed to better understand the effectiveness of BP self-monitoring to lower BP and control hypertension. Medline, Embase, and the Cochrane Library were searched for randomised trials comparing self-monitoring to no self-monitoring in hypertensive patients (June 2016). Two reviewers independently assessed articles for eligibility and the authors of eligible trials were approached requesting IPD. Of 2,846 articles in the initial search, 36 were eligible. IPD were provided from 25 trials, including 1 unpublished study. Data for the primary outcomes-change in mean clinic or ambulatory BP and proportion controlled below target at 12 months-were available from 15/19 possible studies (7,138/8,292 [86%] of randomised participants). Overall, self-monitoring was associated with reduced clinic systolic blood pressure (sBP) compared to usual care at 12 months (-3.2 mmHg, [95% CI -4.9, -1.6 mmHg]). However, this effect was strongly influenced by the intensity of co-intervention ranging from no effect with self-monitoring alone (-1.0 mmHg [-3.3, 1.2]), to a 6.1 mmHg (-9.0, -3.2) reduction when monitoring was combined with intensive support. Self-monitoring was most effective in those with fewer antihypertensive medications and higher baseline sBP up to 170 mmHg. No differences in efficacy were seen by sex or by most comorbidities. Ambulatory BP data at 12 months were available from 4 trials (1,478 patients), which assessed self-monitoring with little or no co-intervention. There was no association between self-monitoring and either lower clinic or ambulatory sBP in this group (clinic -0.2 mmHg [-2.2, 1.8]; ambulatory 1.1 mmHg [-0.3, 2.5]). Results for diastolic blood pressure (dBP) were similar. The main limitation of this work was that significant

  4. The problems of individual monitoring for internal exposure of monazite storage facility workers

    International Nuclear Information System (INIS)

    Ekidin, A.; Kirdin, I.; Yarmoshenko, I.; Zhukovsky, M.

    2006-01-01

    traditionally two situations of internal inhalation exposure by alpha emitting nuclides are considered in radiological protection: occupational exposure due to inhalation of plutonium aerosols; inhalation exposure by 222 Rn daughters in working places and in home. for these situations the problems of radioactive aerosols intake, nuclide dynamics in human body, internal dosimetry, nuclide excretion, monitoring of internal exposure have been investigated in details especially for plutonium inhalation exposure. The results of these studies are presented in details in ICRP Publications and UNSCEAR reports. However there is very specific case in which the special analysis of internal inhalation exposure is need. it is the working places with anomalous, extremely high concentration of thoron ( 220 Rn) daughters. The problems of internal radiation exposure of workers in such working place are the main topic of this publication. (authors)

  5. Neutron Imaging Reveals Internal Plant Hydraulic Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Jeffrey [ORNL; Bilheux, Hassina Z [ORNL; Kang, Misun [ORNL; Voisin, Sophie [ORNL; Cheng, Chu-Lin [ORNL; Horita, Jusuke [ORNL; Perfect, Edmund [ORNL

    2013-01-01

    Many terrestrial ecosystem processes are constrained by water availability and transport within the soil. Knowledge of plant water fluxes is thus critical for assessing mechanistic processes linked to biogeochemical cycles, yet resolution of root structure and xylem water transport dynamics has been a particularly daunting task for the ecologist. Through neutron imaging, we demonstrate the ability to non-invasively monitor individual root functionality and water fluxes within Zea mays L. (maize) and Panicum virgatum L. (switchgrass) seedlings growing in a sandy medium. Root structure and growth were readily imaged by neutron radiography and neutron computed tomography. Seedlings were irrigated with water or deuterium oxide and imaged through time as a growth lamp was cycled on to alter leaf demand for water. Sub-millimeter scale resolution reveals timing and magnitudes of root water uptake, redistribution within the roots, and root-shoot hydraulic linkages, relationships not well characterized by other techniques.

  6. A panel of microsatellites to individually identify leopards and its application to leopard monitoring in human dominated landscapes

    Directory of Open Access Journals (Sweden)

    Selvaraj Velu

    2009-12-01

    Full Text Available Abstract Background Leopards are the most widely distributed of the large cats, ranging from Africa to the Russian Far East. Because of habitat fragmentation, high human population densities and the inherent adaptability of this species, they now occupy landscapes close to human settlements. As a result, they are the most common species involved in human wildlife conflict in India, necessitating their monitoring. However, their elusive nature makes such monitoring difficult. Recent advances in DNA methods along with non-invasive sampling techniques can be used to monitor populations and individuals across large landscapes including human dominated ones. In this paper, we describe a DNA-based method for leopard individual identification where we used fecal DNA samples to obtain genetic material. Further, we apply our methods to non-invasive samples collected in a human-dominated landscape to estimate the minimum number of leopards in this human-leopard conflict area in Western India. Results In this study, 25 of the 29 tested cross-specific microsatellite markers showed positive amplification in 37 wild-caught leopards. These loci revealed varied levels of polymorphism (four-12 alleles and heterozygosity (0.05-0.79. Combining data on amplification success (including non-invasive samples and locus specific polymorphisms, we showed that eight loci provide a sibling probability of identity of 0.0005, suggesting that this panel can be used to discriminate individuals in the wild. When this microsatellite panel was applied to fecal samples collected from a human-dominated landscape, we identified 7 individuals, with a sibling probability of identity of 0.001. Amplification success of field collected scats was up to 72%, and genotype error ranged from 0-7.4%. Conclusion Our results demonstrated that the selected panel of eight microsatellite loci can conclusively identify leopards from various kinds of biological samples. Our methods can be used to

  7. Emotional Self-Regulation of Individuals with Autism Spectrum Disorders: Smartwatches for Monitoring and Interaction

    Directory of Open Access Journals (Sweden)

    Juan C. Torrado

    2017-06-01

    Full Text Available In this paper, we analyze the needs of individuals with Autism Spectrum Disorders (ASD to have a pervasive, feasible and non-stigmatizing form of assistance in their emotional self-regulation, in order to ease certain behavioral issues that undermine their mental health throughout their life. We argue the potential of recent widespread wearables, and more specifically smartwatches, to achieve this goal. Then, a smartwatch system that implements a wide range of self-regulation strategies and infers outburst patterns from physiological signals and movement is presented, along with an authoring tool for smartphones that is to be used by caregivers or family members to create and edit these strategies, in an adaptive way. We conducted an intensive experiment with two individuals with ASD who showed varied, representative behavioral responses to their emotional dysregulation. Both users were able to employ effective, customized emotional self-regulation strategies by means of the system, recovering from the majority of mild stress episodes and temper tantrums experienced in the nine days of experiment in their classroom.

  8. Individual monitoring with official electronic dosemeters in Germany - concepts and reality

    International Nuclear Information System (INIS)

    Martini, E.; Wahl, W.; Huebner, S.; Freynhagen, D.; Staemmler, M.

    2005-01-01

    Full text: Active (electronic) personal dosemeters (APD) are radiometers, which are equipped as active or passive dosimeters. They can directly indicate a dose rate and/or the dose integrated during a certain period (direct-indicating, active electronic personal dosemeters mentioned) or only over a separate reader (direct-selectable, passive electronic personal dosemeters mentioned). A concept is presented for the use of passive or active electronic personal dosemeters in Germany as official dosemeters, e.g. in hospitals. The concept features a net-based approach for secure data communication between readers for passive and active electronic personal dosemeters und the official personal dosimetry monitoring service(s), taking the German policies (StrISchV und RoeV in hospitals) into account. The net-based solution includes a processor controlled interface via TCP/IP connected to the dosimetry reader(s), und reader interfaces, an official interim data bank and all the necessary equipment such as PC, Raid-configuration, USV support, network connection and further details. Investigations have been started to achieve highest-level data manipulation security, data completeness und data correctness. (author)

  9. Instrumental neutron activation analysis of 23 individual food articles from a high altitude region. Part 1. Determination of 14 essential minor and trace elements

    International Nuclear Information System (INIS)

    Waheed, S.; Zaidi, J.H.; Ahmad, S.; Saleem, M.

    2002-01-01

    Twenty-three individual food items commonly consumed in a high altitude region (Kashmir) have been investigated using instrumental neutron activation analysis. The concentration of Ca, Cl, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Se, Sn, and Zn is reported for these food articles. For quality assurance of our data, IAEA and NIST standard reference materials have also been studied. The dietary intake of these elements was calculated in accordance with the weekly food selection habits of the residents of this area. The dietary contribution of most of these elements was found to be in agreement to the RDA/ESadi levels. The purpose was to design a database of essential elements for this area and to study the adequacy levels of these elements in different dietary items. Fairly adequate intake of Ca, Co, Cr, Cu, Fe, Mg, Mn, Mo, Se, Sn, and Zn through these foodstuffs is reported, whereas, lower intakes through these items were found for Cl, K, and Na. (author)

  10. Conversion coefficients for individual monitoring calculated with integrated tiger series, ITS3, Monte Carlo code

    International Nuclear Information System (INIS)

    Devine, R.T.; Hsu, Hsiao-Hua

    1994-01-01

    The current basis for conversion coefficients for calibrating individual photon dosimeters in terms of dose equivalents is found in the series of papers by Grosswent. In his calculation the collision kerma inside the phantom is determined by calculation of the energy fluence at the point of interest and the use of the mass energy absorption coefficient. This approximates the local absorbed dose. Other Monte Carlo methods can be sued to provide calculations of the conversion coefficients. Rogers has calculated fluence-to-dose equivalent conversion factors with the Electron-Gamma Shower Version 3, EGS3, Monte Carlo program and produced results similar to Grosswent's calculations. This paper will report on calculations using the Integrated TIGER Series Version 3, ITS3, code to calculate the conversion coefficients in ICRU Tissue and in PMMA. A complete description of the input parameters to the program is given and comparison to previous results is included

  11. Monitoring functional capability of individuals with lower limb amputations using mobile phones.

    Directory of Open Access Journals (Sweden)

    Mark V Albert

    Full Text Available To be effective, a prescribed prosthetic device must match the functional requirements and capabilities of each patient. These capabilities are usually assessed by a clinician and reported by the Medicare K-level designation of mobility. However, it is not clear how the K-level designation objectively relates to the use of prostheses outside of a clinical environment. Here, we quantify participant activity using mobile phones and relate activity measured during real world activity to the assigned K-levels. We observe a correlation between K-level and the proportion of moderate to high activity over the course of a week. This relationship suggests that accelerometry-based technologies such as mobile phones can be used to evaluate real world activity for mobility assessment. Quantifying everyday activity promises to improve assessment of real world prosthesis use, leading to a better matching of prostheses to individuals and enabling better evaluations of future prosthetic devices.

  12. Studies on application of neutron activation analysis -Applied research on air pollution monitoring and development of analytical method of environmental samples

    International Nuclear Information System (INIS)

    Chung, Yong Sam; Moon, Jong Hwa; Chung, Young Ju; Jeong, Eui Sik; Lee, Sang Mi; Kang, Sang Hun; Cho, Seung Yeon; Kwon, Young Sik; Chung, Sang Wuk; Lee, Kyu Sung; Chun, Ki Hong; Kim, Nak Bae; Lee, Kil Yong; Yoon, Yoon Yeol; Chun, Sang Ki.

    1997-09-01

    This research report is written for results of applied research on air pollution monitoring using instrumental neutron activation analysis. For identification and standardization of analytical method, 24 environmental samples are analyzed quantitatively, and accuracy and precision of this method are measured. Using airborne particulate matter and biomonitor chosen as environmental indicators, trace elemental concentrations of sample collected at urban and rural site monthly are determined ant then the calculation of statistics and the factor analysis are carried out for investigation of emission source. Facilities for NAA are installed in a new HANARO reactor, functional test is performed for routine operation. In addition, unified software code for NAA is developed to improve accuracy, precision and abilities of analytical processes. (author). 103 refs., 61 tabs., 19 figs

  13. Glucose Monitoring in Individuals With Diabetes Using a Long-Term Implanted Sensor/Telemetry System and Model.

    Science.gov (United States)

    Lucisano, Joseph Y; Routh, Timothy L; Lin, Joe T; Gough, David A

    2017-09-01

    The use of a fully implanted first-generation prototype sensor/telemetry system is described for long-term monitoring of subcutaneous tissue glucose in a small cohort of people with diabetes. Sensors are based on a membrane containing immobilized glucose oxidase and catalase coupled to oxygen electrodes and a telemetry system, integrated as an implant. The devices remained implanted for up to 180 days, with signals transmitted every 2 min to external receivers. The data include signal recordings from glucose clamps and spontaneous glucose excursions, matched, respectively, to reference blood glucose and finger-stick values. The sensor signals indicate dynamic tissue glucose, for which there is no independent standard, and a model describing the relationship between blood glucose and the signal is, therefore, included. The values of all model parameters have been estimated, including the permeability of adjacent tissues to glucose, and equated to conventional mass transfer parameters. As a group, the sensor calibration varied randomly at an average rate of -2.6%/week. Statistical correlation indicated strong association between the sensor signals and reference glucose values. Continuous long-term glucose monitoring in individuals with diabetes is feasible with this system. All therapies for diabetes are based on glucose control, and therefore, require glucose monitoring. This fully implanted long-term sensor/telemetry system may facilitate a new era of management of the disease.

  14. External individual monitoring: experiments and simulations using Monte Carlo Method; Monitoracao individual externa: experimentos e simulacoes com o metodo de Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Carla da Costa

    2005-07-01

    In this work, we have evaluated the possibility of applying the Monte Carlo simulation technique in photon dosimetry of external individual monitoring. The GEANT4 toolkit was employed to simulate experiments with radiation monitors containing TLD-100 and CaF{sub 2}:NaCl thermoluminescent detectors. As a first step, X ray spectra were generated impinging electrons on a tungsten target. Then, the produced photon beam was filtered in a beryllium window and additional filters to obtain the radiation with desired qualities. This procedure, used to simulate radiation fields produced by a X ray tube, was validated by comparing characteristics such as half value layer, which was also experimentally measured, mean photon energy and the spectral resolution of simulated spectra with that of reference spectra established by international standards. In the construction of thermoluminescent dosimeter, two approaches for improvements have. been introduced. The first one was the inclusion of 6% of air in the composition of the CaF{sub 2}:NaCl detector due to the difference between measured and calculated values of its density. Also, comparison between simulated and experimental results showed that the self-attenuation of emitted light in the readout process of the fluorite dosimeter must be taken into account. Then, in the second approach, the light attenuation coefficient of CaF{sub 2}:NaCl compound estimated by simulation to be 2,20(25) mm{sup -1} was introduced. Conversion coefficients C{sub p} from air kerma to personal dose equivalent were calculated using a slab water phantom with polymethyl-metacrilate (PMMA) walls, for reference narrow and wide X ray spectrum series [ISO 4037-1], and also for the wide spectra implanted and used in routine at Laboratorio de Dosimetria. Simulations of backscattered radiations by PMMA slab water phantom and slab phantom of ICRU tissue-equivalent material produced very similar results. Therefore, the PMMA slab water phantom that can be easily

  15. Cosmic Rays and Dynamical Meteorology, 2. Snow Effect In Different Multiplicities According To Neutron Monitor Data of Emilio Segre' Observatory

    Science.gov (United States)

    Dorman, L. I.; Iucci, N.; Pustil'Nik, L. A.; Sternlieb, A.; Villoresi, G.; Zukerman, I. G.

    On the basis of cosmic ray hourly data obtained by NM of Emilio Segre' Observatory (hight 2025 m above s.l., cut-off rigidity for vertical direction 10.8 GV) we determine the snow effect in CR for total neutron intensity and for multiplicities m=1, m=2, m=3, m=4, m=5, m=6, and m=7. For comparison and excluding primary CR variations we use also hourly data on neutron multiplicities obtained by Rome NM (about sea level, cut-off rigidity 6.7 GV). In this paper we will analize effects of snow in periods from 4 January 2000 to 15 April 2000 with maximal absorption effect about 5%, and from 21 December 2000 up to 31 March 2001 with maximal effect 13% in the total neu- tron intensity. We use the periods without snow to determine regeression coefficients between primary CR variations observed by NM of Emilio Segre' Observatory, and by Rome NM. On the basis of obtained results we develop a method to correct data on snow effect by using several NM hourly data. On the basis of our data we estimate the accuracy with what can be made correction of NM data of stations where the snow effect can be important.

