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Sample records for total neutron counts

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

    Energy Technology Data Exchange (ETDEWEB)

    Rossa, Riccardo [Belgian nuclear research centre SCK.CEN (Belgium); Universite Libre de Bruxelles (Belgium); Borella, Alessandro; Van der Meer, Klaas [Belgian nuclear research centre SCK.CEN. Boeretang 200, 2400 Mol (Belgium); Labeau, Pierre-Etienne; Pauly, Nicolas [Universite Libre de Bruxelles. Av. F. D. Roosevelt 50, B1050 Brussels (Belgium)

    2015-07-01

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

  2. Fast counting electronics for neutron coincidence counting

    International Nuclear Information System (INIS)

    Swansen, J.E.

    1987-01-01

    This patent describes a high speed circuit for accurate neutron coincidence counting comprising: neutron detecting means for providing an above-threshold signal upon neutron detection; amplifying means inputted by the neutron detecting means for providing a pulse output having a pulse width of about 0.5 microseconds upon the input of each above threshold signal; digital processing means inputted by the pulse output of the amplifying means for generating a pulse responsive to each input pulse from the amplifying means and having a pulse width of about 50 nanoseconds effective for processing an expected neutron event rate of about 1 Mpps: pulse stretching means inputted by the digital processing means for producing a pulse having a pulse width of several milliseconds for each pulse received form the digital processing means; visual indicating means inputted by the pulse stretching means for producing a visual output for each pulse received from the digital processing means; and derandomizing means effective to receive the 50 ns neutron event pulses from the digital processing means for storage at a rate up to the neutron event rate of 1 Mpps and having first counter means for storing the input neutron event pulses

  3. Total neutron-counting plutonium inventory measurement systems (PIMS) and their potential application to near real time materials accountancy (NRTMA)

    International Nuclear Information System (INIS)

    Driscall, I.; Fox, G.H.; Orr, C.H.; Whitehouse, K.R.

    1988-01-01

    A radiometric method of determining the inventory of an operating plutonium plant is described. An array of total neutron counters distributed across the plant is used to estimate hold-up at each plant item. Corrections for the sensitivity of detectors to plutonium in adjacent plant items are achieved through a matrix approach. This paper describes our experience in design, calibration and operation of a Plutonium Inventory Measurement System (PIMS) on an oxalate precipitation plutonium finishing line. Data from a recent trial of Near-Real-Time Materials Accounting (NRTMA) using the PIMS are presented and used to illustrate its present performance and problem areas. The reader is asked to consider what role PIMS might have in future accountancy systems

  4. NIF total neutron yield diagnostic

    International Nuclear Information System (INIS)

    Cooper, Gary W.; Ruiz, Carlos L.

    2001-01-01

    We have designed a total neutron yield diagnostic for the National Ignition Facility (NIF) which is based on the activation of In and Cu samples. The particular approach that we have chosen is one in which we calibrate the entire counting system and which we call the ''F factor'' method. In this method, In and/or Cu samples are exposed to known sources of DD and DT neutrons. The activated samples are then counted with an appropriate system: a high purity Ge detector for In and a NaI coincidence system for Cu. We can then calculate a calibration factor, which relates measured activity to total neutron yield. The advantage of this approach is that specific knowledge of such quantities as cross sections and detector efficiencies is not needed. Unless the actual scattering environment of the NIF can be mocked up in the calibration experiment, the F factor will have to be modified using the results of a numerical simulation of the NIF scattering environment. In this article, the calibration factor methodology will be discussed and experimental results for the calibration factors will be presented. Total NIF neutron yields of 10 9 --10 19 can be measured with this method assuming a 50 cm stand-off distance can be employed for the lower yields

  5. Project and construction of counting system for neutron probe

    International Nuclear Information System (INIS)

    Monteiro, W.P.

    1985-01-01

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

  6. Inventory verification measurements using neutron multiplicity counting

    International Nuclear Information System (INIS)

    Ensslin, N.; Foster, L.A.; Harker, W.C.; Krick, M.S.; Langner, D.G.

    1998-01-01

    This paper describes a series of neutron multiplicity measurements of large plutonium samples at the Los Alamos Plutonium Facility. The measurements were corrected for bias caused by neutron energy spectrum shifts and nonuniform multiplication, and are compared with calorimetry/isotopics. The results show that multiplicity counting can increase measurement throughput and yield good verification results for some inventory categories. The authors provide recommendations on the future application of the technique to inventory verification

  7. Changes in total and differential white cell counts, total lymphocyte ...

    African Journals Online (AJOL)

    Background: Published reports on the possible changes in the various immune cell populations, especially the total lymphocyte and CD4 cell counts, during the menstrual cycle in Nigerian female subjects are relatively scarce. Aim: To determine possible changes in the total and differential white blood cell [WBC] counts, ...

  8. Quantitative monitoring of the fluorination process by neutron counting

    International Nuclear Information System (INIS)

    Russo, P.A.; Appert, Q.D.; Biddle, R.S.; Kelley, T.A.; Martinez, M.M.; West, M.H.

    1993-01-01

    Plutonium metal is produced by reducing PuF 4 prepared from PuO 2 by fluorination. Both fluorination and reduction are batch processes at the Los Alamos Plutonium Facility. The conversion of plutonium oxide to fluoride greatly increases the neutron yield, a result of the high cross section for alpha-neutron (α,n) reactions on fluorine targets compared to the (more than 100 times) smaller α,n yield on oxygen targets. Because of the increase, total neutron counting can be used to monitor the conversion process. This monitoring ability can lead to an improved metal product, reduced scrap for recycle, waste reduction, minimized reagent usage, and reduce personnel radiation exposures. A new stirred-bed fluorination process has been developed simultaneously with a recent evaluation of an automated neutron-counting instrument for quantitative process monitoring. Neutrons are counted with polyethylene-moderated 3 He-gas proportional counters. Results include a calibration of the real-time neutron-count-rate indicator for the extent of fluorination using reference values obtained from destructive analysis of samples from the blended fluoroinated batch

  9. Calibration of the JET neutron yield monitors using the delayed neutron counting technique

    International Nuclear Information System (INIS)

    van Belle, P.; Jarvis, O.N.; Sadler, G.; de Leeuw, S.; D'Hondt, P.; Pillon, M.

    1990-01-01

    The time-resolved neutron yield is routinely measured on the JET tokamak using a set of fission chambers. At present, the preferred technique is to employ activation reactions to determine the neutron fluence at a well-chosen position and to relate the measured fluence to the total neutron emission by means of neutron transport calculations. The delayed neutron counting method is a particularly convenient method of performing the activation measurement and the fission cross sections are accurately known. This paper outlines the measurement technique as used on JET

  10. More accurate thermal neutron coincidence counting technique

    International Nuclear Information System (INIS)

    Baron, N.

    1978-01-01

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

  11. Statistical data filtration in neutron coincidence counting

    International Nuclear Information System (INIS)

    Beddingfield, D.H.; Menlove, H.O.

    1992-11-01

    We assessed the effectiveness of statistical data filtration to minimize the contribution of matrix materials in 200-ell drums to the nondestructive assay of plutonium. Those matrices were examined: polyethylene, concrete, aluminum, iron, cadmium, and lead. Statistical filtration of neutron coincidence data improved the low-end sensitivity of coincidence counters. Spurious data arising from electrical noise, matrix spallation, and geometric effects were smoothed in a predictable fashion by the statistical filter. The filter effectively lowers the minimum detectable mass limit that can be achieved for plutonium assay using passive neutron coincidence counting

  12. Neutron coincidence counting with digital signal processing

    International Nuclear Information System (INIS)

    Bagi, Janos; Dechamp, Luc; Dransart, Pascal; Dzbikowicz, Zdzislaw; Dufour, Jean-Luc; Holzleitner, Ludwig; Huszti, Joseph; Looman, Marc; Marin Ferrer, Montserrat; Lambert, Thierry; Peerani, Paolo; Rackham, Jamie; Swinhoe, Martyn; Tobin, Steve; Weber, Anne-Laure; Wilson, Mark

    2009-01-01

    Neutron coincidence counting is a widely adopted nondestructive assay (NDA) technique used in nuclear safeguards to measure the mass of nuclear material in samples. Nowadays, most neutron-counting systems are based on the original-shift-register technology, like the (ordinary or multiplicity) Shift-Register Analyser. The analogue signal from the He-3 tubes is processed by an amplifier/single channel analyser (SCA) producing a train of TTL pulses that are fed into an electronic unit that performs the time- correlation analysis. Following the suggestion of the main inspection authorities (IAEA, Euratom and the French Ministry of Industry), several research laboratories have started to study and develop prototypes of neutron-counting systems with PC-based processing. Collaboration in this field among JRC, IRSN and LANL has been established within the framework of the ESARDA-NDA working group. Joint testing campaigns have been performed in the JRC PERLA laboratory, using different equipment provided by the three partners. One area of development is the use of high-speed PCs and pulse acquisition electronics that provide a time stamp (LIST-Mode Acquisition) for every digital pulse. The time stamp data can be processed directly during acquisition or saved on a hard disk. The latter method has the advantage that measurement data can be analysed with different values for parameters like predelay and gate width, without repeating the acquisition. Other useful diagnostic information, such as die-away time and dead time, can also be extracted from this stored data. A second area is the development of 'virtual instruments.' These devices, in which the pulse-processing system can be embedded in the neutron counter itself and sends counting data to a PC, can give increased data-acquisition speeds. Either or both of these developments could give rise to the next generation of instrumentation for improved practical neutron-correlation measurements. The paper will describe the

  13. Secondary standard neutron detector for measuring total reaction cross sections

    International Nuclear Information System (INIS)

    Sekharan, K.K.; Laumer, H.; Gabbard, F.

    1975-01-01

    A neutron detector has been constructed and calibrated for the accurate measurement of total neutron-production cross sections. The detector consists of a polyethylene sphere of 24'' diameter in which 8- 10 BF 3 counters have been installed radially. The relative efficiency of this detector has been determined for average neutron energies, from 30 keV to 1.5 MeV by counting neutrons from 7 Li(p,n) 7 Be. By adjusting the radial positions of the BF 3 counters in the polyethylene sphere the efficiency for neutron detection was made nearly constant for this energy range. Measurement of absolute efficiency for the same neutron energy range has been done by counting the neutrons from 51 V(p,n) 51 Cr and 57 Fe(p,n) 57 Co reactions and determining the absolute number of residual nuclei produced during the measurement of neutron yield. Details of absolute efficiency measurements and the use of the detector for measurement of total neutron yields from neutron producing reactions such as 23 Na(p,n) 23 Mg are given

  14. Method of inspecting Raschig rings by neutron absorption counting

    International Nuclear Information System (INIS)

    Morris, R.N.; Murri, R.L.; Hume, M.W.

    1979-01-01

    A neutron counting method for inspecting borosilicate glass Raschig rings and an apparatus designed specifically for this method are discussed. The neutron count ratios for rings of a given thickness show a linear correlation to the boron oxide content of the rings. The count ratio also has a linear relationship to the thickness of rings of a given boron oxide content. Consequently, the experimentally-determined count ratio and physically-measured thickness of Raschig rings can be used to statistically predict their boron oxide content and determine whether or not they meet quality control acceptance criteria

  15. Computed neutron coincidence counting applied to passive waste assay

    Energy Technology Data Exchange (ETDEWEB)

    Bruggeman, M.; Baeten, P.; De Boeck, W.; Carchon, R. [Nuclear Research Centre, Mol (Belgium)

    1997-11-01

    Neutron coincidence counting applied for the passive assay of fissile material is generally realised with dedicated electronic circuits. This paper presents a software based neutron coincidence counting method with data acquisition via a commercial PC-based Time Interval Analyser (TIA). The TIA is used to measure and record all time intervals between successive pulses in the pulse train up to count-rates of 2 Mpulses/s. Software modules are then used to compute the coincidence count-rates and multiplicity related data. This computed neutron coincidence counting (CNCC) offers full access to all the time information contained in the pulse train. This paper will mainly concentrate on the application and advantages of CNCC for the non-destructive assay of waste. An advanced multiplicity selective Rossi-alpha method is presented and its implementation via CNCC demonstrated. 13 refs., 4 figs., 2 tabs.

  16. Computed neutron coincidence counting applied to passive waste assay

    International Nuclear Information System (INIS)

    Bruggeman, M.; Baeten, P.; De Boeck, W.; Carchon, R.

    1997-01-01

    Neutron coincidence counting applied for the passive assay of fissile material is generally realised with dedicated electronic circuits. This paper presents a software based neutron coincidence counting method with data acquisition via a commercial PC-based Time Interval Analyser (TIA). The TIA is used to measure and record all time intervals between successive pulses in the pulse train up to count-rates of 2 Mpulses/s. Software modules are then used to compute the coincidence count-rates and multiplicity related data. This computed neutron coincidence counting (CNCC) offers full access to all the time information contained in the pulse train. This paper will mainly concentrate on the application and advantages of CNCC for the non-destructive assay of waste. An advanced multiplicity selective Rossi-alpha method is presented and its implementation via CNCC demonstrated. 13 refs., 4 figs., 2 tabs

  17. A measurement of the neutron lifetime by counting trapped protons

    CERN Document Server

    Snow, W M; Dewey, M S; Fei, X; Gilliam, D M; Greene, G L; Nico, J S; Wietfeldt, F E

    2000-01-01

    A measurement of the neutron lifetime tau sub n performed by trapping and counting decay protons from in-beam neutron decays in a Penning trap is in progress at the National Institute of Standards and Technology (NIST). A description of the measurement technique, the status of the data analysis, and prospects for improvements in the measurement are discussed.

  18. Bioassay method for Uranium in urine by Delay Neutron counting

    International Nuclear Information System (INIS)

    Suratman; Purwanto; Sukarman-Aminjoyo

    1996-01-01

    A bioassay method for uranium in urine by neutron counting has been studied. The aim of this research is to obtain a bioassay method for uranium in urine which is used for the determination of internal dose of radiation workers. The bioassay was applied to the artificially uranium contaminated urine. The weight of the contaminant was varied. The uranium in the urine was irradiated in the Kartini reactor core, through pneumatic system. The delayed neutron was counted by BF3 neutron counter. Recovery of the bioassay was between 69.8-88.8 %, standard deviation was less than 10 % and the minimum detection was 0.387 μg

  19. Repeatability of differential goat bulk milk culture and associations with somatic cell count, total bacterial count, and standard plate count

    OpenAIRE

    Koop, G.; Dik, N.; Nielen, M.; Lipman, L.J.A.

    2010-01-01

    The aims of this study were to assess how different bacterial groups in bulk milk are related to bulk milk somatic cell count (SCC), bulk milk total bacterial count (TBC), and bulk milk standard plate count (SPC) and to measure the repeatability of bulk milk culturing. On 53 Dutch dairy goat farms, 3 bulk milk samples were collected at intervals of 2 wk. The samples were cultured for SPC, coliform count, and staphylococcal count and for the presence of Staphylococcus aureus. Furthermore, SCC ...

  20. Repeatability of differential goat bulk milk culture and associations with somatic cell count, total bacterial count, and standard plate count

    NARCIS (Netherlands)

    Koop, G.; Dik, N.; Nielen, M.; Lipman, L.J.A.

    2010-01-01

    The aims of this study were to assess how different bacterial groups in bulk milk are related to bulk milk somatic cell count (SCC), bulk milk total bacterial count (TBC), and bulk milk standard plate count (SPC) and to measure the repeatability of bulk milk culturing. On 53 Dutch dairy goat farms,

  1. A neutron detector for measurement of total neutron production cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Sekharan, K K; Laumer, H; Kern, B D; Gabbard, F [Kentucky Univ., Lexington (USA). Dept. of Physics and Astronomy

    1976-03-01

    A neutron detector has been constructed and calibrated for the accurate measurement of total neutron production cross sections. The detector consists of a polyethylene sphere of 60 cm diameter in which eight /sup 10/BF/sub 3/ counters have been installed radially. The relative efficiency of this detector has been determined for average neutron energies from 30 keV to 1.5 MeV by counting neutrons from /sup 7/Li(p, n)/sup 7/Be. By adjusting the radial positions of the BF/sub 3/ counters in the polyethylene sphere the efficiency for neutron detection was made nearly constant for this energy range. Measurement of absolute efficiency for the same neutron energy range has been done by counting the neutrons from /sup 51/V(p, n)/sup 51/Cr and /sup 57/Fe(p, n)/sup 57/Co reactions and determining the absolute number of residual nuclei produced during the measurement of neutron yield. Details of absolute efficiency measurements and the use of the detector for determination of neutron production cross sections are given.

  2. A neutron detector for measurement of total neutron production cross sections

    International Nuclear Information System (INIS)

    Sekharan, K.K.; Laumer, H.; Kern, B.D.; Gabbard, F.

    1976-01-01

    A neutron detector has been constructed and calibrated for the accurate measurement of total neutron production cross sections. The detector consists of a polyethylene sphere of 60 cm diameter in which eight 10 BF 3 counters have been installed radially. The relative efficiency of this detector has been determined for average neutron energies from 30 keV to 1.5 MeV by counting neutrons from 7 Li(p, n) 7 Be. By adjusting the radial positions of the BF 3 counters in the polyethylene sphere the efficiency for neutron detection was made nearly constant for this energy range. Measurement of absolute efficiency for the same neutron energy range has been done by counting the neutrons from 51 V(p, n) 51 Cr and 57 Fe(p, n) 57 Co reactions and determining the absolute number of residual nuclei produced during the measurement of neutron yield. Details of absolute efficiency measurements and the use of the detector for determination of neutron production cross sections are given. (Auth.)

  3. Total neutron cross section for 181Ta

    Directory of Open Access Journals (Sweden)

    Schilling K.-D.

    2010-10-01

    Full Text Available The neutron time of flight facility nELBE, produces fast neutrons in the energy range from 0.1 MeV to 10 MeV by impinging a pulsed relativistic electron beam on a liquid lead circuit [1]. The short beam pulses (∼10 ps and a small radiator volume give an energy resolution better than 1% at 1 MeV using a short flight path of about 6 m, for neutron TOF measurements. The present neutron source provides 2 ⋅ 104  n/cm2s at the target position using an electron charge of 77 pC and 100 kHz pulse repetition rate. This neutron intensity enables to measure neutron total cross section with a 2%–5% statistical uncertainty within a few days. In February 2008, neutron radiator, plastic detector [2] and data acquisition system were tested by measurements of the neutron total cross section for 181Ta and 27Al. Measurement of 181Ta was chosen because lack of high quality data in an anergy region below 700 keV. The total neutron cross – section for 27Al was measured as a control target, since there exists data for 27Al with high resolution and low statistical error [3].

  4. Measurement of the neutron lifetime by counting trapped protons

    International Nuclear Information System (INIS)

    Byrne, J.; Dawber, P.G.; Spain, J.A.; Williams, A.P.; Dewey, M.S.; Gilliam, D.M.; Greene, G.L.; Lamaze, G.P.; Scott, R.D.; Pauwels, J.; Eykens, R.; Lamberty, A.

    1990-01-01

    The neutron lifetime τ n has been measured by counting decay protons stored in a Penning trap whose magnetic axis coincided with a neutron-beam axis. The result of the measurement is τ n =893.6±5.3 s, which agrees well with the value predicted by precise measurements of the β-decay asymmetry parameter A and the standard model

  5. Automated uranium analysis by delayed-neutron counting

    International Nuclear Information System (INIS)

    Kunzendorf, H.; Loevborg, L.; Christiansen, E.M.

    1980-10-01

    Automated uranium analysis by fission-induced delayed-neutron counting is described. A short description is given of the instrumentation including transfer system, process control, irradiation and counting sites, and computer operations. Characteristic parameters of the facility (sample preparations, background, and standards) are discussed. A sensitivity of 817 +- 22 counts per 10 -6 g U is found using irradiation, delay, and counting times of 20 s, 5 s, and 10 s, respectively. Presicion is generally less than 1% for normal geological samples. Critical level and detection limits for 7.5 g samples are 8 and 16 ppb, respectively. The importance of some physical and elemental interferences are outlined. Dead-time corrections of measured count rates are necessary and a polynomical expression is used for count rates up to 10 5 . The presence of rare earth elements is regarded as the most important elemental interference. A typical application is given and other areas of application are described. (auther)

  6. Reducing neutron multiplicity counting bias for plutonium warhead authentication

    Energy Technology Data Exchange (ETDEWEB)

    Goettsche, Malte

    2015-06-05

    Confidence in future nuclear arms control agreements could be enhanced by direct verification of warheads. It would include warhead authentication. This is the assessment based on measurements whether a declaration that a specific item is a nuclear warhead is true. An information barrier can be used to protect sensitive information during measurements. It could for example show whether attributes such as a fissile mass exceeding a threshold are met without indicating detailed measurement results. Neutron multiplicity measurements would be able to assess a plutonium fissile mass attribute if it were possible to show that their bias is low. Plutonium measurements have been conducted with the He-3 based Passive Scrap Multiplicity Counter. The measurement data has been used as a reference to test the capacity of the Monte Carlo code MCNPX-PoliMi to simulate neutron multiplicity measurements. The simulation results with their uncertainties are in agreement with the experimental results. It is essential to use cross-sections which include neutron scattering with the detector's polyethylene molecular structure. Further MCNPX-PoliMi simulations have been conducted in order to study bias that occurs when measuring samples with large plutonium masses such as warheads. Simulation results of solid and hollow metal spheres up to 6000 g show that the masses are underpredicted by as much as 20%. The main source of this bias has been identified in the false assumption that the neutron multiplication does not depend on the position where a spontaneous fission event occurred. The multiplication refers to the total number of neutrons leaking a sample after a primary spontaneous fission event, taking induced fission into consideration. The correction of the analysis has been derived and implemented in a MATLAB code. It depends on four geometry-dependent correction coefficients. When the sample configuration is fully known, these can be exactly determined and remove this type of

  7. Neutron counting and gamma spectroscopy with PVT detectors

    International Nuclear Information System (INIS)

    Mitchell, Dean James; Brusseau, Charles A.

    2011-01-01

    Radiation portals normally incorporate a dedicated neutron counter and a gamma-ray detector with at least some spectroscopic capability. This paper describes the design and presents characterization data for a detection system called PVT-NG, which uses large polyvinyl toluene (PVT) detectors to monitor both types of radiation. The detector material is surrounded by polyvinyl chloride (PVC), which emits high-energy gamma rays following neutron capture reactions. Assessments based on high-energy gamma rays are well suited for the detection of neutron sources, particularly in border security applications, because few isotopes in the normal stream of commerce have significant gamma ray yields above 3 MeV. Therefore, an increased count rate for high-energy gamma rays is a strong indicator for the presence of a neutron source. The sensitivity of the PVT-NG sensor to bare 252 Cf is 1.9 counts per second per nanogram (cps/ng) and the sensitivity for 252 Cf surrounded by 2.5 cm of polyethylene is 2.3 cps/ng. The PVT-NG sensor is a proof-of-principal sensor that was not fully optimized. The neutron detector sensitivity could be improved, for instance, by using additional moderator. The PVT-NG detectors and associated electronics are designed to provide improved resolution, gain stability, and performance at high-count rates relative to PVT detectors in typical radiation portals. As well as addressing the needs for neutron detection, these characteristics are also desirable for analysis of the gamma-ray spectra. Accurate isotope identification results were obtained despite the common impression that the absence of photopeaks makes data collected by PVT detectors unsuitable for spectroscopic analysis. The PVT detectors in the PVT-NG unit are used for both gamma-ray and neutron detection, so the sensitive volume exceeds the volume of the detection elements in portals that use dedicated components to detect each type of radiation.

  8. Some target assay uncertainties for passive neutron coincidence counting

    International Nuclear Information System (INIS)

    Ensslin, N.; Langner, D.G.; Menlove, H.O.; Miller, M.C.; Russo, P.A.

    1990-01-01

    This paper provides some target assay uncertainties for passive neutron coincidence counting of plutonium metal, oxide, mixed oxide, and scrap and waste. The target values are based in part on past user experience and in part on the estimated results from new coincidence counting techniques that are under development. The paper summarizes assay error sources and the new coincidence techniques, and recommends the technique that is likely to yield the lowest assay uncertainty for a given material type. These target assay uncertainties are intended to be useful for NDA instrument selection and assay variance propagation studies for both new and existing facilities. 14 refs., 3 tabs

  9. Neutron diffraction measurements at the INES diffractometer using a neutron radiative capture based counting technique

    Energy Technology Data Exchange (ETDEWEB)

    Festa, G. [Centro NAST, Universita degli Studi di Roma Tor Vergata, Roma (Italy); Pietropaolo, A., E-mail: antonino.pietropaolo@roma2.infn.it [Centro NAST, Universita degli Studi di Roma Tor Vergata, Roma (Italy); Grazzi, F.; Barzagli, E. [CNR-ISC Firenze (Italy); Scherillo, A. [CNR-ISC Firenze (Italy); ISIS facility Rutherford Appleton Laboratory (United Kingdom); Schooneveld, E.M. [ISIS facility Rutherford Appleton Laboratory (United Kingdom)

    2011-10-21

    The global shortage of {sup 3}He gas is an issue to be addressed in neutron detection. In the context of the research and development activity related to the replacement of {sup 3}He for neutron counting systems, neutron diffraction measurements performed on the INES beam line at the ISIS pulsed spallation neutron source are presented. For these measurements two different neutron counting devices have been used: a 20 bar pressure squashed {sup 3}He tube and a Yttrium-Aluminum-Perovskite scintillation detector. The scintillation detector was coupled to a cadmium sheet that registers the prompt radiative capture gamma rays generated by the (n,{gamma}) nuclear reactions occurring in cadmium. The assessment of the scintillator based counting system was done by performing a Rietveld refinement analysis on the diffraction pattern from an ancient Japanese blade and comparing the results with those obtained by a {sup 3}He tube placed at the same angular position. The results obtained demonstrate the considerable potential of the proposed counting approach based on the radiative capture gamma rays at spallation neutron sources.

  10. Control of the neutron detector count rate by optical imaging

    International Nuclear Information System (INIS)

    Roquemore, A.L.; Johnson, L.C.

    1992-01-01

    The signal processing electronics used for the NE451 detectors on the TFTR multichannel neutron collimator are presently showing saturation effects at high counting rates equivalent to neutron yields of ∼10 16 n/s. While nonlinearity due to pulse pileup can be corrected for in most present TFTR experiments, additional steps are required for neutron source strengths above ∼3x10 16 n/s. These pulse pileup effects could be reduced by inserting sleeves in the collimator shielding to reduce the neutron flux in the vicinity of the detectors or by reducing the volume of detector exposed to the flux. We describe a novel method of avoiding saturation by optically controlling the number neutron events processed by the detector electronics. Because of the optical opacity of the ZnS-plastic detectors such as NE451, photons from a proton-recoil scintillation arise from a spatially localized area of the detector. By imaging a selected portion of the detector onto a photomultiplier, we reduce the effective volume of the detector in a controllable, reversible way. A prototype system, consisting of a focusing lens, a field lens, and a variable aperture, has been constructed. Results of laboratory feasibility tests are presented

  11. Improving Neutron Measurement Capabilities; Expanding the Limits of Correlated Neutron Counting

    Energy Technology Data Exchange (ETDEWEB)

    Santi, Peter Angelo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Geist, William H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dougan, Arden [National Nuclear Security Administration (NNSA), Washington, DC (United States)

    2015-11-05

    A number of technical and practical limitations exist within the neutron correlated counting techniques used in safeguards, especially within the algorithms that are used to process and analyze the detected neutron signals. A multi-laboratory effort is underway to develop new and improved analysis and data processing algorithms based on fundamental physics principles to extract additional or more accurate information about nuclear material bearing items.

  12. Correlation between total lymphocyte count, hemoglobin, hematocrit and CD4 count in HIV patients in Nigeria.

    Science.gov (United States)

    Emuchay, Charles Iheanyichi; Okeniyi, Shemaiah Olufemi; Okeniyi, Joshua Olusegun

    2014-04-01

    The expensive and technology limited setting of CD4 count testing is a major setback to the initiation of HAART in a resource limited country like Nigeria. Simple and inexpensive tools such as Hemoglobin (Hb) measurement and Total Lymphocyte Count (TLC) are recommended as substitute marker. In order to assess the correlations of these parameters with CD4 count, 100 "apparently healthy" male volunteers tested HIV positive aged ≥ 20 years but ≤ 40 years were recruited and from whom Hb, Hct, TLC and CD4 count were obtained. The correlation coefficients, R, the Nash-Sutcliffe Coefficient of Efficiency (CoE) and the p-values of the ANOVA model of Hb, Hct and TLC with CD4 count were assessed. The assessments show that there is no significant relationship of any of these parameters with CD4 count and the correlation coefficients are very weak. This study shows that Hb, Hct and TLC cannot be substitute for CD4 count as this might lead to certain individuals' deprivation of required treatment.

  13. Total bacterial count and somatic cell count in refrigerated raw milk stored in communal tanks

    Directory of Open Access Journals (Sweden)

    Edmar da Costa Alves

    2014-09-01

    Full Text Available The current industry demand for dairy products with extended shelf life has resulted in new challenges for milk quality maintenance. The processing of milk with high bacterial counts compromises the quality and performance of industrial products. The study aimed to evaluate the total bacteria counts (TBC and somatic cell count (SCC in 768 samples of refrigerated raw milk, from 32 communal tanks. Samples were collected in the first quarter of 2010, 2011, 2012 and 2013 and analyzed by the Laboratory of Milk Quality - LQL. Results showed that 62.5%, 37.5%, 15.6% and 27.1% of the means for TBC in 2010, 2011, 2012 and 2013, respectively, were above the values established by legislation. However, we observed a significant reduction in the levels of total bacterial count (TBC in the studied periods. For somatic cell count, 100% of the means indicated values below 600.000 cells/mL, complying with the actual Brazilian legislation. The values found for the somatic cell count suggests the adoption of effective measures for the sanitary control of the herd. However, the results must be considered with caution as it highlights the need for quality improvements of the raw material until it achieves reliable results effectively.

  14. Total neutron cross section of lead

    International Nuclear Information System (INIS)

    Kanda, K.; Aizawa, O.

    1976-01-01

    The total thermal-neutron cross section of natural lead under various physical conditions was measured by the transmission method. It became clear that the total cross section at room temperature previously reported is lower than the present data. The total cross section at 400, 500, and 600 0 C, above the melting point of lead, 327 0 C, was also measured, and the changes in the cross section as a function of temperature were examined, especially near and below the melting point. The data obtained for the randomly oriented polycrystalline state at room temperature were in reasonable agreement with the theoretical values calculated by the THRUSH and UNCLE-TOM codes

  15. Total variation-based neutron computed tomography

    Science.gov (United States)

    Barnard, Richard C.; Bilheux, Hassina; Toops, Todd; Nafziger, Eric; Finney, Charles; Splitter, Derek; Archibald, Rick

    2018-05-01

    We perform the neutron computed tomography reconstruction problem via an inverse problem formulation with a total variation penalty. In the case of highly under-resolved angular measurements, the total variation penalty suppresses high-frequency artifacts which appear in filtered back projections. In order to efficiently compute solutions for this problem, we implement a variation of the split Bregman algorithm; due to the error-forgetting nature of the algorithm, the computational cost of updating can be significantly reduced via very inexact approximate linear solvers. We present the effectiveness of the algorithm in the significantly low-angular sampling case using synthetic test problems as well as data obtained from a high flux neutron source. The algorithm removes artifacts and can even roughly capture small features when an extremely low number of angles are used.

  16. Calibration and automatic counting in a neutrons dosimeter

    International Nuclear Information System (INIS)

    Tavera-Davila, M.L.

    1991-01-01

    Over the past decade, the majority of improvements in spectrometry have not come from improved detectors but from better computing facilities, in Folding codes, and nuclear data. However several types of passive neutron detectors have the potential for development into crude, low resolution spectrometers, to be worn by individuals, making them attractive to be subject of more time of investigation. This thesis contributes to the understanding of the properties of solid state nuclear tracks (SSNTD) in order to use them in neutron dosimetry and spectrometry. In the first chapter the basic principles on neutron interaction with matter and some relevant considerations about detection and dosimetry are presented. The third chapter deals with detection properties of solid state nuclear track detectors (SSNTD). Calibration methods are presented for three different applications, detection of heavy ions, radon and neutrons. In chapter 4, some equations are derived which predict the whole efficiency formation of thin plastic detectors as a function of range, angle, and type of inciding particle as well as residual thickness. Using experimental data on proton registration properties in thin plastic detectors and the former derived equations, mathematical expressions are developed to predict the sparking counting efficiency for recoll protons and trions produced by neutrons in SSNTD. Chapter five deals with the comparison between experimental results and theoretical results of chapter 4. In chapter 6 experimental optimum parameters for electrochemical etching of thin plastic detectors are presented. The electrochemical etching efficiency is compared with the spark countering efficiency obtained in chapter 5. In chapter 7, general comments on applications to neutron dosimetry are presented. (Author)

  17. Monte Carlo calculations of the neutron coincidence gate utilisation factor for passive neutron coincidence counting

    CERN Document Server

    Bourva, L C A

    1999-01-01

    The general purpose neutron-photon-electron Monte Carlo N-Particle code, MCNP sup T sup M , has been used to simulate the neutronic characteristics of the on-site laboratory passive neutron coincidence counter to be installed, under Euratom Safeguards Directorate supervision, at the Sellafield reprocessing plant in Cumbria, UK. This detector is part of a series of nondestructive assay instruments to be installed for the accurate determination of the plutonium content of nuclear materials. The present work focuses on one aspect of this task, namely, the accurate calculation of the coincidence gate utilisation factor. This parameter is an important term in the interpretative model used to analyse the passive neutron coincidence count data acquired using pulse train deconvolution electronics based on the shift register technique. It accounts for the limited proportion of neutrons detected within the time interval for which the electronics gate is open. The Monte Carlo code MCF, presented in this work, represents...

  18. Validity of total leucocytes count and neutrophil count (differential leucocytes) in diagnosing suspected acute appendicitis

    International Nuclear Information System (INIS)

    Anwar, M.W.; Abid, I.