  16. Development of an electronic monitor for the determination of individual radon and thoron exposure

    International Nuclear Information System (INIS)

    Irlinger, Josef

    2015-01-01

    The carcinogenic effect of the radio isotope 222 Rn of the noble gas radon and its progeny, as well as its residential distribution, are well studied. In contrast, the knowledge about the effects and average dwelling concentration levels of its radio isotope 220 Rn (thoron) is still limited. Generally, this isotope has been assumed to be a negligible contributor to the effective annual dose. However, only recently it has been pointed out in several international studies, that the dose due to thoron exceeds the one from 222 Rn under certain conditions. Additionally, radon monitors may show a considerable sensitivity towards thoron which was also not accounted for in general. Therefore a reliable, inexpensive exposimeter, which allows to distinguish between decays of either radon and thoron, is required to conduct further studies. The scope of this thesis was to develop an electronic radon/thoron exposimeter which features small size, low weight and minimal power consumption. The design is based on the diffusion chamber principle and employs state-of-the-art alpha particle spectroscopy to measure activity concentrations. The device was optimized via inlet layout and filter selection for high thoron diffusion. Calibration measurements showed a similar sensitivity of the monitor towards radon and thoron, with a calibration factor of cf 222 Rn = 16.2 ± 0.9 Bq m -3 /cph and cf 220 Rn = 14.4 ± 0.8 Bq m -3 /cph, respectively. Thus, the radon sensitivity of the device was enhanced by a factor two compared to a previous prototype. The evaluation method developed in this work, in accordance with ISO 11665 standards, was validated by intercomparison measurements. The detection limits for radon and thoron were determined to be C 2 22 Rn = 44.0 Bq m -3 and C 2 20 Rn = 40.0 Bq m -3 , respectively, in case of a low radon environment, a one-hour measurement interval, and a background count rate of zero. In contrast, in mixed radon/thoron concentrations where the 212 Po peak must

  17. Cerebral Blood Flow Autoregulation in Sepsis for the Intensivist: Why Its Monitoring May Be the Future of Individualized Care.

    Science.gov (United States)

    Goodson, Carrie M; Rosenblatt, Kathryn; Rivera-Lara, Lucia; Nyquist, Paul; Hogue, Charles W

    2018-02-01

    Cerebral blood flow (CBF) autoregulation maintains consistent blood flow across a range of blood pressures (BPs). Sepsis is a common cause of systemic hypotension and cerebral dysfunction. Guidelines for BP management in sepsis are based on historical concepts of CBF autoregulation that have now evolved with the availability of more precise technology for its measurement. In this article, we provide a narrative review of methods of monitoring CBF autoregulation, the cerebral effects of sepsis, and the current knowledge of CBF autoregulation in sepsis. Current guidelines for BP management in sepsis are based on a goal of maintaining mean arterial pressure (MAP) above the lower limit of CBF autoregulation. Bedside tools are now available to monitor CBF autoregulation continuously. These data reveal that individual BP goals determined from CBF autoregulation monitoring are more variable than previously expected. In patients undergoing cardiac surgery with cardiopulmonary bypass, for example, the lower limit of autoregulation varied between a MAP of 40 to 90 mm Hg. Studies of CBF autoregulation in sepsis suggest patients frequently manifest impaired CBF autoregulation, possibly a result of BP below the lower limit of autoregulation, particularly in early sepsis or with sepsis-associated encephalopathy. This suggests that the present consensus guidelines for BP management in sepsis may expose some patients to both cerebral hypoperfusion and cerebral hyperperfusion, potentially resulting in damage to brain parenchyma. The future use of novel techniques to study and clinically monitor CBF autoregulation could provide insight into the cerebral pathophysiology of sepsis and offer more precise treatments that may improve functional and cognitive outcomes for survivors of sepsis.

  18. Electronic imaging applied to neutron radiography

    International Nuclear Information System (INIS)

    Garrett, D.A.; Bracher, D.A.

    1976-01-01

    A commercially - available image intensifier was used with a scan conversion memory and a mobile 252 Cf based neutron radiography system to obtain neutron radiographs on a television monitor in 0.5 minutes to 10.0 minutes

  19. Quality assurance and quality control programme in use at the individual monitoring service of ITN-DPRSN

    Energy Technology Data Exchange (ETDEWEB)

    Alves, J.G.; Novais, I.; Rangel, S.; Flores, E. [Instituto Tecnologico e Nuclear, Dept. de Proteccao Radiologica e Seguranca Nuclear Estrada Nacional, Sacavem (Portugal)

    2006-07-01

    The Individual Monitoring Service (I.M.S.) of the Departamento de Proteccao Radiologica e Seguranca Nuclear (D.P.R.S.N.) at the Instituto Tecnologico e Nuclear (I.T.N.) in Portugal operates a thermoluminescence dosimetry system to monitor approximately 3,000 workers for external radiation exposure on a monthly basis. The workers come from nearly 230 facilities in the medical, research and conventional industry fields of activity and almost 85% of the people monitored in 2005 are from medical facilities. The TLD system in use is based on two Harshaw 6600 automatic readers and on the Harshaw 8814 T.L. card and holder containing two detector elements of LiF:Mg,Ti (TLD-100) for the evaluation of Hp(10) and Hp(0.07). All the workers are monitored on a monthly basis using whole body dosemeters. The I.M.S. has implemented a Quality Assurance and Quality Control (Q.A./Q.C.) programme that covers all the aspects of monitoring, from the monitoring request of a customer to the final issue of a dose report. The main aspects of the Q.A./Q.C. programme implemented at the I.M.S. will be presented in this paper using fluxograms and schemes. Several issues will be addressed, e.g., administrative procedures, technical procedures, dealing with complaints, training of staff, etc. The relationship of the I.M.S. with external entities like the customer, the regulatory authority, the central dose registry, the calibration facility, suppliers, maintenance providers, etc. will be mentioned on the administrative procedures described as well as on the technical procedures where applicable. The main technical procedures will be presented in this paper and references will be made to a TLD Quality Control database internally developed and designed for the storage of important Q.C. parameters like the element correction coefficients, reader calibration factors, electronic quality control data generated on a daily basis, and the study of their evolution with time. (author)

  20. Quality assurance and quality control programme in use at the individual monitoring service of ITN-DPRSN

    International Nuclear Information System (INIS)

    Alves, J.G.; Novais, I.; Rangel, S.; Flores, E.

    2006-01-01

    The Individual Monitoring Service (I.M.S.) of the Departamento de Proteccao Radiologica e Seguranca Nuclear (D.P.R.S.N.) at the Instituto Tecnologico e Nuclear (I.T.N.) in Portugal operates a thermoluminescence dosimetry system to monitor approximately 3,000 workers for external radiation exposure on a monthly basis. The workers come from nearly 230 facilities in the medical, research and conventional industry fields of activity and almost 85% of the people monitored in 2005 are from medical facilities. The TLD system in use is based on two Harshaw 6600 automatic readers and on the Harshaw 8814 T.L. card and holder containing two detector elements of LiF:Mg,Ti (TLD-100) for the evaluation of Hp(10) and Hp(0.07). All the workers are monitored on a monthly basis using whole body dosemeters. The I.M.S. has implemented a Quality Assurance and Quality Control (Q.A./Q.C.) programme that covers all the aspects of monitoring, from the monitoring request of a customer to the final issue of a dose report. The main aspects of the Q.A./Q.C. programme implemented at the I.M.S. will be presented in this paper using fluxograms and schemes. Several issues will be addressed, e.g., administrative procedures, technical procedures, dealing with complaints, training of staff, etc. The relationship of the I.M.S. with external entities like the customer, the regulatory authority, the central dose registry, the calibration facility, suppliers, maintenance providers, etc. will be mentioned on the administrative procedures described as well as on the technical procedures where applicable. The main technical procedures will be presented in this paper and references will be made to a TLD Quality Control database internally developed and designed for the storage of important Q.C. parameters like the element correction coefficients, reader calibration factors, electronic quality control data generated on a daily basis, and the study of their evolution with time. (author)

  1. Neutron diagnostics at the Wendelstein 7-X stellarator

    Science.gov (United States)

    Schneider, W.; Wiegel, B.; Grünauer, F.; Burhenn, R.; Koch, S.; Schuhmacher, H.; Zimbal, A.

    2012-03-01

    The stellarator W7-X, presently under construction at the Institute for Plasma Physics in Greifswald, will be equipped with a set of neutron monitors in order to study the time behaviour of neutron emission generated during D-D plasma operation and neutral beam heating with Deuterium. Each of these neutron monitors consists of several neutron detector tubes inserted in a dedicated moderator. The neutron monitors at W7-X are designed to monitor neutron yields with a time resolution of 5 ms and with a statistical uncertainty of better than 15%. One of the monitors is located in the centre above the stellarator. The other five monitors are distributed around the torus. A prerequisite for the determination of the absolute neutron source strength produced by D(d,n)3He fusion reactions in the plasma is an in-situ calibration with a neutron source of known source strength. During such a calibration procedure, the neutron source will be moved along the torus axis and the count rates of the different neutron monitors will be measured. In a first benchmark experiment, an 241AmBe neutron source was moved along the torus axis within one module of the stellarator and the neutron signals were measured by a De Pangher Long Counter outside of the cryostat chamber as a function of the neutron source position. These measurements have been compared with predictions of Monte Carlo calculations (MCNP) of the neutron propagation from the location of the neutron source to the long counter. The concept of neutron monitors will be reported together with results from the benchmark experiment and results from MCNP calculations. The neutron monitor system is the first part of several neutron diagnostic systems such as neutron activation system, neutron profile camera planned for future neutron analysis. A short survey of these neutron diagnostic tools of W7-X will be given.

  2. Neutron monitor calibration with 241AmBe(α, n), 252Cf , 252Cf+D2O and 238PuBe(α, n) used in dose evaluation near Linac

    International Nuclear Information System (INIS)

    Salgado, Ana Paula; Pereira, Walsan Wagner; Patrao, Karla Cristina de Souza; Fonseca, Evaldo Simoes da

    2009-01-01

    The use of linear accelerators in Radiotherapy is becoming increasingly more common. From the Radiation Protection point of view, these instruments represent an advance relative to cobalt and caesium irradiators, mainly due to the absence of radioactive material. On the other hand, accelerators with energies over 10 MeV contaminate with neutrons the therapeutic beam. These neutrons are generated when high-energy photons interact with high-atomic-number materials such as tungsten and lead present in the accelerator itself. Photo-neutrons can also interact with other materials, present in the treatment room, consequently modifying the initial spectrum and causing other types of interactions which privilege the gamma capture. In this way, the measurement of the photo-neutron spectrum can be necessary in a radiometric survey. The present work carries through measurements in a linear accelerator of 15 MeV using three neutron area monitors calibrated using four radioactive sources: three ISO reference sources, 241 AmBe (α, n), 252 Cf (f, n) and 252 C f+D 2 O, and a 238 P uBe(α, n) source. As the three first sources, this last one was standardized in the LMNRI/IRD manganese bath system. Comparison and evaluation of the response of these instruments were thereby made, analyzing whether the reading of the detectors using standard sources is adequate. In conclusion, the analysis of the response of neutron area calibrated detectors enable the use of them in an environment containing medical linear accelerator. (author)

  3. Experimental Studies of Boronophenylalanine ({sup 10}BPA) Biodistribution for the Individual Application of Boron Neutron Capture Therapy (BNCT) for Malignant Melanoma Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Carpano, Marina; Perona, Marina; Rodriguez, Carla [Department of Radiobiology, National Atomic Energy Commission, San Martín (Argentina); Nievas, Susana; Olivera, Maria; Santa Cruz, Gustavo A. [Department of Boron Neutron Capture Therapy, National Atomic Energy Commission, San Martín (Argentina); Brandizzi, Daniel; Cabrini, Romulo [Department of Radiobiology, National Atomic Energy Commission, San Martín (Argentina); School of Dentistry, University of Buenos Aires, Buenos Aires (Argentina); Pisarev, Mario [Department of Radiobiology, National Atomic Energy Commission, San Martín (Argentina); National Research Council of Argentina, Buenos Aires (Argentina); Department of Human Biochemistry, School of Medicine, University of Buenos Aires, Buenos Aires (Argentina); Juvenal, Guillermo Juan [Department of Radiobiology, National Atomic Energy Commission, San Martín (Argentina); National Research Council of Argentina, Buenos Aires (Argentina); Dagrosa, Maria Alejandra, E-mail: dagrosa@cnea.gov.ar [Department of Radiobiology, National Atomic Energy Commission, San Martín (Argentina); National Research Council of Argentina, Buenos Aires (Argentina)

    2015-10-01

    Purpose: Patients with the same histopathologic diagnosis of cutaneous melanoma treated with identical protocols of boron neutron capture therapy (BNCT) have shown different clinical outcomes. The objective of the present studies was to evaluate the biodistribution of boronophenilalanina ({sup 10}BPA) for the potential application of BNCT for the treatment of melanoma on an individual basis. Methods and Materials: The boronophenilalanine (BPA) uptake was evaluated in 3 human melanoma cell lines: MEL-J, A375, and M8. NIH nude mice were implanted with 4 10{sup 6} MEL-J cells, and biodistribution studies of BPA (350 mg/kg intraperitoneally) were performed. Static infrared imaging using a specially modified infrared camera adapted to measure the body infrared radiance of small animals was used. Proliferation marker, Ki-67, and endothelial marker, CD31, were analyzed in tumor samples. Results: The in vitro studies demonstrated different patterns of BPA uptake for each analyzed cell line (P<.001 for MEL-J and A375 vs M8 cells). The in vivo studies showed a maximum average boron concentration of 25.9 ± 2.6 μg/g in tumor, with individual values ranging between 11.7 and 52.0 μg/g of {sup 10}B 2 hours after the injection of BPA. Tumor temperature always decreased as the tumors increased in size, with values ranging between 37°C and 23°C. A significant correlation between tumor temperature and tumor-to-blood boron concentration ratio was found (R{sup 2} = 0.7, rational function fit). The immunohistochemical studies revealed, in tumors with extensive areas of viability, a high number of positive cells for Ki-67, blood vessels of large diameter evidenced by the marker CD31, and a direct logistic correlation between proliferative status and boron concentration difference between tumor and blood (R{sup 2} = 0.81, logistic function fit). Conclusion: We propose that these methods could be suitable for designing new screening protocols applied before melanoma BNCT

  4. Personal monitoring of 218Po and 214Po radionuclide deposition onto individuals under normal environmental exposure conditions

    International Nuclear Information System (INIS)

    Eatough, J.P.; Worley, A.; Moss, G.R.

    1999-01-01

    Personal dosemeters have been utilized to monitor the deposition of the radon decay products 218 Po and 214 Po onto individuals under normal environmental exposure conditions. Each detector consists of TASTRAK alpha-sensitive plastic incorporated into an ordinary working wristwatch. Subsequent analysis provides energy discrimination of the detected alpha-particle decays, and allows events from the individual radon decay products 218 Po and 214 Po, attached to the detector surface, to be uniquely identified. Assuming similar deposition onto skin and detector surfaces, the activity per unit area of deposited radionuclides can be determined for exposed skin. Forty-one personal dosemeters were issued to volunteers selected through the hospital medical physics departments at Reading, Northampton, Exeter and Plymouth. Each volunteer was also issued with a personal radon dosemeter to determine their individual radon exposure. The volunteers wore the two dosemeters simultaneously and continuously for a period of around one month. Correlations were observed between the radon exposure of the individual and the activity per unit area of 218 Po and 214 Po on the detector surface. From these correlations it can be estimated that at the UK average radon exposure of 20 Bq m -3 , the number of decays/cm 2 /year on continuously exposed skin surface is between 3500 and 28 000 for 218 Po, and between 7000 and 21 000 for 214 Po. These results can be combined with theoretical modelling of the dose distribution in the skin to yield the alpha-particle radiation dose to any identified target cells. (author)

  5. Assessment of the results of the 1998 Intercomparison of Individual Monitoring Systems under IAEA Model Project RLA/9/030

    International Nuclear Information System (INIS)

    Da Silva, Teogenes

    1999-01-01

    In this report the results of an intercomparison program within the framework of the IAEA model project RLA/9/030 are presented. This is the first phase of the study the main purpose was to establish a mechanism to identify and improve the current situation of each country as far as the performance of each individual monitoring system is concerned. This phase as was coordinated by Brazil through the Centro de Desenvolvimento da Tecnologia Nuclear that verified the performance of the participant laboratories. The following countries were invited to participate in the 1998 intercomparison: Bolivia, Costa Rica, Guatemala, Nicaragua, Panama, Jamaica and Paraguay. The performance of the laboratories was evaluated for dose assessment in terms of photon dose equivalent Hx

  6. Individual monitoring of immune responses in rainbow trout after cohabitation and intraperitoneal injection challenge with Yersinia ruckeri.

    Science.gov (United States)

    M Monte, Milena; Urquhart, Katy; Secombes, Christopher J; Collet, Bertrand

    2016-08-01

    Yersinia ruckeri, the causative agent of enteric red mouth disease (ERM), is a widely studied pathogen in disease models using rainbow trout. This infection model, mostly based on intraperitoneally injection or bath immersion challenges, has an impact on both components (innate and adaptive) of the fish immune system. Although there has been much attention in studying its host-pathogen interactions, there is still a lack of knowledge regarding the impact of a cohabitation challenge. To tackle this we used a newly established non-lethal sampling method (by withdrawing a small amount of blood) in rainbow trout which allowed the individual immune monitoring before (non-infected) and after infection with Yersinia ruckeri either by intraperitoneal (i.p.) injection or by cohabitation (cohab). A range of key immune genes were monitored during the infection by real-time PCR, and results were compared between the two infection routes. Results indicated that inflammatory (IL-1β1 and IL-8) cytokines and certain antimicrobial peptides (cathelicidins) revealed a different pattern of expression between the two infected groups (i.p. vs cohab), in comparison to adaptive immune cytokines (IL-22, IFN-γ and IL-4/13A) and β-defensins. This suggests a different involvement of distinct immune markers according to the infection model, and the importance of using a cohabitation challenge as a more natural disease model that likely simulates what would occur in the environment. Copyright © 2016. Published by Elsevier Ltd.

  7. Evaluation of personal dose equivalent 'HP(d)' in a external individual monitoring system for X and gamma radiation

    International Nuclear Information System (INIS)

    Santoro, C.; Antonio Filho, J.; Santos, M.A.P.

    2007-01-01

    The good of individual monitoring for external radiation is the assessment of occupational exposure from X and γ radiations in order to assure that the radiological conditions of the workplace are acceptable, safe and satisfactory. The evaluation of radiations doses for workers must not exceed dose limits specified for workers, according to national regulatory agencies. Nowadays, there are two external monitoring systems in use, both based on ICRU definitions. In the conventional system, the workers doses are evaluated in terms of Hx. The personal dosimeter is worn over chest surface and it is calibrated in function of air kerma. In the new system, the workers doses are evaluated in terms of HP(d) and the personal dosimeter is calibrated in function of phantom doses. The aim of this paper is to adapt an external dosimetry laboratory (based on photographic dosimetry) to evaluate the personal dosimeters in terms of HP(d). In this way, a simple methodology, based on linear programming, was utilized. In this adaptation, calibration curves were obtained for radiation qualities (W and N series) described by International Organization for Standardization (ISO 4037-1, 1995). These calibration curves offer a better accuracy on dose determinations and energy below 140 keV, improving the quality of service rendered the society. (author)

  8. Measurement channel of neutron flow based on software

    International Nuclear Information System (INIS)

    Rivero G, T.; Benitez R, J. S.

    2008-01-01

    The measurement of the thermal power in nuclear reactors is based mainly on the measurement of the neutron flow. The presence of these in the reactor core is associated to neutrons released by the fission reaction of the uranium-235. Once moderate, these neutrons are precursors of new fissions. This process it is known like chain reaction. Thus, the power to which works a nuclear reactor, he is proportional to the number of produced fissions and as these depend on released neutrons, also the power is proportional to the number of present neutrons. The measurement of the thermal power in a reactor is realized with called instruments nuclear channels. To low power (level source), these channels measure the individual counts of detected neutrons, whereas to a medium and high power, they measure the electrical current or fluctuation of the same one that generate the fission neutrons in ionization chambers especially designed to detect neutrons. For the case of TRIGA reactors, the measurement channels of neutron flow use discreet digital electronic technology makes some decades already. Recently new technological tools have arisen that allow developing new versions of nuclear channels of simple form and compacts. The present work consists of the development of a nuclear channel for TRIGA reactors based on the use of the correlated signal of a fission chamber for ample interval. This new measurement channel uses a data acquisition card of high speed and the data processing by software that to the being installed in a computer is created a virtual instrument, with what spreads in real time, in graphic and understandable form for the operator, the power indication to which it operates the nuclear reactor. This system when being based on software, offers a major versatility to realize changes in the signal processing and power monitoring algorithms. The experimental tests of neutronic power measurement show a reliable performance through seven decades of power, with a

  9. Technical note: validation of a system for monitoring individual feeding and drinking behavior and intake in group-housed cattle.

    Science.gov (United States)

    Chapinal, N; Veira, D M; Weary, D M; von Keyserlingk, M A G

    2007-12-01

    The objective of this study was to validate a system for monitoring individual feeding and drinking behavior and intake in group-housed cattle. A total of 42 Holstein cows were tested with access to 24 feed bins and 4 water bins. For the purposes of this validation experiment, we focused our observations on 4 water bins and 13 feed bins. When the cow approached the feed or water bin, an antenna detected the cow's unique passive transponder and lowered the barrier, allowing the cow access to the feed or water. For each visit to the bin, the system recorded the cow number, bin number, initial and final times and weight and calculated the visit duration and intake. Bins were also monitored by direct observation and time-lapse video recording for 2 d per bin, with observations for 4 and 6 h/d for the feed and water bins, respectively. Data from direct observations were compared with the electronic data recorded by the system. Feed disappearance over 24 h was assessed by using an external scale over 3 consecutive 24-h periods, and these values were compared with the sum of intakes across all visits to that bin for the same time periods. The system showed a high specificity (100%) and sensitivity (100 and 99.76% for the feed and water bins, respectively) for cow identification. The duration of the feeding and drinking visits and the feed and water intake per visit, as estimated by the monitoring system, were highly correlated with those obtained by direct observation (R(2) >/= 0.99 in all the cases). The comparison of the total feed that disappeared from each bin in 24 h with the sum of the feed cows consumed from that bin during the same period differed by less than 1 kg (29.92 +/- 0.90 kg and 29.24 +/- 0.90 kg as estimated by manual weighing and by the electronic system, respectively). This difference could be attributed to changes in feed moisture during the 24-h period. In conclusion, this electronic system is a useful tool for monitoring intakes and feeding and

  10. Calibration of the radiation monitors from DESY and SPring-8 at the quasi-mono-energetic neutron beams using 100 and 300 MeV 7Li(p,n) reaction at RCNP in Osaka Japan in November 2014

    Science.gov (United States)

    Leuschner, Albrecht; Asano, Yoshihiro; Klett, Alfred

    2017-09-01

    At the ring cyclotron facility of the Research Center for Nuclear Physics (RCNP) Osaka University, Osaka, Japan a series of measurement campaigns had been continued with quasi mono-energetic neutron beams in November 2014. A 7Li target was bombarded with 100 and 300 MeV protons and the generated neutron beams were directed into a long time-of-flight tunnel at 0 and 25 degrees deflection angle with respect to the proton beam. At a distance of 41 m the cross section of the neutron beam was large enough for the illumination of square meter sized objects like extended range rem-counters. The research institutes SPring-8/RIKEN, Japan, and DESY, Germany, participated in this campaign for the calibration of 4 different types of active ambient dose rate monitors: LB 6411, LB 6411-Pb, LB 6419 and LB 6420. The measurements of their responses are reported and compared with the calculated values.

  11. Calibration of the radiation monitors from DESY and SPring-8 at the quasi-mono-energetic neutron beams using 100 and 300 MeV 7Li(p,n reaction at RCNP in Osaka Japan in November 2014

    Directory of Open Access Journals (Sweden)

    Leuschner Albrecht

    2017-01-01

    Full Text Available At the ring cyclotron facility of the Research Center for Nuclear Physics (RCNP Osaka University, Osaka, Japan a series of measurement campaigns had been continued with quasi mono-energetic neutron beams in November 2014. A 7Li target was bombarded with 100 and 300 MeV protons and the generated neutron beams were directed into a long time-of-flight tunnel at 0 and 25 degrees deflection angle with respect to the proton beam. At a distance of 41 m the cross section of the neutron beam was large enough for the illumination of square meter sized objects like extended range rem-counters. The research institutes SPring-8/RIKEN, Japan, and DESY, Germany, participated in this campaign for the calibration of 4 different types of active ambient dose rate monitors: LB 6411, LB 6411-Pb, LB 6419 and LB 6420. The measurements of their responses are reported and compared with the calculated values.

  12. A neutron well logging system

    International Nuclear Information System (INIS)

    1980-01-01

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

  13. Inconsistencies of neutron flux parameters for k(0) standardization in neutron activation analysis determined with the use of Au+Zr and Au+Mo+Cr monitor sets at the LVR-15 reactor in Rez

    Czech Academy of Sciences Publication Activity Database

    Kubešová, Marie; Kučera, Jan

    2012-01-01

    Roč. 293, č. 2 (2012), s. 665-674 ISSN 0236-5731 R&D Projects: GA ČR GA202/09/0363 Institutional support: RVO:61389005 Keywords : Neutron activation analysis * K(0) standardization * Neutron flux parameters Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.467, year: 2012

  14. On the neutron bursts origin.

    CERN Document Server

    Stenkin, Yu V

    2002-01-01

    The origin of the neutron bursts in Extensive Air Showers (EAS) is explained using results of the experiments and CORSIKA based Monte-Carlo simulations. It is shown that events with very high neutron multiplicity observed last years in neutron monitors as well as in surrounding detectors, are caused by usual EAS core with primary energies > 1 PeV. No exotic processes were needed for the explanation.

  15. Some neutronics of innovative subcritical assembly with fast neutron spectrum

    International Nuclear Information System (INIS)

    Kiyavitskaya, H.; Fokov, Yu.; Rutkovskaya, Ch.; Sadovich, S.; Kasuk, D.; Gohar, Y.; Bolshinsky, I.

    2013-01-01

    Conclusion: • New assembly can be used to: • develop the experimental techniques and adapt the existing ones for monitoring the sub-criticality level, neutron spectra measurements, etc; • study the spatial kinetics of sub-critical and critical systems with fast neutron spectra; • measure the transmutation reaction rates of minor-actinides etc

  16. NuSTAR + XMM-Newton monitoring of the neutron star transient AX J1745.6-2901

    Science.gov (United States)

    Ponti, G.; Bianchi, S.; Muñoz-Darias, T.; Mori, K.; De, K.; Rau, A.; De Marco, B.; Hailey, C.; Tomsick, J.; Madsen, K. K.; Clavel, M.; Rahoui, F.; Lal, D. V.; Roy, S.; Stern, D.

    2018-01-01

    AX J1745.6-2901 is a high-inclination (eclipsing) transient neutron star (NS) low-mass X-ray binary showcasing intense ionized Fe K absorption. We present here the analysis of 11 XMM-Newton and 15 NuSTAR new data sets (obtained between 2013 and 2016), therefore tripling the number of observations of AX J1745.6-2901 in outburst. Thanks to simultaneous XMM-Newton and NuSTAR spectra, we greatly improve on the fitting of the X-ray continuum. During the soft state, the emission can be described by a disc blackbody (kT ∼ 1.1-1.2 keV and inner disc radius rDBB ∼ 14 km), plus hot (kT ∼ 2.2-3.0 keV) blackbody radiation with a small emitting radius (rBB ∼ 0.5 - 0.8 km) likely associated with the boundary layer or NS surface, plus a faint Comptonization component. Imprinted on the spectra are clear absorption features created by both neutral and ionized matter. Additionally, positive residuals suggestive of an emission Fe K α disc line and consistent with relativistic ionized reflection are present during the soft state, while such residuals are not significant during the hard state. The hard-state spectra are characterized by a hard (Γ ∼ 1.9-2.1) power law, showing no evidence for a high energy cut-off (kTe > 60-140 keV) and implying a small optical depth (τ soft state that significantly weakens during the hard state. Optical (GROND) and radio (GMRT) observations suggest for AX J1745.6-2901 a standard broad-band spectral energy distribution as typically observed in accreting NSs.

  17. Analysis of unstable chromosome alterations frequency induced by neutron-gamma mixed field radiation

    International Nuclear Information System (INIS)

    Souza, Priscilla L.G.; Brandao, Jose Odinilson de C.; Vale, Carlos H.F.P.; Santos, Joelan A.L.; Vilela, Eudice C.; Lima, Fabiana F.; Calixto, Merilane S.; Santos, Neide

    2009-01-01

    Nowadays monitoring chromosome alterations in peripheral blood lymphocytes have been used to access the radiation absorbed dose in individuals exposed accidental or occupationally to gamma radiation. However there are not many studies based on the effects of mixed field neutron-gamma. The radiobiology of neutrons has great importance because in nuclear factories worldwide there are several hundred thousand individuals monitored as potentially receiving doses of neutron. In this paper it was observed the frequencies of unstable chromosome alterations induced by a gamma-neutron mixed field. Blood was obtained from one healthy donor and exposed to mixed field neutron-gamma sources 241 AmBe (20 Ci) at the Neutron Calibration Laboratory (NCL-CRCN/NE-PE-Brazil). The chromosomes were observed at metaphase, following colcemid accumulation and 1000 well-spread metaphases were analyzed for the presence of chromosome alterations by two experienced scorers. The results suggest that there is the possibility of a directly proportional relationship between absorbed dose of neutron-gamma mixed field radiation and the frequency of unstable chromosome alterations analyzed in this paper. (author)

  18. A system utilizing radio frequency identification (RFID) technology to monitor individual rodent behavior in complex social settings.

    Science.gov (United States)

    Howerton, Christopher L; Garner, Joseph P; Mench, Joy A

    2012-07-30

    Pre-clinical investigation of human CNS disorders relies heavily on mouse models. However these show low predictive validity for translational success to humans, partly due to the extensive use of rapid, high-throughput behavioral assays. Improved assays to monitor rodent behavior over longer time scales in a variety of contexts while still maintaining the efficiency of data collection associated with high-throughput assays are needed. We developed an apparatus that uses radio frequency identification device (RFID) technology to facilitate long-term automated monitoring of the behavior of mice in socially or structurally complex cage environments. Mice that were individually marked and implanted with transponders were placed in pairs in the apparatus, and their locations continuously tracked for 24 h. Video observation was used to validate the RFID readings. The apparatus and its associated software accurately tracked the locations of all mice, yielding information about each mouse's location over time, its diel activity patterns, and the amount of time it was in the same location as the other mouse in the pair. The information that can be efficiently collected in this apparatus has a variety of applications for pre-clinical research on human CNS disorders, for example major depressive disorder and autism spectrum disorder, in that it can be used to quantify validated endophenotypes or biomarkers of these disorders using rodent models. While the specific configuration of the apparatus described here was designed to answer particular experimental questions, it can be modified in various ways to accommodate different experimental designs. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Results of 1999 Spectral Gamma-Ray and Neutron Moisture Monitoring of Boreholes at Specific Retention Facilities in the 200 East Area, Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    DG Horton; RR Randall

    2000-01-18

    Twenty-eight wells and boreholes in the 200 East Are% Hanford Site, Washington were monitored in 1999. The monitored facilities were past-practice liquid waste disposal facilities and consisted of six cribs and nineteen ''specific retention'' cribs and trenches. Monitoring consisted of spectral gamma-ray and neutron moisture logging. All data are included in Appendix B. The isotopes {sup 137}Cs, {sup 60}Co, {sup 235}U, {sup 238}U, and {sup 154}Eu were identified on spectral gamma logs from boreholes monitoring the PUREX specific retention facilities; the isotopes {sup 137}Cs, {sup 60}Co, {sup 125}Sb, and {sup 154}Eu were identified on the logs from boreholes at the BC Controlled Area cribs and trenches; and {sup 137}Cs, {sup 60}Co, and {sup 125}Sb were, identified on the logs from boreholes at the BX specific retention trenches. Three boreholes in the BC Controlled Area and one at the BX trenches had previous spectral gamma logs available for comparison with 1999 logs. Two of those logs showed that changes in the subsurface distribution of {sup 137}CS and/or {sup 60}Co had occurred since 1992. Although the changes are not great, they do point to continued movement of contaminants in the vadose zone. The logs obtained in 1999 create a larger baseline for comparison with future logs. Numerous historical gross gamma logs exist from most of the boreholes logged. Qualitative comparison of those logs with the 1999 logs show many substantial changes, most of which reflect the decay of deeper short-lived isotopes, such as {sup 106}Ru and {sup 125}Sb, and the much slower decay of shallower and longer-lived isotopes such as {sup 137}Cs. The radionuclides {sup 137}Cs and {sup 60}Co have moved in two boreholes since 1992. Given the amount of movement and the half-lives of the isotopes, it is expected that they will decay to insignificant amounts before reaching groundwater. However, gamma ray logging cannot detect many of the contaminants of interest such

  20. Performance test of dosimetric services in the EU member states and Switzerland for the routine assessment of individual doses (photon, beta and neutron)

    DEFF Research Database (Denmark)

    Bordy, J.M.; Stadtmann, H.; Ambrosi, P.

    2000-01-01

    The results are given of a consolidated performance test for whole-body, and extremity personal dosemeters broadly representative of those in use in the EU member states and Switzerland. Beta, photon and neutron personal dosemeters were used to assess the routine services ability to determine...

  1. New Organic Scintillators for Neutron Detection

    Science.gov (United States)

    2016-03-01

    New Organic Scintillators for Neutron Detection Distribution Statement A. Approved for public release; distribution is unlimited. March...Title: New Organic Scintillators for Neutron Detection I. Abstract In this project, Radiation Monitoring Devices (RMD) proposes to develop novel...boron containing organic single crystal detectors for neutron detection as an alternative for 3He based detectors that will fulfill the needs of the

  2. neutron spectrum parameters in two irradiation channels

    African Journals Online (AJOL)

    DR. AMINU

    2010-06-01

    Jun 1, 2010 ... spectrum parameters in one inner and one outer irradiation channels were determined using the ... the determination of neutron flux parameters required .... Qo,i = Io/σo the ratio of resonance integral to thermal neutron capture cross section at neutron velocity of 2200 m/s for the ith monitor. Experimental.

  3. Scope of neutron interferometry

    International Nuclear Information System (INIS)

    Rauch, H.