    2012-01-01

    Objective: To compare the diagnostic accuracy of Total Leucocytes Count (TLC) with Neutrophil count; Differential Leucocytes Count (DLC) in diagnosing cases of suspected acute appendicitis. Study design: Validation study. Place and duration of the study: Department of Surgery, Combined Military Hospital (CMH) Rawalpindi, from April 2008 to October 2008. Method: A total of 100 patients of Pain right iliac fossae who underwent appendicectomy were included. Detailed history of all the patients was taken for pain in right lower abdomen, its severity, its nature, relieving or provoking factors. Clinical examination was done in detail. Total and Differential Leucocytes Count was done. Every patient's appendix was examined grossly after appendicectomy for evidence of appendicitis. Diagnostic measures of TLC and DLC were calculated by standard formulas. Results: Sensitivity and specificity of TLC is 86.9% and 81.25% respectively and that of DLC is 82% and 68.75% respectively. Accuracy was 86% for TLC and 80% for DLC. Conclusion: TLC is more sensitive, specific and accurate test as compared to DLC and it should be used as diagnostic aid for suspected acute appendicitis cases. (author)

  19. Application of neutron multiplicity counting to waste assay

    Energy Technology Data Exchange (ETDEWEB)

    Pickrell, M.M.; Ensslin, N. [Los Alamos National Lab., NM (United States); Sharpe, T.J. [North Carolina State Univ., Raleigh, NC (United States)

    1997-11-01

    This paper describes the use of a new figure of merit code that calculates both bias and precision for coincidence and multiplicity counting, and determines the optimum regions for each in waste assay applications. A {open_quotes}tunable multiplicity{close_quotes} approach is developed that uses a combination of coincidence and multiplicity counting to minimize the total assay error. An example is shown where multiplicity analysis is used to solve for mass, alpha, and multiplication and tunable multiplicity is shown to work well. The approach provides a method for selecting coincidence, multiplicity, or tunable multiplicity counting to give the best assay with the lowest total error over a broad spectrum of assay conditions. 9 refs., 6 figs.

  20. Use of the total motile sperm count to predict total fertilization failure in in vitro fertilization

    NARCIS (Netherlands)

    Repping, Sjoerd; van Weert, Janne-Meije; Mol, Ben W. J.; de Vries, Jan W. A.; van der Veen, Fulco

    2002-01-01

    Objective: To evaluate the capacity of baseline characteristics and total motile sperm count (TMC) to predict total fertilization failure (TIFF) in patients undergoing IVF. Design: Retrospective cohort study. Setting: University hospital. Patient(s): Eight hundred ninety-two couples with a total of

  1. Sustaining IAEA Neutron Coincidence Counting: Past, Present and Future

    International Nuclear Information System (INIS)

    Longo, J.; Schaffer, K.M.; Nordquist, H.

    2015-01-01

    Los Alamos National Laboratory's IAEA Neutron Coincidence Counting (INCC) code is the standard tool for neutron coincidence counting measurements. INCC software and its' predecessors were originally implemented in the 1970s. The measurement and analysis techniques perfected in the code arise from many years of laboratory and field experience by nuclear engineers and physicists. Covering the full arc of INCC's lifecycle, we discuss the engineering approaches used for conception, original development, worldwide deployment of the stand-alone Windows application, more than a decade of sustained maintenance support, and our recent work to carry INCC successfully into future applications. We delve into the recent re-architecture of the INCC code base, an effort to create a maintainable and extensible architecture designed to preserve the existing INCC code base while adding support for new analyzes and instruments (e.g., List Mode PTR-32 and the List Mode Multiplicity Module). INCC now consists of separate modules implementing attended instrumentation control, data file processing, statistical and Pu mass calculation and analyzes, list mode counting and analyzes, reporting functions, and a database support library. Separating functional capabilities in this architecture enables better testing, isolates development risk and enables the use of INCC features in other software systems. We discuss our approach to handling divergent data and protocol support as a result of this re-architecture. INCC has complex testing requirements; we show how the testing effort was reduced by breaking the software into separate modules. This new architecture enables integration of INCC analysis into the IAEA's new Integrated Review and Analysis Programme (iRAP) data review system. iRAP is based on the respected Euratom Comprehensive Review Inspector Software Package (CRISP) software framework, and is expected to be the future data review system for IAEA and Euratom

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

    Energy Technology Data Exchange (ETDEWEB)

    Goddard, Braden, E-mail: goddard.braden@gmail.com [Nuclear Security Science and Policy Institute, Texas A and M University, College Station, Texas 77843 (United States); Charlton, William [Nuclear Security Science and Policy Institute, Texas A and M University, College Station, Texas 77843 (United States); Peerani, Paolo [European Commission, EC-JRC-ITU, Ispra (Italy)

    2014-03-01

    Uranium is present in most nuclear fuel cycle facilities ranging from uranium mines, enrichment plants, fuel fabrication facilities, nuclear reactors, and reprocessing plants. The isotopic, chemical, and geometric composition of uranium can vary significantly between these facilities, depending on the application and type of facility. Examples of this variation are: enrichments varying from depleted (∼0.2 wt% {sup 235}U) to high enriched (>20 wt% {sup 235}U); compositions consisting of U{sub 3}O{sub 8}, UO{sub 2}, UF{sub 6}, metallic, and ceramic forms; geometries ranging from plates, cans, and rods; and masses which can range from a 500 kg fuel assembly down to a few grams fuel pellet. Since {sup 235}U is a fissile material, it is routinely safeguarded in these facilities. Current techniques for quantifying the {sup 235}U mass in a sample include neutron coincidence counting. One of the main disadvantages of this technique is that it requires a known standard of representative geometry and composition for calibration, which opens up a pathway for potential erroneous declarations by the State and reduces the effectiveness of safeguards. In order to address this weakness, the authors have developed a neutron coincidence counting technique which uses the first principle point-model developed by Boehnel instead of the “known standard” method. This technique was primarily tested through simulations of 1000 g U{sub 3}O{sub 8} samples using the Monte Carlo N-Particle eXtended (MCNPX) code. The results of these simulations showed good agreement between the simulated and exact {sup 235}U sample masses.

  3. Counting neutrons with a commercial S-CMOS camera

    Directory of Open Access Journals (Sweden)

    Patrick Van Esch

    2018-01-01

    Full Text Available It is possible to detect individual flashes from thermal neutron impacts in a ZnS scintillator using a CMOS camera looking at the scintillator screen, and off line image processing. Some preliminary results indicated that the efficiency of recognition could be improved by optimizing the light collection and the image processing. We will report on this ongoing work which is a result from the collaboration between ESS Bilbao and the ILL. The main progress to be reported is situated on the level of the on-line treatment of the imaging data. If this technology is to work on a genuine scientific instrument, it is necessary that all the processing happens on line, to avoid the accumulation of large amounts of image data to be analyzed off line. An FPGA-based real-time full-deca mode VME-compatible CameraLink board has been developed at the SCI of the ILL, which is able to manage the data flow from the camera and convert it in a reasonable “neutron impact” data flow like from a usual neutron counting detector. The main challenge of the endeavor is the optical light collection from the scintillator. While the light yield of a ZnS scintillator is a priori rather important, the amount of light collected with a photographic objective is small. Different scintillators and different light collection techniques have been experimented with and results will be shown for different setups improving upon the light recuperation on the camera sensor. Improvements on the algorithm side will also be presented. The algorithms have to be at the same time efficient in their recognition of neutron signals, in their rejection of noise signals (internal and external to the camera but also have to be simple enough to be easily implemented in the FPGA. The path from the idea of detecting individual neutron impacts with a CMOS camera to a practical working instrument detector is challenging, and in this paper we will give an overview of the part of the road that has

  4. Counting neutrons with a commercial S-CMOS camera

    Science.gov (United States)

    Patrick, Van Esch; Paolo, Mutti; Emilio, Ruiz-Martinez; Estefania, Abad Garcia; Marita, Mosconi; Jon, Ortega

    2018-01-01

    It is possible to detect individual flashes from thermal neutron impacts in a ZnS scintillator using a CMOS camera looking at the scintillator screen, and off line image processing. Some preliminary results indicated that the efficiency of recognition could be improved by optimizing the light collection and the image processing. We will report on this ongoing work which is a result from the collaboration between ESS Bilbao and the ILL. The main progress to be reported is situated on the level of the on-line treatment of the imaging data. If this technology is to work on a genuine scientific instrument, it is necessary that all the processing happens on line, to avoid the accumulation of large amounts of image data to be analyzed off line. An FPGA-based real-time full-deca mode VME-compatible CameraLink board has been developed at the SCI of the ILL, which is able to manage the data flow from the camera and convert it in a reasonable "neutron impact" data flow like from a usual neutron counting detector. The main challenge of the endeavor is the optical light collection from the scintillator. While the light yield of a ZnS scintillator is a priori rather important, the amount of light collected with a photographic objective is small. Different scintillators and different light collection techniques have been experimented with and results will be shown for different setups improving upon the light recuperation on the camera sensor. Improvements on the algorithm side will also be presented. The algorithms have to be at the same time efficient in their recognition of neutron signals, in their rejection of noise signals (internal and external to the camera) but also have to be simple enough to be easily implemented in the FPGA. The path from the idea of detecting individual neutron impacts with a CMOS camera to a practical working instrument detector is challenging, and in this paper we will give an overview of the part of the road that has already been walked.

  5. Observation of neutron standing waves at total reflection by precision gamma spectroscopy

    International Nuclear Information System (INIS)

    Aksenov, V.L.; Gundorin, N.A.; Nikitenko, Yu.V.; Popov, Yu.P.; Cser, L.

    1998-01-01

    Total reflection of polarized neutrons from the layered structure glass/Fe (1000 A Angstrom)/Gd (50 A Angstrom) is investigated by registering neutrons and gamma-quanta from thermal neutron capture. The polarization ratio of gamma counts of neutron beams polarized in and opposite the direction of the magnetic field is measured. The polarization ratio is larger than unity for the neutron wavelengths λ 2.2 A Angstrom. Such behaviour of the wavelength dependence of the gamma-quanta polarization ratio points to the fact that over the surface of the Fe Layer a neutron standing wave caused by the interference of the incident neutron wave and the wave refracted from the magnetized Fe layer is formed

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

    Energy Technology Data Exchange (ETDEWEB)

    Crane, T.W.

    1980-03-01

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

  7. Monte Carlo calculations of the neutron coincidence gate utilisation factor for passive neutron coincidence counting

    International Nuclear Information System (INIS)

    Bourva, L.C.A.; Croft, S.

    1999-01-01

    The general purpose neutron-photon-electron Monte Carlo N-Particle code, MCNP TM , has been used to simulate the neutronic characteristics of the on-site laboratory passive neutron coincidence counter to be installed, under Euratom Safeguards Directorate supervision, at the Sellafield reprocessing plant in Cumbria, UK. This detector is part of a series of nondestructive assay instruments to be installed for the accurate determination of the plutonium content of nuclear materials. The present work focuses on one aspect of this task, namely, the accurate calculation of the coincidence gate utilisation factor. This parameter is an important term in the interpretative model used to analyse the passive neutron coincidence count data acquired using pulse train deconvolution electronics based on the shift register technique. It accounts for the limited proportion of neutrons detected within the time interval for which the electronics gate is open. The Monte Carlo code MCF, presented in this work, represents a new evaluation technique for the estimation of gate utilisation factors. It uses the die-away profile of a neutron coincidence chamber generated either by MCNP TM , or by other means, to simulate the neutron detection arrival time pattern originating from independent spontaneous fission events. A shift register simulation algorithm, embedded in the MCF code, then calculates the coincidence counts scored within the electronics gate. The gate utilisation factor is then deduced by dividing the coincidence counts obtained with that obtained in the same Monte Carlo run, but for an ideal detection system with a coincidence gate utilisation factor equal to unity. The MCF code has been benchmarked against analytical results calculated for both single and double exponential die-away profiles. These results are presented along with the development of the closed form algebraic expressions for the two cases. Results of this validity check showed very good agreement. On this

  8. Neutron radiography imaging with 2-dimensional photon counting method and its problems

    International Nuclear Information System (INIS)

    Ikeda, Y.; Kobayashi, H.; Niwa, T.; Kataoka, T.

    1988-01-01

    A ultra sensitive neutron imaging system has been deviced with a 2-dimensional photon counting camara (ARGUS 100). The imaging system is composed by a 2-dimensional single photon counting tube and a low background vidicon followed with an image processing unit and frame memories. By using the imaging system, electronic neutron radiography (NTV) has been possible under the neutron flux less than 3 x 10 4 n/cm 2 ·s. (author)

  9. The design of systems for the determination of plutonium by passive neutron counting

    International Nuclear Information System (INIS)

    Hooton, B.W.

    1978-10-01

    The properties of moderators and other materials commonly used in systems for determination of plutonium by passive neutron counting have been investigated. The neutron flux from spontaneous fission and (α,n) reactions has been evaluated and the design characteristics of a number of systems have been determined by Monte Carlo tracking of neutrons. (author)

  10. The optimum choice of gate width for neutron coincidence counting

    Energy Technology Data Exchange (ETDEWEB)

    Croft, S., E-mail: crofts@ornl.gov [Safeguards and Security Technology (SST), Global Nuclear Security Technology Divisions, PO Box 2008, Building 5700, MS-6166, Oak Ridge, TN 37831-6166 (United States); Henzlova, D.; Favalli, A.; Hauck, D.K.; Santi, P.A. [Safeguards Science and Technology Group (NEN-1), Nuclear Engineering and Nonproliferation Division, MS-E540, Los Alamos, NM 87545 (United States)

    2014-11-11

    In the measurement field of international nuclear safeguards, passive neutron coincidence counting is used to quantify the spontaneous fission rate of certain special nuclear materials. The shift register autocorrelation analysis method is the most commonly used approach. However, the Feynman-Y technique, which is more commonly applied in reactor noise analysis, provides an alternative means to extract the correlation information from a pulse train. In this work we consider how to select the optimum gate width for each of these two time-correlation analysis techniques. The optimum is considered to be that which gives the lowest fractional precision on the net doublets rate. Our theoretical approach is approximate but is instructional in terms of revealing the key functional dependence. We show that in both cases the same performance figure of merit applies so that common design criteria apply to the neutron detector head. Our prediction is that near optimal results, suitable for most practical applications, can be obtained from both techniques using a common gate width setting. The estimated precision is also comparable in the two cases. The theoretical expressions are tested experimentally using {sup 252}Cf spontaneous fission sources measured in two thermal well counters representative of the type in common use by international inspectorates. Fast accidental sampling was the favored method of acquiring the Feynman-Y data. Our experimental study confirmed the basic functional dependences predicted although experimental results when available are preferred. With an appropriate gate setting Feynman-Y analysis provides an alternative to shift register analysis for safeguards applications which is opening up new avenues of data collection and data reduction to explore.

  11. Time Evolving Fission Chain Theory and Fast Neutron and Gamma-Ray Counting Distributions

    International Nuclear Information System (INIS)

    Kim, K. S.; Nakae, L. F.; Prasad, M. K.; Snyderman, N. J.; Verbeke, J. M.

    2015-01-01

    Here, we solve a simple theoretical model of time evolving fission chains due to Feynman that generalizes and asymptotically approaches the point model theory. The point model theory has been used to analyze thermal neutron counting data. This extension of the theory underlies fast counting data for both neutrons and gamma rays from metal systems. Fast neutron and gamma-ray counting is now possible using liquid scintillator arrays with nanosecond time resolution. For individual fission chains, the differential equations describing three correlated probability distributions are solved: the time-dependent internal neutron population, accumulation of fissions in time, and accumulation of leaked neutrons in time. Explicit analytic formulas are given for correlated moments of the time evolving chain populations. The equations for random time gate fast neutron and gamma-ray counting distributions, due to randomly initiated chains, are presented. Correlated moment equations are given for both random time gate and triggered time gate counting. There are explicit formulas for all correlated moments are given up to triple order, for all combinations of correlated fast neutrons and gamma rays. The nonlinear differential equations for probabilities for time dependent fission chain populations have a remarkably simple Monte Carlo realization. A Monte Carlo code was developed for this theory and is shown to statistically realize the solutions to the fission chain theory probability distributions. Combined with random initiation of chains and detection of external quanta, the Monte Carlo code generates time tagged data for neutron and gamma-ray counting and from these data the counting distributions.

  12. Total lymphocyte count and subpopulation lymphocyte counts in relation to dietary intake and nutritional status of peritoneal dialysis patients.

    Science.gov (United States)

    Grzegorzewska, Alicja E; Leander, Magdalena

    2005-01-01

    Dietary deficiency causes abnormalities in circulating lymphocyte counts. For the present paper, we evaluated correlations between total and subpopulation lymphocyte counts (TLC, SLCs) and parameters of nutrition in peritoneal dialysis (PD) patients. Studies were carried out in 55 patients treated with PD for 22.2 +/- 11.4 months. Parameters of nutritional status included total body mass, lean body mass (LBM), body mass index (BMI), and laboratory indices [total protein, albumin, iron, ferritin, and total iron binding capacity (TIBC)]. The SLCs were evaluated using flow cytometry. Positive correlations were seen between TLC and dietary intake of niacin; TLC and CD8 and CD16+56 counts and energy delivered from protein; CD4 count and beta-carotene and monounsaturated fatty acids 17:1 intake; and CD19 count and potassium, copper, vitamin A, and beta-carotene intake. Anorexia negatively influenced CD19 count. Serum albumin showed correlations with CD4 and CD19 counts, and LBM with CD19 count. A higher CD19 count was connected with a higher red blood cell count, hemoglobin, and hematocrit. Correlations were observed between TIBC and TLC and CD3 and CD8 counts, and between serum Fe and TLC and CD3 and CD4 counts. Patients with a higher CD19 count showed a better clinical-laboratory score, especially less weakness. Patients with a higher CD4 count had less expressed insomnia. Quantities of ingested vitamins and minerals influence lymphocyte counts in the peripheral blood of PD patients. Evaluation of TLC and SLCs is helpful in monitoring the effectiveness of nutrition in these patients.

  13. Total lymphocyte count as a substitute to cd4 count in management of hiv infected individuals in resource limited society

    International Nuclear Information System (INIS)

    Daud, M.Y.; Qazi, R.A.

    2015-01-01

    Pakistan is a resource limited society and gold standard parameters to monitor HIV disease activity are very costly. The objective of the study was to evaluate total lymphocyte count (TLC) as a surrogate to CD4 count to monitor disease activity in HIV/AIDS in resource limited society. Methods: This cross sectional study was carried out at HIV/AIDS treatment centre, Pakistan Institute of Medical Sciences (PIMS), Islamabad. A total of seven hundred and seventy four (774) HIV positive patients were enrolled in this study, and their CD4 count and total lymphocyte count were checked to find any correlation between the two by using Spearman ranked correlation coefficient. Results: The mean CD4 count was (434.30 ± 269.23), with minimum CD4 count of (9.00), and maximum of (1974.00). The mean total lymphocyte count (TLC) was (6764.0052 ± 2364.02) with minimum TLC (1200.00) and maximum TLC was (20200.00). Using the Pearson's correlation (r) there was a significant and positive correlation between TLC and CD4 count. (r2=0.127 and p=0.000) at 0.01 level. Conclusion: Our study showed a significant positive correlation between CD4 count and total lymphocyte count (TLC), so TLC can be used as a marker of disease activity in HIV infected patients. (author)

  14. Development of slow neutron dose meter by track counting

    International Nuclear Information System (INIS)

    Nozaki, Tetsuya; Takeuchi, Hiroshi; Hasnel, S.; Honda, Teruyuki; Harasawa, Susumu.

    1993-01-01

    Prototypes of a plate type and two types of semispherical dosemeter were manufactured and their performances were tested. Polyallyl diglycol carbonate (PADC) was employed as neutron detector and covered with natural LiF and 6 Li-enriched LiF ceramics. They were irradiated in the TRIGA II Reactor of the Rikkyo University, and the sensitivity characteristics for incident angles and neutron energies were analyzed. It is concluded that it may be possible to manufacture small sized neutron dosemeter of flat response to wide energy range from thermal neutrons to epithermal neutrons with sufficient sensitivity for personal monitoring, using LiF ceramic as neutron filters and neutron converters. However the following issues are to be solved: the optimization of thickness of the LiF filter, the effects of albedo of the human body, and the applicability to the intermediate neutrons. (A.Y.)

  15. The IAEA neutron coincidence counting (INCC) and the DEMING least-squares fitting programs

    International Nuclear Information System (INIS)

    Krick, M.S.; Harker, W.C.; Rinard, P.M.; Wenz, T.R.; Lewis, W.; Pham, P.; Ridder, P. de

    1998-01-01

    Two computer programs are described: (1) the INCC (IAEA or International Neutron Coincidence Counting) program and (2) the DEMING curve-fitting program. The INCC program is an IAEA version of the Los Alamos NCC (Neutron Coincidence Counting) code. The DEMING program is an upgrade of earlier Windows reg-sign and DOS codes with the same name. The versions described are INCC 3.00 and DEMING 1.11. The INCC and DEMING codes provide inspectors with the software support needed to perform calibration and verification measurements with all of the neutron coincidence counting systems used in IAEA inspections for the nondestructive assay of plutonium and uranium

  16. Pulse-shape discrimination in radioanalytical methods. Part I. Delayed fission neutron counting

    International Nuclear Information System (INIS)

    Posta, S.; Vacik, J.; Hnatowicz, V.; Cervena, J.

    1999-01-01

    In this study the principle of pulse shape discrimination (PSD) has been employed in delayed fission neutron counting (DNC) method. Effective elimination of unwanted gamma background signals in measured radiation spectra has been proved. (author)

  17. DAWN GRAND MAP CERES TPE NEUTRON COUNTS V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — A global map thermal+epithermal neutron counting rates binned on twenty-degree quasi-equal-area pixels is provided. The map was determined from a time series of the...

  18. Absolute measurement of the subcriticality based on the third order neutron correlation in consideration of the finite nature of neutron counts data

    International Nuclear Information System (INIS)

    Endo, Tomohiro; Kitamura, Yasunori; Yamane, Yoshihiro

    2003-01-01

    We have studied a measurement of subcriticality by using the neutron correlation method. Furuhashi proposed an absolute measurement of subcriticality by using the third order neutron correlation factor X in addition to the second order neutron correlation factor Y. In actual experiments, the number of neutron counts data is not infinity so that we take the effect of the finite nature of the neutron counts data into account. We derived new formulas in consideration of the number of data and verified them. (author)

  19. Methematical model of a neutron counting system used for the characteristics control of spontaneously fissioning material

    International Nuclear Information System (INIS)

    Bessis, J.

    1986-09-01

    Methods are described for calculating the probabilities, p(m), of detection of m neutrons, inside a split millisecond counting gate, m varying from zero to some units. At the present stage, these methods suppose the source to be very small. Using the generating function concept, they concern both possible modes of the counting system, for opening gates, i.e.: 1) Trigger pulses randomly with regard to the emitted neutrons, 2) Trigger pulses from the detected neutrons themselves. Computed values are finally compared to the measured ones. This comparison seems to be very favourable, since the respective deviations are often lower than 1 % [fr

  20. Short communication: Repeatability of differential goat bulk milk culture and associations with somatic cell count, total bacterial count, and standard plate count.

    Science.gov (United States)

    Koop, G; Dik, N; Nielen, M; Lipman, L J A

    2010-06-01

    The aims of this study were to assess how different bacterial groups in bulk milk are related to bulk milk somatic cell count (SCC), bulk milk total bacterial count (TBC), and bulk milk standard plate count (SPC) and to measure the repeatability of bulk milk culturing. On 53 Dutch dairy goat farms, 3 bulk milk samples were collected at intervals of 2 wk. The samples were cultured for SPC, coliform count, and staphylococcal count and for the presence of Staphylococcus aureus. Furthermore, SCC (Fossomatic 5000, Foss, Hillerød, Denmark) and TBC (BactoScan FC 150, Foss) were measured. Staphylococcal count was correlated to SCC (r=0.40), TBC (r=0.51), and SPC (r=0.53). Coliform count was correlated to TBC (r=0.33), but not to any of the other variables. Staphylococcus aureus did not correlate to SCC. The contribution of the staphylococcal count to the SPC was 31%, whereas the coliform count comprised only 1% of the SPC. The agreement of the repeated measurements was low. This study indicates that staphylococci in goat bulk milk are related to SCC and make a significant contribution to SPC. Because of the high variation in bacterial counts, repeated sampling is necessary to draw valid conclusions from bulk milk culturing. 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  1. Passive neutron coincidence counting with plastic scintillators for the characterization of radioactive waste drums

    Energy Technology Data Exchange (ETDEWEB)

    Deyglun, C.; Simony, B.; Perot, B.; Carasco, C. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Saurel, N.; Colas, S. [CEA, DAM, Valduc, F-21120 Is-sur-Tille (France); Collot, J. [Laboratoire de Physique Subatomique et de Cosmologie, Universite Grenoble Alpes, CNRS/IN2P3, Grenoble (France)

    2015-07-01

    The quantification of radioactive material is essential in the fields of safeguards, criticality control of nuclear processes, dismantling of nuclear facilities and components, or radioactive waste characterization. The Nuclear Measurement Laboratory (LMN) of CEA is involved in the development of time-correlated neutron detection techniques using plastic scintillators. Usually, 3He proportional counters are used for passive neutron coincidence counting owing to their high thermal neutron capture efficiency and gamma insensitivity. However, the global {sup 3}He shortage in the past few years has made these detectors extremely expensive. In addition, contrary to {sup 3}He counters for which a few tens of microseconds are needed to thermalize fast neutrons, in view to maximize the {sup 3}He(n,p){sup 3}H capture cross section, plastic scintillators are based on elastic scattering and therefore the light signal is formed within a few nanoseconds, correlated pulses being detected within a few dozen- or hundred nanoseconds. This time span reflects fission particles time of flight, which allows reducing accordingly the duration of the coincidence gate and thus the rate of random coincidences, which may totally blind fission coincidences when using {sup 3}He counters in case of a high (α,n) reaction rate. However, plastic scintillators are very sensitive to gamma rays, requiring the use of a thick metallic shield to reduce the corresponding background. Cross talk between detectors is also a major issue, which consists on the detection of one particle by several detectors due to elastic or inelastic scattering, leading to true but undesired coincidences. Data analysis algorithms are tested to minimize cross-talk in simultaneously activated detectors. The distinction between useful fission coincidences and the correlated background due to cross-talk, (α,n) and induced (n,2n) or (n,n'γ) reactions, is achieved by measuring 3-fold coincidences. The performances of a

  2. Distinguishing Pu Metal from Pu Oxide and Determining alpha-ratio using Fast Neutron Counting

    Energy Technology Data Exchange (ETDEWEB)

    Verbeke, J. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chapline, G. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nakae, L. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Prasad, M. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sheets, S. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Snyderman, N. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-01-07

    We describe a new method for determining the ratio of the rate of (α, n) source neutrons to the rate of spontaneous fission neutrons, the so called α-ratio. This method is made possible by fast neutron counting with liquid scintillator detectors, which can determine the shape of the fast neutron spectrum. The method utilizes the spectral difference between fission spectrum neutrons from Pu metal and the spectrum of (α, n) neutrons from PuO2. Our method is a generalization of the Cifarelli-Hage method for determining keff for fissile assemblies, and also simultaneously determines keff along with the α-ratio.

  3. Determining {sup 252}Cf source strength by absolute passive neutron correlation counting

    Energy Technology Data Exchange (ETDEWEB)

    Croft, S. [Oak Ridge National Laboratory, Oak Ridge, TN 37831-6166 (United States); Henzlova, D., E-mail: henzlova@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2013-06-21

    Physically small, lightly encapsulated, radionuclide sources containing {sup 252}Cf are widely used for a vast variety of industrial, medical, educational and research applications requiring a convenient source of neutrons. For many quantitative applications, such as detector efficiency calibrations, the absolute strength of the neutron emission is needed. In this work we show how, by using a neutron multiplicity counter the neutron emission rate can be obtained with high accuracy. This provides an independent and alternative way to create reference sources in-house for laboratories such as ours engaged in international safeguards metrology. The method makes use of the unique and well known properties of the {sup 252}Cf spontaneous fission system and applies advanced neutron correlation counting methods. We lay out the foundation of the method and demonstrate it experimentally. We show that accuracy comparable to the best methods currently used by national bodies to certify neutron source strengths is possible.

  4. Fly's Eye: a counting camera for thermal neutrons, some applications, problems, and prospects

    International Nuclear Information System (INIS)

    Davidson, J.B.

    1975-01-01

    An area detector for thermal neutrons based on image intensification techniques is described and some capabilities and limitations of the detection system are discussed. Among the former are high spatial resolution high instantaneous counting rate, electronic zoom, time-gating, and integration. The detector is limited in that the maximum counting rate for a resolution element is 60 regularly spaced counts per second. Also, the nonuniformity of response over the detector limits the useful size and requires point-by-point calibration. In addition, a higher efficiency for neutron detection would be desirable. Some typical applications of the system are: crystal inspection, neutron magnetic diffraction topography, and searches for temperature induced changes in diffraction patterns. The future application of solid state television sensors and microchannel plate intensifiers to improve the system are briefly mentioned. (U.S.)

  5. Fly's eye: a counting camera for thermal neutrons: some applications, problems, and prospects

    International Nuclear Information System (INIS)

    Davidson, J.B.

    1976-01-01

    An area detector for thermal neutrons based on image intensification techniques is described. Some capabilities and limitations of the detection system are discussed. Among the former are high spatial resolution, high instantaneous counting rate, electronic zoom, time-gating, and integration. The detector is limited in that the maximum counting rate for a resolution element is 60 regularly spaced counts per second. Also, the nonuniformity of response over the detector puts a limit on the useful size and necessitates point-by-point calibration. In addition, a higher efficiency for neutron detection would be desirable. Some typical applications of the system are crystal inspection, neutron magnetic diffraction topography, and searches for temperature-induced changes in diffraction patterns. The future application of solid-state television sensors and microchannel-plate intensifiers to improve the system is briefly mentioned

  6. Feynman variance-to-mean in the context of passive neutron coincidence counting

    Energy Technology Data Exchange (ETDEWEB)

    Croft, S., E-mail: scroft@lanl.gov [Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM 87545 (United States); Favalli, A.; Hauck, D.K.; Henzlova, D.; Santi, P.A. [Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM 87545 (United States)

    2012-09-11

    Passive Neutron Coincidence Counting (PNCC) based on shift register autocorrelation time analysis of the detected neutron pulse train is an important Nondestructive Assay (NDA) method. It is used extensively in the quantification of plutonium and other spontaneously fissile materials for purposes of nuclear materials accountancy. In addition to the totals count rate, which is also referred to as the singles, gross or trigger rate, a quantity known as the reals coincidence rate, also called the pairs or doubles, is obtained from the difference between the measured neutron multiplicities in two measurement gates triggered by the incoming events on the pulse train. The reals rate is a measure of the number of time correlated pairs present on the pulse train and this can be related to the fission rates (and hence material mass) since fissions emit neutrons in bursts which are also detected in characteristic clusters. A closely related measurement objective is the determination of the reactivity of systems as they approach criticality. In this field an alternative autocorrelation signature is popular, the so called Feynman variance-to-mean technique which makes use of the multiplicity histogram formed the periodic, or clock-triggered opening of a coincidence gate. Workers in these two application areas share common challenges and improvement opportunities but are often separated by tradition, problem focus and technical language. The purpose of this paper is to recognize the close link between the Feynman variance-to-mean metric and traditional PNCC using shift register logic applied to correlated pulse trains. We, show using relationships for the late-gate (or accidentals) histogram recorded using a multiplicity shift register, how the Feynman Y-statistic, defined as the excess variance-to-mean ratio, can be expressed in terms of the singles and doubles rates familiar to the safeguards and waste assay communities. These two specialisms now have a direct bridge between

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-01

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

  8. Neutron total scattering cross sections of elemental antimony

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.B.; Guenther, P.T.; Whalen, J.F.

    1982-11-01

    Neutron total cross sections are measured from 0.8 to 4.5 MeV with broad resolutions. Differential-neutron-elastic-scattering cross sections are measured from 1.5 to 4.0 MeV at intervals of 50 to 200 keV and at scattering angles distributed between 20 and 160 degrees. Lumped-level neutron-inelastic-scattering cross sections are measured over the same angular and energy range. The exPerimental results are discussed in terms of an optical-statistical model and are compared with respective values given in ENDF/B-V.

  9. Neutron total scattering cross sections of elemental antimony

    International Nuclear Information System (INIS)

    Smith, A.B.; Guenther, P.T.; Whalen, J.F.

    1982-11-01

    Neutron total cross sections are measured from 0.8 to 4.5 MeV with broad resolutions. Differential-neutron-elastic-scattering cross sections are measured from 1.5 to 4.0 MeV at intervals of 50 to 200 keV and at scattering angles distributed between 20 and 160 degrees. Lumped-level neutron-inelastic-scattering cross sections are measured over the same angular and energy range. The exPerimental results are discussed in terms of an optical-statistical model and are compared with respective values given in ENDF/B-V

  10. Is total lymphocyte count related to nutritional markers in hospitalized older adults?

    Directory of Open Access Journals (Sweden)

    Vânia Aparecida LEANDRO-MERHI

    Full Text Available ABSTRACT BACKGROUND Older patients are commonly malnourished during hospital stay, and a high prevalence of malnutrition is found in hospitalized patients aged more than 65 years. OBJECTIVE To investigate whether total lymphocyte count is related to other nutritional markers in hospitalized older adults. METHODS Hospitalized older adults (N=131 were recruited for a cross-sectional study. Their nutritional status was assessed by the Nutritional Risk Screening (NRS, anthropometry, and total lymphocyte count. The statistical analyses included the chi-square test, Fisher's exact test, and Mann-Whitney test. Spearman's linear correlation coefficient determined whether total lymphocyte count was correlated with the nutritional markers. Multiple linear regression determined the parameters associated with lymphocyte count. The significance level was set at 5%. RESULTS According to the NRS, 41.2% of the patients were at nutritional risk, and 36% had mild or moderate depletion according to total lymphocyte count. Total lymphocyte count was weakly correlated with mid-upper arm circumference (r=0.20507; triceps skinfold thickness (r=0.29036, and length of hospital stay (r= -0.21518. Total lymphocyte count in different NRS categories differed significantly: older adults who were not at nutritional risk had higher mean and median total lymphocyte count ( P =0.0245. Multiple regression analysis showed that higher lymphocyte counts were associated with higher triceps skinfold thicknesses and no nutritional risk according to the NRS. CONCLUSION Total lymphocyte count was correlated with mid-upper arm circumference, triceps skinfold thickness, and nutritional risk according to the NRS. In multiple regression the combined factors that remained associated with lymphocyte count were NRS and triceps skinfold thickness. Therefore, total lymphocyte count may be considered a nutritional marker. Other studies should confirm these findings.

  11. Solid-State Neutron Multiplicity Counting System Using Commercial Off-the-Shelf Semiconductor Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Rozhdestvenskyy, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-09

    This work iterates on the first demonstration of a solid-state neutron multiplicity counting system developed at Lawrence Livermore National Laboratory by using commercial off-the-shelf detectors. The system was demonstrated to determine the mass of a californium-252 neutron source within 20% error requiring only one-hour measurement time with 20 cm2 of active detector area.