    1978-01-01

    This paper deals with the interferometry of well separated coherent beams, where the phase of the beams can be manipulated individually. The basic equation of the dynamical neutron diffraction theory are recalled. The various contributions to the interaction of as low neutron with its surroundings are discussed: the various terms denote the nuclear, magnetic, electromagnetic, intrinsic, gravitational, and weak interaction respectively. Applications to nuclear physics, fundamental physics and solid state physics are successively envisaged

  4. Technical requirements for implementation of an individual monitoring service for evaluation of operational quantity HP(10) using thermoluminescent dosimetry

    International Nuclear Information System (INIS)

    Francisco, Adelaide Benedita Armando

    2016-01-01

    This work aims to establish technical requirements for the development of a TLDs system for the assessment of operational quantity H P (10), in order to implement an external individual monitoring service in countries who do not have. This allows a better understanding of the technic and the thermoluminescent dosimetry system, thus contributing to identify the technical criteria to be followed by a dosimetry laboratory and evaluation of the dosimetric system performance. For this, the review of the specific literature of the dosimetry field was conducted and later the type and performance tests that must be followed by a dosimetric system were reproduced in practice. In additional was made a analysis of internationals standards norms and the technical regulation used in Brazil, to define the essentials type testes to a dosimetric system. To check the performance of a dosimetry system, a performance analysis of the Brazilian TLDs system was carried out over the past 6 years using the trumpet curve, where it was observed that most of TLDs system, in this review period, were approved and have excellent performance. The technical requirements for the development of a thermoluminescent dosimetry system ensure that the system provides technically reliable results and allow demonstration of compliance with the standard criteria established by national and international standards, and the implementation of the dosimetry system, is verified the compliance of the annual doses limits set for occupationally exposed. (author)

  5. A-site order–disorder in the NdBaMn2O5+δ SOFC electrode material monitored in situ by neutron diffraction under hydrogen flow

    KAUST Repository

    Tonus, Florent

    2017-05-11

    The A-site disordered perovskite manganite, Nd0.5Ba0.5MnO3, has been obtained by heating the A-site-ordered and vacancy ordered layered double perovskite, NdBaMn2O5, in air at 1300 °C for 5 h. Combined transmission electron microscopy (TEM) images and neutron powder diffraction (NPD) analysis at 25 °C revealed that Nd0.5Ba0.5MnO3 has a pseudotetragonal unit cell with orthorhombic symmetry (space group Imma, √2ap × 2ap × √2ap) at 20 °C with the cell dimensions a = 5.503(1) Å, b = 7.7962(4) Å, c = 5.502(1) Å, in contrast to Pm[3 with combining macron]m or Cmcm that have been previously stated from X-ray diffraction studies. The in situ neutron diffraction study carried out on Nd0.5Ba0.5MnO3 in hydrogen flow up to T ∼ 900 °C, allows monitoring the A-site cation disorder–order structural phase transition of this representative member of potential SOFC anode materials between air sintering conditions and hydrogen working conditions. Oxygen loss from Nd0.5Ba0.5MnO3 proceeds with retention of A-site disorder until the oxygen content reaches the Nd0.5Ba0.5MnO2.5 composition at 600 °C. The phase transition to layered NdBaMn2O5 and localization of the oxygen vacancies in the Nd layer proceeds at 800 °C with retention of the oxygen content. Impedance spectroscopy measurements for the oxidized A-site ordered electrode material, NdBaMn2O6, screen printed on a Ce0.9Gd0.1O2−δ (CGO) electrolyte showed promising electrochemical performance in air at 700 °C with a polarization resistance of 1.09 Ω cm2 without any optimization.

  6. Development of Web based system for individual internal monitoring programme; Desenvolvimento de um sistema baseado na Web para suporte ao programa de monitoracao individual interna do IPEN

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Vanessa Rogeria de

    2007-07-01

    The purposes of the internal monitoring, in general, are to verify and document that each worker is protected adequately against risks from radionuclide intakes and the protection complies with legal requirements. Therefore, an overall radiation protection programme, starts with an assessment to identify work situations in which there is a risk of internal contamination of workers and to quantify the likely intake of radioactive material and the resulting committed effective dose. As a part of a continuous improvement of the monitoring programme for occupationally exposed workers at IPEN, it is being developed a Web based system to access the internal dosimetry database. The system was implemented using Hypertext Preprocessor, PHP, and a PostgreSQL database. This system will introduce a new paradigm in the routine of the internal dosimetry service, providing a fast access to the information among the measurement laboratories staff, dose evaluation group and the radiation protection supervisor. The database maintains information about worker identification, physical and chemical characteristics of the radionuclide, type of monitoring, measurement data and the dose. Moreover, this information will be readily available to provide support for regulatory compliance and quality control requirements. (author)

  7. Neutron guide

    Science.gov (United States)

    Greene, Geoffrey L.

    1999-01-01

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

  8. Individual monitoring of internal exposure of 131I of workers from the nuclear medicine service FUESMEN, Argentina

    International Nuclear Information System (INIS)

    Arenas, G.; Acosta, N.; Venier, V.; Bedoya Toboo, C.

    2013-01-01

    It is presented the FUESMEN experience in routine monitoring of thyroid internal doses due to inhalation of 131 I in workers of the Nuclear Medicine Service in normal operation or accidental exposure. It is used a surface contamination monitor, type Geiger Mueller, calibrated with a acrylic phantom based on specifications of the simulator of thyroid of ICRU 48 with 131 I reference activity. Through the obtained measurements is achieved to validate the use of Portable Monitor to carry out preliminary exploration on the monitoring scenarios of incidental situations

  9. Technical recommendations for the use of thermoluminescence for dosimetry in individual monitoring for photons and electrons from external sources

    International Nuclear Information System (INIS)

    1975-01-01

    The principles of thermoluminescence dosimetry and the role it may play in the field of personnel dosimetry are presented. Technical recommendations are made as an indication of what is generally regarded as good practice and they are intended to be of assistance in avoiding the common sources of error. Errors due to: the detector; the evaluation procedure; the thermal treatment; at the sensitivity of the detector to neutrons. The recommendations are concerned with: the choice of detector material; design of thermoluminescent dosemeters; read-out procedure; reader; handling procedures; dose evaluations; automation; documentation and data handling

  10. Neutron physics

    CERN Document Server

    Reuss, Paul

    2008-01-01

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

  11. Rossi-{alpha} and Feynmann Y functions for non-Poissonian pulsed sources of neutrons in the stochastic pulsing method: Application to subcriticality monitoring in ADS and comparison with the results of Poissonian pulsed neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Cobo, J.L. [Department of Chemical and Nuclear Engineering, Universidad Politecnica, Camino de Vera s/n, Valencia 46022 (Spain)], E-mail: jlcobos@iqn.upv.es; Pena, J. [Department of Applied Mathematics, Universidad Politecnica, Camino de Vera s/n, Valencia 46022 (Spain); Gonzalez, E. [Department of Fission Energy, CIEMAT, Avenida Complutense 22, Madrid 28040 (Spain)

    2008-12-15

    In this paper, analytical expressions for the Rossi-{alpha} and the Feynmann Y functions are deduced for the case of Poissonian and non-Poissonian neutron sources when the stochastic pulsing method is used. These analytical expressions are used to fit the experimental data and to obtain the prompt neutron time constant. Also we perform in this paper a comparison of the results obtained for the Rossi-{alpha} and Feynmann Y functions with Poissonian and non-Poissonian neutron sources, and we study how much change the shape of these functions when the fission probability decreases and the capture probability increases due to the depletion with time of the fuel, and the increase of the fission products. Some comparisons with experimental data and with the results of other authors have been performed. Another important question analyzed in this paper and that it is interesting from an academic point of view is that the average number of detected counts induced by one single neutron injected in the system at an arbitrary time t', should obey in point kinetics theory an adjoint equation in the time domain. Also the cross-factorial moment of the number of counts induced by one neutron in two counting intervals should obey also an adjoint equation in the time domain with a source term that depends on the first moments. These results are a consequence of more general results that have been obtained using stochastic transport theory for the one particle probability generating function or Kernel generating function.

  12. Latitudinal and radial variation of >2 GeV/n protons and alpha-particles at solar maximum: ULYSSES COSPIN/KET and neutron monitor network observations

    Directory of Open Access Journals (Sweden)

    A. V. Belov

    Full Text Available Ulysses, launched in October 1990, began its second out-of-ecliptic orbit in September 1997. In 2000/2001 the spacecraft passed from the south to the north polar regions of the Sun in the inner heliosphere. In contrast to the first rapid pole to pole passage in 1994/1995 close to solar minimum, Ulysses experiences now solar maximum conditions. The Kiel Electron Telescope (KET measures also protons and alpha-particles in the energy range from 5 MeV/n to >2 GeV/n. To derive radial and latitudinal gradients for >2 GeV/n protons and alpha-particles, data from the Chicago instrument on board IMP-8 and the neutron monitor network have been used to determine the corresponding time profiles at Earth. We obtain a spatial distribution at solar maximum which differs greatly from the solar minimum distribution. A steady-state approximation, which was characterized by a small radial and significant latitudinal gradient at solar minimum, was interchanged with a highly variable one with a large radial and a small – consistent with zero – latitudinal gradient. A significant deviation from a spherically symmetric cosmic ray distribution following the reversal of the solar magnetic field in 2000/2001 has not been observed yet. A small deviation has only been observed at northern polar regions, showing an excess of particles instead of the expected depression. This indicates that the reconfiguration of the heliospheric magnetic field, caused by the reappearance of the northern polar coronal hole, starts dominating the modulation of galactic cosmic rays already at solar maximum.

    Key words. Interplanetary physics (cosmic rays; energetic particles – Space plasma physics (charged particle motion and acceleration

  13. Latitudinal and radial variation of >2 GeV/n protons and alpha-particles at solar maximum: ULYSSES COSPIN/KET and neutron monitor network observations

    Directory of Open Access Journals (Sweden)

    A. V. Belov

    2003-06-01

    Full Text Available Ulysses, launched in October 1990, began its second out-of-ecliptic orbit in September 1997. In 2000/2001 the spacecraft passed from the south to the north polar regions of the Sun in the inner heliosphere. In contrast to the first rapid pole to pole passage in 1994/1995 close to solar minimum, Ulysses experiences now solar maximum conditions. The Kiel Electron Telescope (KET measures also protons and alpha-particles in the energy range from 5 MeV/n to >2 GeV/n. To derive radial and latitudinal gradients for >2 GeV/n protons and alpha-particles, data from the Chicago instrument on board IMP-8 and the neutron monitor network have been used to determine the corresponding time profiles at Earth. We obtain a spatial distribution at solar maximum which differs greatly from the solar minimum distribution. A steady-state approximation, which was characterized by a small radial and significant latitudinal gradient at solar minimum, was interchanged with a highly variable one with a large radial and a small – consistent with zero – latitudinal gradient. A significant deviation from a spherically symmetric cosmic ray distribution following the reversal of the solar magnetic field in 2000/2001 has not been observed yet. A small deviation has only been observed at northern polar regions, showing an excess of particles instead of the expected depression. This indicates that the reconfiguration of the heliospheric magnetic field, caused by the reappearance of the northern polar coronal hole, starts dominating the modulation of galactic cosmic rays already at solar maximum.Key words. Interplanetary physics (cosmic rays; energetic particles – Space plasma physics (charged particle motion and acceleration

  14. Neutron multiplicity recordings during GLE

    Science.gov (United States)

    Eduard, Vashenyuk; Leonid, Schur; Balabin, Yuri; Gvozdevsky, Boris

    A neutron multiplicity can give the information on a spectrum of primary solar protons and its variations during ground level enhancements (GLE). Such rare events are detected by ground based neutron monitors. With the help of the multiplicity recorder designed in PGI the variations of multiplicities during the GLE of December 13, 2006 on the neutron monitor in Barentsburg (Spitsbergen) have been studied. The neutron monitor in Barentsburg (18-NM-64) was put into operation on April, 2003. The recently developed data acquisition system is based on a PC equipped with two extension cards. One of them is ADLINK PCI-7233H, which is a high-speed 32-channel digital input card. The other is ADLINK PCI-8554, 12-channel counter/timer card. The specially written collecting program runs continuously. It captures the data registered by the two cards and stores the data to the hard disk. The PCI-7233H card registers pulses from all 18 channels of the neutron monitor and intervals between them. PCI-8554 card counts pulses from atmospheric pressure and temperature sensors. On the basis of this device the multiplicity recorder is realized to register the count rates on multiplicities (2-10). During the GLE on 13 December, 2006 significant increase of the count rates of multiplicities from 2 up to 5 was detected. The multiplicity spectrum changes are compared with the solar proton spectrum dynamics during event. The spectra of relativistic solar protons were derived by modeling technique from the worldwide neutron monitor network.

  15. Neutron radiography

    International Nuclear Information System (INIS)

    Hiraoka, Eiichi

    1988-01-01

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

  16. Self-monitoring practices, attitudes, and needs of individuals with bipolar disorder: implications for the design of technologies to manage mental health.

    Science.gov (United States)

    Murnane, Elizabeth L; Cosley, Dan; Chang, Pamara; Guha, Shion; Frank, Ellen; Gay, Geri; Matthews, Mark

    2016-05-01

    To understand self-monitoring strategies used independently of clinical treatment by individuals with bipolar disorder (BD), in order to recommend technology design principles to support mental health management. Participants with BD (N = 552) were recruited through the Depression and Bipolar Support Alliance, the International Bipolar Foundation, and WeSearchTogether.org to complete a survey of closed- and open-ended questions. In this study, we focus on descriptive results and qualitative analyses. Individuals reported primarily self-monitoring items related to their bipolar disorder (mood, sleep, finances, exercise, and social interactions), with an increasing trend towards the use of digital tracking methods observed. Most participants reported having positive experiences with technology-based tracking because it enables self-reflection and agency regarding health management and also enhances lines of communication with treatment teams. Reported challenges stem from poor usability or difficulty interpreting self-tracked data. Two major implications for technology-based self-monitoring emerged from our results. First, technologies can be designed to be more condition-oriented, intuitive, and proactive. Second, more automated forms of digital symptom tracking and intervention are desired, and our results suggest the feasibility of detecting and predicting emotional states from patterns of technology usage. However, we also uncovered tension points, namely that technology designed to support mental health can also be a disruptor. This study provides increased understanding of self-monitoring practices, attitudes, and needs of individuals with bipolar disorder. This knowledge bears implications for clinical researchers and practitioners seeking insight into how individuals independently self-manage their condition as well as for researchers designing monitoring technologies to support mental health management. © The Author 2016. Published by Oxford University

  17. Fusion neutronics

    CERN Document Server

    Wu, Yican

    2017-01-01

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

  18. Different spectra with the same neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R.; Ortiz R, J. M.; Hernandez D, V. M.; Martinez B, M. R.; Hernandez A, B.; Ortiz H, A. A. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Mercado, G. A., E-mail: fermineutron@yahoo.co [Universidad Autonoma de Zacatecas, Unidad Academica de Matematicas, Jardin Juarez No. 147, 98000 Zacatecas (Mexico)

    2010-02-15

    Using as source term the spectrum of a {sup 239}Pu-Be source several neutron spectra have been calculated using Monte Carlo methods. The source term was located in the centre of spherical moderators made of light water, heavy water and polyethylene of different diameters. Also a {sup 239}Pu-Be source was used to measure its neutron spectrum, bare and moderated by water. The neutron spectra were measured at 100 cm with a Bonner spheres spectrometer. Monte Carlo calculations were used to calculate the neutron spectra of bare and water-moderated spectra that were compared with those measured with the spectrometer. Resulting spectra are similar to those found in power plants with PWR, BWR and Candu nuclear reactors. Beside the spectra the dosimetric features were determined. Using moderators and a single neutron source can be produced neutron spectra alike those found in workplaces, this neutron fields can be utilized to calibrate neutron dosimeters and area monitors. (Author)

  19. Different spectra with the same neutron source

    International Nuclear Information System (INIS)

    Vega C, H. R.; Ortiz R, J. M.; Hernandez D, V. M.; Martinez B, M. R.; Hernandez A, B.; Ortiz H, A. A.; Mercado, G. A.

    2010-01-01

    Using as source term the spectrum of a 239 Pu-Be source several neutron spectra have been calculated using Monte Carlo methods. The source term was located in the centre of spherical moderators made of light water, heavy water and polyethylene of different diameters. Also a 239 Pu-Be source was used to measure its neutron spectrum, bare and moderated by water. The neutron spectra were measured at 100 cm with a Bonner spheres spectrometer. Monte Carlo calculations were used to calculate the neutron spectra of bare and water-moderated spectra that were compared with those measured with the spectrometer. Resulting spectra are similar to those found in power plants with PWR, BWR and Candu nuclear reactors. Beside the spectra the dosimetric features were determined. Using moderators and a single neutron source can be produced neutron spectra alike those found in workplaces, this neutron fields can be utilized to calibrate neutron dosimeters and area monitors. (Author)

  20. Conceptual design of neutron diagnostic systems for fusion experimental reactor

    International Nuclear Information System (INIS)

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

    1994-01-01

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

  1. Radial Flux Distribution of Low-Energy Neutrons.

    Science.gov (United States)

    Higinbotham, J.

    1979-01-01

    Describes an experiment designed to illustrate the basic principle involved in the process of moderation of fast neutrons by water, and the monitoring of the low-energy neutron flux using indium as a probe. (GA)

  2. The neutron

    International Nuclear Information System (INIS)

    Cheetham, A.K.

    1990-01-01

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

  3. Atmospheric neutrons

    International Nuclear Information System (INIS)

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

    1976-01-01

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

  4. Comparison of non-invasive individual monitoring of the training and health of athletes with commercially available wearable technologies

    Directory of Open Access Journals (Sweden)

    Peter eDüking

    2016-03-01

    Full Text Available Athletes adapt their training daily to optimize performance, as well as avoid fatigue, overtraining and other undesirable effects on their health. To optimize training load, each athlete must take his/her own personal objective and subjective characteristics into consideration and an increasing number of wearable technologies (wearables provide convenient monitoring of various parameters. Accordingly, it is important to help athletes decide which parameters are of primary interest and which wearables can monitor these parameters most effectively. Here, we discuss the wearable technologies available for non-invasive monitoring of various parameters concerning an athlete’s training and health. On the basis of these considerations, we suggest directions for future development. Furthermore, we propose that a combination of several wearables is most effective for accessing all relevant parameters, disturbing the athlete as little as possible, and optimizing performance and promoting health.

  5. Performance test of dosimetric services in the EU member states and Switzerland for the routine assessment of individual doses (photon, beta and neutron)

    DEFF Research Database (Denmark)

    Bordy, J.M.; Stadtmann, H.; Ambrosi, P.

    2000-01-01

    of the dosimetry of routine services. It was assumed that each service would have already done a type test before performing routine dosimetry: the radiation fields were chosen to simulate, as far as possible, workplace radiation fields by mixing combining energies and incident angles. The results of photon......The results are given of a consolidated performance test for whole-body, and extremity personal dosemeters broadly representative of those in use in the EU member states and Switzerland. Beta, photon and neutron personal dosemeters were used to assess the routine services ability to determine...... and report personal dose equivalents. In total, 69 sets of dosemeters were entered in the test by 34 services. About 1000 dosemeters were irradiated. One purpose of the consolidated performance test and the analysis of the results was to enable the assessment of criteria for the acceptability...

  6. Glycaemic control in type 1 diabetes during real time continuous glucose monitoring compared with self monitoring of blood glucose: meta-analysis of randomised controlled trials using individual patient data.

    Science.gov (United States)

    Pickup, John C; Freeman, Suzanne C; Sutton, Alex J

    2011-07-07

    To determine the clinical effectiveness of real time continuous glucose monitoring compared with self monitoring of blood glucose in type 1 diabetes. Meta-analysis of randomised controlled trials. Cochrane database for randomised controlled trials, Ovid Medline, Embase, Google Scholar, lists of papers supplied by manufacturers of continuous glucose monitors, and cited literature in retrieved articles. Studies reviewed Randomised controlled trials of two or more months' duration in men and non-pregnant women with type 1 diabetes that compared real time continuous glucose monitoring with self monitoring of blood glucose and where insulin delivery was the same in both arms. Analysis Two step meta-analysis of individual patient data with the primary outcome of final glycated haemoglobin (HbA(1c)) percentage and area under the curve of hypoglycaemia (glucose concentration glucose monitoring and 443 to self monitoring of blood glucose. The overall mean difference in HbA(1c) for continuous glucose monitoring versus self monitoring of blood glucose was -0.30% (95% confidence interval -0.43% to -0.17%) (-3.0, -4.3 to -1.7 mmol/mol). A best fit regression model of determinants of final HbA(1c) showed that for every one day increase of sensor usage per week the effect of continuous glucose monitoring versus self monitoring of blood glucose increased by 0.150% (95% credibility interval -0.194% to -0.106%) (1.5, -1.9 to -1.1 mmol/mol) and every 1% (10 mmol/mol) increase in baseline HbA(1c) increased the effect by 0.126% (-0.257% to 0.0007%) (1.3, -2.6 to 0.0 mmol/mol). The model estimates that, for example, a patient using the sensor continuously would experience a reduction in HbA(1c) of about 0.9% (9 mmol/mol) when the baseline HbA(1c) is 10% (86 mmol/mol). The overall reduction in area under the curve of hypoglycaemia was -0.28 (-0.46 to -0.09), corresponding to a reduction in median exposure to hypoglycaemia of 23% for continuous glucose monitoring compared with self

  7. Boron neutron capture therapy (BNCT) for liver metastasis in an experimental model: dose–response at five-week follow-up based on retrospective dose assessment in individual rats

    Energy Technology Data Exchange (ETDEWEB)

    Emiliano C. C. Pozzi; Veronica A. Trivilin; Lucas L. Colombo; Andrea Monti Hughes; Silvia I. Thorp; Jorge E. Cardoso; Marcel A. Garabalino; Ana J. Molinari; Elisa M. Heber; Paula Curotto; Marcelo Miller; Maria E. Itoiz; Romina F. Aromando; David W. Nigg; Amanda E. Schwint

    2013-11-01

    Boron neutron capture therapy (BNCT) was proposed for untreatable colorectal liver metastases. Employing an experimental model of liver metastases in rats, we recently demonstrated that BNCT mediated by boronophenylalanine (BPA-BNCT) at 13 Gy prescribed to tumor is therapeutically useful at 3-week follow-up. The aim of the present study was to evaluate dose–response at 5-week follow-up, based on retrospective dose assessment in individual rats. BDIX rats were inoculated with syngeneic colon cancer cells DHD/K12/TRb. Tumor-bearing animals were divided into three groups: BPA-BNCT (n = 19), Beam only (n = 8) and Sham (n = 7) (matched manipulation, no treatment). For each rat, neutron flux was measured in situ and boron content was measured in a pre-irradiation blood sample for retrospective individual dose assessment. For statistical analysis (ANOVA), individual data for the BPA-BNCT group were pooled according to absorbed tumor dose, BPA-BNCT I: 4.5–8.9 Gy and BPA-BNCT II: 9.2–16 Gy. At 5 weeks post-irradiation, the tumor surface area post-treatment/pre-treatment ratio was 12.2 +/- 6.6 for Sham, 7.8 +/- 4.1 for Beam only, 4.4 +/- 5.6 for BPA-BNCT I and 0.45 +/- 0.20 for BPA-BNCT II; tumor nodule weight was 750 +/- 480 mg for Sham, 960 +/- 620 mg for Beam only, 380 +/- 720 mg for BPA-BNCT I and 7.3 +/- 5.9 mg for BPA-BNCT II. The BPA-BNCT II group exhibited statistically significant tumor control with no contributory liver toxicity. Potential threshold doses for tumor response and significant tumor control were established at 6.1 and 9.2 Gy, respectively.

  8. Enhancement of Self-Monitoring in a Web-Based Weight Loss Program by Extra Individualized Feedback and Reminders: Randomized Trial.

    Science.gov (United States)

    Hutchesson, Melinda Jane; Tan, Chor Yin; Morgan, Philip; Callister, Robin; Collins, Clare

    2016-04-12

    Self-monitoring is an essential behavioral strategy for effective weight loss programs. Traditionally, self-monitoring has been achieved using paper-based records. However, technology is now more frequently used to deliver treatment programs to overweight and obese adults. Information technologies, such as the Internet and mobile phones, allow innovative intervention features to be incorporated into treatment that may facilitate greater adherence to self-monitoring processes, provide motivation for behavior change, and ultimately lead to greater weight loss success. The objective of our study was to determine whether the consistency of self-monitoring differed between participants randomly assigned to a basic or an enhanced 12-week commercial Web-based weight loss program. We randomly assigned a sample of 301 adults (mean age 42.3 years; body mass index 31.3 kg/m2; female 176/301, 58.5%) to the basic or enhanced group. The basic program included tools for self-monitoring (online food and exercise diary, and a weekly weigh-in log) with some feedback and reminders to weigh in (by text or email). The enhanced program included the basic components, as well as extra individualized feedback on self-monitoring entries and reminders (by text, email, or telephone) to engage with self-monitoring tools. We evaluated the level of self-monitoring by examining the consistency of self-monitoring of food, exercise, and weight during the 12 weeks. Consistency was defined as the number of weeks during which participants completed a criterion number of entries (ie, ≥3 days of online food or exercise diary records per week and ≥1 weigh-in per week). The enhanced group's consistency of use of self-monitoring tools was significantly greater than that of the basic group throughout the 12 weeks (median consistency for food 8 vs 3 weeks, respectively, Pself-monitoring behaviors in a Web-based weight loss program. Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN

  9. Neutron source multiplication method

    International Nuclear Information System (INIS)

    Clayton, E.D.

    1985-01-01

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

  10. Neutronic reactor

    International Nuclear Information System (INIS)

    Wende, C.W.J.

    1976-01-01

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

  11. Neutron diffraction

    International Nuclear Information System (INIS)

    Bacon, G.E.

    1983-01-01

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

  12. Neutron holography

    International Nuclear Information System (INIS)

    Beynon, T.D.

    1986-01-01

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

  13. Neutron tubes

    Science.gov (United States)

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

    2008-03-11

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

  14. Neutron source

    Science.gov (United States)

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

    1975-10-21

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

  15. Neutron reflectometry

    DEFF Research Database (Denmark)

    Klösgen-Buchkremer, Beate Maria

    2014-01-01

    Neutron (and X-ray) reflectometry constitute complementary interfacially sensitive techniques that open access to studying the structure within thin films of both soft and hard condensed matter. Film thickness starts oxide surfaces on bulk substrates, proceeding to (pauci-)molecular layers and up...... to hundreds of nanometers. Thickness resolution for flat surfaces is in the range of few Ǻngstrøm, and as a peculiar benefit, the presence and properties of buried interfaces are accessible. Focus here will be on neutron reflectometry, a technique that is unique in applications involving composite organic...... films or films with magnetic properties. The reason is the peculiar property of neutron light since the mass of a neutron is close to the one of a proton, and since it bears a magnetic moment. The optical properties of matter, when interacting with neutrons, are described by a refractive index...

  16. Neutron source

    International Nuclear Information System (INIS)

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

    1975-01-01

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

  17. Design, construction and characterization of a dosimeter for neutron radiation

    International Nuclear Information System (INIS)

    Souto, Eduardo de Brito

    2007-01-01

    An individual dosimeter for neutron-gamma mixed field dosimetry was design and developed aiming monitoring the increasing number of workers potentially exposed to neutrons. The proposed dosimeter was characterized to an Americium-Beryllium source spectrum and dose range of radiation protection interest (up to 20 mSv). Thermoluminescent albedo dosimetry and nuclear tracks dosimetry, traditional techniques found in the international literature, with materials of low cost and national production, were used. A commercial polycarbonate, named SS-1, was characterized for solid state tack detector application. The chemical etching parameters and the methodology of detectors evaluation were determined. The response of TLD-600, TLD-700 and SS-1 were studied and algorithms for dose calculation of neutron and gamma radiation of Americium- Beryllium sources were proposed. The ratio between thermal, albedo and fast neutrons responses, allows analyzing the spectrum to which the dosimeter was submitted and correcting the track detector response to variations in the radiation incidence angle. The new dosimeter is fully characterized, having sufficient performance to be applied as neutron dosimeter in Brazil. (author)

  18. Individual based, long term monitoring of acacia trees in hyper arid zone: Integration of a field survey and a remote sensing approach

    Science.gov (United States)

    Isaacson, Sivan; Blumberg, Dan G.; Ginat, Hanan; Shalmon, Benny

    2013-04-01

    Vegetation in hyper arid zones is very sparse as is. Monitoring vegetation changes in hyper arid zones is important because any reduction in the vegetation cover in these areas can lead to a considerable reduction in the carrying capacity of the ecological system. This study focuses on the impact of climate fluctuations on the acacia population in the southern Arava valley, Israel. The period of this survey includes a sequence of dry years with no flashfloods in most of the plots that ended in two years with vast floods. Arid zone acacia trees play a significant role in the desert ecosystem by moderating the extreme environmental conditions including radiation, temperature, humidity and precipitation. The trees also provide nutrients for the desert dwellers. Therefore, acacia trees in arid zones are considered to be `keystone species', because they have major influence over both plants and animal species, i.e., biodiversity. Long term monitoring of the acacia tree population in this area can provide insights into long term impacts of climate fluctuations on ecosystems in arid zones. Since 2000, a continuous yearly based survey on the three species of acacia population in seven different plots is conducted in the southern Arava (established by Shalmon, ecologist of the Israel nature and parks authority). The seven plots representing different ecosystems and hydrological regimes. A yearly based population monitoring enabled us to determine the mortality and recruitment rate of the acacia populations as well as growing rates of individual trees. This survey provides a unique database of the acacia population dynamics during a sequence of dry years that ended in a vast flood event during the winter of 2010. A lack of quantitative, nondestructive methods to estimate and monitor stress status of the acacia trees, led us to integrate remote sensing tools (ground and air-based) along with conventional field measurements in order to develop a long term monitoring of acacia

  19. Meta-analysis of individual patient data in randomised trials of self monitoring of blood glucose in people with non-insulin treated type 2 diabetes.

    Science.gov (United States)

    Farmer, Andrew J; Perera, Rafael; Ward, Alison; Heneghan, Carl; Oke, Jason; Barnett, Anthony H; Davidson, Mayer B; Guerci, Bruno; Coates, Vivien; Schwedes, Ulrich; O'Malley, Simon

    2012-02-27

    To assess the effectiveness of self monitoring blood glucose levels in people with non-insulin treated type 2 diabetes compared with clinical management without self monitoring, and to explore the effects in specific patient groups. Meta-analysis based on individual participant data. Medline, Embase, and a recent systematic review of trials on self monitoring of blood glucose. Chief investigators of trials published since 2000 were approached for additional information and individual patient data. Randomised controlled trials in patients with non-insulin treated type 2 diabetes comparing an intervention using self monitoring of blood glucose with clinical management not using self monitoring. Trials published from 2000 with at least 80 participants were included. Individual patient data were collected from electronic files and checked for integrity. All randomised participants were analysed using the intention to treat principle. A random effects model of complete cases was used to assess efficacy, a sensitivity analysis comprised imputed data, and prespecified subgroup analyses were carried out for age, sex, previous use of self monitoring, duration of diabetes, and levels of glycated haemoglobin (HbA(1c)) at baseline. 2552 patients were randomised in the six included trials. A mean reduction in HbA(1c) level of -2.7 mmol/mol (95% confidence interval -3.9 to -1.6; 0.25%) was observed for those using self monitoring of blood glucose levels compared with no self monitoring at six months. The mean reduction in HbA(1c) level between groups was 2.0 mmol/mol (3.2 to 0.8; 0.25%) at three months (five trials) and 2.5 mmol/mol (4.1 to 0.9; 0.35%) at 12 months (three trials). These estimates were unchanged after imputing missing data, and estimates of effect in trials with higher loss to follow-up or a possibility of co-intervention compared with those with lower loss to follow-up and no co-intervention did not differ significantly (P=0.21). The difference in HbA(1c) levels

  20. Calculations to support JET neutron yield calibration: Modelling of neutron emission from a compact DT neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Čufar, Aljaž, E-mail: aljaz.cufar@ijs.si [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Batistoni, Paola [ENEA, Department of Fusion and Nuclear Safety Technology, I-00044 Frascati, Rome (Italy); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Conroy, Sean [Uppsala University, Department of Physics and Astronomy, PO Box 516, SE-75120 Uppsala (Sweden); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Ghani, Zamir [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Lengar, Igor [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Milocco, Alberto; Packer, Lee [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Pillon, Mario [ENEA, Department of Fusion and Nuclear Safety Technology, I-00044 Frascati, Rome (Italy); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Popovichev, Sergey [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Snoj, Luka [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

    2017-03-01

    At the Joint European Torus (JET) the ex-vessel fission chambers and in-vessel activation detectors are used as the neutron production rate and neutron yield monitors respectively. In order to ensure that these detectors produce accurate measurements they need to be experimentally calibrated. A new calibration of neutron detectors to 14 MeV neutrons, resulting from deuterium–tritium (DT) plasmas, is planned at JET using a compact accelerator based neutron generator (NG) in which a D/T beam impinges on a solid target containing T/D, producing neutrons by DT fusion reactions. This paper presents the analysis that was performed to model the neutron source characteristics in terms of energy spectrum, angle–energy distribution and the effect of the neutron generator geometry. Different codes capable of simulating the accelerator based DT neutron sources are compared and sensitivities to uncertainties in the generator's internal structure analysed. The analysis was performed to support preparation to the experimental measurements performed to characterize the NG as a calibration source. Further extensive neutronics analyses, performed with this model of the NG, will be needed to support the neutron calibration experiments and take into account various differences between the calibration experiment and experiments using the plasma as a source of neutrons.

  1. Calculations to support JET neutron yield calibration: Modelling of neutron emission from a compact DT neutron generator

    Science.gov (United States)

    Čufar, Aljaž; Batistoni, Paola; Conroy, Sean; Ghani, Zamir; Lengar, Igor; Milocco, Alberto; Packer, Lee; Pillon, Mario; Popovichev, Sergey; Snoj, Luka; JET Contributors

    2017-03-01

    At the Joint European Torus (JET) the ex-vessel fission chambers and in-vessel activation detectors are used as the neutron production rate and neutron yield monitors respectively. In order to ensure that these detectors produce accurate measurements they need to be experimentally calibrated. A new calibration of neutron detectors to 14 MeV neutrons, resulting from deuterium-tritium (DT) plasmas, is planned at JET using a compact accelerator based neutron generator (NG) in which a D/T beam impinges on a solid target containing T/D, producing neutrons by DT fusion reactions. This paper presents the analysis that was performed to model the neutron source characteristics in terms of energy spectrum, angle-energy distribution and the effect of the neutron generator geometry. Different codes capable of simulating the accelerator based DT neutron sources are compared and sensitivities to uncertainties in the generator's internal structure analysed. The analysis was performed to support preparation to the experimental measurements performed to characterize the NG as a calibration source. Further extensive neutronics analyses, performed with this model of the NG, will be needed to support the neutron calibration experiments and take into account various differences between the calibration experiment and experiments using the plasma as a source of neutrons.