  12. Porosity effects in the neutron total cross section of graphite

    International Nuclear Information System (INIS)

    Santisteban, J. R; Dawidowski, J; Petriw, S. N

    2009-01-01

    Graphite has been used in nuclear reactors since the birth of the nuclear industry due to its good performance as a neutron moderator material. Graphite is still an option as moderator for generation IV reactors due to its good mechanical and thermal properties at high operation temperatures. So, there has been renewed interest in a revision of the computer libraries used to describe the neutron cross section of graphite. For sub-thermal neutron energies, polycrystalline graphite shows a larger total cross section (between 4 and 8 barns) than predicted by existing theoretical models (0.2 barns). In order to investigate the origin of this discrepancy we measured the total cross section of graphite samples of three different origins, in the energy range from 0.001 eV to 10 eV. Different experimental arrangements and sample treatments were explored, to identify the effect of various experimental parameters on the total cross section measurement. The experiments showed that the increase in total cross section is due to neutrons scattered around the forward direction. We associate these small-angle scattered neutrons (SANS) to the porous structure of graphite, and formulate a very simple model to compute its contribution to the total cross section of the material. This results in an analytic expression that explicitly depends on the density and mean size of the pores, which can be easily incorporated in nuclear library codes. [es

  13. High sensitivity neutron activation analysis using coincidence counting method

    International Nuclear Information System (INIS)

    Suzuki, Shogo; Okada, Yukiko; Hirai, Shoji

    1999-01-01

    Four kinds of standard samples such as river sediment (NIES CRM No.16), Typical Japanese Diet, otoliths and river water were irradiated by TRIGA-II (100 kW, 3.7x10 12 n cm -2 s -1 ) for 6 h. After irradiation and cooling, they were analyzed by the coincidence counting method and a conventional γ-ray spectrometry. Se, Ba and Hf were determined by 75 Se 265 keV, 131 Ba 496 keV and 181 Hf 482 keV. On the river sediment sample, Ba and Hf showed the same values by two methods, but Se value contained Ta by the conventional method, although the coincidence counting method could analyze Se. On Typical Japanese Diet and otoliths, Se could be determined by two methods and Ba and Hf determined by the coincidence counting method but not determined by the conventional method. Se value in the river water agreed with the authorization value. (S.Y.)

  14. Etude de la diagraphie neutron du granite de Beauvoir. Effet neutron des altérations et de la matrice du granite. Calibration granite. Porosité totale à l'eau et porosité neutron Analysis of the Beauvoir Granite Neutron Log. Neutron Effect of Alterations and of the Granite Matrix. Granite Calibration. Total Water Porosity and Neutron Porosity

    Directory of Open Access Journals (Sweden)

    Galle C.

    2006-11-01

    relationship between the N neutron counting rate and the PorosityNc standard neutron porosity (limestone calibration was analysed (Fig. 2 and Fig. 3. For neutron porosities ranging from 0. 5 to 100%, we also examined the behaviour of N as a function of the borehole diameter (Fig. 4. To avoid the problem of correcting the hole effect and to be able to compare the porosities determined by neutron logging and measurements performed on core samples no matter what the depth was, the neutron counting rate was recalculated (N63 for a constant diameter of 63 mm (chosen arbitrarily, (Fig. 5. Then, a calibration curve between the N63 counting rate and the PorosityNR total reconstituted neutron porosity was determined for all the granite samples. From this relationship, we calculated a PorosityNg neutron porosity, called granitecalibration neutron porosity. Then PorosityNR, PorosityNg and PorosityNc were compared (Fig. 7, Fig. 9 and Fig. 10. By substracting the PorosityNma neutron matrix effect from PorosityNg and PorosityNc, we obtained the ng and nc water content values that we compared to the n water content measured on core samples (Fig. 8 and Fig. 11. PorosityNR, PorosityNg and neutron porosities and n, ng and nc water contents (free water saturation, were compared for the different alteration facies of the Beauvoir granite (Fig. 12. On the whole, there was a better (qualitative and quantitative relationship between the PorosityNR total neutron porosity and the PorosityNg granitecalibration neutron porosity (which are about 9%, than with PorosityNc. The PorosityNc neutron porosity issuing from the limestone calibration was underestimated because the rock neutron matrix effect was not taken into account (around 7% for the Beauvoir granite. Concerning water contents, limestone calibration led to nc water content values that, in 60% of the cases, were less than 0% and hence unusable. On the other hand, the ng water content obtained from the granitecalibration neutron porosity was more

  15. Neutron total cross section measurements on 249Cf

    International Nuclear Information System (INIS)

    Carlton, R.F.; Harvey, J.A.; Hill, N.W.; Pandey, M.S.; Benjamin, R.W.

    1979-01-01

    Neutron total cross section measurements were performed on a sample of 249 Cf (5.65 mg total weight) with the ORELA as a source of pulsed neutrons. The sample, the inverse thickness of which was 1542 barns/atom, consisted of 85.3% 249 Cf and 14.4% 249 Bk, and was cooled to liquid nitrogen temperature. Analyses were also made of data from a thin sample (l/n = 17430) of 65% 249 Cf in the region of the large fission resonance at 0.7 eV. Fifty-five resonances in 249 Cf were observed and analyzed over the energy range 0.1 eV to 90 eV by use of an R-matrix multilevel formalism. The resonance parameters obtained were used to determine the level spacing and the s-wave neutron and fission strength functions. Thermal total cross section measurements were also performed. 5 figures, 3 tables

  16. Evaluation of the 238U neutron total cross section

    International Nuclear Information System (INIS)

    Smith, A.; Poenitz, W.P.; Howerton, R.J.

    1982-12-01

    Experimental energy-averaged neutron total cross sections of 238 U were evaluated from 0.044 to 20.0 MeV using regorous numerical methods. The evaluated results are presented together with the associated uncertainties and correlation matrix. They indicate that this energy-averaged neutron total cross section is known to better than 1% over wide energy regions. There are somwewhat larger uncertainties at low energies (e.g., less than or equal to 0.2 MeV), near 8 MeV and above 15 MeV. The present evaluation is compard with values given in ENDF/B-V

  17. Selection of non-destructive assay methods: Neutron counting or calorimetric assay?

    International Nuclear Information System (INIS)

    Cremers, T.L.; Wachter, J.R.

    1994-01-01

    The transition of DOE facilities from production to D ampersand D has lead to more measurements of product, waste, scrap, and other less attractive materials. Some of these materials are difficult to analyze by either neutron counting or calorimetric assay. To determine the most efficacious analysis method, variety of materials, impure salts and hydrofluorination residues have been assayed by both calorimetric assay and neutron counting. New data will be presented together with a review of published data. The precision and accuracy of these measurements are compared to chemistry values and are reported. The contribution of the gamma ray isotopic determination measurement to the overall error of the calorimetric assay or neutron assay is examined and discussed. Other factors affecting selection of the most appropriate non-destructive assay method are listed and considered

  18. Study on changes of sperm count and testis tissue in black mouse after neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Ki Jung; Seo, Won Sook [KAERI, Daejeon (Korea, Republic of); Son, Hwa Young [Chungnam National Univ., Daejeon (Korea, Republic of)

    2006-03-15

    For the purpose of the biological effect in black mouse by neutron irradiation, mice were irradiated with 16 or 32 Gy neutron (flux: 1.036739E+09) by lying flat pose at BNCT facility on HANARO Reactors. And 90 days later of irradiation, physical changes of testis and testis tissue were examined. There were no weight changes but a little bit volume changes and sperm counts in the tests. Atrophy of seminiferous tubules irradiated with 32 Gy neutron is increased in number and severity and those in stage VI showed depletion of spermatogonia and pachytene spermatocytes compared to the non-irradiated control group. Testis damage of black mouse was not recovered after long time by 32 Gy neutron irradiation.

  19. Study on changes of sperm count and testis tissue in black mouse after neutron irradiation

    International Nuclear Information System (INIS)

    Chun, Ki Jung; Seo, Won Sook; Son, Hwa Young

    2006-01-01

    For the purpose of the biological effect in black mouse by neutron irradiation, mice were irradiated with 16 or 32 Gy neutron (flux: 1.036739E+09) by lying flat pose at BNCT facility on HANARO Reactors. And 90 days later of irradiation, physical changes of testis and testis tissue were examined. There were no weight changes but a little bit volume changes and sperm counts in the tests. Atrophy of seminiferous tubules irradiated with 32 Gy neutron is increased in number and severity and those in stage VI showed depletion of spermatogonia and pachytene spermatocytes compared to the non-irradiated control group. Testis damage of black mouse was not recovered after long time by 32 Gy neutron irradiation

  20. Development of a high-count-rate neutron detector with position sensitivity and high efficiency

    International Nuclear Information System (INIS)

    Nelson, R.; Sandoval, J.

    1996-01-01

    While the neutron scattering community is bombarded with hints of new technologies that may deliver detectors with high-count-rate capability, high efficiency, gamma-ray insensitivity, and high resolution across large areas, only the time-tested, gas-filled 3 He and scintillation detectors are in widespread use. Future spallation sources with higher fluxes simply must exploit some of the advanced detector schemes that are as yet unproved as production systems. Technologies indicating promise as neutron detectors include pixel arrays of amorphous silicon, silicon microstrips, microstrips with gas, and new scintillation materials. This project sought to study the competing neutron detector technologies and determine which or what combination will lead to a production detector system well suited for use at a high-intensity neutron scattering source

  1. Neutron reflection effect on total absorption detector method used in SWINPC neutron multiplication experiment for beryllium

    International Nuclear Information System (INIS)

    Tian Dongfeng; Ho Yukun; Yang Fujia

    2001-01-01

    The SWINPC integral experiment on neutron multiplication in bulk beryllium showed that there were marked discrepancies between experimental data and calculated values with the ENDF/B-VI data. The calculated values become higher than experimental ones as the sample thickness increases. Several works had been devoted to find problems existing in the experiment. This paper discusses the neutron reflection effect on the total absorption detector method which was used in the experiment to measure the neutron leakage from samples. One systematic correction is suggested to make the experimental values agree with the calculated ones with the ENDF/B-VI data within experimental errors. (author)

  2. A Monte Carlo Model for Neutron Coincidence Counting with Fast Organic Liquid Scintillation Detectors

    International Nuclear Information System (INIS)

    Gamage, Kelum A.A.; Joyce, Malcolm J.; Cave, Frank D.

    2013-06-01

    Neutron coincidence counting is an established, nondestructive method for the qualitative and quantitative analysis of nuclear materials. Several even-numbered nuclei of the actinide isotopes, and especially even-numbered plutonium isotopes, undergo spontaneous fission, resulting in the emission of neutrons which are correlated in time. The characteristics of this i.e. the multiplicity can be used to identify each isotope in question. Similarly, the corresponding characteristics of isotopes that are susceptible to stimulated fission are somewhat isotope-related, and also dependent on the energy of the incident neutron that stimulates the fission event, and this can hence be used to identify and quantify isotopes also. Most of the neutron coincidence counters currently used are based on 3 He gas tubes. In the 3 He-filled gas proportional-counter, the (n, p) reaction is largely responsible for the detection of slow neutrons and hence neutrons have to be slowed down to thermal energies. As a result, moderator and shielding materials are essential components of many systems designed to assess quantities of fissile materials. The use of a moderator, however, extends the die-away time of the detector necessitating a larger coincidence window and, further, 3 He is now in short supply and expensive. In this paper, a simulation based on the Monte Carlo method is described which has been performed using MCNPX 2.6.0, to model the geometry of a sector-shaped liquid scintillation detector in response to coincident neutron events. The detection of neutrons from a mixed-oxide (MOX) fuel pellet using an organic liquid scintillator has been simulated for different thicknesses of scintillators. In this new neutron detector, a layer of lead has been used to reduce the gamma-ray fluence reaching the scintillator. The effect of lead for neutron detection has also been estimated by considering different thicknesses of lead layers. (authors)

  3. Determination of phosphorus in biological samples by thermal neutron activation followed by β--counting

    International Nuclear Information System (INIS)

    Weginwar, R.G.; Samudralwar, D.L.; Garg, A.N.

    1989-01-01

    Phosphorus was determined using the β - emitter 32 P by instrumental neutron activation analysis (INAA) in several NBS and IAEA standards, and in samples of biological origin such as human and animal blood, cancerous tissue, edible plant leaves, diets, milk samples, etc. The method involves thermal neutron irradiation (for 2-10 h in a reactor) followed by β - counting on an end-window gas flow proportional counter using aluminium filter. The results are within ±10% of the certified values in most cases. (author) 29 refs.; 3 tabs

  4. White Blood Cell Count and Total and Cause-Specific Mortality in the Women's Health Initiative.

    Science.gov (United States)

    Kabat, Geoffrey C; Kim, Mimi Y; Manson, JoAnn E; Lessin, Lawrence; Lin, Juan; Wassertheil-Smoller, Sylvia; Rohan, Thomas E

    2017-07-01

    White blood cell (WBC) count appears to predict total mortality and coronary heart disease (CHD) mortality, but it is unclear to what extent the association reflects confounding by smoking, underlying illness, or comorbid conditions. We used data from the Women's Health Initiative to examine the associations of WBC count with total mortality, CHD mortality, and cancer mortality. WBC count was measured at baseline in 160,117 postmenopausal women and again in year 3 in 74,375 participants. Participants were followed for a mean of 16 years. Cox proportional hazards models were used to estimate the relative mortality hazards associated with deciles of baseline WBC count and of the mean of baseline + year 3 WBC count. High deciles of both baseline and mean WBC count were positively associated with total mortality and CHD mortality, whereas the association with cancer mortality was weaker. The association of WBC count with mortality was independent of smoking and did not appear to be influenced by previous disease history. The potential clinical utility of this common laboratory test in predicting mortality risk warrants further study. © The Author 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Association of peripheral total and differential leukocyte counts with obesity-related complications in young adults.

    Science.gov (United States)

    Yoshimura, Aya; Ohnishi, Shunsuke; Orito, Chieko; Kawahara, Yukako; Takasaki, Hiroyo; Takeda, Hiroshi; Sakamoto, Naoya; Hashino, Satoshi

    2015-01-01

    Obesity has been demonstrated to be associated with elevated leukocytes in adults and children. This study assessed the associations between peripheral total and differential leukocyte counts and obesity-related complications in young adults. 12 obese (median age 21.5 (range 19-28) years, median BMI 35.7 (range 32.0-44.9) kg/m(2)) and 11 normal (median age 23 (range 18-27) years, median BMI 19.5 (range 18.1-21.7) kg/m(2)) adults were enrolled. Complete blood count and serum levels of liver enzymes, fasting blood glucose, insulin and lipids were measured, and the homeostasis model assessment of insulin resistance was calculated. Fat mass was calculated using a bioimpedance analysis device, and ultrasonography was performed to measure fat thickness and to detect fatty change of the liver. Total leukocyte and monocyte counts were significantly increased in obese young adults. Total leukocyte count was associated with liver enzyme levels, insulin resistance as well as visceral and subcutaneous fat thickness. Neutrophil count was associated with insulin resistance. Lymphocyte count was associated with serum liver enzymes, insulin resistance, and dyslipidemia. Monocyte count was associated with serum liver enzyme, insulin resistance, visceral and subcutaneous fat thickness, body fat mass, and percentage body fat. The results of this study suggest that chronic low-grade systemic inflammation is associated with obesity-related complications such as nonalcoholic fatty liver disease, insulin resistance, and dyslipidemia in young adults. © 2015 S. Karger GmbH, Freiburg.

  6. Sensitive and transportable gadolinium-core plastic scintillator sphere for neutron detection and counting

    Energy Technology Data Exchange (ETDEWEB)

    Dumazert, Jonathan; Coulon, Romain; Carrel, Frédérick; Corre, Gwenolé; Normand, Stéphane [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France); Méchin, Laurence [CNRS, UCBN, Groupe de Recherche en Informatique, Image, Automatique et Instrumentation de Caen, 14050 Caen (France); Hamel, Matthieu [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France)

    2016-08-21

    Neutron detection forms a critical branch of nuclear-related issues, currently driven by the search for competitive alternative technologies to neutron counters based on the helium-3 isotope. The deployment of plastic scintillators shows a high potential for efficient detectors, safer and more reliable than liquids, more easily scalable and cost-effective than inorganic. In the meantime, natural gadolinium, through its 155 and mostly 157 isotopes, presents an exceptionally high interaction probability with thermal neutrons. This paper introduces a dual system including a metal gadolinium core inserted at the center of a high-scale plastic scintillator sphere. Incident fast neutrons are thermalized by the scintillator shell and then may be captured with a significant probability by gadolinium 155 and 157 nuclei in the core. The deposition of a sufficient fraction of the capture high-energy prompt gamma signature inside the scintillator shell will then allow discrimination from background radiations by energy threshold, and therefore neutron detection. The scaling of the system with the Monte Carlo MCNPX2.7 code was carried out according to a tradeoff between the moderation of incident fast neutrons and the probability of slow neutron capture by a moderate-cost metal gadolinium core. Based on the parameters extracted from simulation, a first laboratory prototype for the assessment of the detection method principle has been synthetized. The robustness and sensitivity of the neutron detection principle are then assessed by counting measurement experiments. Experimental results confirm the potential for a stable, highly sensitive, transportable and cost-efficient neutron detector and orientate future investigation toward promising axes.

  7. Sensitive and transportable gadolinium-core plastic scintillator sphere for neutron detection and counting

    International Nuclear Information System (INIS)

    Dumazert, Jonathan; Coulon, Romain; Carrel, Frédérick; Corre, Gwenolé; Normand, Stéphane; Méchin, Laurence; Hamel, Matthieu

    2016-01-01

    Neutron detection forms a critical branch of nuclear-related issues, currently driven by the search for competitive alternative technologies to neutron counters based on the helium-3 isotope. The deployment of plastic scintillators shows a high potential for efficient detectors, safer and more reliable than liquids, more easily scalable and cost-effective than inorganic. In the meantime, natural gadolinium, through its 155 and mostly 157 isotopes, presents an exceptionally high interaction probability with thermal neutrons. This paper introduces a dual system including a metal gadolinium core inserted at the center of a high-scale plastic scintillator sphere. Incident fast neutrons are thermalized by the scintillator shell and then may be captured with a significant probability by gadolinium 155 and 157 nuclei in the core. The deposition of a sufficient fraction of the capture high-energy prompt gamma signature inside the scintillator shell will then allow discrimination from background radiations by energy threshold, and therefore neutron detection. The scaling of the system with the Monte Carlo MCNPX2.7 code was carried out according to a tradeoff between the moderation of incident fast neutrons and the probability of slow neutron capture by a moderate-cost metal gadolinium core. Based on the parameters extracted from simulation, a first laboratory prototype for the assessment of the detection method principle has been synthetized. The robustness and sensitivity of the neutron detection principle are then assessed by counting measurement experiments. Experimental results confirm the potential for a stable, highly sensitive, transportable and cost-efficient neutron detector and orientate future investigation toward promising axes.

  8. Moisture corrections in neutron coincidence counting of PuO2

    International Nuclear Information System (INIS)

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

    1987-01-01

    Passive neutron coincidence counting is capable of 1% assay accuracy for pure, well-characterized PuO 2 samples that contain plutonium masses from a few tens of grams to several kilograms. Moisture in the sample can significantly bias the assay high by changing the (α,n) neutron production, the sample multiplication, and the detection efficiency. Monte Carlo calculations and an analytical model of coincidence counting have been used to quantify the individual and cumulative effects of moisture biases for two PuO 2 sample sizes and a range of moisture levels from 0 to 9 wt %. Results of the calculations suggest a simple correction procedure for moisture bias that is effective from 0 to 3 wt % H 2 O. The procedure requires that the moisture level in the sample be known before the coincidence measurement

  9. Implementation and Initial Testing of Advanced Processing and Analysis Algorithms for Correlated Neutron Counting

    Energy Technology Data Exchange (ETDEWEB)

    Santi, Peter Angelo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Cutler, Theresa Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Favalli, Andrea [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Koehler, Katrina Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Henzl, Vladimir [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Henzlova, Daniela [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Parker, Robert Francis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Croft, Stephen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-01

    In order to improve the accuracy and capabilities of neutron multiplicity counting, additional quantifiable information is needed in order to address the assumptions that are present in the point model. Extracting and utilizing higher order moments (Quads and Pents) from the neutron pulse train represents the most direct way of extracting additional information from the measurement data to allow for an improved determination of the physical properties of the item of interest. The extraction of higher order moments from a neutron pulse train required the development of advanced dead time correction algorithms which could correct for dead time effects in all of the measurement moments in a self-consistent manner. In addition, advanced analysis algorithms have been developed to address specific assumptions that are made within the current analysis model, namely that all neutrons are created at a single point within the item of interest, and that all neutrons that are produced within an item are created with the same energy distribution. This report will discuss the current status of implementation and initial testing of the advanced dead time correction and analysis algorithms that have been developed in an attempt to utilize higher order moments to improve the capabilities of correlated neutron measurement techniques.

  10. Sensitivity analysis of physical/operational parameters in neutron multiplicity counting

    International Nuclear Information System (INIS)

    Peerani, P.; Marin Ferrer, M.

    2007-01-01

    In this paper, we perform a sensitivity study on the influence of various physical and operational parameters on the results of neutron multiplicity counting. The purpose is to have a better understanding of the importance of each component and its contribution to the measurement uncertainty. Then we will be able to determine the optimal conditions for the operational parameters and for detector design and as well to point out weaknesses in the knowledge of critical fundamental nuclear data

  11. Experimental evaluation of the extended Dytlewski-style dead time correction formalism for neutron multiplicity counting

    Science.gov (United States)

    Lockhart, M.; Henzlova, D.; Croft, S.; Cutler, T.; Favalli, A.; McGahee, Ch.; Parker, R.

    2018-01-01

    Over the past few decades, neutron multiplicity counting has played an integral role in Special Nuclear Material (SNM) characterization pertaining to nuclear safeguards. Current neutron multiplicity analysis techniques use singles, doubles, and triples count rates because a methodology to extract and dead time correct higher order count rates (i.e. quads and pents) was not fully developed. This limitation is overcome by the recent extension of a popular dead time correction method developed by Dytlewski. This extended dead time correction algorithm, named Dytlewski-Croft-Favalli(DCF), is detailed in reference Croft and Favalli (2017), which gives an extensive explanation of the theory and implications of this new development. Dead time corrected results can then be used to assay SNM by inverting a set of extended point model equations which as well have only recently been formulated. The current paper discusses and presents the experimental evaluation of practical feasibility of the DCF dead time correction algorithm to demonstrate its performance and applicability in nuclear safeguards applications. In order to test the validity and effectiveness of the dead time correction for quads and pents, 252Cf and SNM sources were measured in high efficiency neutron multiplicity counters at the Los Alamos National Laboratory (LANL) and the count rates were extracted up to the fifth order and corrected for dead time. In order to assess the DCF dead time correction, the corrected data is compared to traditional dead time correction treatment within INCC. The DCF dead time correction is found to provide adequate dead time treatment for broad range of count rates available in practical applications.

  12. Rapid uranium analysis by delayed neutron counting of neutron activated samples

    International Nuclear Information System (INIS)

    Papadopoulos, N.N.

    1985-01-01

    The uranium analyzer at the Nuclear Research Center ''Demokritos'' and the delayed neutron method have been used to determine the uranium content in lignite, in chemically enriched samples and in solutions of extractable uranium. The results are compared with data obtained by other methods. In the case of dissolved extractable uranium. The results are in good agreement with X-ray fluorescence data in the range 100 ppm to 2000 ppm while beyond these limits the discrepancies between neutron and spectrophotometric data are observed. The results for lignite samples are in good agreement with gamma spectrometric data. Discrepancies indicate that more extensive intercomparisons are needed to check the reliability of various methods

  13. Detection of Salmonella sp., Vibrio sp. and total plate count bacteria on blood cockle (Anadara granosa)

    Science.gov (United States)

    Ekawati, ER; Yusmiati, S. N. H.

    2018-01-01

    Blood cockle (Anadara granosa) has high level of zinc and protein, which is beneficial for therapeutic function for malnourished particularly stunting case in children. Zinc in animal foods is more absorbable than that from vegetable food. Blood cockle (Anadara granosa) is rich in nutrient and an excellent environment for the growth of microorganisms. This research aimed to identify the contamination of Salmonella sp., Vibrio sp. and total plate count bacteria on blood cockle (Anadara granosa). This was observation research with laboratory analysis. Salmonella sp. and Vibrio sp. were detected from blood cockle. Total plate count was determine of the total amount of the bacteria. Results detected from 20 samples of blood cockle showed that all samples were negative of Salmonella sp. and 1 sample positive Vibrio sp. The result of total plate count bacteria was < 5 x 105 colony/g sample.

  14. Immature germ cells in semen - correlation with total sperm count and sperm motility

    Directory of Open Access Journals (Sweden)

    Priya S Patil

    2013-01-01

    Conclusions: Round cells in semen can be differentiated into immature germ cells and leucocytes using simple staining methods. The differential counts mentioned in a semen report give valuable and clinically relevant information. In this study, we observed a negative correlation between total count and immature germ cells, as well as sperm motility and shedding of immature germ cells. The latter was statistically significant with a P value 0.000.

  15. Uranium mass and neutron multiplication factor estimates from time-correlation coincidence counts

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Wenxiong [China Academy of Engineering Physics, Center for Strategic Studies, Beijing 100088 (China); Li, Jiansheng [China Academy of Engineering Physics, Institute of Nuclear Physics and Chemistry, Mianyang 621900 (China); Zhu, Jianyu [China Academy of Engineering Physics, Center for Strategic Studies, Beijing 100088 (China)

    2015-10-11

    Time-correlation coincidence counts of neutrons are an important means to measure attributes of nuclear material. The main deficiency in the analysis is that an attribute of an unknown component can only be assessed by comparing it with similar known components. There is a lack of a universal method of measurement suitable for the different attributes of the components. This paper presents a new method that uses universal relations to estimate the mass and neutron multiplication factor of any uranium component with known enrichment. Based on numerical simulations and analyses of 64 highly enriched uranium components with different thicknesses and average radii, the relations between mass, multiplication and coincidence spectral features have been obtained by linear regression analysis. To examine the validity of the method in estimating the mass of uranium components with different sizes, shapes, enrichment, and shielding, the features of time-correlation coincidence-count spectra for other objects with similar attributes are simulated. Most of the masses and multiplications for these objects could also be derived by the formulation. Experimental measurements of highly enriched uranium castings have also been used to verify the formulation. The results show that for a well-designed time-dependent coincidence-count measuring system of a uranium attribute, there are a set of relations dependent on the uranium enrichment by which the mass and multiplication of the measured uranium components of any shape and size can be estimated from the features of the source-detector coincidence-count spectrum.

  16. Fast-neutron total and scattering cross sections of niobium

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.B.; Guenther, P.T.; Whalen, J.F.

    1982-07-01

    Neutron total cross sections of niobium were measured from approx. = 0.7 to 4.5 MeV at intervals of less than or equal to 50 keV with broad resolution. Differential-elastic-scattering cross sections were measured from approx. = 1.5 to 4.0 MeV at intervals of 0.1 to 0.2 MeV and at 10 to 20 scattering angles distributed between approx. = 20 and 160 degrees. Inelastically-scattered neutrons, corresponding to the excitation of levels at: 788 +- 23, 982 +- 17, 1088 +- 27, 1335 +- 35, 1504 +- 30, 1697 +- 19, 1971 +- 22, 2176 +- 28, 2456 +- (.), and 2581 +- (.) keV, were observed. An optical-statistical model, giving a good description of the observables, was deduced from the measured differential-elastic-scattering cross sections. The experimental-results were compared with the respective evaluated quantities given in ENDF/B-V.

  17. Fast-neutron total and scattering cross sections of niobium

    International Nuclear Information System (INIS)

    Smith, A.B.; Guenther, P.T.; Whalen, J.F.

    1982-07-01

    Neutron total cross sections of niobium were measured from approx. = 0.7 to 4.5 MeV at intervals of less than or equal to 50 keV with broad resolution. Differential-elastic-scattering cross sections were measured from approx. = 1.5 to 4.0 MeV at intervals of 0.1 to 0.2 MeV and at 10 to 20 scattering angles distributed between approx. = 20 and 160 degrees. Inelastically-scattered neutrons, corresponding to the excitation of levels at: 788 +- 23, 982 +- 17, 1088 +- 27, 1335 +- 35, 1504 +- 30, 1697 +- 19, 1971 +- 22, 2176 +- 28, 2456 +- (.), and 2581 +- (.) keV, were observed. An optical-statistical model, giving a good description of the observables, was deduced from the measured differential-elastic-scattering cross sections. The experimental-results were compared with the respective evaluated quantities given in ENDF/B-V

  18. Measurement of neutron total cross-sections for {sup nat}Dy at Pohang Neutron Facility

    Energy Technology Data Exchange (ETDEWEB)

    Shin, S. G.; Kye, Y. U.; Shvetsov, Valery; Cho, M. H. [POSTECH, Pohang (Korea, Republic of); Namkung, W.; Cho, M. H. [Pohang Accelerator Laboratory, Pohang (Korea, Republic of); Kim, G. N. [Kyungpook National Univ., Daegu (Korea, Republic of); Lee, M. W. [Dongnam Inst. of radiological and Medical Science, Busan (Korea, Republic of)

    2013-05-15

    There are few measurements for Dy below 100 eV. Moreover, there exist discrepancies among the measurements. In the present work, the total neutron cross-sections for {sup nat}Dy were measured by using the time-of-flight (TOF) method at the Pohang Neutron Facility (PNF). The PNF consists of an electron linac, a water-cooled Ta target, and an 11-m-long TOF path. The characteristics of PNF are described elsewhere. We also briefly discuss the future plan to verify our experimental result. We have measured the total neutron cross-sections of {sup nat}Dy in the neutron energy region from 0.1 eV to 100 eV with the TOF method at the Po hang Neutron Facility. The present result is in good agreement with the previous data and the evaluated data in ENDF/B-VI. We would like to get resonance parameters by using SAMMY or REFIT codes.

  19. Immature germ cells in semen - correlation with total sperm count and sperm motility.

    Science.gov (United States)

    Patil, Priya S; Humbarwadi, Rajendra S; Patil, Ashalata D; Gune, Anita R

    2013-07-01

    Current data regarding infertility suggests that male factor contributes up to 30% of the total cases of infertility. Semen analysis reveals the presence of spermatozoa as well as a number of non-sperm cells, presently being mentioned in routine semen report as "round cells" without further differentiating them into leucocytes or immature germ cells. The aim of this work was to study a simple, cost-effective, and convenient method for differentiating the round cells in semen into immature germ cells and leucocytes and correlating them with total sperm counts and motility. Semen samples from 120 males, who had come for investigation for infertility, were collected, semen parameters recorded, and stained smears studied for different round cells. Statistical analysis of the data was done to correlate total sperm counts and sperm motility with the occurrence of immature germ cells and leucocytes. The average shedding of immature germ cells in different groups with normal and low sperm counts was compared. The clinical significance of "round cells" in semen and their differentiation into leucocytes and immature germ cells are discussed. Round cells in semen can be differentiated into immature germ cells and leucocytes using simple staining methods. The differential counts mentioned in a semen report give valuable and clinically relevant information. In this study, we observed a negative correlation between total count and immature germ cells, as well as sperm motility and shedding of immature germ cells. The latter was statistically significant with a P value 0.000.

  20. Conversion factors from counts to chemical ratios for the EURITRACK tagged neutron inspection system

    International Nuclear Information System (INIS)

    El Kanawati, W.; Perot, B.; Carasco, C.; Eleon, C.; Valkovic, V.; Sudac, D.; Obhodas, J.

    2011-01-01

    The EURopean Illicit TRAfficking Countermeasures Kit (EURITRACK) uses 14 MeV neutrons produced by the 3 H(d,n) 4 H fusion reaction to detect explosives and narcotics in cargo containers. Reactions induced by fast neutrons produce gamma rays, which are detected in coincidence with the associated alpha particle to determine the neutron direction. In addition, the neutron path length is obtained from a time-of-flight measurement, thus allowing the origin of the gamma rays inside the container to be determined. Information concerning the chemical composition of the target material is obtained from the analysis of the energy spectrum. The carbon, oxygen, and nitrogen relative count contributions must be converted to chemical proportions to distinguish illicit and benign organic materials. An extensive set of conversion factors based on Monte Carlo numerical simulations has been calculated, taking into account neutron slowing down and photon attenuation in the cargo materials. An experimental validation of the method is presented by comparing the measured chemical fractions of known materials, in the form of bare samples or hidden in a cargo container, to their real chemical composition. Examples of application to real cargo containers are also reported, as well as simulated data with explosives and illicit drugs.

  1. Conversion factors from counts to chemical ratios for the EURITRACK tagged neutron inspection system

    Energy Technology Data Exchange (ETDEWEB)

    El Kanawati, W. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Perot, B., E-mail: bertrand.perot@cea.fr [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Carasco, C.; Eleon, C. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Valkovic, V. [A.C.T.d.o.o., Prilesje 4, 10000 Zagreb (Croatia); Sudac, D.; Obhodas, J. [Ruder Boskovic Institute, Bijenicka c. 54, 10000 Zagreb (Croatia)

    2011-10-21

    The EURopean Illicit TRAfficking Countermeasures Kit (EURITRACK) uses 14 MeV neutrons produced by the {sup 3}H(d,n){sup 4}H fusion reaction to detect explosives and narcotics in cargo containers. Reactions induced by fast neutrons produce gamma rays, which are detected in coincidence with the associated alpha particle to determine the neutron direction. In addition, the neutron path length is obtained from a time-of-flight measurement, thus allowing the origin of the gamma rays inside the container to be determined. Information concerning the chemical composition of the target material is obtained from the analysis of the energy spectrum. The carbon, oxygen, and nitrogen relative count contributions must be converted to chemical proportions to distinguish illicit and benign organic materials. An extensive set of conversion factors based on Monte Carlo numerical simulations has been calculated, taking into account neutron slowing down and photon attenuation in the cargo materials. An experimental validation of the method is presented by comparing the measured chemical fractions of known materials, in the form of bare samples or hidden in a cargo container, to their real chemical composition. Examples of application to real cargo containers are also reported, as well as simulated data with explosives and illicit drugs.

  2. Comparison of MCNP6 and experimental results for neutron counts, Rossi-α, and Feynman-α distributions

    International Nuclear Information System (INIS)

    Talamo, A.; Gohar, Y.; Sadovich, S.; Kiyavitskaya, H.; Bournos, V.; Fokov, Y.; Routkovskaya, C.

    2013-01-01

    MCNP6, the general-purpose Monte Carlo N-Particle code, has the capability to perform time-dependent calculations by tracking the time interval between successive events of the neutron random walk. In fixed-source calculations for a subcritical assembly, the zero time value is assigned at the moment the neutron is emitted by the external neutron source. The PTRAC and F8 cards of MCNP allow to tally the time when a neutron is captured by 3 He(n, p) reactions in the neutron detector. From this information, it is possible to build three different time distributions: neutron counts, Rossi-α, and Feynman-α. The neutron counts time distribution represents the number of neutrons captured as a function of time. The Rossi-a distribution represents the number of neutron pairs captured as a function of the time interval between two capture events. The Feynman-a distribution represents the variance-to-mean ratio, minus one, of the neutron counts array as a function of a fixed time interval. The MCNP6 results for these three time distributions have been compared with the experimental data of the YALINA Thermal facility and have been found to be in quite good agreement. (authors)

  3. Comparison of MCNP6 and experimental results for neutron counts, Rossi-{alpha}, and Feynman-{alpha} distributions

    Energy Technology Data Exchange (ETDEWEB)

    Talamo, A.; Gohar, Y. [Argonne National Laboratory, 9700 S. Cass Ave., Lemont, IL 60439 (United States); Sadovich, S.; Kiyavitskaya, H.; Bournos, V.; Fokov, Y.; Routkovskaya, C. [Joint Institute for Power and Nuclear Research-Sosny, 99 Academician A.K. Krasin Str., Minsk 220109 (Belarus)

    2013-07-01

    MCNP6, the general-purpose Monte Carlo N-Particle code, has the capability to perform time-dependent calculations by tracking the time interval between successive events of the neutron random walk. In fixed-source calculations for a subcritical assembly, the zero time value is assigned at the moment the neutron is emitted by the external neutron source. The PTRAC and F8 cards of MCNP allow to tally the time when a neutron is captured by {sup 3}He(n, p) reactions in the neutron detector. From this information, it is possible to build three different time distributions: neutron counts, Rossi-{alpha}, and Feynman-{alpha}. The neutron counts time distribution represents the number of neutrons captured as a function of time. The Rossi-a distribution represents the number of neutron pairs captured as a function of the time interval between two capture events. The Feynman-a distribution represents the variance-to-mean ratio, minus one, of the neutron counts array as a function of a fixed time interval. The MCNP6 results for these three time distributions have been compared with the experimental data of the YALINA Thermal facility and have been found to be in quite good agreement. (authors)

  4. Evaluation of Bacteriological Quality of Ready-to-eat Chicken Products by Total Viable Count Method

    OpenAIRE

    Ramiz Raja; Asif Iqbal; Yasir Hafiz; Mehboob Willayet; Shakoor Bhat; Mudasir Rather

    2012-01-01

    The present investigation describes the total viable count of ready-to-eat chicken products (chicken patties and chicken rolls) in Srinagar city during two seasons viz. autumn and winter. A total of 120 ready-to-eat chicken products comprising of 60 chicken patties and 60 chicken rolls were tested. The mean bacterial count of 60 chicken patties and 60 chicken rolls was 5.1281 and 4.9395 log10 cfu/g. Bacillus cereus strains were isolated from 25 of chicken patties and 22 of the chicken rolls r...

  5. Determination of the total neutron cross section using average energy shift method for filtered neutron beam

    Directory of Open Access Journals (Sweden)

    О. О. Gritzay

    2016-12-01

    Full Text Available Development of the technique for determination of the total neutron cross sections from the measurements of sample transmission by filtered neutrons, scattered on hydrogen is described. One of the methods of the transmission determination TH52Cr from the measurements of 52Cr sample, using average energy shift method for filtered neutron beam is presented. Using two methods of the experimental data processing, one of which is presented in this paper (another in [1], there is presented a set of transmissions, obtained for different samples and for different measurement angles. Two methods are fundamentally different; therefore, we can consider the obtained processing results, using these methods as independent. In future, obtained set of transmissions is planned to be used for determination of the parameters E0, Гn and R/ of the resonance 52Cr at the energy of 50 keV.

  6. Studies on the characteristics of nuclear track spark counting for neutron monitoring

    International Nuclear Information System (INIS)

    Kawai, H.; Koga, T.; Morishima, H.; Niwa, T.; Nishiwaki, Y.

    1979-01-01

    The fission-track counting method using polycarbonate foil is known to be very effective for neutron monitoring. The detection system consists of a track detector foil placed in contact with a thin layer of fissile material. When the unit is irradiated with neutrons, fission fragments from the fissile material produce tracks in the foil. The foil is then etched chemically to enlarge the tracks to etch-pits, which are counted by an automatic spark counting method suggested by Cross and Tommasino. Spark counting characteristics of the above system using polycarbonate detector foils of different thicknesses and aluminized polyester sheets having different thicknesses of the aluminium which serves as an electrode, and etch-pit sizes in relation to spark counting have been studied. The results obtained are summarized as follows: 1. A growth in etch-pit sizes was observed for etching times of 10 to 50 minutes with Makrofol KG (10 μm thick) and Panlite foils (18 μm thick). As the etching time increased, the number of etch-pits which appeared as round pits increased and the number which appeared rod-like decreased; 2. Round etch-pits seemed to be easily spark-punched; 3. Major and minor diameters of etch-pits produced by fission fragments from the uranium fissile target were larger than those from the thorium target; 4. As the thickness of the Makrofol KG foil increased, the minor diameters of the etch-pits appeared to become smaller and major diameters larger; 5. The foils that appeared to be best suited for routine use were 10 μm thick Makrofol KG or 6 μm thick Lumirror foils. (author)

  7. Validation parameters of instrumental method for determination of total bacterial count in milk

    Directory of Open Access Journals (Sweden)

    Nataša Mikulec

    2004-10-01

    Full Text Available The method of flow citometry as rapid, instrumental and routine microbiological method is used for determination of total bacterial count in milk. The results of flow citometry are expressed as individual bacterial cells count. Problems regarding the interpretation of the results of total bacterial count can be avoided by transformation of the results of flow citometry method onto the scale of reference method (HRN ISO 6610:2001.. The method of flow citometry, like any analitycal method, according to the HRN EN ISO/IEC 17025:2000 standard, requires validation and verification. This paper describes parameters of validation: accuracy, precision, specificity, range, robustness and measuring uncertainty for the method of flow citometry.

  8. Sample design and gamma-ray counting strategy of neutron activation system for triton burnup measurements in KSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Jungmin [Department of Energy System Engineering, Seoul National University, Seoul (Korea, Republic of); Cheon, Mun Seong [ITER Korea, National Fusion Research Institute, Daejeon (Korea, Republic of); Chung, Kyoung-Jae, E-mail: jkjlsh1@snu.ac.kr [Department of Energy System Engineering, Seoul National University, Seoul (Korea, Republic of); Hwang, Y.S. [Department of Energy System Engineering, Seoul National University, Seoul (Korea, Republic of)

    2016-11-01

    Highlights: • Sample design for triton burnup ratio measurement is carried out. • Samples for 14.1 MeV neutron measurements are selected for KSTAR. • Si and Cu are the most suitable materials for d-t neutron measurements. • Appropriate γ-ray counting strategies for each selected sample are established. - Abstract: On the purpose of triton burnup measurements in Korea Superconducting Tokamak Advanced Research (KSTAR) deuterium plasmas, appropriate neutron activation system (NAS) samples for 14.1 MeV d-t neutron measurements have been designed and gamma-ray counting strategy is established. Neutronics calculations are performed with the MCNP5 neutron transport code for the KSTAR neutral beam heated deuterium plasma discharges. Based on those calculations and the assumed d-t neutron yield, the activities induced by d-t neutrons are estimated with the inventory code FISPACT-2007 for candidate sample materials: Si, Cu, Al, Fe, Nb, Co, Ti, and Ni. It is found that Si, Cu, Al, and Fe are suitable for the KSATR NAS in terms of the minimum detectable activity (MDA) calculated based on the standard deviation of blank measurements. Considering background gamma-rays radiated from surrounding structures activated by thermalized fusion neutrons, appropriate gamma-ray counting strategy for each selected sample is established.

  9. Bioassay method for Uranium in urine by Delay Neutron counting; Metoda Bioassay Uranium dalam urin dengan pencacahan Netron Kasip

    Energy Technology Data Exchange (ETDEWEB)

    Suratman,; Purwanto,; Sukarman-Aminjoyo, [Yogyakarta Nuclear Research Centre, National Atomic Energy Agency, Yogyakarta (Indonesia)

    1996-04-15

    A bioassay method for uranium in urine by neutron counting has been studied. The aim of this research is to obtain a bioassay method for uranium in urine which is used for the determination of internal dose of radiation workers. The bioassay was applied to the artificially uranium contaminated urine. The weight of the contaminant was varied. The uranium in the urine was irradiated in the Kartini reactor core, through pneumatic system. The delayed neutron was counted by BF3 neutron counter. Recovery of the bioassay was between 69.8-88.8 %, standard deviation was less than 10 % and the minimum detection was 0.387 {mu}g.

  10. Automated facility for analysis of soil samples by neutron activation, counting, and data control

    International Nuclear Information System (INIS)

    Voegele, A.L.; Jesse, R.H.; Russell, W.L.; Baker, J.

    1978-01-01

    An automated facility remotely and automatically analyzes soil, water, and sediment samples for uranium. The samples travel through pneumatic tubes and switches to be first irradiated by neutrons and then counted for resulting neutron and gamma emission. Samples are loaded into special carriers, or rabbits, which are then automatically loaded into the pneumatic transfer system. The sample carriers have been previously coded with an identification number, which can be automatically read in the system. This number is used for correlating and filing data about the samples. The transfer system, counters, and identification system are controlled by a network of microprocessors. A master microprocessor initiates routines in other microprocessors assigned to specific tasks. The software in the microprocessors is unique for this type of application and lends flexibility to the system

  11. Influence of materials and counting-rate effects on 3He neutron spectrometry

    International Nuclear Information System (INIS)

    Evans, A.E.

    1984-01-01

    The high energy resolution of the Cuttler-Shalev 3 He neutron spectrometer causes spectral measurements with this instrument to be strongly susceptible to artifacts caused by the presence of scattering or absorbing materials in or near the detector or the source, and to false peaks generated by pileup coincidences of the rather long-risetime pulses from the detector. These effects are particularly important when pulse-height distributions vary over several orders of magnitude in count rate versus channel. A commercial pile-up elimination circuit greatly improves but does not eliminate the pileup problem. Previously reported spurious peaks in the pulse-height distributions from monoenergetic neutron sources have been determined to be due to the influence of the iron in the detector wall. 6 references, 9 figures

  12. Two reports: (i) Correlation properties of delayed neutrons from fast neutron induced fission. (ii) Method and set-up for measurements of trace level content of heavy fissionable elements based on delayed neutron counting

    International Nuclear Information System (INIS)

    Piksaikin, V.M.; Isaev, S.G.; Goverdovski, A.A.; Pshakin, G.M.

    1998-10-01

    The document includes the following two reports: 'Correlation properties of delayed neutrons from fast neutron induced fission' and 'Method and set-up for measurements of trace level content of heavy fissionable elements based on delayed neutron counting. A separate abstract was prepared for each report

  13. Hematologic status of mice submitted to sublethal total body irradiation with mixed neutron-gamma radiation

    International Nuclear Information System (INIS)

    Herodin, F.; Court, L.

    1989-01-01

    The hematologic status of mice exposed to sublethal whole body irradiation with mixed neutron-gamma radiation (mainly neutrons) is studied. A slight decrease of the blood cell count is still observed below 1 Gy. The recovery of bone marrow granulocyte-macrophage progenitors seems to require more time than after pure gamma irradiation [fr

  14. Neutron total cross section measurements of gold and tantalum at the nELBE photoneutron source

    CERN Document Server

    Hannaske, Roland; Beyer, Roland; Junghans, Arnd; Bemmerer, Daniel; Birgersson, Evert; Ferrari, Anna; Grosse, Eckart; Kempe, Mathias; Kögler, Toni; Marta, Michele; Massarczyk, Ralph; Matic, Andrija; Schramm, Georg; Schwengner, Ronald; Wagner, Andreas

    2014-01-01

    Neutron total cross sections of 197 Au and nat Ta have been measured at the nELBE photoneutron source in the energy range from 0.1 - 10 MeV with a statistical uncertainty of up to 2 % and a total systematic uncertainty of 1 %. This facility is optimized for the fast neutron energy range and combines an excellent t ime structure of the neutron pulses (electron bunch width 5 ps) with a short flight path of 7 m. Because of the low instantaneous neutron flux transmission measurements of neutron total cross sections are possible, that exhibit very different beam and back ground conditions than found at other neutron sources.

  15. A ppendicitis with Positive Ultrasound and its Relation to Total and Differential Leucocytic Count

    International Nuclear Information System (INIS)

    Saleh, G.M.; Sabek, E.A.S.; Elessiely, E.S.; Ibrahim, E.M.

    2016-01-01

    Background:The most common cause of acute surgical abdomen is acute appendicitis and the most commonly done emergency surgery is appendectomy. Although a battery of tests and different scoring methods are available for diagnosis of acute appendicitis, it is very difficult to prevent negative explorations for appendicectomy (15 - 30%). None of the tests has satisfactory Sensitivity and specificity that can be relied upon. Objectives: The aim of the present study was to evaluate the role of total and differential leukocyte count, and ultrasonography (USG) of abdomen in diagnosing acute appendicitis and reducing the rates of negative appendicectomies and to prevent complications like perforation, peritonitis, and the longer the delay between diagnosis and surgery, the more likely is the perforation leading to peritonitis. In addition, emphasis was given to whether combining the investigations for the same patient would improve the diagnostic accuracy. Materials and Methods : A total of 76 clinically diagnosed patients of acute appendicitis, posted for emergency appendicectomy were included in the study in General Surgery Department of EL-Salam Hospital. This study was conducted in the period October 2012 to September 2013. Preoperatively blood tests for, total leukocyte count, differential leukocyte count(DLC) and USG abdomen were done. All patients were subjected to histological examination postoperatively, which was taken as the gold standard. The three investigations results were correlated with histopathological examination reports to evaluate their role in diagnosis of acute appendicitis. Results: In the present study, the US has the highest sensitivity and specificity (90%, 80%) followed by Total leucocyte count (87.5%, 90%), white Neutrophil count (78.75%, 80%). Combining US and WBC count increases the sensitivity and specificity of the tests (96.25%, 80%). Conclusion: US contains important diagnostic information and hence should always be included in the

  16. Passive non destructive assay of hull waste by gross neutron counting method

    International Nuclear Information System (INIS)

    Andola, Sanjay; Sur, Amit; Rawool, A.M.; Sharma, B.; Kaushik, T.C.; Gupta, S.C.; Basu, Sekhar; Raman Kumar; Agarwal, K.

    2014-01-01

    The special nuclear material accounting (SNMA) is an important and necessary issue now in nuclear waste management. The hull waste generated from dissolution of spent fuel contains small amounts of Uranium and Plutonium and other actinides due to undissolved trapped material inside zircoalloy tubes. We report here on the development of a Passive Hull monitoring system using gross neutron counting technique and its implementation with semiautomatic instrumentation. The overall sensitivity of the 3 He detector banks placed at 75 cm from the centre of loaded hull cask comes out to 5.2 x 10 -3 counts per neutron (c/n) while with standard Pu-Be source placed in same position it comes out to be 3.1 x 10 3 c/n. The difference in the efficiency is mainly because of the differences in the geometry and size of hull cask as well as difference in the energy spectrum of hull waste and Pu-Be source. This is accounted through Monte Carlo computations. The Pu mass in solid waste comes out as expected and varies with the surface dose rate of drum in almost a proportional manner. Being simple and less time consuming, this setup has been installed for routine assay of solid Hull waste at NRB, Tarapur

  17. Total body neutron activation analysis of calcium: calibration and normalisation

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, N S.J.; Eastell, R; Ferrington, C M; Simpson, J D; Strong, J A [Western General Hospital, Edinburgh (UK); Smith, M A; Tothill, P [Royal Infirmary, Edinburgh (UK)

    1982-05-01

    An irradiation system has been designed, using a neutron beam from a cyclotron, which optimises the uniformity of activation of calcium. Induced activity is measured in a scanning, shadow-shield whole-body counter. Calibration has been effected and reproducibility assessed with three different types of phantom. Corrections were derived for variations in body height, depth and fat thickness. The coefficient of variation for repeated measurements of an anthropomorphic phantom was 1.8% for an absorbed dose equivalent of 13 mSv (1.3 rem). Measurements of total body calcium in 40 normal adults were used to derive normalisation factors which predict the normal calcium in a subject of given size and age. The coefficient of variation of normalised calcium was 6.2% in men and 6.6% in women, with the demonstration of an annual loss of 1.5% after the menopause. The narrow range should make single measurements useful for diagnostic purposes.

  18. Effect of warm-smoking on total microbial count of meat products

    Directory of Open Access Journals (Sweden)

    A Javadi

    2007-11-01

    Full Text Available The frankfurters are amongst the most famous and popular sausages in the world and beef and poultry meat are used in Iran for their preparation. The techniques of warm smoking at 42°c for two hours and then hot smoking together with steam cooking at 8°c for one hour are utilized in proportion of this product. In spite of its carcinogenic properties, smoke is used to create color, flavor and odor and to improve the preservative qualities of sausages. In this study, 14 sausage samples were taken from each of the stages of frankfurter production line including pre-smoking, post- warm smoking and post-hot smoking, their total microbial counts (aerobic mesophiles determined and the means of the three stages compared using the ANOVA statistical test. The results indicated that the total microbial count increased significantly (P

  19. 235U Determination using In-Beam Delayed Neutron Counting Technique at the NRU Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, M. T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bentoumi, G. [Canadian Nuclear Labs., Chalk River, ON (Canada); Corcoran, E. C. [Royal Military College of Canada, Kingston, ON (United States); Dimayuga, I. [Canadian Nuclear Labs., Chalk River, ON (Canada); Kelly, D. G. [Royal Military College of Canada, Kingston, ON (United States); Li, L. [Canadian Nuclear Labs., Chalk River, ON (Canada); Sur, B. [Canadian Nuclear Labs., Chalk River, ON (Canada); Rogge, R. B. [Canadian Nuclear Labs., Chalk River, ON (Canada)

    2015-11-17

    This paper describes a collaborative effort that saw the Royal Military College of Canada (RMC)’s delayed neutron and gamma counting apparatus transported to Canadian Nuclear Laboratories (CNL) for use in the neutron beamline at the National Research Universal (NRU) reactor. Samples containing mg quantities of fissile material were re-interrogated, and their delayed neutron emissions measured. This collaboration offers significant advantages to previous delayed neutron research at both CNL and RMC. This paper details the determination of 235U content in enriched uranium via the assay of in-beam delayed neutron magnitudes and temporal behavior. 235U mass was determined with an average absolute error of ± 2.7 %. This error is lower than that obtained at RMCC for the assay of 235U content in aqueous solutions (3.6 %) using delayed neutron counting. Delayed neutron counting has been demonstrated to be a rapid, accurate, and precise method for special nuclear material detection and identification.

  20. Correction for variable moderation and multiplication effects associated with thermal neutron coincidence counting

    International Nuclear Information System (INIS)

    Baron, N.

    1978-01-01

    A correction is described for multiplication and moderation when doing passive thermal neutron coincidence counting nondestructive assay measurements on powder samples of PuO 2 mixed arbitrarily with MgO, SiO 2 , and moderating material. The multiplication correction expression is shown to be approximately separable into the product of two independent terms; F/sub Pu/ which depends on the mass of 240 Pu, and F/sub αn/ which depends on properties of the matrix material. Necessary assumptions for separability are (1) isotopic abundances are constant, and (2) fission cross sections are independent of incident neutron energy: both of which are reasonable for the 8% 240 Pu powder samples considered here. Furthermore since all prompt fission neutrons are expected to have nearly the same energy distributions, variations among different samples can be due only to the moderating properties of the samples. Relative energy distributions are provided by a thermal neutron well counter having two concentric rings of 3 He proportional counters placed symmetrically about the well. Measured outer-to-inner ring ratios raised to an empirically determined power for coincidences, (N/sup I//N/sup O/)/sup Z/, and singles, (T/sup O//T/sup I/)/sup delta/, provide corrections for moderation and F/sub αn/ respectively, and F/sub Pu/ is approximated by M 240 /sup X//M 240 . The exponents are calibration constants determined by a least squares fitting procedure using standards' data. System calibration is greatly simplified using the separability principle. Once appropriate models are established for F/sub Pu/ and F/sub αn/, only a few standards are necessary to determine the calibration constants associated with these terms. Since F/sub Pu/ is expressed as a function of M 240 , correction for multiplication in a subsequent assay demands only a measurement of F/sub αn/

  1. Monte Carlo simulation of gamma-ray total counting efficiency for a Phoswich detector

    Energy Technology Data Exchange (ETDEWEB)

    Yalcin, S. [Education Faculty, Kastamonu University, 37200 Kastamonu (Turkey)], E-mail: syalcin@kastamonu.edu.tr; Gurler, O. [Department of Physics, Faculty of Arts and Sciences, Uludag University, Gorukle Campus, 16059 Bursa (Turkey); Gundogdu, O. [Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, GU2 7XH (United Kingdom); NCCPM, Medical Physics, Royal Surrey County Hospital, Guildford, GU2 7XX (United Kingdom); Kaynak, G. [Department of Physics, Faculty of Arts and Sciences, Uludag University, Gorukle Campus, 16059 Bursa (Turkey)

    2009-01-15

    The LB 1000-PW detector is mainly used for determining total alpha, beta and gamma activity of low activity natural sources such as water, soil, air filters and any other environmental sources. Detector efficiency needs to be known in order to measure the absolute activity of such samples. This paper presents results on the total gamma counting efficiency of a Phoswich detector from point and disk sources. The directions of photons emitted from the source were determined by Monte Carlo techniques and the true path lengths in the detector were determined by analytical equations depending on photon directions. Results are tabulated for various gamma energies.

  2. Monte Carlo simulation of gamma-ray total counting efficiency for a Phoswich detector

    International Nuclear Information System (INIS)

    Yalcin, S.; Gurler, O.; Gundogdu, O.; Kaynak, G.

    2009-01-01

    The LB 1000-PW detector is mainly used for determining total alpha, beta and gamma activity of low activity natural sources such as water, soil, air filters and any other environmental sources. Detector efficiency needs to be known in order to measure the absolute activity of such samples. This paper presents results on the total gamma counting efficiency of a Phoswich detector from point and disk sources. The directions of photons emitted from the source were determined by Monte Carlo techniques and the true path lengths in the detector were determined by analytical equations depending on photon directions. Results are tabulated for various gamma energies

  3. Investigation of the behaviour of both dead time and observed counting rates of He-3 gas filled neutron detector

    Energy Technology Data Exchange (ETDEWEB)

    Adib, M.; Eid, Y.; Abdel Kawy, A.; Maayouf, R.M.A.; Shuriet, G.M.; Hamouda, I.

    1981-01-01

    The behaviour of the dead time of He-3 detector, operating at both the proportional and the corona discharge regions, is investigated as a function of the neutron reaction rate inside the detector. The applied experimental method makes use of the fluctuations, due to the detector dead time in the observed counting rates from Poisson's distribution. In order to check the validity of the experimental method used in the present work, the dead time of BF/sub 3/ neutron detectors with different efficiencies (due to different enrichement in B-10) were determined. It is shown that the observed counting rate from the He-3 detector operating at the proportional region for neutron reaction rates ranging from 8 x 10/sup 3/ to 2.5 x 10/sup 4/ reaction/sec decreases with the increase of the neutron reaction rate. Such behaviour was not observed when operating the He-3 detector at the corona discharge region.

  4. Investigation of the behaviour of both dead time and observed counting rates of He-3 gas filled neutron detector

    International Nuclear Information System (INIS)

    Adib, M.; Eid, Y.; Abdel Kawy, A.; Maayouf, R.M.A.; Shuriet, G.M.; Hamouda, I.

    1981-01-01

    The behaviour of the dead time of He-3 detector, operating at both the proportional and the corona discharge regions, is investigated as a function of the neutron reaction rate inside the detector. The applied experimental method makes use of the fluctuations, due to the detector dead time in the observed counting rates from Poisson's distribution. In order to check the validity of the experimental method used in the present work, the dead time of BF 3 neutron detectors with different efficiencies (due to different enrichement in B-10) were determined. It is shown that the observed counting rate from the He-3 detector operating at the proportional region for neutron reaction rates ranging from 8 x 10 3 to 2.5 x 10 4 reaction/sec decreases with the increase of the neutron reaction rate. Such behaviour was not observed when operating the He-3 detector at the corona discharge region. (orig.) [de

  5. An examination of the time-dependent background counts of the delayed neutron counting system at the Royal Military College of Canada

    International Nuclear Information System (INIS)

    Sellers, M.T.; Corcoran, E.C.; Kelly, D.G.

    2011-01-01

    A delayed neutron counting (DNC) system for the analysis of special nuclear materials (SNM) has been constructed and calibrated at the Royal Military College of Canada. The polyethylene vials used to transport SNM samples have been found to contribute a time-dependent count rate, B(t), far above the system background. B(t) has been found to be independent of polyethylene mass and shows a dependence on irradiation position in the SLOWPOKE-2 reactor and irradiation time. A comparison of B(t) and the theoretical delayed neutron production from the fission of small amounts of 235 U has indicated that trace amounts of uranium may be present in the DNC system tubing. (author)

  6. Neutron coincidence counting based on time interval analysis with dead time corrected one and two dimensional Rossi-alpha distributions: an application for passive neutron waste assay

    International Nuclear Information System (INIS)

    Bruggeman, M.; Baeten, P.; De Boeck, W.; Carchon, R.

    1996-03-01

    The report describes a new neutron multiplicity counting method based on Rossi-alpha distributions. The report also gives the necessary dead time correction formulas for the multiplicity counting method. The method was tested numerically using a Monte Carlo simulation of pulse trains. The use of this multiplicity method in the field of waste assay is explained: it can be used to determine the amount of fissile material in a waste drum without prior knowledge of the actual detection efficiency

  7. Neutron generation time of the reactor 'crocus' by an interval distribution method for counts collected by two detectors

    International Nuclear Information System (INIS)

    Haldy, P.-A.; Chikouche, M.

    1975-01-01

    The distribution is considered of time intervals between a count in one neutron detector and the consequent event registered in a second one. A 'four interval' probability generating function was derived by means of which the expression for the distribution of the time intervals, lasting from triggering detection in the first detector to subsequent count in the second, one could be obtained. The experimental work was conducted in the zero thermal power reactor Crocus, using a neutron source provided by spontaneous fission, a BF 3 counter for the first detector and an He 3 detector for the second instrument. (U.K.)

  8. Determination of total bacterial count in raw milk by flow cytometry

    Directory of Open Access Journals (Sweden)

    Dubravka Samaržija

    2004-01-01

    Full Text Available The automatic flow cytometry as routine method for total bacterial count determination of raw ex-farm milk has recently been accepted in Croatia. This method significantly differs from the reference method (Standard Plate Count mostly in the presentation of the results obtained. Therefore, this paper summarized experiences in the application of flow cytometry in the dairy laboratories practice. The principle and the practice of the method, methodological details and factors influencing the results were described. In order to avoid problems regarding the interpretation of the results, which aregeneral problems of the quantitative microbiology, this article try to explain an appropriate conversion of the results with regards to SPC/ml, as an official method for the bacteriological quality proposal by the national legislation.

  9. Design criteria for pulse transformers used in neutron detector pulse counting channels

    International Nuclear Information System (INIS)

    Powler, E.P.

    1963-10-01

    The need for long cables between the detector and head amplifier in neutron pulse counting channels has led to the development of systems in which a transformer is used to 'match' the high impedance of a fission or proportional counter to the characteristic impedance of the cable. A further transformer can be used to match the cable to the input of a low noise pulse amplifier if this has a high impedance. This report is intended to give the designer sufficient information to optimise a system and predict the performance in terms of signal to noise ratio, resolving time and gain. Related problems are covered and include the use of balanced twin cables, the requirements of temperatures up to 500 deg. C and the need for high interference rejection. Two systems are described in some detail to emphasise the principles of design. (author)

  10. Relationship of Total Motile Sperm Count and Percentage Motile Sperm to Successful Pregnancy Rates Following Intrauterine Insemination

    OpenAIRE

    Pasqualotto, Eleonora B.; Daitch, James A.; Hendin, Benjamin N.; Falcone, Tommaso; Thomas, Anthony J.; Nelson, David R.; Agarwal, Ashok

    1999-01-01

    Purpose:This study sought (i) to investigate the relationship between postwash total motile sperm count and postwash percentage motile sperm in predicting successful intrauterine insemination and (ii) to determine the minimal postwash total motile sperm count required to achieve pregnancy with intrauterine insemination.

  11. Improving neutron multiplicity counting for the spatial dependence of multiplication: Results for spherical plutonium samples

    Energy Technology Data Exchange (ETDEWEB)

    Göttsche, Malte, E-mail: malte.goettsche@physik.uni-hamburg.de; Kirchner, Gerald

    2015-10-21

    The fissile mass deduced from a neutron multiplicity counting measurement of high mass dense items is underestimated if the spatial dependence of the multiplication is not taken into account. It is shown that an appropriate physics-based correction successfully removes the bias. It depends on four correction coefficients which can only be exactly determined if the sample geometry and composition are known. In some cases, for example in warhead authentication, available information on the sample will be very limited. MCNPX-PoliMi simulations have been performed to obtain the correction coefficients for a range of spherical plutonium metal geometries, with and without polyethylene reflection placed around the spheres. For hollow spheres, the analysis shows that the correction coefficients can be approximated with high accuracy as a function of the sphere's thickness depending only slightly on the radius. If the thickness remains unknown, less accurate estimates of the correction coefficients can be obtained from the neutron multiplication. The influence of isotopic composition is limited. The correction coefficients become somewhat smaller when reflection is present.

  12. Can Serum Albumin Level and Total Lymphocyte Count be Surrogates for Malnutrition to Predict Wound Complications After Total Knee Arthroplasty?

    Science.gov (United States)

    Morey, Vivek M; Song, Young Dong; Whang, Ji Sup; Kang, Yeon Gwi; Kim, Tae Kyun

    2016-06-01

    Although the serum albumin level and total lymphocyte count (TLC) have been reported as valid and reliable markers for defining malnutrition, their cutoff levels and predictive values for wound complications in patients undergoing total knee arthroplasty (TKA) remain questionable. A total of 3169 TKAs performed between April 2003 and December 2013 were retrospectively reviewed. We determined the prevalence of malnutrition on applying different definitions, with various cutoff values of serum albumin and TLC and analyzed the variations in outcome. The differences between groups with and without malnutrition in terms of functional outcome and complications were determined using Student's t test and analysis of variance. Multivariate logistic regression analysis was conducted to identify the independent risk factors. Among all the patients (N = 3169), the serum albumin level and TLC varied widely, with means of 4.1 g/dL and 2189 cells/mm(3), respectively. The prevalence of malnutrition (21%) as per the conventional definition (serum albumin level malnutrition was defined as serum albumin malnutrition for predicting wound complications after TKA. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. A high-sensitivity neutron counter and waste-drum counting with the high-sensitivity neutron instrument

    International Nuclear Information System (INIS)

    Hankins, D.E.; Thorngate, J.H.

    1993-04-01

    At Lawrence Livermore National Laboratory (LLNL), a highly sensitive neutron counter was developed that can detect and accurately measure the neutrons from small quantities of plutonium or from other low-level neutron sources. This neutron counter was originally designed to survey waste containers leaving the Plutonium Facility. However, it has proven to be useful in other research applications requiring a high-sensitivity neutron instrument

  14. Monte Carlo efficiency calibration of a neutron generator-based total-body irradiator

    International Nuclear Information System (INIS)

    Shypailo, R.J.; Ellis, K.J.

    2009-01-01

    Many body composition measurement systems are calibrated against a single-sized reference phantom. Prompt-gamma neutron activation (PGNA) provides the only direct measure of total body nitrogen (TBN), an index of the body's lean tissue mass. In PGNA systems, body size influences neutron flux attenuation, induced gamma signal distribution, and counting efficiency. Thus, calibration based on a single-sized phantom could result in inaccurate TBN values. We used Monte Carlo simulations (MCNP-5; Los Alamos National Laboratory) in order to map a system's response to the range of body weights (65-160 kg) and body fat distributions (25-60%) in obese humans. Calibration curves were constructed to derive body-size correction factors relative to a standard reference phantom, providing customized adjustments to account for differences in body habitus of obese adults. The use of MCNP-generated calibration curves should allow for a better estimate of the true changes in lean tissue mass that many occur during intervention programs focused only on weight loss. (author)

  15. Generation of neutron standing waves at total reflection of polarized neutrons

    International Nuclear Information System (INIS)

    Aksenov, V.L.; Nikitenko, Yu.V.; Kozhevnikov, S.V.; Radu, F.; Kruijs, R.; Rekveldt, M.Th.

    1999-01-01

    The regime of neutron standing waves at reflection of polarized thermal neutrons from the structure glass/Cu (1000 A Angstrom)/Ti (2000 A Angstrom)/Co (60 A Angstrom)/Ti (300 A Angstrom) in a magnetic field directed at an angle to the sample plane is realized. The intensity of neutrons with a particular spin projection on the external magnetic field direction appears to be a periodic function of the neutron wavelength and the glancing angle of the reflected beam. It is shown that the neutron standing wave regime can be a very sensitive method for the determination of changes in the spatial position of magnetic noncollinear layers. (author)

  16. Neutron multimonochromator-bipolarizer based on magnetic multilayer Fe/Co and new scheme for the total neutron polarization analysis

    International Nuclear Information System (INIS)

    Syromyatnikov, V.G.; Zaw Lin, Kyaw

    2017-01-01

    In this paper, we present a new neutron-optical element, Neutron Multimonochromator-Bipolarizer (NMB). It consists of a multimultilayer structure made of 12 periodic multilayer Fe/Co magnetic nanostructures whose period increases with distance from the substrate. Results are presented of calculations of the reflection coefficients from the NMB. We propose a new scheme of the total neutron polarization analysis for the time-of-flight method in the reflectometry. In this scheme, double NMB is used as a polarizer and there is no spin-flipper before the sample. NMB can be used in polarized neutron reflectometry, in SESANS, and for research of low-angle and inelastic scattering of polarized neutrons. (paper)

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

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

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

  18. Measurement of the neutron total cross section of sodium

    International Nuclear Information System (INIS)

    Larson, D.C.; Harvey, J.A.; Hill, M.W.

    1976-01-01

    The transmission of neutrons through a sample of pure sodium was measured in the energy range 40 keV to 20 MeV. The measurement points out several areas for improvement in the sodium evaluation for ENDF/B-V, the most important being the broadening of the minimum at 300 keV

  19. Anomalies from aerial spectrometric and total count radiometric surveys in the southeastern United States

    International Nuclear Information System (INIS)

    Lee, C.H.; Lawton, D.E.

    1978-01-01

    Aerial radiometric reconnaissance surveys are conducted because of their cost, time, and manpower savings compared to surface studies. Two types of aerial surveys are being flown in the southeastern United States: total count gamma-ray surveys for the Coastal Plains Regional Commission and the US Geological Survey, and differential gamma-ray spectrometric surveys for the US Department of Energy. Anomalous radioactivity detected during aerial surveys is related to higher concentrations of naturally occurring uranium, or to cultural activities, natural causes, or mapping errors which simulate real uranium anomalies. Each anomaly should be ground checked; however, several types of anomalies may be eliminated by evaluation of the aerial data in the office if field time is limited

  20. Experimental device for obtaining calibration factor for the total count technique

    International Nuclear Information System (INIS)

    Gonçalves, Eduardo R.; Braz, Delson; Brandão, Luís Eduardo B.