  2. Intercomparison for individual monitoring of external exposure from photon radiation. Results of a co-ordinated research project 1996-1998

    International Nuclear Information System (INIS)

    1999-12-01

    This TECDOC presents the results of a Co-ordinated Research Project on Intercomparison for Individual Monitoring of External Exposure from photon radiation. The International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (BSS) have endorsed the use of the operational quantities for monitoring purposes. Specifically, personal dose equivalent, H p (d), is to be used for individual dosimetry to demonstrate compliance with the exposure limit recommendations, while for workplace area monitoring the ambient dose equivalent and the directional dose equivalent are recommended. In view of the technical difficulties associated with the introduction of these operational quantities the IAEA decided to assist Member States in their provision of appropriate dosimetry for occupational protection. In this respect, intercomparisons have proven to be a cost effective method of providing such support. A Co-ordinated Research Project (CRP) was started in 1997 on Intercomparison for Individual Monitoring of External Exposure from photon radiation, involving more than twenty laboratories from eastern Europe and the countries of the former Soviet Union, and focusing on personnel dosimetry services for nuclear power plants. This CRP was part of the activities of the IAEA Occupational Protection Programme, the objective4s of which are to promote and internationally harmonized approach for optimizing occupational radiation protection through: the development of guides, within the IAEA activities for establishing standards for radiation protection, for restricting radiation exposures in the workplace and for applying current occupational radiation protection techniques, and the promotion of the application of these guidelines. The preparatory phase included, in May 1997, a workshop aimed at familiarizing the participants with the new operational quantities

  3. Research and development activities of the Neutron Physics Division for the period January 1979-December 1979

    International Nuclear Information System (INIS)

    Basu, T.K.; Vohra, Y.K.

    1980-01-01

    Research and Development (R and D) activities of the Neutron Physics Division of the Bhabha Atomic Research Centre, Bombay during the calendar year 1979 are reported in the form of individual summaries. The Division's R and D work covers the fields of reactor neutron physics, applied neutronics, fusion plasma pinches, materials physics, crystallography and seismology. Some of the highlights of these activities are: (1) the development of a criticality formula for PURNIMA-II, a BeO reflected 233 U-uranyl nitrate solution critical experiment, (2) commissioning of a 21 K3, 50 KV fast capacitor bank for experiments of high-density plasma focus devices, (3) the design of a bore-hole model to develop carbon-oxygen logging method for identifying the oil and water zones in sand-stone formations in the earth's sub-surface using neutrons from a 14 MeV neutron generator, (4) proposal of a theoretical model for the equation of state of high-density matter in the intermediate pressure (approximately 10-100 Megabar) region, (5) development of a quantitative relation between the crater dimensions and the mound kinetic energy imparted by the shock from an underground nuclear explosion, and (6) texture studies of uranium fuel element samples using neutron diffraction. Progress of work on PURNIMA-II experiment, fusion blanket neutronics experiment, monitoring of nuclear explosions and discriminating them from earthquakes using seismic and microbarographic data is also reported. (M.G.B.)

  4. Photon and neutron doses of the personnel using moisture and density measurement devices

    International Nuclear Information System (INIS)

    Carinou, E.; Papadomarkaki, E.; Tritakis, P.; Hourdakis, C.I.; Kamenopoulou, V.

    2006-01-01

    The objective of this study is to present the evolution of the photon doses received by the workers who use mobile devices for measuring the moisture and the density in various materials and to estimate the neutron doses. The workers employed in more than 30 construction companies in Greece were 76 in 2004. The devices used for that purpose incorporate a 137 Cs source for density measurements and an 241 Am-Be source for moisture measurements of soil, asphalt or concrete. Photon and neutron measurements were performed occasionally during the on site inspections. The results of the measurements showed that the photon and neutron dose rates were not negligible. The workers were monitored for photon radiation using film badges (Kodak Type 2, Holder NRPB type) till the year 2000 and then TLD badges issued by the Greek Atomic Energy Commission (GAEC), on a monthly basis. Since the neutron dose rates measured by a rem-meter were not so high, no neutron dosemeters were issued for them. Their personal dose equivalent data for photons are kept in the National Dose Registry Information System (N.D.R.I.S.) in G.A.E.C. and were used for statistical analysis for the period from 1997 till 2004. As far as the neutrons are concerned, a Monte Carlo code was used to simulate the measuring devices and the working positions in order to calculate the neutron individual doses. (authors)

  5. Development of in vitro bioanalysis technique for individual monitoring of {sup 32}P; Desenvolvimento de técnicas de bioanálise in vitro para monitoração individual de {sup 32}P

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Ana Paula F. de; Dantas, Bernardo M.; Sousa, Wanderson O., E-mail: bmdantas@ird.gov.br [Instituto de Radioproteção e Dosimetria /Divisão de Dosimetria, Rio de Janeiro-RJ (Brazil)

    2017-07-01

    {sup 32}P is usually handled in the form of liquid unsealed sources in medical facilities, in research and teaching institutions, and in industrial radiopharmaceutical production plants. Such practices represent a risk of internal exposure in routine activities and in case of accidents. The estimation of {sup 32}P incorporation can be accomplished through in vitro bioassay. This paper presents a methodology to analyze {sup 32}P in biological samples, applicable to internal individual monitoring using liquid scintillation technique. Based on the experimental results it is possible to conclude that the technique presents enough sensitivity to detect activities that result in committed effective dose in the order of 1 mSv. (author)

  6. Neutron-chamber detectors and applications

    International Nuclear Information System (INIS)

    Fehlau, P.E.; Atwater, H.F.; Coop, K.L.

    1990-01-01

    Detector applications in Nuclear Safeguards and Waste Management have included measuring neutrons from fission and (alpha,n) reactions with well-moderated neutron proportional counters, often embedded in a slab of polyethylene. Other less-moderated geometries are useful for detecting both bare and moderated fission-source neutrons with good efficiency. The neutron chamber is an undermoderated detector design comprising a large, hollow, polyethylene-walled chamber containing one or more proportional counters. Neutron-chamber detectors are relatively inexpensive; can have large apertures, usually through a thin chamber wall; and offer very good detection efficiency per dollar. Neutron-chamber detectors have also been used for monitoring vehicles and for assaying large crates of transuranic waste. Our Monte Carlo calculations for a new application (monitoring low-density waste for concealed plutonium) illustrate the advantages of the hollow-chamber design for detecting moderated fission sources. 9 refs., 6 figs., 2 tabs

  7. The structure dependence of deformation behavior of transformation-induced plasticity-assisted steel monitoring by in-situ neutron diffraction

    Czech Academy of Sciences Publication Activity Database

    Muránsky, Ondrej; Šittner, Petr; Zrník, J.; Oliver, E.C.

    2008-01-01

    Roč. 39, č. 13 (2008), s. 3097-3104 ISSN 1073-5623 R&D Projects: GA ČR GES3T/06/E002 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z10480505 Keywords : TRIP steel * neutron diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.389, year: 2008

  8. Neutron and high-contrast X-ray micro-radiography as complementary tools for monitoring organosilicon consolidants in natural building stones

    Czech Academy of Sciences Publication Activity Database

    Slavíková, M.; Krejčí, F.; Kotlík, P.; Jakůbek, J.; Tomandl, Ivo; Vacík, Jiří

    2014-01-01

    Roč. 338, NOV (2014), s. 42-47 ISSN 0168-583X R&D Projects: GA TA ČR TA01010237; GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : stone consolidation * neutron radiography * X-ray radiography * Organosilicon consolidants Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.124, year: 2014

  9. Comparing Infants' Use of Featural and Spatiotemporal Information in an Object Individuation Task Using a New Event-Monitoring Design

    Science.gov (United States)

    Krojgaard, Peter

    2007-01-01

    Discussions have recently taken place on whether spatiotemporal information is more important than featural information when infants attempt to individuate objects. Hitherto, spatiotemporal and featural information have only been compared directly by using cognitively demanding "event-mapping" designs" (e.g. Xu & Carey, 1996 ), whereas the simpler…

  10. Neutron diffraction

    International Nuclear Information System (INIS)

    James, M.; Howard, C.J.; Kennedy, S.

    1999-01-01

    Diffraction methods, especially X-ray diffraction, are widely used in materials science. Neutron diffraction is in many ways similar to X-ray diffraction, but is also complementary to the X-ray technique so that in some cases it yields information not accessible using X-rays. Successes of neutron diffraction include the elucidation of the crystal structures of high temperature superconductors and materials that display colossal magnetoresistance, the phase analysis of zirconia engineering ceramics, in depth stress determination in composites, successful determination of the structures of metal hydrides, transition metal polymer complexes and the determination of magnetic structure. A brief description of current studies, using neutron diffraction is given

  11. Fast neutron dosimetry

    International Nuclear Information System (INIS)

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

    1991-01-01

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

  12. Estimating individual-level exposure to airborne polycyclic aromatic hydrocarbons throughout the gestational period based on personal, indoor, and outdoor monitoring.

    Science.gov (United States)

    Choi, Hyunok; Perera, Frederica; Pac, Agnieszka; Wang, Lu; Flak, Elzbieta; Mroz, Elzbieta; Jacek, Ryszard; Chai-Onn, Tricia; Jedrychowski, Wieslaw; Masters, Elizabeth; Camann, David; Spengler, John

    2008-11-01

    Current understanding on health effects of long-term polycyclic aromatic hydrocarbon (PAH) exposure is limited by lack of data on time-varying nature of the pollutants at an individual level. In a cohort of pregnant women in Krakow, Poland, we examined the contribution of temporal, spatial, and behavioral factors to prenatal exposure to airborne PAHs within each trimester and developed a predictive model of PAH exposure over the entire gestational period. We monitored nonsmoking pregnant women (n = 341) for their personal exposure to pyrene and eight carcinogenic PAHs-benz[a]anthracene, chrysene/isochrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene [B(a)P], indeno[1,2,3-c,d]pyrene, dibenz[a,h]anthracene, and benzo[g,h,i]perylene-during their second trimester for a consecutive 48-hr period. In a subset (n = 78), we monitored indoor and outdoor levels simultaneously with the personal monitoring during the second trimester with an identical monitor. The subset of women was also monitored for personal exposure for a 48-hr period during each trimester. We repeatedly administered a questionnaire on health history, lifestyle, and home environment. The observed personal, indoor, and outdoor B(a)P levels we observed in Krakow far exceed the recommended Swedish guideline value for B(a)P of 0.1 ng/m(3). Based on simultaneously monitored levels, the outdoor PAH level alone accounts for 93% of total variability in personal exposure during the heating season. Living near the Krakow bus depot, a crossroad, and the city center and time spent outdoors or commuting were not associated with higher personal exposure. During the nonheating season only, a 1-hr increase in environmental tobacco smoke (ETS) exposure was associated with a 10-16% increase in personal exposure to the nine measured PAHs. A 1 degrees C decrease in ambient temperature was associated with a 3-5% increase in exposure to benz[a]anthracene, benzo[k]fluoranthene, and dibenz[a,h]anthracene, after

  13. Hand book on the use of TLD badge based on CaSO4:Dy teflon TLD discs for individual monitoring

    International Nuclear Information System (INIS)

    Pradhan, A.S.; Adtani, M.M.; Varadharajan, G.; Bakshi, A.K.; Srivastava, Kshama; Bihari, R.R.

    2002-10-01

    Individual monitoring is one of the most important aspects of a radiation protection programme. In India, an official and centralized personnel monitoring service to radiation workers started in 1952. With the indigenous development of a TLD badge system in 1975 at Bhabha Atomic Research Centre, decentralization of monitoring service was initiated. At present, about 40,000 radiation workers are monitored using this system through twelve TLD units located in different parts of the country, including a private accredited laboratory. Regulatory and other inspecting bodies have often asked outstation TLD units to produce a duly approved document on the procedures being practiced for the assessment of personal doses. A need for such a document has also been felt to ensure the uniformity in processing of dosemeters, recording and reporting of doses by different TLD units and to provide guidelines regarding the infrastructure requirement. This document in the form of a handbook has been prepared to cater to the above needs. The handbook is expected to provide necessary guidelines not only to the newcomers/ forthcoming units and the existing laboratories but also to help the regulators, inspectors and assessors. (author)

  14. Individual medicine in inflammatory bowel disease: monitoring bioavailability, pharmacokinetics and immunogenicity of anti-tumour necrosis factor-alpha antibodies

    DEFF Research Database (Denmark)

    Bendtzen, Klaus; Ainsworth, Mark; Steenholdt, Casper

    2009-01-01

    Antibody constructs targeting tumour necrosis factor-alpha (TNF) have become important in the management of several chronic immunoinflammatory diseases. Four recombinant anti-TNF drugs are currently approved for clinical use in patients with various chronic inflammatory diseases, three of which...... are effective in chronic inflammatory bowel disease. These proteins can dramatically lower disease activity and, in some patients, induce remission. Unfortunately, however, not all patients respond favourably to anti-TNF antibodies. For example, patients suffering from Crohn's disease do not benefit from...... for circulating levels of functional anti-TNF drugs and ADAs is therefore warranted so that treatment can be tailored to the individual patient (individual medicine or personal medicine) in order that effective and economical long-term therapy can be given with minimal risks to the patients....

  15. Interpretation of the results from individual monitoring of workers at the Nuclear Fuel Fabrication Facility, Brazil; Interpretacao de resultados de monitoracao individual interna da Fabrica de Combustivel Nuclear - FCN

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Marcelo Xavier de

    2005-07-01

    In nuclear fuel fabrication facilities, workers are exposed to different compounds of enriched uranium. Although in this kind of facility the main route of intake is inhalation, ingestion may occur in some situations, and also a mixture of both. The interpretation of the bioassay data is very complex, since it is necessary taking into account all the different parameters, which is a big challenge. Due to the high cost of the individual monitoring programme for internal dose assessment in the routine monitoring programmes, usually only one type of measurement is assigned. In complex situations like the one described in this study, where several parameters can compromise the accuracy of the bioassay interpretation it is need to have a combination of techniques to evaluate the internal dose. According to ICRP 78 (1997), the general order of preference of measurement methodologies in terms of accuracy of interpretation is: body activity measurement, excreta analysis and personal air sampling. Results of monitoring of working environment may provide information that assists in the interpretation on particle size, chemical form, solubility and date of intake. A group of fifteen workers from controlled area of the studied nuclear fuel fabrication facility was selected to evaluate the internal dose using all different available techniques during a certain period. The workers were monitored for determination of uranium content in the daily urinary and faecal excretion (collected over a period of 3 consecutive days), chest counting and personal air sampling. The results have shown that at least two types of sensitivity techniques must be used, since there are some sources of uncertainties on the bioassay interpretation, like mixture of uranium compounds intake and different routes of intake. The combination of urine and faeces analysis has shown to be the more appropriate methodology for assessing internal dose in this situation. The chest counting methodology has not shown

  16. Neutron scattering

    International Nuclear Information System (INIS)

    Furrer, A.

    1993-01-01

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

  17. CMOS-Based Neutron Spectroscopic Dosimeter (CNSD), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Monitoring space radiation and the dose received by astronauts is important, especially for future long-duration missions. Neutrons contribute a significant...

  18. CMOS-Based Neutron Spectroscopic Dosimeter (CNSD) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Monitoring space radiation and the dose received by astronauts is important, especially for future long-duration missions. Neutrons contribute a significant...

  19. New Neutron Dosimeter

    CERN Multimedia

    2001-01-01

    CERN has been operating an Individual Dosimetry Service for neutrons for about 35 years. The service was based on nuclear emulsions in the form of film packages which were developed and scanned in the Service. In 1999, the supplier of theses packages informed CERN that they will discontinue production of this material. TIS-RP decided to look for an external service provider for individual neutron dosimetry. After an extensive market survey and an invitation for tender, a supplier that met the stringent technical requirements set up by CERN's host states for personal dosimeters was identified. The new dosimeter is based on a track-etching technique. Neutrons have the capability of damaging plastic material. The microscopic damage centres are revealed by etching them in a strong acid. The resulting etch pits can be automatically counted and their density is proportional to dose equivalent from neutrons. On the technical side, the new dosimeter provides an improved independence of its response from energy and th...

  20. Calibration issues for neutron diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Sadler, G.J. [JET Joint Undertaking, Abingdon (United Kingdom); Adams, J.M. [AEA Technology, Harwell (United Kingdom); Barnes, C.W. [Los Alamos National Lab., NM (United States)] [and others

    1997-12-01

    The performance of diagnostic systems are limited by their weakest constituents, including their calibration issues. Neutron diagnostics are notorious for problems encountered while determining their absolute calibrations, due mainly to the nature of the neutron transport problem. In order to facilitate the determination of an accurate and precise calibration, the diagnostic design should be such as to minimize the scattered neutron flux. ITER will use a comprehensive set of neutron diagnostics--comprising radial and vertical neutron cameras, neutron spectrometers, a neutron activation system and internal and external fission chambers--to provide accurate measurements of fusion power and power densities as a function of time. The calibration of such an important diagnostic system merits careful consideration. Some thoughts have already been given to this subject during the conceptual design phase in relation to the time-integrated neutron activation and time-dependent neutron yield monitors. However, no overall calibration strategy has been worked out so far. This paper represents a first attempt to address this vital issue. Experience gained from present large tokamaks (JET, TFTR and JT60U) and proposals for ITER are reviewed. The need to use a 14-MeV neutron generator as opposed to radioactive sources for in-situ calibration of D-T diagnostics will be stressed. It is clear that the overall absolute determination of fusion power will have to rely on a combination of nuclear measuring techniques, for which the provision of accurate and independent calibrations will constitute an ongoing process as ITER moves from one phase of operation to the next.

  1. Long-Range Neutron Detection

    International Nuclear Information System (INIS)

    Peurrung, A.J.; Stromswold, D.C.; Hansen, R.R.; Reeder, P.L.; Barnett, D.S.

    1999-01-01

    A neutron detector designed for detecting neutron sources at distances of 50 to 100 m has been constructed and tested. This detector has a large surface area (1 m 2 ) to enhance detection efficiency, and it contains a collimator and shielding to achieve direction sensitivity and reduce background. An unusual feature of the detector is that it contains no added moderator, such as polyethylene, to moderate fast neutrons before they reach the 3 He detector. As a result, the detector is sensitive mainly to thermal neutrons. The moderator-free design reduces the weight of the detector, making it more portable, and it also aids in achieving directional sensitivity and background reduction. Test results show that moderated fission-neutron sources of strength about 3 x 10 5 n/s can be detected at a distance out to 70 m in a counting time of 1000 s. The best angular resolution of the detector is obtained at distances of 30 m or less. As the separation .distance between the source and detector increases, the contribution of scattered neutrons to the measured signal increases with a resultant decrease in the ability to detect the direction to a distant source. Applications for which the long-range detector appears to be suitable include detecting remote neutron sources (including sources in moving vehicles) and monitoring neutron storage vaults for the intrusion of humans and the effects they make on the detected neutron signal. Also, the detector can be used to measure waste for the presence of transuranic material in the presence of high gamma-ray background. A test with a neutron source (3 x 10 5 n/s) in a vehicle showed that the detector could readily measure an increase in count rate at a distance of 10 m for vehicle speeds up to 35 mph (the highest speed tested). These results. indicate that the source should be detectable at this distance at speeds up to 55 mph

  2. Complicated systems for neutron detection

    International Nuclear Information System (INIS)

    Kozlov, I.M.; Nikotin, O.P.; Chekrenev, A.S.

    1982-01-01

    The design of the system for detecting delayed neutrons due to heavy nuclei photofission is described. The system comprises a large number of 3 He proportional counters of thermal neutrons. Each counter is equipped with an individual amplifier, discriminator and pUlse shaper. The tuning of a detector comprising several counters has been realized by changing the discrimination voltage in such a manner that the point of the ν radiation initial counting for all counters is under the same voltage of the high voltage source. Such method permits not only to reduce the tuning time but to obtain also an optimum value of perfect separation of signals from neutrons and ν radiation. Data processing has been performed by the commutator which permits to add signals in different versions. The choice of the version has been determined by output control potentials. The commutator functions have been recorded in the symbols of algebra logics. The described detector with the commutator has been employed in kinetic measurements of photofission delayed neutrons, for detecting fission neutrons with neutron background, from (α, n) for measuring the distribution of a number of instantaneous neutrons per fission act. The above principles of the detectors structure and data processing and recording facilities permit to unite according power supplies any number of thermal neutron counters and apply more complicated circuats of counter signal commutators

  3. FOREWORD: Neutron metrology Neutron metrology

    Science.gov (United States)

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

    2011-12-01

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

  4. Disease, predation and demography: Assessing the impacts of bovine tuberculosis on African buffalo by monitoring at individual and population levels

    Science.gov (United States)

    Cross, P.C.; Heisey, D.M.; Bowers, J.A.; Hay, C.T.; Wolhuter, J.; Buss, P.; Hofmeyr, M.; Michel, A.L.; Bengis, Roy G.; Bird, T.L.F.; du Toit, Johan T.; Getz, W.M.

    2009-01-01

    1. Understanding the effects of disease is critical to determining appropriate management responses, but estimating those effects in wildlife species is challenging. We used bovine tuberculosis (BTB) in the African buffalo Syncerus caffer population of Kruger National Park, South Africa, as a case study to highlight the issues associated with estimating chronic disease effects in a long-lived host. 2. We used known and radiocollared buffalo, aerial census data, and a natural gradient in pathogen prevalence to investigate if: (i) at the individual level, BTB infection reduces reproduction; (ii) BTB infection increases vulnerability to predation; and (iii) at the population level, increased BTB prevalence causes reduced population growth. 3. There was only a marginal reduction in calving success associated with BTB infection, as indexed by the probability of sighting a known adult female with or without a calf (P = 0??065). 4. Since 1991, BTB prevalence increased from 27 to 45% in the southern region and from 4 to 28% in the central region of Kruger National Park. The prevalence in the northern regions was only 1??5% in 1998. Buffalo population growth rates, however, were neither statistically different among regions nor declining over time. 5. Lions Panthera leo did not appear to preferentially kill test-positive buffalo. The best (Akaike's Information Criterion corrected for small sample size) AICc model with BTB as a covariate [exp(??) = 0??49; 95% CI = (0??24-1??02)] suggested that the mortality hazard for positive individuals was no greater than for test-negative individuals. 6. Synthesis and applications. Test accuracy, time-varying disease status, and movement among populations are some of the issues that make the detection of chronic disease impacts challenging. For these reasons, the demographic impacts of bovine tuberculosis in the Kruger National Park remain undetectable despite 6 years of study on known individuals and 40 years of population counts

  5. Neutron dosimetry in boron neutron capture therapy

    International Nuclear Information System (INIS)

    Fairchild, R.G.; Miola, U.J.; Ettinger, K.V.

    1981-01-01

    The recent development of various borated compounds and the utilization of one of these (Na 2 B 12 H 11 SH) to treat brain tumors in clinical studies in Japan has renewed interest in neutron capture therapy. In these procedures thermal neutrons interact with 10 B in boron containing cells through the 10 B(n,α) 7 Li reaction producing charged particles with a maximum range of approx. 10μm in tissue. Borated analogs of chlorpromazine, porphyrin, thiouracil and deoxyuridine promise improved tumor uptake and blood clearance. The therapy beam from the Medical Research Reactor in Brookhaven contains neutrons from a modified and filtered fission spectrum and dosimetric consequences of the use of the above mentioned compounds in conjunction with thermal and epithermal fluxes are discussed in the paper. One of the important problems of radiation dosimetry in capture therapy is determination of the flux profile and, hence, the dose profile in the brain. This has been achieved by constructing a brain phantom made of TE plastic. The lyoluminescence technique provides a convenient way of monitoring the neutron flux distributions; the detectors for this purpose utilize 6 Li and 10 B compounds. Such compounds have been synthesized specially for the purpose of dosimetry of thermal and epithermal beams. In addition, standard lyoluminescent phosphors, like glutamine, could be used to determine the collisional component of the dose as well as the contribution of the 14 N(n,p) 14 C reaction. Measurements of thermal flux were compared with calculations and with measurements done with activation foils

  6. Management of the database originated from individual and environment monitoring carried out in the UNIFESP/HSP complex, SP, Brazil

    International Nuclear Information System (INIS)

    Medeiros, Regina Bitelli; Daros, Kellen Adriana Curci; Almeida, Natalia Correia de; Pires, Silvio Ricardo; Jorge, Luiz Tadeu

    2005-01-01

    The Radiological Protection Sector of the Sao Paulo Hospital/Federal University of Sao Paulo, SP, Brazil manages the records of 457 dosemeters. Once the users must know about the absorbed doses monthly and the need of keep the individuals records until the age of 75 years old and for, at least during 30 years after the end of the occupation of the individual, it became necessary to construct a database and a computerized control to manage the accumulated doses. This control, between 1991 and 1999, was effected by means of a relational database (Cobol 85 - Operating System GCOS 7 (ABC Telematic Bull)). After this period, when the company responsible for dosimetry went on to provide computerized results, the data were stored in a Paradox database (Borland). In 2004, the databases were integrated and were created a third database developed in Oracle (IBM) and a system that allowed the institutional Intranet users to consult their accumulated doses annually and the value of the total effective dose accumulated during working life

  7. Correlation of Magnetic Properties and Residual Stress Distribution Monitored by X-Ray and Neutron Diffraction in Welded AISI 1008 Steel Sheets

    Czech Academy of Sciences Publication Activity Database

    Vourna, P.; Hervoches, Charles; Vrána, Miroslav; Ktena, A.; Hristoforou, E.

    2015-01-01

    Roč. 51, č. 1 (2015), s. 6200104 ISSN 0018-9464 R&D Projects: GA ČR GB14-36566G; GA MŠk LM2011019 EU Projects: European Commission(XE) 283883 - NMI3-II Institutional support: RVO:61389005 Keywords : Magnetic Barkhausen noise (MBN) * neutron diffraction (ND) * residual stress * X- ray diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.277, year: 2015

  8. Imaging with cold neutrons

    International Nuclear Information System (INIS)

    Lehmann, E.H.; Kaestner, A.; Josic, L.; Hartmann, S.; Mannes, D.

    2011-01-01

    Neutrons for imaging purposes are provided mainly from thermal beam lines at suitable facilities around the world. The access to cold neutrons is presently limited to very few places only. However, many challenging options for imaging with cold neutrons have been found out, given by the interaction behavior of the observed materials with neutrons in the cold energy range (3-10 A). For absorbing materials, the interaction probability increases proportionally with the wavelength with the consequence of more contrast but less transmission with cold neutrons. Many materials are predominantly scattering neutrons, in particular most of crystalline structural materials. In these cases, cold neutrons play an important role by covering the energy range of the most important Bragg edges given by the lattice planes of the crystallites. This particular behavior can be used for at least two important aspects-choosing the right energy of the initial beam enables to have a material more or less transparent, and a direct macroscopic visualization of the crystalline structure and its change in a manufacturing process. Since 2006, PSI operates its second beam line for neutron imaging, where cold neutrons are provided from a liquid deuterium cold source (operated at 25 K). It has been designed to cover the most current aspects in neutron imaging research with the help of high flexibility. This has been done with changeable inlet apertures, a turbine based velocity selector, two beam positions and variable detector systems, satisfying the demands of the individual investigation. The most important detection system was found to be a micro-tomography system that enables studies in the presently best spatial resolution. In this case, the high contrast from the sample interaction process and the high detection probability for the cold neutrons combines in an ideal combination for the best possible performance. Recently, it was found out that the energy selective studies might become a

  9. Imaging with cold neutrons

    Science.gov (United States)

    Lehmann, E. H.; Kaestner, A.; Josic, L.; Hartmann, S.; Mannes, D.

    2011-09-01

    Neutrons for imaging purposes are provided mainly from thermal beam lines at suitable facilities around the world. The access to cold neutrons is presently limited to very few places only. However, many challenging options for imaging with cold neutrons have been found out, given by the interaction behavior of the observed materials with neutrons in the cold energy range (3-10 Å). For absorbing materials, the interaction probability increases proportionally with the wavelength with the consequence of more contrast but less transmission with cold neutrons. Many materials are predominantly scattering neutrons, in particular most of crystalline structural materials. In these cases, cold neutrons play an important role by covering the energy range of the most important Bragg edges given by the lattice planes of the crystallites. This particular behavior can be used for at least two important aspects—choosing the right energy of the initial beam enables to have a material more or less transparent, and a direct macroscopic visualization of the crystalline structure and its change in a manufacturing process. Since 2006, PSI operates its second beam line for neutron imaging, where cold neutrons are provided from a liquid deuterium cold source (operated at 25 K). It has been designed to cover the most current aspects in neutron imaging research with the help of high flexibility. This has been done with changeable inlet apertures, a turbine based velocity selector, two beam positions and variable detector systems, satisfying the demands of the individual investigation. The most important detection system was found to be a micro-tomography system that enables studies in the presently best spatial resolution. In this case, the high contrast from the sample interaction process and the high detection probability for the cold neutrons combines in an ideal combination for the best possible performance. Recently, it was found out that the energy selective studies might become a

  10. Repeated assessment of exploration and novelty seeking in the human behavioral pattern monitor in bipolar disorder patients and healthy individuals.

    Directory of Open Access Journals (Sweden)

    Arpi Minassian

    Full Text Available Exploration and novelty seeking are cross-species adaptive behaviors that are dysregulated in bipolar disorder (BD and are critical features of the illness. While these behaviors have been extensively quantified in animals, multivariate human paradigms of exploration are lacking. The human Behavioral Pattern Monitor (hBPM, a human version of the animal open field, identified a signature pattern of hyper-exploration in manic BD patients, but whether exploratory behavior changes with treatment is unknown. The objective of this study was to assess the sensitivity of the hBPM to changes in manic symptoms, a necessary step towards elucidating the neurobiology underlying BD.Twelve acutely hospitalized manic BD subjects and 21 healthy volunteers were tested in the hBPM over three sessions; all subjects were retested one week after their first session and two weeks after their second session. Motor activity, spatial and entropic (degree of unpredictability patterns of exploration, and interactions with novel objects were quantified. Manic BD patients demonstrated greater motor activity, extensive and more unpredictable patterns of exploration, and more object interactions than healthy volunteers during all three sessions. Exploration and novelty-seeking slightly decreased in manic BD subjects over the three sessions as their symptoms responded to treatment, but never to the level of healthy volunteers. Among healthy volunteers, exploration did not significantly decrease over time, and hBPM measures were highly correlated between sessions.Manic BD patients showed a modest reduction in symptoms yet still demonstrated hyper-exploration and novelty seeking in the hBPM, suggesting that these illness features may be enduring characteristics of BD. Furthermore, behavior in the hBPM is not subject to marked habituation effects. The hBPM can be reliably used in a repeated-measures design to characterize exploration and novelty seeking and, in parallel with

  11. A polyethylene-B4C based concrete for enhanced neutron shielding at neutron research facilities

    Science.gov (United States)

    DiJulio, D. D.; Cooper-Jensen, C. P.; Perrey, H.; Fissum, K.; Rofors, E.; Scherzinger, J.; Bentley, P. M.

    2017-07-01

    We present the development of a specialized concrete for neutron shielding at neutron research facilities, based on the addition of hydrogen atoms in the form of polyethylene and also B4C for enhancing the neutron capture properties of the concrete. We show information on the mechanical properties of the concrete and the neutronics, in particular its relevance to modern spallation neutron sources, such as the European Spallation Source (ESS), currently under construction in Lund, Sweden. The new concrete exhibits a 15% lower mass density, a compressible strength of 50% relative to a standard concrete and a significant increase in performance of shielding against MeV neutrons and lower energies. The concrete could find application at the ESS in for example common shielding components, individual beamline shielding and instrument caves. Initial neutronic tests of the concrete, carried out at Lund University, have also verified the performance in the MeV neutron energy range and the results are presented.

  12. Neutron diffraction

    International Nuclear Information System (INIS)

    Elcomb, M.M.

    2002-01-01

    Full text: Thermal neutrons have a particular combination of properties, which make them the probe of choice for a wide range of scattering applications. They penetrate most materials easily, the wavelength matches interatomic spacings, the energy matches the atomic vibrational energies and the magnetic moment allows them to uniquely interact with magnetic structures. Their widely varying scattering length is also used to advantage. It enables the determination of light atoms in the presence of heavy ones: hydrogen in organic molecules, and oxygen in the high Tc superconductors for example, or solving problems in alloy systems where distinction of atoms, which are neighbours in the periodic table, is required. In the 50 years since thermal neutron beams have been used for research there has been a steady increase in applications as technology has advanced. This also applies to the environments in which the materials are studied. In-situ studies at other than ambient temperatures, pressures and magnetic fields are now routine. By using multiple detector channels in powder instruments the data collection rate has increased by an order of magnitude to some extent compensating for the diffuse nature of the neutron source. The applications of neutron scattering are becoming more industrially oriented. The talk will highlight the complementarity of neutrons to other more readily available techniques, and give examples of recent research and applications. Copyright (2002) Australian X-ray Analytical Association Inc

  13. Neutron diffraction

    International Nuclear Information System (INIS)

    Howard, C.J.; Kennedy, S.J.