    2017-01-01

    Nuclear technologies have widely used on industry plants in order to help to solve troubles processes/design or just obtain information of them. The Total Count technique for flow measurement has as main advantages: being an absolute technique, because it is independent of additional devices readings unless the directly used for recording the radioactive cloud, requiring only a single detector to provide the final result; the independence of the internal volume of the transport duct, can be applied in the presence or absence of obstructions; no restriction as to the nature of the product or material to be conveyed; it is a noninvasive technique which allows real-time diagnostics. To use Total Count Technique, knowledge of a geometric calibration factor is required. Called Factor F, it is obtained in the laboratory using an experimental apparatus to faithfully reproduce the geometry of the detection system and the pipeline that being analyzed and using the same radiotracer, therefore, its value is constant for each specific measuring system under survey. This experimental apparatus for obtaining the factor F consisting by a pipe of 2 ″PVC, which simulates a transmission line, where they were deposited 500 ml oil and the use of a specific pipette for use viscous fluids were added sequentially aliquots (50.00 ± 0.01) μl radiotracer (radionuclide photopeak energy of 198 Au 411.8 keV) and analyzing data obtained by three distinct detection systems composed of detectors NaI scintillators 1″ x 1 ″ and a data acquisition system. (author)

  1. Experimental device for obtaining calibration factor for the total count technique

    Energy Technology Data Exchange (ETDEWEB)

    Gonçalves, Eduardo R.; Braz, Delson [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Brandão, Luís Eduardo B. [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Divisao de Reatores

    2017-07-01

    Nuclear technologies have widely used on industry plants in order to help to solve troubles processes/design or just obtain information of them. The Total Count technique for flow measurement has as main advantages: being an absolute technique, because it is independent of additional devices readings unless the directly used for recording the radioactive cloud, requiring only a single detector to provide the final result; the independence of the internal volume of the transport duct, can be applied in the presence or absence of obstructions; no restriction as to the nature of the product or material to be conveyed; it is a noninvasive technique which allows real-time diagnostics. To use Total Count Technique, knowledge of a geometric calibration factor is required. Called Factor F, it is obtained in the laboratory using an experimental apparatus to faithfully reproduce the geometry of the detection system and the pipeline that being analyzed and using the same radiotracer, therefore, its value is constant for each specific measuring system under survey. This experimental apparatus for obtaining the factor F consisting by a pipe of 2 ″PVC, which simulates a transmission line, where they were deposited 500 ml oil and the use of a specific pipette for use viscous fluids were added sequentially aliquots (50.00 ± 0.01) μl radiotracer (radionuclide photopeak energy of 198 Au 411.8 keV) and analyzing data obtained by three distinct detection systems composed of detectors NaI scintillators 1″ x 1 ″ and a data acquisition system. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Lahmann, B., E-mail: lahmann@mit.edu; Milanese, L. M.; Han, W.; Gatu Johnson, M.; Séguin, F. H.; Frenje, J. A.; Petrasso, R. D. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Hahn, K. D.; Jones, B. [Sandia National Laboratory, Albuquerque, New Mexico 87123 (United States)

    2016-11-15

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-11-01

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

  5. Standard test method for nondestructive assay of nuclear material in scrap and waste by passive-Active neutron counting using 252Cf shuffler

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method covers the nondestructive assay of scrap and waste items for U, Pu, or both, using a 252Cf shuffler. Shuffler measurements have been applied to a variety of matrix materials in containers of up to several 100 L. Corrections are made for the effects of matrix material. Applications of this test method include measurements for safeguards, accountability, TRU, and U waste segregation, disposal, and process control purposes (1, 2, 3). 1.1.1 This test method uses passive neutron coincidence counting (4) to measure the 240Pu-effective mass. It has been used to assay items with total Pu contents between 0.03 g and 1000 g. It could be used to measure other spontaneously fissioning isotopes such as Cm and Cf. It specifically describes the approach used with shift register electronics; however, it can be adapted to other electronics. 1.1.2 This test method uses neutron irradiation with a moveable Cf source and counting of the delayed neutrons from the induced fissions to measure the 235U equiva...

  6. Measurement of whole body cellular and collagen nitrogen, potassium, and other elements by neutron activation and whole body counting

    International Nuclear Information System (INIS)

    James, H.M.; Fabricius, P.J.; Dykes, P.W.

    1987-01-01

    Whole body nitrogen can be measured by neutron activation analysis with an acceptable radiation dose; it is an index of body protein which, in normal subjects, is 65% cellular protein and 35% extracellular connective collagen. Whole body potassium can be measured by whole body counting without irradiating the subject; it is an index of body cell mass. We measured whole body nitrogen, potassium, extracellular water, intracellular water, and fat-folds. The differences between 37 malnourished patients and five normal subjects suggested that the patients had 9 kg less cell mass than normal, but no difference in extracellular mass. Measurements were made on eight patients before and after 14 days of total parenteral nutrition; balance of nitrogen intake and excretion also was measured. The changes were consistent with mean increases of 3 kg of cellular mass and 3 kg of fat with no change of extracellular mass. The accuracy and sensitivity of the whole body measurements need further confirmation for use in patients with changing body composition. Where tissue wasting is largely from the cellular compartment, potassium could be a more sensitive index of wasting than nitrogen. Multielement analysis of nitrogen, potassium, chlorine, and carbon will probably be valuable in elucidating body composition in malnutrition

  7. Determination of Li, B, and F by rapid instrumental neutron activation analysis using beta-particle counting

    International Nuclear Information System (INIS)

    Schmidt, J.O.; Palgaard, L.; Gwozdz, R.; Belhage, L.O.

    1984-01-01

    For the simultaneous determination of Li, B, and F, the application of rapid instrument neutron activation analysis was studied using 1.5s of irradiation and β-particle counting of 8 Li, 12 B, and 20 F. The fast transfer facility, Mach-1, the counting equipment, a 4-channel multiplexer, and a time-base controller are discussed. Further, the technique of simultaneous decay curve analysis of three successive decays is presented and quality control by residual analysis is demonstrated. Finally, analytical results are presented of the NBS-environmental standards Coal-1632a and Coal-1635, and of three BCR-coals intended as references materials

  8. Binomial distribution of Poisson statistics and tracks overlapping probability to estimate total tracks count with low uncertainty

    International Nuclear Information System (INIS)

    Khayat, Omid; Afarideh, Hossein; Mohammadnia, Meisam

    2015-01-01

    In the solid state nuclear track detectors of chemically etched type, nuclear tracks with center-to-center neighborhood of distance shorter than two times the radius of tracks will emerge as overlapping tracks. Track overlapping in this type of detectors causes tracks count losses and it becomes rather severe in high track densities. Therefore, tracks counting in this condition should include a correction factor for count losses of different tracks overlapping orders since a number of overlapping tracks may be counted as one track. Another aspect of the problem is the cases where imaging the whole area of the detector and counting all tracks are not possible. In these conditions a statistical generalization method is desired to be applicable in counting a segmented area of the detector and the results can be generalized to the whole surface of the detector. Also there is a challenge in counting the tracks in densely overlapped tracks because not sufficient geometrical or contextual information are available. It this paper we present a statistical counting method which gives the user a relation between the tracks overlapping probabilities on a segmented area of the detector surface and the total number of tracks. To apply the proposed method one can estimate the total number of tracks on a solid state detector of arbitrary shape and dimensions by approximating the tracks averaged area, whole detector surface area and some orders of tracks overlapping probabilities. It will be shown that this method is applicable in high and ultra high density tracks images and the count loss error can be enervated using a statistical generalization approach. - Highlights: • A correction factor for count losses of different tracks overlapping orders. • For the cases imaging the whole area of the detector is not possible. • Presenting a statistical generalization method for segmented areas. • Giving a relation between the tracks overlapping probabilities and the total tracks

  9. Structure analysis of liquids and disordered materials using pulsed neutron diffraction and total scattering

    International Nuclear Information System (INIS)

    Suzuya, Kentaro

    2011-01-01

    Neutron diffraction·total scattering at pulsed neutron source is a powerful method to analyze the complex structure of disordered materials: liquids, glasses, amorphous materials and disordered crystals. The basic idea of the structure of disordered materials, the fundamental diffraction theory for disordered materials, and structure analysis of disordered materials using pulsed neutron diffraction·total scattering technique (TOF method) are described in detail. In addition, the precise information of the world highest class J-PARC MLF spallation neutron source and typical J-PARC neutron total scattering instrument NOVA are also given. Recent structural modelling methods of disordered materials such like reverse Monte Carlo (RMC) simulation method is briefly described using an example of the analysis of a typical disordered material silica glass. (author)

  10. The spark counting of etched fission-fragment tracks in polycarbonate for a personal neutron dosimetry system

    International Nuclear Information System (INIS)

    Harrison, K.G.; Hancock, I.B.; Holt, P.D.; Wylie, J.W.

    1977-10-01

    A new type of personal neutron dosimeter, in which neutron-induced fissions in a thin 237 Np foil are detected by a polycarbonate track-detector, is under development at Harwell for use in a nuclear-fuel reprocessing plant. As part of the development programme, an experimental dosimeter, etching facility and spark counter have been used to study the spark-counting method for counting fission-fragment tracks in polycarbonate. Emphasis has been placed on developing operating procedures for the counter consistent with good overall reproducibility. Existing methods for the optimizing and testing of spark counters is briefly reviewed and a practical operational testing procedure is devised. The optimized system is found to be relatively foolproof in operation and gives good results in unskilled use as well as under carefully-controlled laboratory conditions. (author)

  11. Experimental and theoretical total neutron scattering cross-section of water confined in silica microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Muhrer, G., E-mail: muhrer@lanl.gov [Los Alamos National Laboratory, Los Alamos, 87545 NM (United States); Hartl, M.; Mocko, M.; Tovesson, F.; Daemen, L. [Los Alamos National Laboratory, Los Alamos, 87545 NM (United States)

    2012-07-21

    In the search for moderator materials encapsulated materials have been discussed, but very little is known regarding the effect of encapsulation on neutron moderation properties. As a first step toward a better understanding, we present the measured total neutron cross-section of water confined in silica microspheres and compare the measured data to the predicted theoretical cross-section.

  12. The total neutron cross sections for 14N and 24Mg

    International Nuclear Information System (INIS)

    Bommer, J.

    This report contains tables of the total neutron cross sections of 14 N and 24 Mg as determined in a recent measurement for neutron energies between 1 and 5.3 MeV. Graphic representations and details on the evaluation of the cross sections are included. (orig.) [de

  13. The total neutron cross-section of Nb at different temperatures for neutrons with energies below 1 eV

    International Nuclear Information System (INIS)

    Adib, M.; Abdel-Kawy, A.; Maayouf, R.M.A.; Fayek, M.; Mostafa, M.; Hamouda, I.

    1981-09-01

    Total neutron cross-section measurements have been performed for natural Nb at liquid nitrogen, room and 425 0 K temperatures in the energy range from 2 MeV - 1 eV. The measurements were performed using two time-of-flight spectrometers installed in front of two of the ET-RR-1 reactor horizontal channels. The neutron diffraction pattern of Nb, at room temperature, was obtained using a double axis crystal spectrometer installed also at the ET-RR-1 reactor. The obtained total neutron cross-sections were analyzed using the single level Breit-Wigner formula. The coherent scattering amplitude was determined from the Bragg reflections observed in the total neutron cross-section of Nb and the analysis of its neutron diffraction pattern. The incoherent and thermal inelastic scattering cross-sections of Nb were determined from the analysis of the total cross-section of Nb beyond the cut-off wavelength. The following results have been obtained: sigmasub(t) = (6.30+-0.20)b; sigmasub(coh) = (6.0+-0.3)b; sigmasub(incoh) = (2.0+-1.0)b; bsub(coh) = (6.91+-0.08)fm

  14. High count problems in elemental analysis using pulsed neutron inelastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Vartsky, D; Wielopolski, L; Ellis, K J; Cohn, S H [Brookhaven National Lab., Upton, NY (USA). Medical Dept.

    1983-03-01

    Elemental analysis by neutron inelastic scattering using a miniature intense pulsed neutron source ('Zetatron') was evaluated. The particular problems associated with detector pulse-pile-up during the neutron burst and the limited ability of the analyzer to process on average more than one detector pulse per neutron burst were examined. The severity of these problems is described and a solution using a multiple ADC system is proposed.

  15. Status report and measurement of total cross-sections at the Pohang Neutron Facility

    International Nuclear Information System (INIS)

    Kim, G.N.; Meaze, A.K.M.M.H.; Ahmed, H.

    2004-01-01

    We report the status of the Pohang Neutron Facility which consists of an electron linear accelerator, a water-cooled Ta target, and an 11-m time-of-flight path. It has been equipped with a four-position sample changer controlled remotely by a CAMAC data acquisition system, which allows simultaneous accumulation of the neutron time of flight spectra from 4 different detectors. It is possible to measure the neutron total cross-sections in the neutron energy range from 0.1 eV to 100 eV by using the neutron time of flight method. A 6 LiZnS(Ag) glass scintillator was used as a neutron detector. The neutron flight path from the water-cooled Ta target to the neutron detector was 10.81±0.02 m. The background level was determined by using notch-filters of Co, In, Ta, and Cd sheets. In order to reduce the gamma rays from Bremsstrahlung and those from neutron capture, we employed a neutron-gamma separation system based on their different pulse shapes. The present measurements are in general agreement with the evaluated data in ENDF/B-VI. The resonance parameters were extracted from the transmission data from the SAMMY fitting and compared with the previous ones. (author)

  16. Standard test method for non-destructive assay of nuclear material in waste by passive and active neutron counting using a differential Die-away system

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This test method covers a system that performs nondestructive assay (NDA) of uranium or plutonium, or both, using the active, differential die-away technique (DDT), and passive neutron coincidence counting. Results from the active and passive measurements are combined to determine the total amount of fissile and spontaneously-fissioning material in drums of scrap or waste. Corrections are made to the measurements for the effects of neutron moderation and absorption, assuming that the effects are averaged over the volume of the drum and that no significant lumps of nuclear material are present. These systems are most widely used to assay low-level and transuranic waste, but may also be used for the measurement of scrap materials. The examples given within this test method are specific to the second-generation Los Alamos National Laboratory (LANL) passive-active neutron assay system. 1.1.1 In the active mode, the system measures fissile isotopes such as 235U and 239Pu. The neutrons from a pulsed, 14-MeV ne...

  17. The total kinetic energy release in the fast neutron-induced fission of {sup 232}Th

    Energy Technology Data Exchange (ETDEWEB)

    King, Jonathan; Yanez, Ricardo; Loveland, Walter; Barrett, J. Spencer; Oscar, Breland [Oregon State University, Dept. of Chemistry, Corvallis, OR (United States); Fotiades, Nikolaos; Tovesson, Fredrik; Young Lee, Hye [Los Alamos National Laboratory, Physics Division, Los Alamos, NM (United States)

    2017-12-15

    The post-emission total kinetic energy release (TKE) in the neutron-induced fission of {sup 232}Th was measured (using white spectrum neutrons from LANSCE) for neutron energies from E{sub n} = 3 to 91 MeV. In this energy range the average post-neutron total kinetic energy release decreases from 162.3 ± 0.3 at E{sub n} = 3 MeV to 154.9 ± 0.3 MeV at E{sub n} = 91 MeV. Analysis of the fission mass distributions indicates that the decrease in TKE with increasing neutron energy is a combination of increasing yields of symmetric fission (which has a lower associated TKE) and a decrease in the TKE release in asymmetric fission. (orig.)

  18. Effect of milk temperature during irradiation on total bacterial count and keeping quality

    International Nuclear Information System (INIS)

    Sabbour, M.M.; Dawod, A.H.; Newigy, N.A.; Wahab, G.A.M.

    1989-01-01

    Cows' and buffaloes' milk samples were exposed to different doses of gamma radiation (100, 200 and 300 Kr) at 10 and 30°C. Irradiation of milk at 10°C caused more reduction in total bacterial count than that occurred at 30°C. The rate of microbial destruction due to irradiation at 10°C was higher than that occurred at 30°C. The keeping quality was determined daily for 15 days by clot-on-boiling test for samples kept at room temperature and in a refrigerator. The keeping quality recorded for cows' and buffaloes' milk samples in the refrigerator was 4 days, while it was only 1 day at room temperature. Irradiation of milk at 10°C was more effective than irradiation at 30°C, to increase the keeping quality of irradiated milk kept at refrigeration. Irradiation of milk samples at 10°C by 200 Kr increased the keeping quality for two weeks in the refrigerator, i.e. such a treatment increased the keeping quality by 4 folds

  19. Changes in total viable count and TVB-N content in marinated chicken breast fillets during storage

    Science.gov (United States)

    Baltić, T.; Ćirić, J.; Velebit, B.; Petronijević, R.; Lakićević, B.; Đorđević, V.; Janković, V.

    2017-09-01

    Marination is a popular technique for enhancing meat properties. Depending on the marinade type and ingredients added, marination can improve sensory, chemical and microbiological quality of meat products. In this study, the total viable count and total volatile basic nitrogen (TVB-N) content in marinated chicken breast fillets were investigated. The possible correlation between bacterial growth and formation of TVB-N was also tested. Chicken breast fillets were immersed in a solution of table salt (as a control) orthree different marinades,which consisted of table salt, sodium tripolyphosphate and/or sodium citrate, and stored in air for nine days at 4±1°C. Analyses of the total viable count and TVB-N were performed on days0, 3, 6 and 9 day of storage. The total viable count gradually increased in all examined groups, and statistically significant differences (pchicken were significantly higher (pchicken marinated with sodium citrate was established (pchicken marinated with sodium tripolyphosphate.

  20. Oil flow rate measurements using 198Au and total count technique

    International Nuclear Information System (INIS)

    Goncalves, Eduardo R.; Crispim, Verginia R.

    2013-01-01

    In industrial plants, oil and oil compounds are usually transported by closed pipelines with circular cross-section. The use of radiotracers in oil transport and processing industrial facilities allows calibrating flowmeters, measuring mean residence time in cracking columns, locate points of obstruction or leak in underground ducts, as well as investigating flow behavior or industrial processes such as in distillation towers. Inspection techniques using radiotracers are non-destructive, simple, economic and highly accurate. Among them, Total Count, which uses a small amount of radiotracer with known activity, is acknowledged as an absolute technique for flow rate measurement. A viscous fluid transport system, composed by four PVC pipelines with 13m length (12m horizontal and 1m vertical) and 1/2, 3/4, 1 and 2-inch gauges, respectively, interconnected by maneuvering valves was designed and assembled in order to conduct the research. This system was used to simulate different flow conditions of petroleum compounds and for experimental studies of flow profile in the horizontal and upward directions. As 198 Au presents a single photopeak (411,8 keV), it was the radioisotope chosen for oil labeling, in small amounts (6 ml) or around 200 kBq activity, and it was injected in the oil transport lines. A NaI scintillation detector 2'x 2', with well-defined geometry, was used to measure total activity, determine the calibration factor F and, positioned after a homogenization distance and interconnected to a standardized electronic set of nuclear instrumentation modules (NIM), to detect the radioactive cloud. (author)

  1. Influence of the type of milking and storage of milk on the chem ical composition, Somatic Cell Count and bacterial count Total

    Directory of Open Access Journals (Sweden)

    Aline Leite Peixoto

    2017-03-01

    Full Text Available The refrigeration of milk and the usage of mechanical milking are important to obtain milk in accordance with quality standards. In this work we evaluated the influence of the type of milking process and type of storage on the quality of the refrigerated milk. It was obtained 1363 refrigerated milk samples stored in single or collective expansion tanks, from manually or mechanically milked animals. The experiment was carried out in a 2x2 randomized factorial scheme. Two types of expansion tanks (single and collective and two types of milking (manual and mechanical. The average comparison test and Tukey test was carried out with 95% confidence. The levels of fat, protein, lactose and defatted dry extract, were evaluated according to the type of milking and type of milk storage. The values obtained were higher when compared to the values stabilished by the Ministry of Agriculture, Livestock and Food Supply. The level of milk fat was higher in samples with somatic cell count above 501,000 SC/mL. However, the levels of protein and defatted dry extract were higher in samples with somatic cell count below 500,000 SC/mL. The type of milking and the type of storage have influence on parameters related to milk quality such as levels of fat, protein, lactose and somatic cell count. The milk chemical composition revealed in accordance with the values stabilished by the Brazilian legislation. The total bacterial count did not vary with storage type nor the type of milking.

  2. The evaluation of neutron total cross section for natural iron and aluminium

    International Nuclear Information System (INIS)

    Liu Shirui; Wang Chunhao; Zhao Defang

    1990-05-01

    The experimental data of total cross section were collected and evaluated for natural iron in the energy region from 1 keV to 20 MeV and for natural aluminium from 4.07 keV to 20 MeV. The evaluated data were recommended in the regions for them. The minimum values of Fe total cross section in the keV region were specially recommended. The resonance structures were briefly discussed for both Fe and Al. To make the evaluation better, all experimental measurements of neutron total cross section relative to Fe and Al were studied. Considering the resonance feature of medium weight nuclides, two criteria for selecting total cross section were presented: 1) the correlation between the precission of total cross section and neutron source; 2) the correlation between the accuracy of total cross section and the resolving power of the neutron spectrometer

  3. Neutron detection and multiplicity counting using a boron-loaded plastic scintillator/bismuth germanate phoswich detector array

    International Nuclear Information System (INIS)

    Miller, M.C.

    1998-03-01

    Neutron detection and multiplicity counting has been investigated using a boron-loaded plastic scintillator/bismuth germanate phoswich detector array. Boron-loaded plastic combines neutron moderation (H) and detection ( 10 B) at the molecular level, thereby physically coupling increasing detection efficiency and decreasing die-away time with detector volume. Both of these characteristics address a fundamental limitation of thermal-neutron multiplicity counters, where 3 He proportional counters are embedded in a polyethylene matrix. Separation of the phoswich response into its plastic scintillator and bismuth germanate components was accomplished on a pulse-by-pulse basis using custom integrator and timing circuits. In addition, a custom time-tag module was used to provide a time for each detector event. Analysis of the combined energy and time event stream was performed by calibrating each detector's response and filtering based on the presence of a simultaneous energy deposition corresponding to the 10 B(n,alpha) reaction products in the plastic scintillator (93 keV ee ) and the accompanying neutron-capture gamma ray in the bismuth germanate (478 keV). Time-correlation analysis was subsequently performed on the filtered event stream to obtain shift-register-type singles and doubles count rates. Proof-of-principle measurements were conducted with a variety of gamma-ray and neutron sources including 137 Cs, 54 Mn, AmLi, and 252 Cf. Results of this study indicate that a neutron-capture probability of ∼10% and a die-away time of ∼10 micros are possible with a 4-detector array with a detector volume of 1600 cm 3 . Simulations were performed that indicate neutron-capture probabilities on the order of 50% and die-away times of less than 4 micros are realistically achievable. While further study will be required for practical application of such a detection system, the results obtained in this investigation are encouraging and may lead to a new class of high

  4. Application of the activation analysis using the method of retarded fission neutrons counting for the determination of some fissionable nuclides

    International Nuclear Information System (INIS)

    Armelin, M.J.A.

    1984-01-01

    A system for the detection and counting of delayed neutrons which allows the analysis of some fissile and fertile nuclides, in samples of milligram size, was developed. This was applied for the analysis of natural uranium and thorium and also for determining the 235 U/ 238 U ratio in non-irradiated samples which contain uranium with different degrees of enrichment in 235 U. The spectrum of activated neutrons was varied in order to discriminate the nuclides, by covering or not the sample with a material (cadmium or boron) able to absorb low energy neutrons. Determination of 235 U/ 238 U ratios, through the number of delayed neutrons, was made by drawing a calibration curve using standards ranging from 0.5% to 93% on 235 U; the accuracy of the method was also examined. In a first step, conditions for a simultaneous and non-destructive analysis of uranium and thorium were developed. The interference between these two nuclides was studied, using simulated samples. Real samples were provided by Nuclemon and IAEA. For samples with uranium concentration in the range of percentages and thorium concentration of some ppm, uranium interferes in the determination of thorium through the non-destructive analytical method. For this case, a fast and quantitative chemical method was studied which allows for the separation of thorium from uranium before the determination of throrium concentration by counting the delayed fission neutrons. It was found that the results obtained by both destructive and non-destructive methods are very consistent and can be considered statistically equivalent within a confidence level of 95%. (Author) [pt

  5. [Prediction of the total Japanese cedar pollen counts based on male flower-setting conditions of standard trees].

    Science.gov (United States)

    Yuta, Atsushi; Ukai, Kotaro; Sakakura, Yasuo; Tani, Hideshi; Matsuda, Fukiko; Yang, Tian-qun; Majima, Yuichi

    2002-07-01

    We made a prediction of the Japanese cedar (Cryptomeria japonica) pollen counts at Tsu city based on male flower-setting conditions of standard trees. The 69 standard trees from 23 kinds of clones, planted at Mie Prefecture Science and Technology Promotion Center (Hakusan, Mie) in 1964, were selected. Male flower-setting conditions for 276 faces (69 trees x 4 points of the compass) were scored from 0 to 3. The average of scores and total pollen counts from 1988 to 2000 was analyzed. As the results, the average scores from standard trees and total pollen counts except two mass pollen-scattered years in 1995 and 2000 had a positive correlation (r = 0.914) by linear function. On the mass pollen-scattered years, pollen counts were influenced from the previous year. Therefore, the score of the present year minus that of the previous year were used for analysis. The average scores from male flower-setting conditions and pollen counts had a strong positive correlation (r = 0.994) when positive scores by taking account of the previous year were analyzed. We conclude that prediction of pollen counts are possible based on the male flower-setting conditions of standard trees.

  6. Serum albumin and total lymphocyte count as predictors of outcome in hip fractures.

    LENUS (Irish Health Repository)

    O'Daly, Brendan J

    2012-02-01

    BACKGROUND & AIMS: Hip fractures are a significant cause of mortality and morbidity in the elderly. Malnutrition is a significant contributor to this, however no consensus exists as to the detection or management of this condition. We hypothesise that results of admission serum albumin and total lymphocyte count (TLC), as markers of Protein Energy Malnutrition (PEM) can help predict clinical outcome in hip fracture patients aged over 60 years. METHODS: This retrospective study evaluated the nutritional status of patients with hip fractures using albumin and TLC assays and analysed their prognostic relevance. Clinical outcome parameters studied were delay to operation, duration of in-patient stay, re-admission and in-patient, 3- and 12-month mortality. RESULTS: Four hundred and fifteen hip fracture patients were evaluated. Survival data were available for 377 patients at 12 months. In-hospital mortality for PEM patients was 9.8%, compared with 0% for patients without. Patients with PEM had a higher 12-month mortality compared to patients who had normal values of both laboratory parameters (Odds Ratio 4.6; 95% CI: 1.0-21.3). Serum albumin (Hazard Ratio 0.932, 95% CI: 0.9-1.0) and age (Hazard Ratio 1.04, 95% CI: 1.0-1.1) were found to be significant independent prognostic factors of mortality by Cox regression analysis. CONCLUSIONS: These results highlight the relevance of assessing the nutritional status of patients with hip fractures at the time of admission and emphasises the correlation between PEM and outcome in these patients.

  7. The spin-spin effect in the total neutron cross section of polarized neutrons on polarized 165Ho

    International Nuclear Information System (INIS)

    Fasoli, U.; Galeazzi, G.; Pavan, P.; Toniolo, D.; Zago, G.; Zannoni, R.

    1978-01-01

    The spin-spin effect in the total neutron cross section of polarized neutrons on polarized 165 Ho has been measured in the energy interval 0.4 to 2.5 MeV, in perpendicular geometry. The results are consistent with zero effect. The spin-spin cross section sigmasub(ss) has been theoretically evaluated by a non-adiabatic coupled-channel calculation. From the comparison between the experimental and theoretical results a value Vsub(ss) = 9+-77 keV for the strength of the spin-spin potential has been obtained. Compound-nucleus effects do not seem to be relevant. (Auth.)

  8. Quality of raw cow milk in Republic of Macedonia determined through the testing of somatic cell count and total viable count

    Directory of Open Access Journals (Sweden)

    Angelovski Ljupco

    2008-11-01

    Full Text Available Somatic cells count and total viable count are criteria used to estimate the compliance of raw cow milk with the Book of rules for demands for safety and hygiene and procedures for official controls of milk and milk products, Official Gazette of RM 157/2007. According to the given demands, raw milk operators are obliged to conduct all procedures and to guarantee that milk is in compliance with the criteria laid down in Book of rules. At the same time, Republic of Macedonia have to fulfill EU criteria laid down in Directive 92/46 (Council directive 92/46/EEC laying down the health rules for the production and placing on the market of raw milk, heat-treated milk and milkbased products for quality of raw milk as part of implementation of community legislation and milk production. The independent laboratory for milk quality control at FVM-Skopje, in frame of its activities in the period February- August 2008 has conducted a study for obtaining preliminary results for the situation with raw milk quality produced in R. of Macedonia for somatic cells counts and total viable count. In the study we analyzed 2065 samples for TVC and 1625 samples for SCC of raw milk samples produced in different parts of the country. From the tested samples only 41,8% fulfill criteria for SCC and 41,45% criteria for TVC lay down in Book of rules for 2008. Assessment of the results in light of Council Directive it is obvious that only 42,7% of the samples for SCC and 10,7% for TVC fulfill the criteria of Council Directive having in mind different requirements vs. Book of rules.

  9. Total body-calcium measurements: comparison of two delayed-gamma neutron activation facilities

    International Nuclear Information System (INIS)

    Ma, R.; Ellis, K.J.; Shypailo, R.J.; Pierson, R.N. Jr.

    1999-01-01

    This study compares two independently calibrated delayed-gamma neutron activation (DGNA) facilities, one at the Brookhaven National Laboratory (BNL), Upton, New York, and the other at the Children's Nutrition Research Center (CNRC), Houston, Texas that measure total body calcium (TBCa). A set of BNL phantoms was sent to CNRC for neutron activation analysis, and a set of CNRC phantoms was measured at BNL. Both facilities showed high precision (<2%), and the results were in good agreement, within 5%. (author)

  10. Measurement of total reaction cross sections of exotic neutron rich nuclei

    International Nuclear Information System (INIS)

    Mittig, W.; Chouvel, J.M.; Wen Long, Z.

    1987-01-01

    Total reaction cross-sections of neutron rich nuclei from C to Mg in a thick Si-target have been measured using the detection of the associated γ-rays in a 4Π-geometry. This cross-section strongly increases with neutron excess, indicating an increase of as much as 15% of the reduced strong absorption radius with respect to stable nuclei

  11. The nTOF Total Absorption Calorimeter for neutron capture measurements at CERN

    International Nuclear Information System (INIS)

    Guerrero, C.; Abbondanno, U.; Aerts, G.; Alvarez, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.; Badurek, G.; Baumann, P.; Becvar, F.; Berthoumieux, E.; Calvino, F.; Calviani, M.; Cano-Ott, D.; Capote, R.; Carrapico, C.; Cennini, P.; Chepel, V.

    2009-01-01

    The n T OF Collaboration has built and commissioned a high-performance detector for (n,γ) measurements called the Total Absorption Calorimeter (TAC). The TAC was especially designed for measuring neutron capture cross-sections of low-mass and/or radioactive samples with the accuracy required for nuclear technology and stellar nucleosynthesis. We present a detailed description of the TAC and discuss its overall performance in terms of energy and time resolution, background discrimination, detection efficiency and neutron sensitivity.

  12. Total white blood cell counts and LPS-induced TNF alpha production by monocytes of pregnant, pseudopregnant and cyclic rats

    NARCIS (Netherlands)

    Faas, MM; Moes, H; van der Schaaf, G; de Leij, LFMH; Heineman, MJ

    Pregnancy in the rat may be associated with an activated innate immune system. Therefore, we investigated monocyte function as well as total white blood cell (WBC) counts during the follicular phase of the ovarian cycle, pregnancy and pseudopregnancy in the rat. Rats were equipped with a permanent

  13. Total white blood cell counts and LPS-induced TNF alpha production by monocytes of pregnant, pseudopregnant and cyclic rats

    NARCIS (Netherlands)

    Faas, M. M.; Moes, H.; van der Schaaf, G.; de Leij, L. F. M. H.; Heineman, M. J.

    2003-01-01

    Pregnancy in the rat may be associated with an activated innate immune system. Therefore, we investigated monocyte function as well as total white blood cell (WBC) counts during the follicular phase of the ovarian cycle, pregnancy and pseudopregnancy in the rat. Rats were equipped with a permanent

  14. Total motile sperm count: a better indicator for the severity of male factor infertility than the WHO sperm classification system

    NARCIS (Netherlands)

    Hamilton, J.A.; Cissen, M.; Brandes, M.; Smeenk, J.M.; Bruin, J.P. de; Kremer, J.A.M.; Nelen, W.L.D.M.; Hamilton, C.J.C.M.

    2015-01-01

    STUDY QUESTION: Does the prewash total motile sperm count (TMSC) have a better predictive value for spontaneous ongoing pregnancy (SOP) than the World Health Organization (WHO) classification system? SUMMARY ANSWER: The prewash TMSC shows a better correlation with the spontaneous ongoing pregnancy

  15. Comparative seric TGF(β1, β2) levels and platelets count response in total body irradiated baboons

    International Nuclear Information System (INIS)

    Mestries, J.C.; Veyret, J.; Agay, D.; Van Uye, A.; Caterini, R.; Herodin, F.; Mathieu, J.; Chancerelle, Y.

    1994-01-01

    Total body irradiation associated or not with r-hIL-6 treatment a relation between TGF-β1 and TGF-β2 blood levels and platelets count. During radio-induced thrombocytopenia, by decreasing its ability to inhibit proliferation of stem cells and megakaryocytopoiesis, the TGF-β falling induced a favorable condition for hematopoietic recovery. (author)

  16. Flow cytometry total cell counts : A field study assessing microbiological water quality and growth in unchlorinated drinking water distribution systems

    NARCIS (Netherlands)

    Liu, G.; Van der Mark, E.J.; Verberk, J.Q.; Van Dijk, J.C.

    2013-01-01

    e objective of this study was to evaluate the application of flow cytometry total cell counts (TCCs) as a parameter to assess microbial growth in drinking water distribution systems and to determine the relationships between different parameters describing the biostability of treated water. A

  17. Quantitation of the degree of osteoporosis by measure of total-body calcium employing neutron activation

    International Nuclear Information System (INIS)

    Cohn, S.H.; Zanzi, I.; Vaswani, A.; Wallach, S.; Aloia, J.; Ellis, K.J.

    1975-01-01

    Two techniques for measuring the amount of Ca in the total skeleton were employed: total-body neutron activation analysis (TBNAA) and the determination of the mineral content of a bone of the appendicular skeleton (absorptiometric measurement of the radius, BMC). (U.S.)