    1994-01-01

    A brief account is given of neutron diffraction techniques. Similarities and differences compared with the more familiar X-ray counterparts are discussed. In certain applications, neutron diffraction can be used to obtain information about materials which would be difficult or even impossible to obtain using other techniques. One spectacular success has been the elucidation, from neutron powder diffraction, of the crystal structures of high critical temperature oxide superconductors. There have been substantial contributions in other fields, and these are illustrated by Australian work. The ability of the neutron to penetrate deeply into most materials has been invoked for in-depth determination of stresses in composites and of phase composition in zirconia ceramics. The unique properties of the neutron have been successfully exploited in studies of metal hydrides, to determine where hydrogen is located, and in magnetic structure determination. There is much interest in studying materials under different conditions of temperature and pressure, and kinetic studies under such conditions are now becoming possible. The article includes information on the principles, the instrumentation with particular reference to the instruments installed around the HIFAR reactor at Lucas Heights, and methods for the interpretation of data. 59 refs., 3 tabs., 16 figs

  14. Synthesis of the racemate and individual enantiomers of [[sup 11]C]methylphenidate for studying presynaptic dopaminergic neutron with positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Y.-S.; Sugano, Y.; Fowler, J.S.; Salata, C. (Brookhaven National Lab., Upton, NY (United States))

    1994-10-01

    Carbon-11 labeled dl-threo-methylphenidate (methyl-2-phenyl-2-(2-piperidyl)acetate, Ritalin), a psychostimulant drug widely used to treat attention deficit hyperactivity disorder, was prepared in two steps: O-methylation of the N-protected dl-threo-ritalinic acid derivative with [[sup 11]C]methyl iodide followed by deprotection. The same strategy was applied for the preparation of C-11 labeled individual enantiomers of threo-methylphenidate from N-protected d-threo-l-threo-ritalinic acid. The subsequent C18 sep-pak and reverse-phase HPLC purification resulted in ca. 40% radiochemical yield with a total synthesis time of 40 minutes and an average specific activity of 1.5 Ci/[mu]mole (at EOB). (author).

  15. Synthesis of the racemate and individual enantiomers of [11C]methylphenidate for studying presynaptic dopaminergic neutron with positron emission tomography

    International Nuclear Information System (INIS)

    Ding, Y.-S.; Sugano, Y.; Fowler, J.S.; Salata, C.

    1994-01-01

    Carbon-11 labeled dl-threo-methylphenidate (methyl-2-phenyl-2-(2-piperidyl)acetate, Ritalin), a psychostimulant drug widely used to treat attention deficit hyperactivity disorder, was prepared in two steps: O-methylation of the N-protected dl-threo-ritalinic acid derivative with [ 11 C]methyl iodide followed by deprotection. The same strategy was applied for the preparation of C-11 labeled individual enantiomers of threo-methylphenidate from N-protected d-threo-l-threo-ritalinic acid. The subsequent C18 sep-pak and reverse-phase HPLC purification resulted in ca. 40% radiochemical yield with a total synthesis time of 40 minutes and an average specific activity of 1.5 Ci/μmole (at EOB). (author)

  16. FAST NEUTRON SPECTROMETER

    Science.gov (United States)

    Davis, F.J.; Hurst, G.S.; Reinhardt, P.W.

    1959-08-18

    An improved proton recoil spectrometer for determining the energy spectrum of a fast neutron beam is described. Instead of discriminating against and thereby"throwing away" the many recoil protons other than those traveling parallel to the neutron beam axis as do conventional spectrometers, this device utilizes protons scattered over a very wide solid angle. An ovoidal gas-filled recoil chamber is coated on the inside with a scintillator. The ovoidal shape of the sensitive portion of the wall defining the chamber conforms to the envelope of the range of the proton recoils from the radiator disposed within the chamber. A photomultiplier monitors the output of the scintillator, and a counter counts the pulses caused by protons of energy just sufficient to reach the scintillator.

  17. Neutron radiography

    International Nuclear Information System (INIS)

    Pugliesi, R.; Freitas, A.G. de; Gammal, A.; Rizzatti, M.R.; Vercelli, P.

    1990-01-01

    The objective was to demonstrate the main characteristics of the neutron radiography technique, which has been developed in the Nuclear Physics Department of the IPEN-CNEN-SP. Its employment, in technology varies enormously and includes among others, the inspection of the hydrogen-rich substances, highly radioactive materials, etc. The indirect conversion method with Dysprosium screen was employed. The experimental arrangement used was a neutron collimator installed in the bottom of the IEA-R1 Nuclear Research Reactor pool. Several samples were analysed which were exposed in a neutron flux ∼ 10 7 n/s.cm 2 during 10 minutes. The obtained results confirm the main characteristics of this technique as well as its viability to be developed in this reactor. (author)

  18. neutron radiography

    International Nuclear Information System (INIS)

    Barton, J.P.

    1993-01-01

    Neutron radiography (or radiology) is a diverse filed that uses neutrons of various energies, subthermal, thermal, epithermal or fast in either steady state or pulsed mode to examine objects for industrial, medical, or other purposes, both microscopic and macroscopic. The applications include engineering design, biological studies, nondestructive inspection and materials evaluation. In the past decade, over 100 different centers in some 30 countries have published reports of pioneering activities using reactors, accelerators and isotopic neutron sources. While film transparency and electronic video are most common imaging methods for static or in motion objects respectively, there are other important data gathering techniques, including track etch, digital gauging and computed tomography. A survey of the world-wide progress shows the field to be gaining steadily in its diversity, its sophistication and its importance. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    David L. Chichester; James W. Sterbentz

    2011-05-01

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

  20. Neutron diffraction

    International Nuclear Information System (INIS)

    Heger, G.

    1996-01-01

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

  1. Neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-12-31

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

  2. Effects of Relocation and Individual and Environmental Factors on the Long-Term Stress Levels in Captive Chimpanzees (Pan troglodytes: Monitoring Hair Cortisol and Behaviors.

    Directory of Open Access Journals (Sweden)

    Yumi Yamanashi

    Full Text Available Understanding the factors associated with the long-term stress levels of captive animals is important from the view of animal welfare. In this study, we investigated the effects of relocation in addition to individual and environmental factors related to social management on long-term stress level in group-living captive chimpanzees by examining behaviors and hair cortisol (HC. Specifically, we conducted two studies. The first compared changes in HC levels before and after the relocation of 8 chimpanzees (Study 1 and the second examined the relationship between individual and environmental factors and individual HC levels in 58 chimpanzees living in Kumamoto Sanctuary (KS, Kyoto University (Study 2. We hypothesized that relocation, social situation, sex, and early rearing conditions, would affect the HC levels of captive chimpanzees. We cut arm hair from chimpanzees and extracted and assayed cortisol with an enzyme immunoassay. Aggressive behaviors were recorded ad libitum by keepers using a daily behavior monitoring sheet developed for this study. The results of Study 1 indicate that HC levels increased during the first year after relocation to the new environment and then decreased during the second year. We observed individual differences in reactions to relocation and hypothesized that social factors may mediate these changes. In Study 2, we found that the standardized rate of receiving aggression, rearing history, sex, and group formation had a significant influence on mean HC levels. Relocation status was not a significant factor, but mean HC level was positively correlated with the rate of receiving aggression. Mean HC levels were higher in males than in females, and the association between aggressive interactions and HC levels differed by sex. These results suggest that, although relocation can affect long-term stress level, individuals' experiences of aggression and sex may be more important contributors to long-term stress than

  3. Neutronics of pulsed spallation neutron sources

    CERN Document Server

    Watanabe, N

    2003-01-01

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

  4. Quantitative neutron radiography using neutron absorbing honeycomb

    International Nuclear Information System (INIS)

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

    1993-01-01

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

  5. A fission ionization detector for neutron flux measurements at a spallation source

    Energy Technology Data Exchange (ETDEWEB)

    Wender, S.A. (Los Alamos National Lab., Los Alamos, NM (United States)); Balestrini, S. (Los Alamos National Lab., Los Alamos, NM (United States)); Brown, A. (Los Alamos National Lab., Los Alamos, NM (United States)); Haight, R.C. (Los Alamos National Lab., Los Alamos, NM (United States)); Laymon, C.M. (Los Alamos National Lab., Los Alamos, NM (United States)); Lee, T.M. (Los Alamos National Lab., Los Alamos, NM (United States)); Lisowski, P.W. (Los Alamos National Lab., Los Alamos, NM (United States)); McCorkle, W. (Los Alamos National Lab., Los Alamos, NM (United States)); Nelson, R.O. (Los Alamos National Lab., Los Alamos, NM (United States)); Parker, W. (Los Alamos National Lab., Los Alamos, NM (United States)); Hill, N.W. (Oak Ridge National Lab., Oak Ridge, TN (United States))

    1993-11-15

    The construction of a neutron flux monitor that can measure absolute neutron intensities in the neutron energy range from below 1 MeV to over 500 MeV is described. The detector consists of an ionization chamber with several thin deposits of fissionable material. The ionization chamber is thin enough that it does not significantly affect the neutron beam and may be left in the neutron flight path during experimental measurements to continuously monitor the beam flux. The use of this monitor at the continuous-energy spallation neutron source at the WNR target area at LAMPF is described. (orig.)

  6. A fission ionization detector for neutron flux measurements at a spallation source

    International Nuclear Information System (INIS)

    Wender, S.A.; Balestrini, S.; Brown, A.; Haight, R.C.; Laymon, C.M.; Lee, T.M.; Lisowski, P.W.; McCorkle, W.; Nelson, R.O.; Parker, W.; Hill, N.W.

    1993-01-01

    The construction of a neutron flux monitor that can measure absolute neutron intensities in the neutron energy range from below 1 MeV to over 500 MeV is described. The detector consists of an ionization chamber with several thin deposits of fissionable material. The ionization chamber is thin enough that it does not significantly affect the neutron beam and may be left in the neutron flight path during experimental measurements to continuously monitor the beam flux. The use of this monitor at the continuous-energy spallation neutron source at the WNR target area at LAMPF is described. (orig.)

  7. 14 MeV calibration of JET neutron detectors—phase 1: calibration and characterization of the neutron source

    Science.gov (United States)

    Batistoni, P.; Popovichev, S.; Cufar, A.; Ghani, Z.; Giacomelli, L.; Jednorog, S.; Klix, A.; Lilley, S.; Laszynska, E.; Loreti, S.; Packer, L.; Peacock, A.; Pillon, M.; Price, R.; Rebai, M.; Rigamonti, D.; Roberts, N.; Tardocchi, M.; Thomas, D.; Contributors, JET

    2018-02-01

    In view of the planned DT operations at JET, a calibration of the JET neutron monitors at 14 MeV neutron energy is needed using a 14 MeV neutron generator deployed inside the vacuum vessel by the JET remote handling system. The target accuracy of this calibration is  ±10% as also required by ITER, where a precise neutron yield measurement is important, e.g. for tritium accountancy. To achieve this accuracy, the 14 MeV neutron generator selected as the calibration source has been fully characterised and calibrated prior to the in-vessel calibration of the JET monitors. This paper describes the measurements performed using different types of neutron detectors, spectrometers, calibrated long counters and activation foils which allowed us to obtain the neutron emission rate and the anisotropy of the neutron generator, i.e. the neutron flux and energy spectrum dependence on emission angle, and to derive the absolute emission rate in 4π sr. The use of high resolution diamond spectrometers made it possible to resolve the complex features of the neutron energy spectra resulting from the mixed D/T beam ions reacting with the D/T nuclei present in the neutron generator target. As the neutron generator is not a stable neutron source, several monitoring detectors were attached to it by means of an ad hoc mechanical structure to continuously monitor the neutron emission rate during the in-vessel calibration. These monitoring detectors, two diamond diodes and activation foils, have been calibrated in terms of neutrons/counts within  ±5% total uncertainty. A neutron source routine has been developed, able to produce the neutron spectra resulting from all possible reactions occurring with the D/T ions in the beam impinging on the Ti D/T target. The neutron energy spectra calculated by combining the source routine with a MCNP model of the neutron generator have been validated by the measurements. These numerical tools will be key in analysing the results from the in

  8. Neutron flux stabilization in the NG-150 neutron generators

    International Nuclear Information System (INIS)

    Kuz'min, L.E.; Makarov, S.A.; Pronman, I.M.

    1986-01-01

    Problem of metal tritium target lifetime increase and neutron flux stabilization in the NG-150 neutron generators is studied. Possibility on neutron flux stabilization using the mass analyzer for low-angle (4 deg and 41 deg) mass separation of a beam in thre components, which fall on a target simultaneously, is confirmed experimentally. Basic generator parameters are: accelerating voltage of 150 kV, total beam current on a target of 1.5 mA, beam current density of 0.3-1.6 mA/cm 2 , beam diameter of 8 mm. The initial neutron flux on the targets of 0.73 mg/cm 2 thick constituted 1.1x10 11 ssup(-1). The neutron flux monitoring was accomplished from recoil proton recording by a plastic scintillator. Flux decrease by more than 5% served as a signel for measuring mass analyzer magnetic field providing beam displacement on a target and restoration of the given flux. The NG-150 generator neutron flux stabilization was attained during 2h

  9. Measurement channel of neutron flow based on software; Canal de medicion de flujo neutronico basado en software

    Energy Technology Data Exchange (ETDEWEB)

    Rivero G, T.; Benitez R, J. S. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: trg@nuclear.inin.mx

    2008-07-01

    The measurement of the thermal power in nuclear reactors is based mainly on the measurement of the neutron flow. The presence of these in the reactor core is associated to neutrons released by the fission reaction of the uranium-235. Once moderate, these neutrons are precursors of new fissions. This process it is known like chain reaction. Thus, the power to which works a nuclear reactor, he is proportional to the number of produced fissions and as these depend on released neutrons, also the power is proportional to the number of present neutrons. The measurement of the thermal power in a reactor is realized with called instruments nuclear channels. To low power (level source), these channels measure the individual counts of detected neutrons, whereas to a medium and high power, they measure the electrical current or fluctuation of the same one that generate the fission neutrons in ionization chambers especially designed to detect neutrons. For the case of TRIGA reactors, the measurement channels of neutron flow use discreet digital electronic technology makes some decades already. Recently new technological tools have arisen that allow developing new versions of nuclear channels of simple form and compacts. The present work consists of the development of a nuclear channel for TRIGA reactors based on the use of the correlated signal of a fission chamber for ample interval. This new measurement channel uses a data acquisition card of high speed and the data processing by software that to the being installed in a computer is created a virtual instrument, with what spreads in real time, in graphic and understandable form for the operator, the power indication to which it operates the nuclear reactor. This system when being based on software, offers a major versatility to realize changes in the signal processing and power monitoring algorithms. The experimental tests of neutronic power measurement show a reliable performance through seven decades of power, with a

  10. Fusion neutron diagnostics on ITER tokamak

    Science.gov (United States)

    Bertalot, L.; Barnsley, R.; Direz, M. F.; Drevon, J. M.; Encheva, A.; Jakhar, S.; Kashchuk, Y.; Patel, K. M.; Arumugam, A. P.; Udintsev, V.; Walker, C.; Walsh, M.

    2012-04-01

    ITER is an experimental nuclear reactor, aiming to demonstrate the feasibility of nuclear fusion realization in order to use it as a new source of energy. ITER is a plasma device (tokamak type) which will be equipped with a set of plasma diagnostic tools to satisfy three key requirements: machine protection, plasma control and physics studies by measuring about 100 different parameters. ITER diagnostic equipment is integrated in several ports at upper, equatorial and divertor levels as well internally in many vacuum vessel locations. The Diagnostic Systems will be procured from ITER Members (Japan, Russia, India, United States, Japan, Korea and European Union) mainly with the supporting structures in the ports. The various diagnostics will be challenged by high nuclear radiation and electromagnetic fields as well by severe environmental conditions (ultra high vacuum, high thermal loads). Several neutron systems with different sensitivities are foreseen to measure ITER expected neutron emission from 1014 up to almost 1021 n/s. The measurement of total neutron emissivity is performed by means of Neutron Flux Monitors (NFM) installed in diagnostic ports and by Divertor Neutron Flux Monitors (DNFM) plus MicroFission Chambers (MFC) located inside the vacuum vessel. The neutron emission profile is measured with radial and vertical neutron cameras. Spectroscopy is accomplished with spectrometers looking particularly at 2.5 and 14 MeV neutron energy. Neutron Activation System (NAS), with irradiation ends inside the vacuum vessel, provide neutron yield data. A calibration strategy of the neutron diagnostics has been developed foreseeing in situ and cross calibration campaigns. An overview of ITER neutron diagnostic systems and of the associated challenging engineering and integration issues will be reported.

  11. Neutronic reactor

    International Nuclear Information System (INIS)

    Wende, C.W.J.

    1976-01-01

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

  12. Neutronic reactor

    International Nuclear Information System (INIS)

    Carleton, J.T.

    1977-01-01

    A graphite-moderated nuclear reactor includes channels between blocks of graphite and also includes spacer blocks between adjacent channeled blocks with an axis of extension normal to that of the axis of elongation of the channeled blocks to minimize changes in the physical properties of the graphite as a result of prolonged neutron bombardment. 3 claims, 6 figures

  13. HAV-1-A multipurpose multimonitor for reactor neutron flux characterization

    International Nuclear Information System (INIS)

    Diaz Rizo, O.; Alvarez, I.; Herrera, E.; Lima, L.; Tores, J.; Lopez, M.C.; Ixquiac, M.

    1996-01-01

    A simple method non-solid multi monitor HAV-1 for the systematic evaluation of reactor neutron flux parameters for K o neutron activation analysis is presented. Solution of Au, Zr, Co, Zn, Sn, U and Th (deposited in filter paper) are used to study the parameters alpha and f. Dissolved Lu is used to neutron temperature (Tn) determination, according to the Wescott's formalism. A multipurpose multi monitor HAV-1 preparation, certification and evaluations presented

  14. Neutron stars as cosmic neutron matter laboratories

    International Nuclear Information System (INIS)

    Pines, D.

    1986-01-01

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

  15. Basic of Neutron NDA

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-09-15

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

  16. Estimating individual-level exposure to airborne polycyclic aromatic hydrocarbons throughout the gestational period based on personal, indoor, and outdoor monitoring