  18. Extension of the Dytlewski-style dead time correction formalism for neutron multiplicity counting to any order

    International Nuclear Information System (INIS)

    Croft, Stephen; Favalli, Andrea

    2017-01-01

    Here, neutron multiplicity counting using shift-register calculus is an established technique in the science of international nuclear safeguards for the identification, verification, and assay of special nuclear materials. Typically passive counting is used for Pu and mixed Pu-U items and active methods are used for U materials. Three measured counting rates, singles, doubles and triples are measured and, in combination with a simple analytical point-model, are used to calculate characteristics of the measurement item in terms of known detector and nuclear parameters. However, the measurement problem usually involves more than three quantities of interest, but even in cases where the next higher order count rate, quads, is statistically viable, it is not quantitatively applied because corrections for dead time losses are currently not available in the predominant analysis paradigm. In this work we overcome this limitation by extending the commonly used dead time correction method, developed by Dytlewski, to quads. We also give results for pents, which may be of interest for certain special investigations. Extension to still higher orders, may be accomplished by inspection based on the sequence presented. We discuss the foundations of the Dytlewski method, give limiting cases, and highlight the opportunities and implications that these new results expose. In particular there exist a number of ways in which the new results may be combined with other approaches to extract the correlated rates, and this leads to various practical implementations.

  19. Automation of Sample Transfer and Counting on Fast Neutron ActivationSystem

    International Nuclear Information System (INIS)

    Dewita; Budi-Santoso; Darsono

    2000-01-01

    The automation of sample transfer and counting were the transfer processof the sample to the activation and counting place which have been done byswitch (manually) previously, than being developed by automaticallyprogrammed logic instructions. The development was done by constructed theelectronics hardware and software for that communication. Transfer timemeasurement is on seconds and was done automatically with an error 1.6 ms.The counting and activation time were decided by the user on seconds andminutes, the execution error on minutes was 8.2 ms. This development systemwill be possible for measuring short half live elements and cyclic activationprocesses. (author)

  20. Evaluation of body composition and nitrogen content of renal patients on chronic dialysis as determined by total body neutron activation

    International Nuclear Information System (INIS)

    Cohn, S.H.; Brennan, B.L.; Yasumura, S.; Vartsky, D.; Vaswani, A.N.; Ellis, K.J.

    1983-01-01

    Total body protein (nitrogen), body cell mass (potassium), fat, and water were measured in 15 renal patients on maintenance hemodialysis (MHD). Total body nitrogen was measured by means of prompt γ neutron activation analysis; total body water was determined with tritium labeled water; total body potassium was measured by whole body counting. The extracellular water was determined by a technique utilizing the measurement of total body chloride and plasma chloride. When compared with corresponding values of a control group of the same age, sex, and height, the protein content, body cell mass, and total body fat of the MHD patients were within the normal range. The only significant change was an increase in the extracellular water/body cell mass ratio in the male MHD patients compared to the control. The lack of significant difference of the nitrogen values of the MHD patients compared to matched controls suggests that dialysis minimizes any residual effects of uremic toxicity or protein-calorie malnutrition. These findings further suggest that there is a need to reevaluate the traditional anthropometric and biochemical standards of nutritional status for MHD patients. It was concluded that it is particularly important to measure protein stores of MHD patients with low protein intake to ascertain nutritional status. Finally, in vivo measurement of total body nitrogen and potassium for determination of body composition provides a simple, direct, and accurate assessment of the nutritional status of MHD patients

  1. Nondestructive detection of total viable count changes of chilled pork in high oxygen storage condition based on hyperspectral technology

    Science.gov (United States)

    Zheng, Xiaochun; Peng, Yankun; Li, Yongyu; Chao, Kuanglin; Qin, Jianwei

    2017-05-01

    The plate count method is commonly used to detect the total viable count (TVC) of bacteria in pork, which is timeconsuming and destructive. It has also been used to study the changes of the TVC in pork under different storage conditions. In recent years, many scholars have explored the non-destructive methods on detecting TVC by using visible near infrared (VIS/NIR) technology and hyperspectral technology. The TVC in chilled pork was monitored under high oxygen condition in this study by using hyperspectral technology in order to evaluate the changes of total bacterial count during storage, and then evaluate advantages and disadvantages of the storage condition. The VIS/NIR hyperspectral images of samples stored in high oxygen condition was acquired by a hyperspectral system in range of 400 1100nm. The actual reference value of total bacteria was measured by standard plate count method, and the results were obtained in 48 hours. The reflection spectra of the samples are extracted and used for the establishment of prediction model for TVC. The spectral preprocessing methods of standard normal variate transformation (SNV), multiple scatter correction (MSC) and derivation was conducted to the original reflectance spectra of samples. Partial least squares regression (PLSR) of TVC was performed and optimized to be the prediction model. The results show that the near infrared hyperspectral technology based on 400-1100nm combined with PLSR model can describe the growth pattern of the total bacteria count of the chilled pork under the condition of high oxygen very vividly and rapidly. The results obtained in this study demonstrate that the nondestructive method of TVC based on NIR hyperspectral has great potential in monitoring of edible safety in processing and storage of meat.

  2. Determining eligibility for antiretroviral therapy in resource-limited settings using total lymphocyte counts, hemoglobin and body mass index

    Directory of Open Access Journals (Sweden)

    Solberg Peter

    2007-01-01

    Full Text Available Abstract Background CD4+ T lymphocyte (CD4 cell count testing is the standard method for determining eligibility for antiretroviral therapy (ART, but is not widely available in sub-Saharan Africa. Total lymphocyte counts (TLCs have not proven sufficiently accurate in identifying subjects with low CD4 counts. We developed clinical algorithms using TLCs, hemoglobin (Hb, and body mass index (BMI to identify patients who require ART. Methods We conducted a cross-sectional study of HIV-infected adults in Uganda, who presented for assessment for ART-eligibility with WHO clinical stages I, II or III. Two by two tables were constructed to examine TLC thresholds, which maximized sensitivity for CD4 cell counts ≤ 200 cells μL, while minimizing the number offered ART with counts > 350 cells μL. Hb and BMI values were then examined to try to improve model performance. Results 1787 subjects were available for analysis. Median CD4 cell counts and TLCs, were 239 cells/μL and 1830 cells/μL, respectively. Offering ART to all subjects with a TLCs ≤ 2250 cells/μL produced a sensitivity of 0.88 and a false positive ratio of 0.21. Algorithms that treated all patients with a TLC 3000 cells/μL, and used Hb and/or BMI values to determine eligibility for those with TLC values between 2000 and 3000 cells/μL, marginally improved accuracy. Conclusion TLCs appear useful in predicting who would be eligible for ART based on CD4 cell count criteria. Hb and BMI values may be useful in prioritizing patients for ART, but did not improve model accuracy.

  3. The use of flow cytometry to accurately ascertain total and viable counts of Lactobacillus rhamnosus in chocolate.

    Science.gov (United States)

    Raymond, Yves; Champagne, Claude P

    2015-04-01

    The goals of this study were to evaluate the precision and accuracy of flow cytometry (FC) methodologies in the evaluation of populations of probiotic bacteria (Lactobacillus rhamnosus R0011) in two commercial dried forms, and ascertain the challenges in enumerating them in a chocolate matrix. FC analyses of total (FC(T)) and viable (FC(V)) counts in liquid or dried cultures were almost two times more precise (reproducible) than traditional direct microscopic counts (DCM) or colony forming units (CFU). With FC, it was possible to ascertain low levels of dead cells (FC(D)) in fresh cultures, which is not possible with traditional CFU and DMC methodologies. There was no interference of chocolate solids on FC counts of probiotics when inoculation was above 10(7) bacteria per g. Addition of probiotics in chocolate at 40 °C resulted in a 37% loss in viable cells. Blending of the probiotic powder into chocolate was not uniform which raised a concern that the precision of viable counts could suffer. FCT data can serve to identify the correct inoculation level of a sample, and viable counts (FCV or CFU) can subsequently be better interpreted. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  4. Reflected‑Point‑Reactor Kinetics Model for Neutron Coincidence Counting: Comments on the Equation for the Leakage Self‑Multiplication

    International Nuclear Information System (INIS)

    Croft, S.; McElroy, RD.; Favalli, A.; Hauck, D.; Henzlova, D.; Henzl, V.; Santi, PA.

    2015-01-01

    Passive neutron correlation counting is widely used, for example by international inspection agencies, for the non‑destructive assay of spontaneously fissile nuclear materials for nuclear safeguards. The mass of special nuclear material present in an item is usually estimated from the observed neutron counting rates by using equations based on mathematically describing the object as an isolated multiplying point‑like source. Calibration using representative physical standards can often adequately compensate for this theoretical oversimplification through the introduction and use of effective‑interpretational‑model‑parameters meaning that useful assay results are obtained. In this work we extend the point‑model treatment by including a simple reflector around the fissioning material. Specifically we show how the leakage self‑multiplication equation mathematically connects the traditional bare source and the reflected source cases. In doing so we explicitly demonstrate that although the presence of a simple reflector changes the leakage self‑multiplication the traditional bare‑item point model multiplicity equations retain the same mathematical form. Making and explaining this connection is important because it helps to explain and justify the practical success and use of the traditional point‑model equations even when the assumptions used to generate the key functional dependences are violated. We are not aware that this point has been recognized previously.

  5. The impact of gate width setting and gate utilization factors on plutonium assay in passive correlated neutron counting

    Energy Technology Data Exchange (ETDEWEB)

    Henzlova, D., E-mail: henzlova@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Menlove, H.O. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Croft, S. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Favalli, A.; Santi, P. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2015-10-11

    In the field of nuclear safeguards, passive neutron multiplicity counting (PNMC) is a method typically employed in non-destructive assay (NDA) of special nuclear material (SNM) for nonproliferation, verification and accountability purposes. PNMC is generally performed using a well-type thermal neutron counter and relies on the detection of correlated pairs or higher order multiplets of neutrons emitted by an assayed item. To assay SNM, a set of parameters for a given well-counter is required to link the measured multiplicity rates to the assayed item properties. Detection efficiency, die-away time, gate utilization factors (tightly connected to die-away time) as well as optimum gate width setting are among the key parameters. These parameters along with the underlying model assumptions directly affect the accuracy of the SNM assay. In this paper we examine the role of gate utilization factors and the single exponential die-away time assumption and their impact on the measurements for a range of plutonium materials. In addition, we examine the importance of item-optimized coincidence gate width setting as opposed to using a universal gate width value. Finally, the traditional PNMC based on multiplicity shift register electronics is extended to Feynman-type analysis and application of this approach to Pu mass assay is demonstrated.

  6. The impact of gate width setting and gate utilization factors on plutonium assay in passive correlated neutron counting

    International Nuclear Information System (INIS)

    Henzlova, D.; Menlove, H.O.; Croft, S.; Favalli, A.; Santi, P.

    2015-01-01

    In the field of nuclear safeguards, passive neutron multiplicity counting (PNMC) is a method typically employed in non-destructive assay (NDA) of special nuclear material (SNM) for nonproliferation, verification and accountability purposes. PNMC is generally performed using a well-type thermal neutron counter and relies on the detection of correlated pairs or higher order multiplets of neutrons emitted by an assayed item. To assay SNM, a set of parameters for a given well-counter is required to link the measured multiplicity rates to the assayed item properties. Detection efficiency, die-away time, gate utilization factors (tightly connected to die-away time) as well as optimum gate width setting are among the key parameters. These parameters along with the underlying model assumptions directly affect the accuracy of the SNM assay. In this paper we examine the role of gate utilization factors and the single exponential die-away time assumption and their impact on the measurements for a range of plutonium materials. In addition, we examine the importance of item-optimized coincidence gate width setting as opposed to using a universal gate width value. Finally, the traditional PNMC based on multiplicity shift register electronics is extended to Feynman-type analysis and application of this approach to Pu mass assay is demonstrated

  7. The development of neutron activation, sample transportation and γ-ray counting routine system for numbers of geological samples

    International Nuclear Information System (INIS)

    Shibata Shin-nosuke; Tanaka, Tsuyoshi; Minami, Masayo

    2001-01-01

    A new gamma-ray counting and data processing system for non-destructive neutron activation analysis has been set up in Radioisotope Center in Nagoya University. The system carry out gamma-ray counting, sample change and data processing automatically, and is able to keep us away from parts of complicated operations in INAA. In this study, we have arranged simple analytical procedure that makes practical works easier than previous. The concrete flow is described from the reparation of powder rock samples to gamma-ray counting and data processing by the new INAA system. Then it is run over that the analyses used two Geological Survey of Japan rock reference samples JB-1a and JG-1a in order to evaluate how the new analytical procedure give any speediness and accuracy for analyses of geological materials. Two United States Geological Survey reference samples BCR-1 and G-2 used as the standard respectively. Twenty two elements for JB-1a and 25 elements for JG-1a were analyzed, the uncertainty are <5% for Na, Sc, Fe, Co, La, Ce, Sm, Eu, Yb, Lu, Hf, Ta and Th, and of <10% for Cr, Zn, Cs, Ba, Nd, Tb and U. This system will enable us to analyze more than 1500 geologic samples per year. (author)

  8. Application of laboratory sourceless object counting for the estimation of the neutron dose

    International Nuclear Information System (INIS)

    Cheng Jie; Ning Jing; Zhang Xiaomin; Qu Decheng; Xie Xiangdong; Nan Hongjie

    2011-01-01

    Objective: To estimate the neutron dose using 24 Na energy spectrum analysis method. Methods: Genius-2000 GeomComposer software package was used to calibrate the efficiency of the detector. Results: The detection efficiency of the detector toward γ photon with an energy of 1.368 MeV was quickly found to be 4.05271×10 -3 while the error of the software was 4.0% . The estimated dose value of the neutron irradiation samples was between 1.94 Gy and 2.82 Gy, with an arithmetic mean value of 2.38 Gy. The uncertainty of the dosimetry was about 20.07% . Conclusion: The application of efficiency calibration without a radioactive source of the energy spectrum analysis of the 24 Na contained in human blood with accelerate the estimation process. (authors)

  9. Determination of plutonium content in TRR spent fuel by nondestructive neutron counting

    International Nuclear Information System (INIS)

    Chen, Y.-F.; Sheu, R.-J.; Chiao, L.-H.; Yuan, M.-C.; Jiang, S.-H.

    2010-01-01

    For the nuclear safeguard purpose, this work aims to nondestructively determine the plutonium content in the Taiwan Research Reactor (TRR) spent fuel rods in the storage pool before the stabilization process, which transforms the metal spent fuel rods into oxide powder. A SPent-fuel-Neutron-Counter (SPNC) system was designed and constructed to carry out underwater scan measurements of neutrons emitting from the spent fuel rod, from which the 240 Pu mass in the fuel rod will be determined. The SAS2 H control module of the SCALE 5.1 code package was applied to calculate the 240 Pu-to-Pu mass ratio in the TRR spent fuel rod according to the given power history. This paper presents the methodology and design of our detector system as well as the measurements of four TRR spent fuel rods in the storage pool and the comparison of the measured results with the facility declared values.

  10. Neutron total and scattering cross sections of 6Li in the few MeV region

    International Nuclear Information System (INIS)

    Smith, A.; Guenther, P.; Whalen, J.

    1980-02-01

    Neutron total cross sections of 6 Li are measured from approx. 0.5 to approx. 4.8 MeV at intervals of approx. 10 scattering angles and at incident-neutron intervals of approx.< 100 keV. Neutron differential inelastic-scattering cross sections are measured in the incident-energy range 3.5 to 4.0 MeV. The experimental results are extended to lower energies using measured neutron total cross sections recently reported elsewhere by the authors. The composite experimental data (total cross sections from 0.1 to 4.8 MeV and scattering cross sections from 0.22 to 4.0 MeV) are interpreted in terms of a simple two-level R-matrix model which describes the observed cross sections and implies the reaction cross section in unobserved channels; notably the (n;α)t reaction (Q = 4.783 MeV). The experimental and calculational results are compared with previously reported results as summarized in the ENDF/B-V evaluated nuclear data file

  11. Resonance structure of 32S+n from measurements of neutron total and capture cross sections

    International Nuclear Information System (INIS)

    Halperin, J.; Johnson, C.H.; Winters, R.R.; Macklin, R.L.

    1980-01-01

    Neutron total and capture cross sections of 32 S have been measured up to 1100 keV neutron energy [E/sub exc/( 33 S) =9700 keV]. Spin and parity assignments have been made for 28 of the 64 resonances found in this region. Values of total radiation widths, reduced neutron widths, level spacings, and neutron strength functions have been evaluated for s/sub 1/2/, p/sub 1/2/, p/sub 3/2/, and d/sub 5/2/ levels. Single particle contributions using the valency model account for a significant portion of the total radiation width only for the p/sub 1/2/-wave resonances. A significant number of resonances can be identified with reported levels excited in 32 S(d,p) and 29 Si(α,n) reactions. A calculation of the Maxwellian average cross section appropriate to stellar interiors indicates an average capture cross section at 30 keV, sigma-bar approx. = 4.2(2) mb, a result that is relatively insensitive to the assumed stellar temperature. Direct (potential) capture and the s-wave resonance capture contributions to the thermal capture cross section do not fully account for the reported thermal cross section (530 +- 40 mb) and a bound state is invoked to account for the discrepancy

  12. Fast-neutron total and scattering cross sections of sup 58 Ni and nuclear models

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.B.; Guenther, P.T.; Whalen, J.F. (Argonne National Lab., IL (United States)); Chiba, S. (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment)

    1991-07-01

    The neutron total cross sections of {sup 58}Ni were measured from {approx} 1 to > 10 MeV using white-source techniques. Differential neutron elastic-scattering cross sections were measured from {approx} 4.5 to 10 MeV at {approx} 0.5 MeV intervals with {ge} 75 differential values per distribution. Differential neutron inelastic-scattering cross sections were measured, corresponding to fourteen levels with excitations up to 4.8 MeV. The measured results, combined with relevant values available in the literature, were interpreted in terms of optical-statistical and coupled-channels model using both vibrational and rotational coupling schemes. The physical implications of the experimental results nd their interpretation are discussed in the contexts of optical-statistical, dispersive-optical, and coupled-channels models. 61 refs.

  13. Amino acids analysis by total neutron cross-sections determinations: part V

    International Nuclear Information System (INIS)

    Voi, Dante L.; Ferreira, Francisco de O.; Rocha, Helio F. da

    2013-01-01

    Total neutron cross-sections of twenty essential and non-essential amino acids to human were determined using crystal spectrometer installed on the Argonauta reactor of IEN (Instituto de Engenharia Nuclear (CNEN-RJ) and compared with data generated by parceling and grouping methodologies developed at this institution. For each amino acid was calculated the respective neutron cross-section by molecular structure, conformation and chemistry analysis. The results obtained for eighteen of twenty amino acids confirm the specifications and product formulations indicated by manufactures. These initial results allow to build a neutron cross-sections database as part of quality control of the amino supplied to hospitals for production of nutriments for parenteral or enteral formulations used in critical patients dependent on artificial feed, and for application in future studies of structure and dynamics for more complex molecules, including proteins, enzymes, fatty acids, membranes, organelles and other cell components. (author)

  14. In vivo measurement of total body carbon using 238Pu/Be neutron sources

    International Nuclear Information System (INIS)

    Sutcliffe, J.F.; Mitra, S.; Hill, G.L.

    1990-01-01

    Total body carbon has been measured by in vivo neutron activation analysis (IVNAA) in 278 surgical gastroenterological patients and 29 normal volunteers. This is based on the inelastic scattering reaction { 12 C(n,n') 12 C*} for neutrons with energy above 4.8MeV, producing 4.43 MeV gamma rays. Since only part of the body is scanned, total body carbon is estimated as the ratio of the gamma ray emission from carbon to the emission from hydrogen, using hydrogen as the internal standard. The precision of the estimate is ±1.6kg for a whole body dose of 0.3mSv. There is a significant difference between the estimates of total body water from IVNAA measurements of carbon and nitrogen and measurements of body water in these subjects by tritium dilution (t=3.1, p < 0.005). (author)

  15. Total and Differential Leukocyte Counts in Relation to Incidence of Diabetes Mellitus: A Prospective Population-Based Cohort Study.

    Science.gov (United States)

    Borné, Yan; Smith, J Gustav; Nilsson, Peter M; Melander, Olle; Hedblad, Bo; Engström, Gunnar

    2016-01-01

    High concentrations of leukocytes in blood have been associated with diabetes mellitus. This prospective study aimed to explore whether total and differential leukocyte counts are associated with incidence of diabetes. A missense variant R262W in the SH2B3 (SH2B adaptor protein 3) gene, coding for a protein that negatively regulates hematopoietic cell proliferation, was also studied in relation to incidence of diabetes. Leukocyte count and its subtypes (neutrophils, lymphocytes and mixed cells) were analyzed in 26,667 men and women, 45-73 years old, from the population-based Malmö Diet and Cancer study. Information about the R262W polymorphism (rs3184504) in SH2B3 was genotyped in 24,489 subjects. Incidence of diabetes was studied during a mean follow-up of 14 years. Cox proportional hazards regression was used to examine incidence of diabetes by total and differential leukocyte counts. Mendelian randomization analysis using R262W as an instrumental variable was performed with two-stage least squares regression. A total of 2,946 subjects developed diabetes during the follow-up period. After taking several possible confounders into account, concentrations of total leukocyte count, neutrophils and lymphocytes were all significantly associated with incidence of diabetes. The adjusted hazard ratios (95% confidence interval; quartile 4 vs quartile 1) were 1.37 (1.22-1.53) for total leukocytes, 1.33 (1.19-1.49) for neutrophils and 1.29 (1.15-1.44) for lymphocytes. The R262W polymorphism was strongly associated with leukocytes (0.11x109 cells/l per T allele, p = 1.14 x10-12), lymphocytes (p = 4.3 x10-16), neutrophils (p = 8.0 x10-6) and mixed cells (p = 3.0 x10-6). However, there was no significant association between R262W and fasting glucose, HbA1c or incidence of diabetes. Concentrations of total leukocytes, neutrophils and lymphocytes are associated with incidence of diabetes. However, the lack of association with the R262W polymorphism suggests that the associations

  16. Modified model of neutron resonance widths distribution. Results of total gamma-widths approximation

    International Nuclear Information System (INIS)

    Sukhovoj, A.M.; Khitrov, V.A.

    2011-01-01

    Functional dependences of probability to observe given Γ n 0 value and algorithms for determination of the most probable magnitudes of the modified model of resonance parameter distributions were used for analysis of the experimental data on the total radiative widths of neutron resonances. As in the case of neutron widths, precise description of the Γ γ spectra requires a superposition of three and more probability distributions for squares of the random normally distributed values with different nonzero average and nonunit dispersion. This result confirms the preliminary conclusion obtained earlier at analysis of Γ n 0 that practically in all 56 tested sets of total gamma widths there are several groups noticeably differing from each other by the structure of their wave functions. In addition, it was determined that radiative widths are much more sensitive than the neutron ones to resonance wave functions structure. Analysis of early obtained neutron reduced widths distribution parameters for 157 resonance sets in the mass region of nuclei 35 ≤ A ≤ 249 was also performed. It was shown that the experimental values of widths can correspond with high probability to superposition of several expected independent distributions with their nonzero mean values and nonunit dispersion

  17. Total neutron cross sections of berkelium-249 and californium-249 below 100 eV

    International Nuclear Information System (INIS)

    Benjamin, R.W.; Harvey, J.A.; Hill, N.W.; Pandey, M.S.; Carlton, R.F.

    1979-01-01

    The neutron total cross sections of 249 Bk and 249 Cf have been measured from 0.03 to 100 eV using the Oak Ridge Electron Linear Accelerator (ORELA) as a source of pulsed neutrons. The 1.6 mm dia. cylindrical transmission samples contained initially up to 5.3 mg of 98% 249 Bk and 2% 249 Cf: 4.5 years later, when the final measurements were made, the composition of the samples had become 2.5% 249 Bk, 96.9% 249 Cf, and 0.6% 245 Cm. Samples were cooled with liquid nitrogen to reduce Doppler broadening. Thirty-nine resonances were identified in 249 Bk and analyzed using a single-level Breit-Wigner formalism. Fifty-five resonances were identified in 249 Cf and analyzed using an R-matrix multilevel formalism. Fifty-five resonances were identified in 249 Cf and analyzed using an R-matrix multilevel formalism. The resonance parameters obtained have been used to determine the average level spacings and the s-wave neutron and fission strength functions. Where possible, bound-level parameters were derived to fit the thermal neutron total cross section data

  18. Evaluation of B10Plus+* proportional detectors for neutron coincidence counting

    Energy Technology Data Exchange (ETDEWEB)

    Beddingfield, David H.; Yoon, Seokryung [International Atomic Energy Agency, Vienna International Centre, PO Box 100, 1400 Vienna, (Austria)

    2015-07-01

    GE-Reuter-Stokes (GERS) has developed a new line of neutron proportional counters, the B10Plus+* proportional counter. The detector design is intended to serve as a cost-effective alternative to traditional {sup 3}He proportional counters in a variety of applications. The detector is a hybrid design 10B-lined tube optimized with the addition of a small quantity of 3He gas to improve the detector performance and efficiency. As a demonstration of the B10Plus+* detector, GERS has constructed a Uranium Neutron Collar (UNCL) system consisting of B-10Plus+* proportional counters. GERS has designed and built a demonstration UNCL system intended to match the performance of a Type-I UNCL design in Pressurized Water Reactor (PWR) geometry operating in thermal mode. GERS offered their system on loan to the International Atomic Energy Agency (IAEA) Safeguards Division of Technical and Scientific Services for an assessment of the detector technology and the demonstration system. We have characterized the demonstration UNCL system and compared its performance with a traditional Type-I UNCL design in regular use by the IAEA. This paper summarizes our findings and observations during the characterization and testing activity. (authors)

  19. Immature germ cells in semen ? correlation with total sperm count and sperm motility

    OpenAIRE

    Patil, Priya S.; Humbarwadi, Rajendra S.; Patil, Ashalata D.; Gune, Anita R.

    2013-01-01

    Background: Current data regarding infertility suggests that male factor contributes up to 30% of the total cases of infertility. Semen analysis reveals the presence of spermatozoa as well as a number of non-sperm cells, presently being mentioned in routine semen report as "round cells" without further differentiating them into leucocytes or immature germ cells. Aim: The aim of this work was to study a simple, cost-effective, and convenient method for differentiating the round cells in se...

  20. Sigma-R: an improved version of the delayed neutron counting device for THTR fuel element verification

    International Nuclear Information System (INIS)

    Galantucci, R.; Haas, R.; Janssens, A.; Agostini, P.; Becker, L.; Bernede, M.; Caldon, L.; Cordani, G.; Guardini, S.

    1989-01-01

    SIGMA is a device designed for the Safeguards verification measurements of the 235 U content of THTR (or AVR) pebble fuel elements; it has been in operation for more than 12 years at the HOBEG fuel fabrication plant in HANAU (FRG). The THTR fuel element is a 60 mm diameter sphere composed of particles of a U-Th mixture in a graphite matrix. The device is schematically composed of an irradiation facility where the pebble is irradiated by 252 Cf and a counting facility where the delayed fission neutrons are monitored. The system has recently been thoroughly updated, the modified instrument being called SIGMA-R. SIGMA-R automatically governs the whole charge-discharge, irradiation and counting sequence, collects the measured counts in the microprocessor memory and performs the relevant calculations, including the statistical evaluation. The instructions are given interactively to the inspector through an IRIS terminal. SIGMA-R provides extensive self diagnosis features. The inspector is also informed explicity of malfunctions during routine operation. The instrument is equipped with a permanent memory which facilitates the inspector's work considerably. SIGMA is complementary to the so-called fuel pebble sampling devices (FPSD) which are designed to take a random sample of 10 pebbles out of 1000 directly from the production line. With SIGMA-R it is now possible to measure the 235 U content of THTR pebbles very accurately. The uncertainty essentially is limited to Poisson statistics and allows us to evaluate the 235 U content in routine operation, with a random error down to 0.15% and a systematic uncertainty estimated at 0.25%, the latter coming from calibration and normalization procedures

  1. Gamma-spectrometric and total alpha-beta counting methods for radioactivity analysis of deuterium depleted water

    International Nuclear Information System (INIS)

    Ferdes, Ov. S.; Mladin, C.; Vladu, Mihaela; Bulubasa, G.; Bidica, N.

    2008-01-01

    According to national regulations, as well as to the EU directive on the quality of drinking water, the radionuclide concentrations represent some of the drinking water quality parameters. Among the most important radioactivity content parameters are: the total alpha and total beta concentration (Bq/l); K-40 content, and the gamma-nuclides volume activities. The paper presents the measuring methods for low-level total alpha and/or beta counting of volume samples, as well as the high-resolution gamma-ray spectrometric method used to measure the volume activity of nuclides in drinking water. These methods are applied to monitor the radioactivity content and quality of the QLARIVIA brand of Deuterium depleted water (DDW). There are discussed the performances of these applied methods as well as some preliminary results. (authors)

  2. Preliminary stochastic model for managing Vibrio parahaemolyticus and total viable bacterial counts in a Pacific oyster (Crassostrea gigas) supply chain.

    Science.gov (United States)

    Fernandez-Piquer, Judith; Bowman, John P; Ross, Tom; Estrada-Flores, Silvia; Tamplin, Mark L

    2013-07-01

    Vibrio parahaemolyticus can accumulate and grow in oysters stored without refrigeration, representing a potential food safety risk. High temperatures during oyster storage can lead to an increase in total viable bacteria counts, decreasing product shelf life. Therefore, a predictive tool that allows the estimation of both V. parahaemolyticus populations and total viable bacteria counts in parallel is needed. A stochastic model was developed to quantitatively assess the populations of V. parahaemolyticus and total viable bacteria in Pacific oysters for six different supply chain scenarios. The stochastic model encompassed operations from oyster farms through consumers and was built using risk analysis software. Probabilistic distributions and predictions for the percentage of Pacific oysters containing V. parahaemolyticus and high levels of viable bacteria at the point of consumption were generated for each simulated scenario. This tool can provide valuable information about V. parahaemolyticus exposure and potential control measures and can help oyster companies and regulatory agencies evaluate the impact of product quality and safety during cold chain management. If coupled with suitable monitoring systems, such models could enable preemptive action to be taken to counteract unfavorable supply chain conditions.

  3. On unfolding counting-rate spectra of recoil-proton neutron detectors

    International Nuclear Information System (INIS)

    Yeivin, Yehuda

    1983-01-01

    This note proposes a possible scheme for unfolding recoil-proton neutron detector data, in which at first the undistorted proton source spectrum is derived. The main argument in favour of this scheme is that, compared with the conventional scheme, it necessitates somewhat weaker assumptions with respect to the unknown spectrum above the detector's upper energy cutoff, and would therefore be more reliable. We also demonstrate a simple, elementary proof of the wall effect correction for spherical detectors, and, in order to gain insight of the potential merits of the proposed unfolding scheme, illustrate our main argument by considering a hypothetic linear range-energy relation, in which case complete unfolding becomes possible with no assumptions at all on the proton spectrum above the cutoff energy. (author)

  4. Characterizations of double pulsing in neutron multiplicity and coincidence counting systems

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, Katrina E., E-mail: kkoehler@lanl.gov [Los Alamos National Laboratory, P. O. Box 1663, Los Alamos, NM 87545 (United States); Henzl, Vladimir [Los Alamos National Laboratory, P. O. Box 1663, Los Alamos, NM 87545 (United States); Croft, Stephen S. [Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37831 (United States); Henzlova, Daniela; Santi, Peter A. [Los Alamos National Laboratory, P. O. Box 1663, Los Alamos, NM 87545 (United States)

    2016-10-01

    Passive neutron coincidence/multiplicity counters are subject to non-ideal behavior, such as double pulsing and dead time. It has been shown in the past that double-pulsing exhibits a distinct signature in a Rossi-alpha distribution, which is not readily noticed using traditional Multiplicity Shift Register analysis. However, it has been assumed that the use of a pre-delay in shift register analysis removes any effects of double pulsing. In this work, we use high-fidelity simulations accompanied by experimental measurements to study the effects of double pulsing on multiplicity rates. By exploiting the information from the double pulsing signature peak observable in the Rossi-alpha distribution, the double pulsing fraction can be determined. Algebraic correction factors for the multiplicity rates in terms of the double pulsing fraction have been developed. We discuss the role of these corrections across a range of scenarios.

  5. Total cross section measurement of radioactive isotopes with a thin beam neutron spectrometer

    International Nuclear Information System (INIS)

    Razbudej, V.F.; Vertebnyj, V.P.; Padun, G.S.; Muravitskij, A.V.

    1975-01-01

    The method for measuring the neutron total cross sections of radioactive isotopes by a time-of-flight spectrometer with a narrow (0.17 mm in diameter) beam of thermal neutrons is described. The distinguishing feature of this method is the use of capillary samples with a small amount of substance (0.05-1.0 mg). The energy range is 0.01-0.3 eV. The total cross sections of irradiated samples of sub(153)Eu and sub(151)Eu are measured. From them are obtained the cross sections of sub(152)Eu (Tsub(1/2)=12.4 g) and of sub(154)E (Tsub(1/2)=8.6 yr); they equal 11400+-1400 and 1530+-190 barn at E=0.0253 eV. The cross section of the sub(152)Eu absorption for the thermal spectrum (T=333 K) is determined by the activation method; it is 8900+-1200 barn

  6. How much locomotive activity is needed for an active physical activity level: analysis of total step counts

    Directory of Open Access Journals (Sweden)

    Ohkawara Kazunori

    2011-11-01

    Full Text Available Abstract Background Although physical activity recommendations for public health have focused on locomotive activity such as walking and running, it is uncertain how much these activities contribute to overall physical activity level (PAL. The purpose of the present study was to determine the contribution of locomotive activity to PAL using total step counts measured in a calorimeter study. Methods PAL, calculated as total energy expenditure divided by basal metabolic rate, was evaluated in 11 adult men using three different conditions for 24-hour human calorimeter measurements: a low-activity day (L-day targeted at a low active level of PAL (1.45, and a high-frequency moderate activity day (M-day or a high-frequency vigorous activity day (V-day targeted at an active level of PAL (1.75. These subjects were permitted only light activities except prescribed activities. In a separate group of 41 adults, free-living PAL was evaluated using doubly-labeled water (DLW. In both experiments, step counts per day were also measured using an accelerometer. Results In the human calorimeter study, PAL and step counts were 1.42 ± 0.10 and 8,973 ± 543 steps/d (L-day, 1.82 ± 0.14 and 29,588 ± 1,126 steps/d (M-day, and 1.74 ± 0.15 and 23,755 ± 1,038 steps/d (V-day, respectively. In the DLW study, PAL and step counts were 1.73 ± 0.15 and 10,022 ± 2,605 steps/d, and there was no significant relationship between PAL and daily step counts. Conclusions These results indicate that an enormous number of steps are needed for an active level of PAL if individuals extend physical activity-induced energy expenditure by only locomotive activity. Therefore, non-locomotive activity such as household activity should also play a significant role in increasing PAL under free-living conditions.

  7. Phase space representation of neutron monitor count rate and atmospheric electric field in relation to solar activity in cycles 21 and 22.

    Science.gov (United States)

    Silva, H G; Lopes, I

    Heliospheric modulation of galactic cosmic rays links solar cycle activity with neutron monitor count rate on earth. A less direct relation holds between neutron monitor count rate and atmospheric electric field because different atmospheric processes, including fluctuations in the ionosphere, are involved. Although a full quantitative model is still lacking, this link is supported by solid statistical evidence. Thus, a connection between the solar cycle activity and atmospheric electric field is expected. To gain a deeper insight into these relations, sunspot area (NOAA, USA), neutron monitor count rate (Climax, Colorado, USA), and atmospheric electric field (Lisbon, Portugal) are presented here in a phase space representation. The period considered covers two solar cycles (21, 22) and extends from 1978 to 1990. Two solar maxima were observed in this dataset, one in 1979 and another in 1989, as well as one solar minimum in 1986. Two main observations of the present study were: (1) similar short-term topological features of the phase space representations of the three variables, (2) a long-term phase space radius synchronization between the solar cycle activity, neutron monitor count rate, and potential gradient (confirmed by absolute correlation values above ~0.8). Finally, the methodology proposed here can be used for obtaining the relations between other atmospheric parameters (e.g., solar radiation) and solar cycle activity.

  8. Improovement of statistical counting conditions for the determination of chloride in Beams leaves (Phaseolus vulgaris L.) by thermal neutron activation analysis

    International Nuclear Information System (INIS)

    Ferraz, E.S.B.; Nascimento Filho, V.F.

    1975-04-01

    The use of two radiation peaks from the same gamma-emitting source in the calculation of the corresponding liquid counting rate in multi-element gamma spectrometry is discussed. It is shown that, in the determination of chlorine in Phaseolus vulgaris L. using neutronic activation analysis will result in an increase in accuracy of measurement of approximately 40%

  9. Measurement of total body chlorine by prompt gamma in vivo neutron activation analysis

    International Nuclear Information System (INIS)

    Beddoe, A.H.; Streat, S.J.; Hill, G.L.

    1987-01-01

    A method of measuring total body chlorine (TBCl) by prompt gamma in vivo neutron activation analysis is described depending on the same NaI(Tl) spectra used for determinations of total body nitrogen. Ratios of chlorine to hydrogen are derived and TBCl determined using a model of body composition depending on measured body weight, total body water (by tritium dilution) and protein (6.25 x nitrogen) as well as estimated body minerals and glycogen. The precision of the method based on scanning an anthropomorphic phantom is approximately 9% (SD), for a patient dose equivalent of less than 0.30 mSv. Spectra collected from 67 normal volunteers (32 male, 35 female) yielded mean values of TBCl of 72 +- 19 (SD) g in males and 53.6 +- 15 g in females, in broad agreement with values reported by workers using delayed gamma methods. Results are presented for two human cadavers analysed by neutron activation and conventional chemical analysis; the ratios of TBCl (neutron activation) to TBCl (chemical) were 0.980 +- 0.028 (SEM) and 0.91 +- 0.09. It is suggested that an improvement in precision will be achieved by increasing the scanning time (thereby increasing the radiation dose equivalent) and by adding two more detectors. (author)

  10. High resolution neutron total and capture cross-sections in separated isotopes of copper (6365Cu)

    International Nuclear Information System (INIS)

    Pandey, M.S.

    1975-01-01

    High resolution neutron total and capture cross section measurements have been performed on separated isotopes of copper ( 63 65 Cu). Measurements for capture cross section were made from about 1 keV to a few hundreds of keV. The total cross section measurements were made in the energy interval of approximately 10 keV to 150 keV. The resulting capture data have been analyzed by a generalized least square peak fitting computer code in the energy interval of 2.5 keV to 50 keV. Photon strengths are determined using the data up to approximately 250 keV. The resulting total cross section data have been analyzed by area-analysis on the transmission values and by R-matrix multilevel code on cross section values. Average s- and p-wave level spacing and s- and p-wave strength function values are determined. From the resonance parameters thus obtained, by the analysis, statistical distribution is studied for s- and p-wave level spacings and reduced neutron widths. A comparison has been made for adjacent level spacings with the theoretical predictions of level repulsion (of same J/sup π/) by Wigner considering levels with various spin states separately for s-wave resonances where confident spin assignment has been possible. Reduced neutron widths are compared with the Porter-Thomas distribution. Optical model formulated by Feshbach, Porter and Weiskopf describes the neutron-nucleus interaction. A comparison has been made between experimentally determined values of the s- and p-wave strength functions and that obtainable from optical model calculations, thereby determining the appropriate optical model parameters. The experimental arrangement, pertinent theoretical discussion, and the processes of data reduction and the analyses along with the comparison of the previously reported results with the present work are presented in detail

  11. Normal levels of total body sodium and chlorine by neutron activation analysis

    International Nuclear Information System (INIS)

    Kennedy, N.S.J.; Eastell, R.; Smith, M.A.; Tothill, P.

    1983-01-01

    In vivo neutron activation analysis was used to measure total body sodium and chlorine in 18 male and 18 female normal adults. Corrections for body size were developed. Normalisation factors were derived which enable the prediction of the normal levels of sodium and chlorine in a subject. The coefficient of variation of normalised sodium was 5.9% in men and 6.9% in women, and of normalised chlorine 9.3% in men and 5.5% in women. In the range examined (40-70 years) no significant age dependence was observed for either element. Total body sodium was correlated with total body chlorine and total body calcium. Sodium excess, defined as the amount of body sodium in excess of that associated with chlorine, also correlated well with total body calcium. In females there was a mean annual loss of sodium excess of 1.2% after the menopause, similar to the loss of calcium. (author)

  12. In vivo Prompt Gamma Neutron Activation Analysis Facility for Total Body Nitrogen and Cd

    International Nuclear Information System (INIS)

    Munive, Marco; Revilla, Angel; Solis, Jose L.

    2007-01-01

    A Prompt Gamma Neutron Activation Analysis (PGNAA) system has been designed and constructed to measure the total body nitrogen and Cd for in vivo studies. An aqueous solution of KNO 3 was used as phantom for system calibration. The facility has been used to monitor total body nitrogen (TBN) of mice and found that is related to their diet. Some mice swallowed diluted water with Cl 2 Cd, and the presence of Cd was detected in the animals. The minimum Cd concentration that the system can detect was 20 ppm

  13. Prognostic relevance of lymph node ratio and total lymph node count for small bowel adenocarcinoma.

    Science.gov (United States)

    Tran, Thuy B; Qadan, Motaz; Dua, Monica M; Norton, Jeffrey A; Poultsides, George A; Visser, Brendan C

    2015-08-01

    Nodal metastasis is a known prognostic factor for small bowel adenocarcinoma. The goals of this study were to evaluate the number of lymph nodes (LNs) that should be retrieved and the impact of lymph node ratio (LNR) on survival. Surveillance, Epidemiology, and End Results was queried to identify patients with small bowel adenocarcinoma who underwent resection from 1988 to 2010. Survival was calculated with the Kaplan-Meier method. Multivariate analysis identified predictors of survival. A total of 2,772 patients underwent resection with at least one node retrieved, and this sample included equal numbers of duodenal (n = 1,387) and jejunoileal (n = 1,386) adenocarcinomas. There were 1,371 patients with no nodal metastasis (N0, 49.4%), 928 N1 (33.5%), and 474 N2 (17.1%). The median numbers of LNs examined for duodenal and jejunoileal cancers were 9 and 8, respectively. Cut-point analysis demonstrated that harvesting at least 9 for jejunoileal and 5 LN for duodenal cancers resulted in the greatest survival difference. Increasing LNR at both sites was associated with decreased overall median survival (LNR = 0, 71 months; LNR 0-0.02, 35 months; LNR 0.21-0.4, 25 months; and LNR >0.4, 16 months; P < .001). Multivariate analysis confirmed number of LNs examined, T-stage, LN positivity, and LNR were independent predictors of survival. LNR has a profound impact on survival in patients with small bowel adenocarcinoma. To achieve adequate staging, we recommend retrieving a minimum of 5 LN for duodenal and 9 LN for jejunoileal adenocarcinomas. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Fast-neutron total and scattering cross sections of elemental palladium

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.B.; Guenther, P.T.; Whalen, J.F.

    1982-06-01

    Neutron total cross sections of palladium are measured from approx. = 0.6 to 4.5 MeV with resolutions of approx. = 30 to 70 keV at intervals of less than or equal to 50 keV. Differential neutron elastic- and inelastic-scattering cross sections are measured from 1.4 to 3.85 MeV at intervals of 50 to 100 keV and at 10 to 20 scattering angles distributed between approx. = 20 and 160/sup 0/. The experimental results are compared with respective quantities given in ENDF/B-V and used to deduce an optical potential that provides a good description of the measured values.

  15. Fast-neutron total and scattering cross sections of elemental palladium

    International Nuclear Information System (INIS)

    Smith, A.B.; Guenther, P.T.; Whalen, J.F.

    1982-06-01

    Neutron total cross sections of palladium are measured from approx. = 0.6 to 4.5 MeV with resolutions of approx. = 30 to 70 keV at intervals of less than or equal to 50 keV. Differential neutron elastic- and inelastic-scattering cross sections are measured from 1.4 to 3.85 MeV at intervals of 50 to 100 keV and at 10 to 20 scattering angles distributed between approx. = 20 and 160 0 . The experimental results are compared with respective quantities given in ENDF/B-V and used to deduce an optical potential that provides a good description of the measured values

  16. One-speed neutron transport in spheres with totally absorbing cores

    International Nuclear Information System (INIS)

    Sjoestrand, N.G.

    1988-01-01

    Stationary and time-dependent transport of neutrons of one speed has been studied in spheres with totally absorbing cores. For stationary, critical reactors the number of secondaries per collision has been calculated numerically for various inner and outer radii. In the time-dependent case, the decay constant has been calculated for spherical shells of different inner radii and thicknesses. For a fixed ratio between shell thickness and inner radius, the curve of the decay constant versus shell thickness crosses the Corngold limit in the same way as the curve for a homogeneous sphere. When the ratio goes to zero the curve approaches that for an infinite slab. The behaviour is discussed in view of a new result from collision theory, viz. that the following condition must be fulfilled for a body at the point where the decay constant curve crosses the Corngold limit: the average exit distance of the neutrons is equal to the mean free path for scattering

  17. Fast-neutron total and scattering cross sections of 103Rh

    International Nuclear Information System (INIS)

    Smith, A.B.; Guenther, P.T.; Whalen, J.F.

    1982-07-01

    Fast-neutron total cross sections of 103 Rh are measured with 30 to 50 keV resolutions from 0.7 to 4.5 MeV. Differential elastic- and inelastic-scattering cross sections are measured from 1.45 to 3.85 MeV. Scattered-neutron groups corresponding to excited levels at 334 +- 13, 536 +- 7, 648 +- 25, 796 +- 20, 864 +- 22, 1120 +- 22, 1279 +- 50, 1481 +- 27, 1683 +- 39, 1840 +- 79, 1991 +- 71 and 2050 (tentative) keV are observed. An optical-statistical model is derived from the elastic-scattering results. The experimental values are compared with comparable quantities given in the ENDF/B-V evaluation

  18. Measurement of the polarized neutron---polarized 3He total cross section

    International Nuclear Information System (INIS)

    Keith, C.D.; Gould, C.R.; Haase, D.G.; Seely, M.L.; Huffman, P.R.; Roberson, N.R.; Tornow, W.; Wilburn, W.S.

    1995-01-01

    The first measurements of polarized neutron--polarized 3 He scattering in the few MeV energy region are reported. The total cross section difference Δσ T for transversely polarized target and beam has been measured for neutron energies between 1.9 and 7.5 MeV. Comparison is made to predictions of Δσ T using various descriptions of the 4 He continuum. A brute-force polarized target of solid 3 He has been developed for these measurements. The target is 4.3x10 22 atoms/cm 2 thick and is polarized to 38% at 7 Telsa and 12 mK. copyright 1995 American Institute of Physics

  19. Detection of illicit HEU production in gaseous centrifuge enrichment plants using neutron counting techniques on product cylinders

    International Nuclear Information System (INIS)

    Freeman, Corey R.; Geist, William H.

    2010-01-01

    Innovative and novel safeguards approaches are needed for nuclear energy to meet global energy needs without the threat of nuclear weapons proliferation. Part of these efforts will include creating verification techniques that can monitor uranium enrichment facilities for illicit production of highly-enriched uranium (HEU). Passive nondestructive assay (NDA) techniques will be critical in preventing illicit HEU production because NDA offers the possibility of continuous and unattended monitoring capabilities with limited impact on facility operations. Gaseous centrifuge enrichment plants (GCEP) are commonly used to produce low-enriched uranium (LEU) for reactor fuel. In a GCEP, gaseous UF 6 spins at high velocities in centrifuges to separate the molecules containing 238 U from those containing the lighter 235 U. Unfortunately, the process for creating LEU is inherently the same as HEU, creating a proliferation concern. Insuring that GCEPs are producing declared enrichments poses many difficult challenges. In a GCEP, large cascade halls operating thousands of centrifuges work together to enrich the uranium which makes effective monitoring of the cascade hall economically prohibitive and invasive to plant operations. However, the enriched uranium exiting the cascade hall fills product cylinders where the UF 6 gas sublimes and condenses for easier storage and transportation. These product cylinders hold large quantities of enriched uranium, offering a strong signal for NDA measurement. Neutrons have a large penetrability through materials making their use advantageous compared to gamma techniques where the signal is easily attenuated. One proposed technique for detecting HEU production in a GCEP is using neutron coincidence counting at the product cylinder take off stations. This paper discusses findings from Monte Carlo N-Particle eXtended (MCNPX) code simulations that examine the feasibility of such a detector.

  20. Total motile sperm count has a superior predictive value over the WHO 2010 cut-off values for the outcomes of intracytoplasmic sperm injection cycles.

    Science.gov (United States)

    Borges, E; Setti, A S; Braga, D P A F; Figueira, R C S; Iaconelli, A

    2016-09-01

    The objective of this study was to compare (i) the intracytoplasmic sperm injection outcomes among groups with different total motile sperm count ranges, (ii) the intracytoplasmic sperm injection outcomes between groups with normal and abnormal total motile sperm count, and (iii) the predictive values of WHO 2010 cut-off values and pre-wash total motile sperm count for the intracytoplasmic sperm injection outcomes, in couples with male infertility. This study included data from 518 patients undergoing their first intracytoplasmic sperm injection cycle as a result of male infertility. Couples were divided into five groups according to their total motile sperm count: Group I, total motile sperm count sperm count 1-5 × 10(6) ; group III, total motile sperm count 5-10 × 10(6) ; group IV, total motile sperm count 10-20 × 10(6) ; and group V, total motile sperm count >20 × 10(6) (which was considered a normal total motile sperm count value). Then, couples were grouped into an abnormal and normal total motile sperm count group. The groups were compared regarding intracytoplasmic sperm injection outcomes. The predictive values of WHO 2010 cut-off values and total motile sperm count for the intracytoplasmic sperm injection outcomes were also investigated. The fertilization rate was lower in total motile sperm count group I compared to total motile sperm count group V (72.5 ± 17.6 vs. 84.9 ± 14.4, p = 0.011). The normal total motile sperm count group had a higher fertilization rate (84.9 ± 14.4 vs. 81.1 ± 15.8, p = 0.016) and lower miscarriage rate (17.9% vs. 29.5%, p = 0.041) compared to the abnormal total motile sperm count group. The total motile sperm count was the only parameter that demonstrated a predictive value for the formation of high-quality embryos on D2 (OR: 1.18, p = 0.013), formation of high-quality embryos on D3 (OR: 1.12, p = 0.037), formation of blastocysts on D5 (OR: 1.16, p = 0.011), blastocyst expansion grade on D5

  1. Measurements of the total neutron cross-sections of poly- and mono-germanium crystals at neutron energies below 1 eV

    International Nuclear Information System (INIS)

    Maayouf, R.M.A.; Abdel-Kawy, A.; Abbas, Y.; Habib, N.; Adib, M.; Hamouda, I.

    1983-12-01

    Total neutron cross-section measurements have been performed for poly and mono-germanium crystals in the energy range from 2 meV-1eV. The measurements were performed using two TOF and a double axis crystal spectrometer installed at the ET-RR-1 reactor. The obtained neutron cross-sections were analyzed using the single level Breit-Wigner formula. The coherent scattering amplitude was determined from the Bragg reflections observed in the total neutron cross-section of Ge and the analysis of its neutron diffraction pattern. The incoherent and thermal diffuse scattering cross-sections of Ge were estimated from the analysis of the total cross-section data obtained for Ge mono-crystal

  2. Flow Cytometry Total Cell Counts: A Field Study Assessing Microbiological Water Quality and Growth in Unchlorinated Drinking Water Distribution Systems

    Science.gov (United States)

    Liu, G.; Van der Mark, E. J.; Verberk, J. Q. J. C.; Van Dijk, J. C.

    2013-01-01

    The objective of this study was to evaluate the application of flow cytometry total cell counts (TCCs) as a parameter to assess microbial growth in drinking water distribution systems and to determine the relationships between different parameters describing the biostability of treated water. A one-year sampling program was carried out in two distribution systems in The Netherlands. Results demonstrated that, in both systems, the biomass differences measured by ATP were not significant. TCC differences were also not significant in treatment plant 1, but decreased slightly in treatment plant 2. TCC values were found to be higher at temperatures above 15°C than at temperatures below 15°C. The correlation study of parameters describing biostability found no relationship among TCC, heterotrophic plate counts, and Aeromonas. Also no relationship was found between TCC and ATP. Some correlation was found between the subgroup of high nucleic acid content bacteria and ATP (R 2 = 0.63). Overall, the results demonstrated that TCC is a valuable parameter to assess the drinking water biological quality and regrowth; it can directly and sensitively quantify biomass, detect small changes, and can be used to determine the subgroup of active HNA bacteria that are related to ATP. PMID:23819117

  3. Flow Cytometry Total Cell Counts: A Field Study Assessing Microbiological Water Quality and Growth in Unchlorinated Drinking Water Distribution Systems

    Directory of Open Access Journals (Sweden)

    G. Liu

    2013-01-01

    Full Text Available The objective of this study was to evaluate the application of flow cytometry total cell counts (TCCs as a parameter to assess microbial growth in drinking water distribution systems and to determine the relationships between different parameters describing the biostability of treated water. A one-year sampling program was carried out in two distribution systems in The Netherlands. Results demonstrated that, in both systems, the biomass differences measured by ATP were not significant. TCC differences were also not significant in treatment plant 1, but decreased slightly in treatment plant 2. TCC values were found to be higher at temperatures above 15°C than at temperatures below 15°C. The correlation study of parameters describing biostability found no relationship among TCC, heterotrophic plate counts, and Aeromonas. Also no relationship was found between TCC and ATP. Some correlation was found between the subgroup of high nucleic acid content bacteria and ATP (R2=0.63. Overall, the results demonstrated that TCC is a valuable parameter to assess the drinking water biological quality and regrowth; it can directly and sensitively quantify biomass, detect small changes, and can be used to determine the subgroup of active HNA bacteria that are related to ATP.

  4. Prompt neutrons from {sup 236}U fission fragments

    Energy Technology Data Exchange (ETDEWEB)

    Boldeman, J W; Musgrove, A.R. de L.; Walsch, R L

    1971-03-01

    Measurements were made of prompt neutron emission in the thermal neutron fission of {sup 235}U. The mean neutron emission per fragment was obtained for particular values of the fragment mass and total kinetic energy. A direct neutron counting method was employed and a comparison made with data from previous experiments of this type. (author)

  5. Quantification of protein based on single-molecule counting by total internal reflection fluorescence microscopy with adsorption equilibrium

    International Nuclear Information System (INIS)

    Wang Lei; Xu Guang; Shi Zhikun; Jiang Wei; Jin Wenrui

    2007-01-01

    We developed a sensitive single-molecule imaging method for quantification of protein by total internal reflection fluorescence microscopy with adsorption equilibrium. In this method, the adsorption equilibrium of protein was achieved between solution and glass substrate. Then, fluorescence images of protein molecules in a evanescent wave field were taken by a highly sensitive electron multiplying charge coupled device. Finally, the number of fluorescent spots corresponding to the protein molecules in the images was counted. Alexa Fluor 488-labeled goat anti-rat IgG(H + L) was chosen as the model protein. The spot number showed an excellent linear relationship with protein concentration. The concentration linear range was 5.4 x 10 -11 to 8.1 x 10 -10 mol L -1

  6. SASSI, Total and Differential Elastic and Inelastic Neutron Cross-Sections by Hauser-Feshbach

    International Nuclear Information System (INIS)

    Benzi, V.; Fabbri, F.; Zuffi, L.

    2001-01-01

    1 - Nature of physical problem solved: Neutron total and differential elastic and inelastic cross-section evaluation by means of the statistical model of Hauser-Feshbach (1) as modified by D. Goldman (2) (3). The Goldman modification includes the effect of spin-orbit coupling on transmission coefficients. 2 - Method of solution: For numerical integration the Fox-Goodwins method is used. 3 - Restrictions on the complexity of the problem: Angular momentum I less than or equal to 50. Number of excited levels less than or equal to 30

  7. Total body calcium by neutron activation analysis. Reference data for children

    International Nuclear Information System (INIS)

    Ellis, K.J.; Shypailo, R.J.

    2001-01-01

    There is a paucity of data on the chemical composition of the human body during growth. Total body calcium (TBCa) has been reported for only one male child, aged 41/2 yr. TBCa values for 25 children and 27 young women using in vivo neutron activation analysis have been obtained. TBCa results were lower than those reported for the one male cadaver, as well as the estimates derived for the 'Reference Man' model. It was concluded that the reference values for TBCa may need to be adjusted to appropriately describe skeletal mineralization of contemporary children. (author)

  8. The use of Total Body In Vivo Neutron Activation Analysis (TBIVNAA) in balance studies in rodents

    International Nuclear Information System (INIS)

    Smith, D.A.; Lindsay, R.L.; Anderson, J.

    1976-01-01

    In the investigation of animals subject to alteration in diet or other metabolic experiments, the measurements of change in body calcium, phosphorus, sodium and nitrogen are of considerable interest. However, conventional balance studies are tedious and subject to both random and cumulative error, necessitating as they do accurate estimates of dietary intake and faecal and urinary output. The object of the present study was to determine the usefulness of total body in vivo neutron activation analysis, used at the beginning and end of the experimental period, as an alternative to conventional balance techniques. (orig.) [de

  9. Fast-neutron total and elastic-scattering cross sections of elemental indium

    International Nuclear Information System (INIS)

    Smith, A.B.; Guenther, P.T.; Whalen, J.F.

    1982-11-01

    Broad-resolution neutron total cross sections of elemental indium were measured from 0.8 to 4.5 MeV. Differential-elastic-scattering cross sections were measured from approx. = 1.5 to 3.8 MeV at intervals of approx. = 50 to 200 keV and at scattering angles in the range 20 to 160 degrees. The experimental results are interpreted in terms of the optical-statistical model and are compared with respective values given in ENDF/B-V

  10. Development Of A Method For Measurement Of Total Neutron Cross Sections Based On The Neutron Transmission Method Using A He-3 Counter On Filtered Neutron Beams At Dalat Research Reactor

    International Nuclear Information System (INIS)

    Tran Tuan Anh; Dang Lanh; Nguyen Canh Hai; Nguyen Xuan Hai; Pham Kien; Nguyen Thuy Nham; Pham Ngoc Son; Ho Huu Thang

    2007-01-01

    Determination of total neutron cross sections and average resonance parameters in the energy range from tens keV to hundreds keV is important for fast reactors calculations and designs because this energy range gives the most output of all neutron induced reactions in the spectrum of fast reactors. Besides, the total neutron cross section measurement is also one of the methods for determination of s, p and d-wave neutron strength functions. The purpose of this project is to develop a method for measurement of total neutron cross sections based on the neutron transmission technique using a He-3 counter. The average total neutron cross sections of 238 U were obtained from neutron transmission measurements on filtered neutron beams of 55 keV and 144 keV at the horizontal channel No.4 of the Dalat research reactor. The present results have been compared with the previous measurements, and the evaluated data from ENDF/B-6.8 library. (author)

  11. Evaluation of the total gamma-ray production cross-sections for nonelastic interaction of fast neutrons with iron nuclei

    International Nuclear Information System (INIS)

    Savin, M.V.; Nefedov, Yu.Ya; Livke, A.V.; Zvenigorodskij, A.G.

    2001-01-01

    Experimental data on the total gamma-ray production cross-sections for inelastic interaction of fast neutrons with iron nuclei were analysed. The total gamma-ray production cross-sections, grouped according to E γ , were evaluated in the neutron energy range 0.5-19 MeV. The statistical spline approximation method was used to evaluate the experimental data. Evaluated data stored in the ENDF, JENDL, BROND, and other libraries on gamma-ray production spectra and cross-sections for inelastic interaction of fast neutrons with iron nuclei, were analysed. (author)

  12. Measurements and analysis of the 127I and 129I neutron capture and total cross sections

    International Nuclear Information System (INIS)

    Noguere, G.

    2005-01-01

    Most of the experimental work on the interaction of neutrons with matter has focused on materials important to reactor physics and reactor structures. By comparison, the corresponding data for minor actinides or long-lived fission products are poor. A significant demand has developed for improved neutron cross-section data of these little-studied nuclides due to the surge of interest in the transmutation of nuclear waste. With 400 kg of 129 I produced yearly in the reactors of the EU countries and a very long β - half-life of 1.57 x 10 7 years, iodine requires disposal strategies that will isolate this isotope from the environment for long periods of time. Therefore, 129 I is potentially a key long-lived fission product for transmutation applications, since 129 I transmutes in 130 I after a single neutron capture and decays to 130 Xe with a 12.36 h half-life. Accurate capture cross sections would help to reduce uncertainties in waste management concepts. For that purpose, Time-Of-Flight measurements covering the [0.5 eV-100 keV] energy range have been carried out at the 150 MeV pulsed neutron source GELINA of the Institute for Reference Materials and Measurements (IRMM). Two types of experiments have been performed at the IRMM, namely capture and transmission experiments. They are respectively related to the neutron capture and total cross sections. Since the PbI 2 samples used in this work contain natural and radioactive iodine, extensive measurements of 129 I have been carried out under the same experimental conditions as for the 129 I. The data reduction process was performed with the AGS system, and the resonance parameters were extracted with the SAMMY and REFIT shape analysis codes. In a last step, the parameters have been converted into ENDF-6 format and processed with the NJOY code to produce point-wise and multigroup cross sections, as well as MCNP and ERANOS libraries. (author)

  13. Effects of Wine by-Products on Growth Performance, Complete Blood Count and Total Antioxidant Status in Broilers

    Directory of Open Access Journals (Sweden)

    SM Pascariu

    Full Text Available ABSTRACT This study aimed to investigate the effect of whole grape pomace (GP, grape seed (GS and grape pomace polyphenolic extract (GPEP on growth performance, total antioxidant status (TAS and complete blood count (CBC of 40-day-old chicks (hybrid Cobb 500. A total of 432 unsexed one-day-old chicks were divided into six groups: control (CON and five experimental groups, 10 g/kg GP, 20 g/kg GP, 5 g/kg GS, 10 g/kg GS and 15 mL/L GPEP. The results showed a higher increase in growing rate in 5 g/kg GS group, from the first week of the chicks’ life throughout their growth, the average body weight of the chicks being significantly higher (p0.05 at 40 days of age. As a conclusion, the amount of 5 g/kg seeds, 10 g/kg and 20 g/kg pomace, can be added to the diet of the broilers, the dose of 5 g/kg seeds in the diet offering advantages in growing rate and feed valorization in weight gain.

  14. Failure of Stadard Optical Models to Reproduce Neutron Total Cross Section Difference in the W Isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, J D; Bauer, R W; Dietrich, F S; Grimes, S M; Finlay, R W; Abfalterer, W P; Bateman, F B; Haight, R C; Morgan, G L; Bauge, E; Delaroche, J P; Romain, P

    2001-11-01

    Recently cross section differences among the isotopes{sup 182,184,186}W have been measured as part of a study of total cross sections in the 5-560 MeV energy range. These measurements show oscillations up to 150 mb between 5 and 100 MeV. Spherical and deformed phenomenological optical potentials with typical radial and isospin dependences show very small oscillations, in disagreement with the data. In a simple Ramsauer model, this discrepancy can be traced to a cancellation between radial and isospin effects. Understanding this problem requires a more detailed model that incorporates a realistic description of the neutron and proton density distributions. This has been done with results of Hartree-Fock-Bogolyubov calculations using the Gogny force, together with a microscopic folding model employing a modification of the JLM potential as an effective interaction. This treatment yields a satisfactory interpretation of the observed total cross section differences.

  15. A recent investigation of neutron total cross section of zirconium in the wavelength range (0.1-1.25) Ao

    International Nuclear Information System (INIS)

    Abu El-Ela, M.A.

    1996-01-01

    The neutron total cross section of zirconium has been investigated in the neutron wavelength range (0.1 -1.52) A o by using slow neutron time of flight spectrometer, installed in front of the horizontal channel No.6 of the ETRR-1 reactor (2MW). The results have showed that the neutrons with short wavelength (0.1 - 0.76) A o cannot interact with the crystal structure while it can interact with the free bound atom to give the value (6.2 +0.1) barns for the potential scattering cross section or (the scattering length = 6.2 fermi)). The present measured value is in good agreement with the international published values by different technique. The neutrons with longer wavelength (0.76 - 1.52) A o have showed dependence of the total cross section on the neutron wavelength. Such dependence between the total cross section and the neutron wavelength can not be observed in the reported previous measurements, which can be attributed to the limited number of the measured values. 4 figs

  16. Reference values for maternal total and differential leukocyte counts in different trimesters of pregnancy and the initial postpartum period in western Turkey.

    Science.gov (United States)

    Sanci, Muzaffer; Töz, Emrah; Ince, Onur; Özcan, Aykut; Polater, Kevser; Inan, Abdurrahman Hamdi; Beyan, Emrah; Akkaya, Emrah

    2017-07-01

    The aim of this study was to investigate alterations in the leukocyte and differential leukocyte counts in different trimesters of pregnancy and the initial postpartum period. The study population consisted of 40,325 pregnant women. A full blood count and automated differential leukocyte count were performed and all the haemogram results in the different trimesters of pregnancy were recorded. Percentiles were calculated using statistical software. A total of 82,786 complete blood count evaluations were performed in 40,325 subjects from the 6th to 41st week of pregnancy and in the initial postpartum period. The leukocyte counts increased from the 1st to the 3rd trimester and peaked in the initial postpartum period. Our reference values for the total and differential leukocyte counts may assist clinicians in distinguishing between leukocytosis and pathological elevation of the white blood cell count during pregnancy and the initial postpartum period. Impact statement Pregnancy requires profound adaptation by multiple systems to accommodate the demands of the developing foetus. Similar to all other systems, many haematological changes occur during pregnancy. Studies of normal variation in leukocyte counts were insufficient to distinguish normal from abnormal leukocyte counts during pregnancy and in the initial postpartum period, due to small numbers of patients and a lack of differential leukocyte counts. Without reference leukocyte levels, infections may be more difficult to assess during pregnancy and in the postpartum period. In this study, we report the 3rd, 5th, 10th, 50th, 95th and 99th percentile values for the total and differential leukocyte counts according to trimester in normal pregnancy and the initial postpartum period. Our reference values for the total and differential leukocyte counts in each trimester and the initial postpartum period may assist clinicians in distinguishing between normal leukocytosis and pathological elevation of the white blood

  17. Preliminary results of total kinetic energy modelling for neutron-induced fission

    International Nuclear Information System (INIS)

    Visan, I.; Giubega, G.; Tudora, A.

    2015-01-01

    The total kinetic energy as a function of fission fragments mass TKE(A) is an important quantity entering in prompt emission calculations. The experimentally distributions of TKE(A) are referring to a limited number of fission systems and incident energies. In the present paper, a preliminary model for TKE calculation in neutron induced fission system is presented. The range of fission fragments is chosen as in the Point by Point treatment. The model needs as input only mass excesses and deformation parameters taken from available nuclear databases being based on the following approximations: total excitation energy of fully accelerated fission fragments TXE is calculated from energy balance of neutron-induced fission systems as sum of the total excitation energy at scission E*sciss and deformation energy Edef. The deformation energy at scission is given by minimizing the potential energy at the scission configuration. At the scission point, the fission system is described by two spheroidal fragments nearly touching by a pre-scission distance or neck caused by the nuclear forces between fragments. Therefore, the Columbian repulsion depending on neck and, consequently, on the fragments deformation at scission, is essentially in TKE determination. An approximation is made based on the fission modes. For the very symmetric fission, the dominant super long channel is characterized by long distance between fragments leading to low TKE values. Due to magic and double-magic shells closure, the dominant S1 fission mode for pairs with heavy fragment mass AH around 130-134 is characterized by spherical heavy fragment shape and easily deformed light fragment. The nearly spherical shape of the complementary fragments are characterized by minimum distance, and consequently to maximum TKE values. The results obtained for TKE(A) are in good agreement with existing experimental data for many neutron induced fission systems, e.g. ''2''3''3&apos

  18. Comparison of pregnancy rates in pre-treatment male infertility and low total motile sperm count at insemination.

    Science.gov (United States)

    Xiao, Cheng Wei; Agbo, Chioma; Dahan, Michael H

    2016-01-01

    In intrauterine insemination (IUI), total motile sperm count (TMSC) is an important predictor of pregnancy. However, the clinical significance of a poor TMSC on the day of IUI in a patient with prior normal semen analysis (SA) is unclear. We performed this study to determine if these patients perform as poorly as those who had male factor infertility diagnosed prior to commencing treatment. 147 males with two abnormal SA based on the 2010 World Health Organization criteria underwent 356 IUI with controlled ovarian hyper-stimulation (COH). Their pregnancy rates were compared to 120 males who had abnormal TMSC at the time of 265 IUI with COH, in a retrospective university-based study. The two groups were comparable in female age (p = 0.11), duration of infertility (p = 0.17), previous pregnancies (p = 0.13), female basal serum FSH level (p = 0.54) and number of mature follicles on the day of ovulation trigger (p = 0.27). Despite better semen parameters on the day of IUI in the pre-treatment male factor infertility group (TMSC mean ± SD: 61 ± 30 million vs. 3.5 ± 2 million, p male factor infertility. More studies should be performed to confirm these findings.

  19. Near infrared system coupled chemometric algorithms for enumeration of total fungi count in cocoa beans neat solution.

    Science.gov (United States)

    Kutsanedzie, Felix Y H; Chen, Quansheng; Hassan, Md Mehedi; Yang, Mingxiu; Sun, Hao; Rahman, Md Hafizur

    2018-02-01

    Total fungi count (TFC) is a quality indicator of cocoa beans when unmonitored leads to quality and safety problems. Fourier transform near infrared spectroscopy (FT-NIRS) combined with chemometric algorithms like partial least square (PLS); synergy interval-PLS (Si-PLS); synergy interval-genetic algorithm-PLS (Si-GAPLS); Ant colony optimization - PLS (ACO-PLS) and competitive-adaptive reweighted sampling-PLS (CARS-PLS) was employed to predict TFC in cocoa beans neat solution. Model results were evaluated using the correlation coefficients of the prediction (Rp) and calibration (Rc); root mean square error of prediction (RMSEP), and the ratio of sample standard deviation to RMSEP (RPD). The developed models performance yielded 0.951≤Rp≤0.975; and 3.15≤RPD≤4.32. The models' prediction stability improved in the order of PLS

  20. Effect of gamma irradiation on shelf life extension, total counts of microbials and biochemical sensory change on luncheon meat

    International Nuclear Information System (INIS)

    Al-Bachir, M.; Mehyou, A.

    1999-11-01

    To investigate the effect of gamma irradiation and sodium nitrate on storability and marketability of luncheon, packed luncheon was exposed to several treatments; gamma irradiation at doses 0, 1, 2, 3 and 4 KGy using a 60 CO package irradiator, mixed with sodium nitrite (NaNO 2 ) 60 mg/Kg meat, with no irradiation and a combined treatment of both NaNO 2 treatment and irradiated with a dose of 2 KGy only. Half of the irradiated and unirradiated samples were stored in refrigeration (1-4 centigrade), to study storability and the second half were stored at room temperature (18-20 centigrade) to study marketability of luncheon. During storage period the population of microorganisms, biochemical changes and sensory properties were evaluated every two weeks for the refrigerated samples and weekly for the unrefrigerated samples. The results indicated that gamma irradiation and sodium nitrite reduced the counts of microorganisms and increased the shelf-life of luncheon. Both treatments (irradiation, sodium nitrite) increased total acidity, lipid oxidation, and the volatile basic nitrogen (VBN) immediately after processing and reduced all of them through out storage. Sensory evaluation (firmness, color, taste, and flavor) indicated no significant differences (P>0.05) between treated and untreated samples. (author)

  1. Effect of gamma irradiation on shelf life extension, total counts of microbials and biochemical sensory change on luncheon meat

    Energy Technology Data Exchange (ETDEWEB)

    Al-Bachir, M; Mehyou, A [Atomic Energy Commission, Dept. of Radiation Technology, Damascus (Syrian Arab Republic)

    1999-11-01

    To investigate the effect of gamma irradiation and sodium nitrate on storability and marketability of luncheon, packed luncheon was exposed to several treatments; gamma irradiation at doses 0, 1, 2, 3 and 4 KGy using a {sup 60} CO package irradiator, mixed with sodium nitrite (NaNO{sub 2}) 60 mg/Kg meat, with no irradiation and a combined treatment of both NaNO{sub 2} treatment and irradiated with a dose of 2 KGy only. Half of the irradiated and unirradiated samples were stored in refrigeration (1-4 centigrade), to study storability and the second half were stored at room temperature (18-20 centigrade) to study marketability of luncheon. During storage period the population of microorganisms, biochemical changes and sensory properties were evaluated every two weeks for the refrigerated samples and weekly for the unrefrigerated samples. The results indicated that gamma irradiation and sodium nitrite reduced the counts of microorganisms and increased the shelf-life of luncheon. Both treatments (irradiation, sodium nitrite) increased total acidity, lipid oxidation, and the volatile basic nitrogen (VBN) immediately after processing and reduced all of them through out storage. Sensory evaluation (firmness, color, taste, and flavor) indicated no significant differences (P>0.05) between treated and untreated samples. (author)

  2. TOTAL HEMOCYTE COUNT AND HEMOLYMPH GLUCOSE CONCENRATION RESPONSE OF SPINY LOBSTER Panulirus homarus ON RATIO OF SHELTER

    Directory of Open Access Journals (Sweden)

    Suhaiba Djai

    2017-11-01

    Full Text Available This research was conducted to assess the physiological response of the lobster Panulirus homarus for the ratio of the shelters. The method used completely randomized design with two replicates of each treatments with shelter ratio (A 1 : 5, (B 3 : 5, (C 4 : 5, (D 5 : 5. Weight average for 184 lobsters with the stocking density of 23 lobsters for each treatment was 32.64 ± 0.58 g. The experiment was conducted for 60 days. The lobster was fed with trash fish and acclimatized for 7 days before the experiment. Observations on the physiologycal of every 10 days. The physiological responses that observed were total hemocyte count (THC and hemolymph glucose concentration. The results showed that 4:5 was the best lobster shelter ratio because it could reduce stress levels. This is indicated by the stable values of THC and hemolymph glucose level during the experiment and supported by the growth of 57.28 ± 0.15 g and survival rate of 91.31 ± 2.60%. Keywords: lobster, Panulirus homarus, ratio, shelter, THC, glucose

  3. Changes in body chemical composition with age measured by total-body neutron activation

    International Nuclear Information System (INIS)

    Cohn, S.H.; Vaswani, A.; Zanzi, I.; Aloia, J.F.; Roginsky, M.S.; Ellis, K.J.

    1976-01-01

    Total-body levels of calcium and phosphorus (reflecting skeletal mass) and total-body levels of potassium (reflecting muscle mass) were measured by neutron activation analysis in 39 men and 40 women ages 30 to 90 yr. In order to intercompare the total body calcium (TBCa) values in a heterogeneous population, such as this, it was necessary to normalize the data for skeletal size. The normalization consisted of dividing the absolute calcium level by the predicted calcium level for each individual matched to a set of critical parameters. The parameter used in the computation of normal values were age, sex, muscle mass, i.e., total body potassium (TBK) and height. For the calcium data of the women, it was necessary to add an age correction factor after the age of 55 yr. The calcium ratio (mean ratio of the predicted to measured TBCa) in men was 1.000 +- 7.8 percent and in women 0.996 +- 7.1 percent. The TBCa of normal males and females can thus be predicted to +-13 percent (at the 90 percent confidence level). An exception to this was found in males (70 to 90 yr) who exhibited a mean calcium ratio greater than 1.13

  4. [Study on modeling method of total viable count of fresh pork meat based on hyperspectral imaging system].

    Science.gov (United States)

    Wang, Wei; Peng, Yan-Kun; Zhang, Xiao-Li

    2010-02-01

    Once the total viable count (TVC) of bacteria in fresh pork meat exceeds a certain number, it will become pathogenic bacteria. The present paper is to explore the feasibility of hyperspectral imaging technology combined with relevant modeling method for the prediction of TVC in fresh pork meat. For the certain kind of problem that has remarkable nonlinear characteristic and contains few samples, as well as the problem that has large amount of data used to express the information of spectrum and space dimension, it is crucial to choose a logical modeling method in order to achieve good prediction result. Based on the comparative result of partial least-squares regression (PLSR), artificial neural networks (ANNs) and least square support vector machines (LS-SVM), the authors found that the PLSR method was helpless for nonlinear regression problem, and the ANNs method couldn't get approving prediction result for few samples problem, however the prediction models based on LS-SVM can give attention to the little training error and the favorable generalization ability as soon as possible, and can make them well synchronously. Therefore LS-SVM was adopted as the modeling method to predict the TVC of pork meat. Then the TVC prediction model was constructed using all the 512 wavelength data acquired by the hyperspectral imaging system. The determination coefficient between the TVC obtained with the standard plate count for bacterial colonies method and the LS-SVM prediction result was 0.987 2 and 0.942 6 for the samples of calibration set and prediction set respectively, also the root mean square error of calibration (RMSEC) and the root mean square error of prediction (RMSEP) was 0.207 1 and 0.217 6 individually, and the result was considerably better than that of MLR, PLSR and ANNs method. This research demonstrates that using the hyperspectral imaging system coupled with the LS-SVM modeling method is a valid means for quick and nondestructive determination of TVC of pork

  5. Mass number dependence of total neutron cross section; a discussion based on the semi-classical optical model

    International Nuclear Information System (INIS)

    Angeli, Istvan

    1990-01-01

    The dependence of total neutron cross section on mass number can be calculated by the black nucleus formula, according to the optical model. The fine structure of mass number dependence is studied, and a correction factor formula is given on the basis of a semi-classical optical model. Yielding results in good agreement with experimental data. In addition to the mass number dependence, the neutron-energy dependence can also be calculated using this model. (K.A.)

  6. Determination of Total Arsenic in Seaweed Products by Neutron Activation Analysis

    International Nuclear Information System (INIS)

    Salim, N.; Santoso, M.; Yanuar, A.; Damayanti; Kartawinata, T.G.

    2013-01-01

    Seaweed products are widely consumed as food nowadays. Seaweeds are known to contain arsenic due to their capability to accumulate arsenic from the environment. Arsenic is a known toxic element which naturally occurs in the environment. Ingestion of high levels of arsenic will cause several adverse health effects. Arsenic in food occurs at trace concentrations which require sensitive and selective analysis methods to perform elemental analysis on. Validated neutron activation analysis was used to determine the arsenic contents in seaweed products namely catoni from domestic product and nori from foreign products. The total arsenic concentration in the samples analyzed ranges from 0.79 mg/kg to 30.14 mg/kg with mean concentration 14.39 mg/kg. The estimated exposure to arsenic contributed by the analyzed products is from 0.07% up to 8.54% of the established provisional tolerable daily intake (PTDI) which is still far below the maximum tolerable level. (author)

  7. Determination of Total Arsenic in Seaweed Products by Neutron Activation Analysis

    Directory of Open Access Journals (Sweden)

    N. Salim

    2013-04-01

    Full Text Available Seaweed products are widely consumed as food nowadays. Seaweeds are known to contain arsenic due to their capability to accumulate arsenic from the environment. Arsenic is a known toxic element which naturally occurs in the environment. Ingestion of high levels of arsenic will cause several adverse health effects. Arsenic in food occurs at trace concentrations which require sensitive and selective analysis methods to perform elemental analysis on. Validated neutron activation analysis was used to determine the arsenic contents in seaweed products namely catoni from domestic product and nori from foreign products. The total arsenic concentration in the samples analyzed ranges from 0.79 mg/kg to 30.14 mg/kg with mean concentration 14.39 mg/kg. The estimated exposure to arsenic contributed by the analyzed products is from 0.07% up to 8.54% of the established provisional tolerable daily intake (PTDI which is still far below the maximum tolerable level

  8. Measurement of fluorine total concentration in dental enamel using fast neutron activation

    International Nuclear Information System (INIS)

    Mouadili, A.; Vernais, J.; Isabelle, D.B.

    1988-01-01

    Fluorine which is present in dental enamel, at the level of a few tens to a few hundred ppm, plays an important role in the behaviour of this tissue. Therefore quantitative determination is of interest for particular studies of the dental system. We present a nuclear nondestructive method to determine the total fluorine content in dental enamel by cyclotron-produced fast-neutron activation. The 19 F(n,2n) reaction leads to 18 F which is a β + emitter with a 109.8 min half-life. The irradiated sample activity is measured by detecting in coincidence the annihilation photons. A fluorine standard is used for calibration. The detection limit is of the order of 1 ppm, while the reproducibility is better than 95% [pt

  9. The determination by irradiation with a pulsed neutron generator and delayed neutron counting of the amount of fissile material present in a sample; Determination de la quantite de matiere fissile presente dans un echantillon par irradiation au moyen d'une source pulsee de neutrons et comptage des neutrons retardes

    Energy Technology Data Exchange (ETDEWEB)

    Beliard, L; Janot, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-07-01

    A preliminary study was conducted to determine the amount of fissile material present in a sample. The method used consisted in irradiating the sample by means of a pulsed neutron generator and delayed neutron counting. Results show the validity of this method provided some experimental precautions are taken. Checking on the residual proportion of fissile material in leached hulls seems possible. (authors) [French] Ce rapport rend compte d'une etude preliminaire effectuee en vue de determiner la quantite de matiere fissile presente dans un echantillon. La methode utilisee consiste a irradier l'echantillon considere au moyen d'une source puisee de neutrons et a compter les neutrons retardes produits. Les resultats obtenus permettent de conclure a la validite de la methode moyennant certaines precautions. Un controle de la teneur residuelle en matiere fissile des gaines apres traitement semble possible. (auteurs)

  10. Evaluation of white cell count and differential in synovial fluid for diagnosing infections after total hip or knee arthroplasty.

    Directory of Open Access Journals (Sweden)

    Xinhua Qu

    Full Text Available BACKGROUND: The accuracy of synovial fluid (SF white cell count (WCC and polymorphonuclear (PMN cell evaluation for predicting prosthetic joint infection (PJI at the total hip arthroplasty (THA or total knee arthroplasty (TKA site is unknown. Therefore, we performed a meta-analysis to summarize the diagnostic validity of SF-WCC and SF-PMN for diagnosing PJI. METHODS: The MEDLINE, EMBASE, and OVID databases were searched for studies that had evaluated the diagnostic validity of SF-WCC and SF-PMN between January 1990 and May 2013. Meta-analysis methods were used to pool sensitivity, specificity, diagnostic odd ratios (DORs, the area under the receiver-operating characteristic curve (AUC, positive likelihood ratios (PLR, negative likelihood ratios (NLR, and post-test probability. We also conducted heterogeneity, publication bias, subgroup, and meta-regression analyses. RESULTS: Fifteen articles (15 SF-WCC and 14 SF-PMN that included a total of 2787 patients fulfilled the inclusion criteria and were considered for analysis. The pooled sensitivity and specificity for PJI detection was 0.88 (95% confidence intervals [CI], 0.81-0.93 and 0.93 (95% CI, 0.88-0.96 for SF-WCC and 0.90 (95% CI, 0.84-0.93 and 0.88 (95% CI, 0.83-0.92 for SF-PMN, respectively. The AUC was 0.96 for SF-WCC and 0.95 for SF-PMN. PLR and NLR were 13.3 and 0.13 for SF-WCC, and 7.6 and 0.12 for SF-PMN, respectively. There was no evidence of publication bias. Low-clinical-scenario (pre-test probability, 20% post-test probabilities were 3% for both negative SF-WCC and SF-PMN results. The subgroup analyses indicated that the sensitivity/specificity of THA were 0.73/0.96 for SF-WCC and 0.85/0.83 for SF-PMN, whereas those of TKA were 0.90/0.91 for SF-WCC and 0.90/0.88 for SF-PMN. We also found that collection of SF-WCC preoperatively had a higher sensitivity than that obtained intraoperatively (0.91 vs. 0.77. CONCLUSIONS: SF-WCC and SF-PMN have an adequate and clinically acceptable

  11. Evaluation of the performance of a point-of-care method for total and differential white blood cell count in clozapine users.

    Science.gov (United States)

    Bui, H N; Bogers, J P A M; Cohen, D; Njo, T; Herruer, M H

    2016-12-01

    We evaluated the performance of the HemoCue WBC DIFF, a point-of-care device for total and differential white cell count, primarily to test its suitability for the mandatory white blood cell monitoring in clozapine use. Leukocyte count and 5-part differentiation was performed by the point-of-care device and by routine laboratory method in venous EDTA-blood samples from 20 clozapine users, 20 neutropenic patients, and 20 healthy volunteers. From the volunteers, also a capillary sample was drawn. Intra-assay reproducibility and drop-to-drop variation were tested. The correlation between both methods in venous samples was r > 0.95 for leukocyte, neutrophil, and lymphocyte counts. The correlation between point-of-care (capillary sample) and routine (venous sample) methods for these cells was 0.772; 0.817 and 0.798, respectively. Only for leukocyte and neutrophil counts, the intra-assay reproducibility was sufficient. The point-of-care device can be used to screen for leukocyte and neutrophil counts. Because of the relatively high measurement uncertainty and poor correlation with venous samples, we recommend to repeat the measurement with a venous sample if cell counts are in the lower reference range. In case of clozapine therapy, neutropenia can probably be excluded if high neutrophil counts are found and patients can continue their therapy. © 2016 John Wiley & Sons Ltd.

  12. Determination of trace elements in scallop and fish otolith by instrumental neutron activation analysis using anti-coincidence and coincidence counting methods

    International Nuclear Information System (INIS)

    Suzuki, Shogo; Okada, Yukiko; Hirai, Shoji

    2005-01-01

    Trace element concentrations in scallop reference material and fish otolith certified reference materials prepared at the National Institute for Environmental Studies (NIES) of Japan were determined by instrumental neutron activation analysis (INAA). Nine aliquots of scallop sample (ca. 252∼507 mg) and five aliquots of fish otolith sample (ca. 502 ∼ 988 mg) and comparative standards were irradiated for a short time (10 s) at a thermal neutron flux of 1.5 x 10 12 n cm -2 s -1 (pneumatic transfer) and for a long time (6 h) at a thermal neutron flux of 3.7 x 10 12 n cm -2 s -1 (central thimble) in the Rikkyo University Research Reactor (100 kW). The irradiated samples were measured by conventional γ-ray spectrometry using a coaxial Ge detector, and by anti-coincidence and coincidence γ-ray spectrometry with a coaxial Ge detector and a well-type NaI (Tl) detector to determine as many trace elements as possible with high sensitivity. The concentrations of 34 elements of the NIES No.15 scallop reference material and 16 elements of the NIES No.22 fish otolith CRM were determined. Using the coincidence counting method to determine Se, Ba and Hf, the lower limit of the determination was improved by 2 times compared with the conventional counting method. (author)

  13. Neutron--neutron logging

    International Nuclear Information System (INIS)

    Allen, L.S.

    1977-01-01

    A borehole logging tool includes a steady-state source of fast neutrons, two epithermal neutron detectors, and two thermal neutron detectors. A count rate meter is connected to each neutron detector. A first ratio detector provides an indication of the porosity of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two epithermal neutron detectors. A second ratio detector provides an indication of both porosity and macroscopic absorption cross section of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two thermal neutron detectors. By comparing the signals of the two ratio detectors, oil bearing zones and salt water bearing zones within the formation being logged can be distinguished and the amount of oil saturation can be determined. 6 claims, 2 figures

  14. Importance of isovector effects in reproducing neutron total cross section differences in the W isotopes

    International Nuclear Information System (INIS)

    Dietrich, F.S.; Anderson, J.D.; Bauer, R.W.; Grimes, S.M.; Finlay, R.W.; Abfalterer, W.P.; Bateman, F.B.; Haight, R.C.; Morgan, G.L.; Bauge, E.; Delaroche, J.-P.; Romain, P.

    2003-01-01

    Cross section differences among the isotopes 182,184,186 W have been measured as a part of a study of total cross sections in the 5-560 MeV energy range. These difference measurements show oscillations up to 150 mb between 5 and 100 MeV. Calculations with spherical and deformed phenomenological optical potentials employing standard radial and isospin dependences show much smaller oscillations than the experimental data. In a simple Ramsauer model, this discrepancy can be traced to a cancellation between radial and isospin effects. Understanding this problem requires a more detailed model that incorporates a realistic description of the neutron and proton density distributions. This has been done with the results of Hartree-Fock-Bogoliubov calculations using the Gogny force, together with a microscopic folding model employing a modification of the Jeukenne, Lejeune, and Mahaux potential as an effective interaction. This treatment yields a satisfactory interpretation of the observed total cross section differences up to 200 MeV. The calculations have been extended above that energy with a folding model based on an empirical effective interaction

  15. Fast-neutron total and scattering cross sections of 58Ni

    International Nuclear Information System (INIS)

    Jorgensen, C.B.; Guenther, P.T.; Smith, A.B.; Whalen, J.F.

    1981-09-01

    Neutron total cross sections of 58 Ni were measured at 25 keV intervals from 0.9 to 4.5 MeV with 50 to 100 keV resolutions. Attention was given to self-shielding corrections to the observed total cross sections. Differential elastic- and inelastic-scattering cross sections were measured at 50 keV intervals from 1.35 to 4.0 MeV with 50 to 100 keV resolutions. Inelastic excitation of levels at 1.458 +- 0.009, 2.462 +- 0.010, 2.791 +- 0.015, 2.927 +- 0.012 and 3.059 +- 0.025 MeV was observed. The experimental results were interpreted in terms of optical-statistical and coupled-channels models. A spherical optical-statistical model was found generally descriptive of an energy-average of the experimental results. However, detailed considerations suggested significant contributions from direct-vibrational interactions, particularly associated with the excitation of the first 2+ level

  16. Deformation effect in the fast neutron total cross section of aligned /sup 59/Co

    Energy Technology Data Exchange (ETDEWEB)

    Fasoli, U.; Pavan, P.; Toniolo, D.; Zago, G.; Zannoni, R.; Galeazzi, G.

    1982-07-19

    The variation of the total neutron cross section, ..delta.. sigma/sub align/, on /sup 59/Co due to nuclear alignment of the target in the beam direction, has been measured over the energy range from 0.8 to 20 MeV, employing a cobalt single-crystal with a 34% nuclear alignment degree. The results show that ..delta.. sigma/sub align/ oscillates from a minimum of -5% at about 2.5 MeV to a maximum of +1% at about 10 MeV. The data were successfully fitted by optical model coupled-channel calculations. The coupling terms were deduced from a model representing the /sup 59/Co nucleus as a virbrational /sup 60/Ni core coupled to a proton-hole in a (lf 7/2) shell, without free parameters. The optical model parameters were determined by fitting the total cross-section independently measured. The theoretical calculations show that, at lower energies, ..delta.. sigma/sub align/ depends appreciably on the coupling with the low-lying levels.

  17. Deformation effect in the fast neutron total cross section of alligned 59Co

    International Nuclear Information System (INIS)

    Fasoli, U.; Pavan, P.; Toniolo, D.; Zago, G.; Zannoni, R.; Galeazzi, G.

    1982-01-01

    The variation of the total neutron cross section, DELTAsigmasub(align), on 59 Co due to nuclear alignement of the target in the beam direction, has been measured over the energy range from 0.8 to 20 MeV, emploing a cobalt single-crystal with a 34% nuclear alignment degree. The results show that DELTAsigmasub(align) oscillates from a minimum of -5% at about 2.5 MeV to a maximum of +1% at about 10 MeV. The data were succesfully fitted by optical model coupled-channel calculations. The coupling terms were deduced from a model representing the 59 Co nucleus as a vibrational 60 Ni core coupled to a proton hole in a (lf7/2) shell, without free parameters. The optical model parameters were determined by fitting the total cross section independently measured. The theoretical calculations show that, at lower energies, DELTAsigmasub(align) depends appreciably on the coupling with the low-liyng levels

  18. Deformation effect in the fast neutron total cross section of aligned 59Co

    International Nuclear Information System (INIS)

    Fasoli, U.; Pavan, P.; Toniolo, D.; Zago, G.; Zannoni, R.; Galeazzi, G.

    1983-01-01

    The variation of the total neutron cross section, Δsigma/sub align/, on 59 Co due to nuclear alignment of the target has been measured over the energy range from 0.8 to 20 MeV employing a cobalt single crystal with a 34% nuclear alignment. The results show that Δsigma/sub align/ oscillates from a minimum of -5% at about 2.5 MeV to a maximum of +1% at about 10 MeV. The data were successfully fitted by optical model coupled-channel calculations. The coupling terms were deduced from a model representing the 59 Co nucleus as a vibrational 60 Ni core coupled to a proton hole in a (1f/sub 7/2/) shell, without free parameters. The optical model parameters were determined by fitting the total cross section, which was independently measured. The theoretical calculations show that, at lower energies, Δsigma/sub align/ depends appreciably on the coupling with the low-lying levels

  19. Total reaction cross sections and neutron-removal cross sections of neutron-rich light nuclei measured by the COMBAS fragment-separator

    Science.gov (United States)

    Hue, B. M.; Isataev, T.; Erdemchimeg, B.; Artukh, A. G.; Aznabaev, D.; Davaa, S.; Klygin, S. A.; Kononenko, G. A.; Khuukhenkhuu, G.; Kuterbekov, K.; Lukyanov, S. M.; Mikhailova, T. I.; Maslov, V. A.; Mendibaev, K.; Sereda, Yu M.; Penionzhkevich, Yu E.; Vorontsov, A. N.

    2017-12-01

    Preliminary results of measurements of the total reaction cross sections σR and neutron removal cross section σ-xn for weakly bound 6He, 8Li, 9Be and 10Be nuclei at energy range (20-35) A MeV with 28Si target is presented. The secondary beams of light nuclei were produced by bombardment of the 22Ne (35 A MeV) primary beam on Be target and separated by COMBAS fragment-separator. In dispersive focal plane a horizontal slit defined the momentum acceptance as 1% and a wedge degrader of 200 μm Al was installed. The Bρ of the second section of the fragment-separator was adjusted for measurements in energy range (20-35) A MeV. Two-neutron removal cross sections for 6He and 10Be and one -neutron removal cross sections 8Li and 9Be were measured.

  20. Instrumentation and procedures for moisture corrections to passive neutron coincidence counting assays of bulk PuO2 and MOX powders

    International Nuclear Information System (INIS)

    Stewart, J.E.; Menlove, H.O.; Ferran, R.R.; Aparo, M.; Zeppa, P.; Troiani, F.

    1993-05-01

    For passive neutron-coincidence-counting verification measurements of PuO 2 and MOX powder, assay biases have been observed that result from moisture entrained in the sample. This report describes a unique set of experiments in which MOX samples, with a range of moisture concentrations, were produced and used to calibrate and evaluate two prototype moisture monitors. A new procedure for moisture corrections to PuO 2 and MOX verification measurements yields MOX assays accurate to 1.5% (1σ) for 0.6- and 1.1-kg samples. Monte Carlo simulations were used to extend the measured moisture calibration data to higher sample masses. A conceptual design for a high-efficiency neutron coincidence counter with improved sensitivity to moisture is also presented

  1. Total motile sperm count: a better indicator for the severity of male factor infertility than the WHO sperm classification system.

    Science.gov (United States)

    Hamilton, J A M; Cissen, M; Brandes, M; Smeenk, J M J; de Bruin, J P; Kremer, J A M; Nelen, W L D M; Hamilton, C J C M

    2015-05-01

    Does the prewash total motile sperm count (TMSC) have a better predictive value for spontaneous ongoing pregnancy (SOP) than the World Health Organization (WHO) classification system? The prewash TMSC shows a better correlation with the spontaneous ongoing pregnancy rate (SOPR) than the WHO 2010 classification system. According to the WHO classification system, an abnormal semen analysis can be diagnosed as oligozoospermia, astenozoospermia, teratozoospermia or combinations of these and azoospermia. This classification is based on the fifth percentile cut-off values of a cohort of 1953 men with proven fertility. Although this classification suggests accuracy, the relevance for the prognosis of an infertile couple and the choice of treatment is questionable. The TMSC is obtained by multiplying the sample volume by the density and the percentage of A and B motility spermatozoa. We analyzed data from a longitudinal cohort study among unselected infertile couples who were referred to three Dutch hospitals between January 2002 and December 2006. Of the total cohort of 2476 infertile couples, only the couples with either male infertility as a single diagnosis or unexplained infertility were included (n = 1177) with a follow-up period of 3 years. In all couples a semen analysis was performed. Based on the best semen analysis if more tests were performed, couples were grouped according to the WHO classification system and the TMSC range, as described in the Dutch national guidelines for male infertility. The primary outcome measure was the SOPR, which occurred before, during or after treatments, including expectant management, intrauterine insemination, in vitro fertilization or intracytoplasmic sperm injection. After adjustment for the confounding factors (female and male age, duration and type of infertility and result of the postcoital test) the odd ratios (ORs) for risk of SOP for each WHO and TMSC group were calculated. The couples with unexplained infertility were

  2. Determination of migration of phosphorus-based additives from food packaging material into food-simulating solvents by neutron activation/Cerenkov counting

    International Nuclear Information System (INIS)

    Lickly, T.D.; Quinn, T.; Blanchard, F.A.; Murphy, P.G.

    1988-01-01

    Samples of food-simulating solvents exposed to food-packaging materials that contain phosphorus-based additives have been examined for migration of phosphorus-containing compounds from the packaging material, using neutron activation/Cerenkov counting. This method has the advantage that commercially produced packaging materials can be used (no elaborate sample preparation as with other radiotracer methods) and no elaborate sample processing techniques are needed to reach the desired levels (low ng/mL) as is usual with most chromatographic or spectroscopic techniques. (author)

  3. Performance of the postwash total motile sperm count as a predictor of pregnancy at the time of intrauterine insemination: a meta-analysis

    NARCIS (Netherlands)

    van Weert, Janne-Meije; Repping, Sjoerd; van Voorhis, Bradley J.; van der Veen, Fulco; Bossuyt, Patrick M. M.; Mol, Ben W. J.

    2004-01-01

    Objective: To assess the performance and clinical value of the postwash total motile sperm count (postwash TMC) as a test to predict intrauterine insemination (IUI) outcome. Design: Meta-analysis of diagnostic tests. Setting: Tertiary fertility center. Patient(s): Patients undergoing IUI.

  4. Neutron detection system for extremely low count rate. Calculation, construction and employment in search for 'cold fusion'

    International Nuclear Information System (INIS)

    Mayer, R.E.; Patino, N.E.; Florido, P.C.; Gomez, S.E.; Granada, J.R.; Gillette, V.H.

    1993-01-01

    A 22% efficiency thermal neutron detection system was designed for the investigation of neutron emission from pulsed D 2 O electrolysis. Reasons are discussed for the choice of 10 atm 3 He proportional counters. Optimization calculations carried out through standard reactor code system (AMPX-II) are presented along with construction details and characteristics of the associated electronics. Experimental verification of calculated efficiency and examples of measurements performed with the detector are included. (orig.)

  5. Neutron television camera detector

    International Nuclear Information System (INIS)

    Arndt, U.W.; Gilmore, D.J.

    1976-01-01

    A neutron area detector system is being developed at the Institut Laue-Langevin which is based on a system for x-rays. The system has a large counting rate capability; this is extremely important where the total background count exceeds the total counts in the signals of interest. Its spatial resolution is of the order of one mm, while the screen size is 400 mm. The main limitation of the system is its limited counting efficiency, and this is directly attributable to the optical self-absorption of the neutron phosphor. All coherent noise in the system, i.e., all noise synchronized with the TV scans, has to be kept lower than the first bit threshold. However, this requirement can be relaxed when dealing with diffraction patterns, such as those from single crystals, for which a local background is subtracted from the pattern

  6. A pulse shape discriminator with high precision of neutron and gamma ray selection at high counting rate

    International Nuclear Information System (INIS)

    Bialkowski, J.; Moszynski, M.; Wolski, D.

    1989-01-01

    A pulse shape discriminator based on the zero-crossing principle is described. Due to dc negative feedback loops stabilizing the shaping amplifier and the zero-crossing discriminator, the working of the circuit is not affected by the high counting rate and the temperature variations. The pileup rejection circuit built into the discriminator improves the quality of the n-γ separation at high counting rates. A full γ-ray rejection is obtained for a recoil energy of electrons down to 25 keV. At high counting rates the remaining γ-ray contribution is evidently due to the pileup effect which is equal to about 2% at 4x10 5 counts/s. (orig.)

  7. New neutron capture and total cross section measurements on 88Sr and their impact on s-process nucleosynthesis

    International Nuclear Information System (INIS)

    Koehler, P.E.; Spencer, R.R.; Guber, K.H.

    1998-01-01

    The authors have made new and improved measurements of the neutron capture and total cross sections of 88 Sr at the Oak Ridge Electron Linear Accelerator (ORELA). Improvements over previous measurements include a wider incident neutron energy range, the use of metallic rather than carbonate samples, better background subtraction, reduced sensitivity to sample-dependent backgrounds, and better pulse-height weighting functions. Because of its small cross section, the 88 Sr(n,γ) reaction is an important bottleneck during the s-process nucleosynthesis. Hence, an accurate determination of this rate is needed to better constrain the neutron exposure in s-process models and to more fully exploit the recently discovered isotopic anomalies in certain meteorites. They describe the experimental procedures, compare the results to previous data, and discuss their astrophysical impact

  8. Neutron total, scattering and inelastic gamma-ray cross sections of yttrium at few MeV energies

    International Nuclear Information System (INIS)

    Budtz-Joergensen, C.; Guenther, P.; Smith, A.; Whalen, J.; McMurray, W.R.; Renan, M.J.; Heerden, I.J. van

    1984-01-01

    Neutron total, scattering and (n; n', γ) cross sections of elemental yttrium ( 89 Y) were measured in the few-MeV region. The neutron total-cross-section measurements were made with broad resolutions from approx.=0.5 to 4.2 MeV in steps of < or approx.0.1 MeV. Neutron elastic- and inelastic-scattering cross sections were measured from approx.=1.5 to 4.0 MeV, at incident-neutron energy intervals of approx.=50 keV and at ten or more scattering angles distributed between 20 and 160 degrees using neutron detection. Inelastic-scattering cross sections were also determined using the (n; n', γ) reaction at incident energies from 1.6 to 3.8 MeV at intervals of 0.1 MeV. Gamma-rays and/or inelastically-scattered neutrons were observed corresponding to the excitation of levels at: 909.0+-0.5, 1,507.4+-0.3, 1,744.5+-0.3, 2,222.6+-0.5, 2,530+-0.8, 2,566.4+-1.0, 2,622.5+-1.0, 2,871.9+-1.5, 2,880.6+-2.0, 3,067.0+-2.0, 3,107.0+-2.0, 3,140.0+-2.0, 3,410.0+-2.0, 3,450.0+-2.0, 3,504.0+-1.5, 3,514.0+-2.0, 3,556.0+-2.0, 3,619.0+-3.0, 3,629.0+-3.0 and 3,715.0+-3.0 keV. The experimental results are discussed in terms of the spherical-optical-statistical, coupled-channels, and core-coupling models, and in the context of previously reported excited-level structure. (orig.)

  9. The effect of surface texture on total reflection of neutrons and X-rays from modified interfaces

    DEFF Research Database (Denmark)

    Goldar, A.; Roser, S.J.; Hughes, A.

    2002-01-01

    X-ray and neutron scattering from macroscopically rough surfaces and interfaces is considered and a new method of analysis based on the variation of the shape of the total reflection edge in the reflectivity profile is proposed. It was shown that in the limit that the correlation length and the h......X-ray and neutron scattering from macroscopically rough surfaces and interfaces is considered and a new method of analysis based on the variation of the shape of the total reflection edge in the reflectivity profile is proposed. It was shown that in the limit that the correlation length...... and the height of the surface roughness are larger than the wavelength (at least 100 times bigger) of the incoming beam, the total reflection edge in the reflection profile becomes rounded. This technique allows direct analysis of the variation of the reflectivity pro le in terms of the structure of the surface...

  10. Analysis of total hydrogen content in palm oil and palm kernel oil using thermal neutron moderation method

    International Nuclear Information System (INIS)

    Akaho, E.H.K.; Dagadu, C.P.K.; Maaku, B.T.; Anim-Sampong, S.; Kyere, A.W.K.; Jonah, S.A.

    2001-01-01

    A fast and non-destructive technique based on thermal neutron moderation has been used for determining the total hydrogen content in two types of red palm oil (dzomi and amidze) and palm kernel oil produced by traditional methods in Ghana. An equipment consisting of an 241 Am-Be neutron source and 3 He neutron detector was used in the investigation. The equipment was originally designed for detection of liquid levels in petrochemical and other process industries. Standards in the form of liquid hydrocarbons were used to obtain calibration lines for thermal neutron reflection parameter as a function of hydrogen content. Measured reflection parameters with respective hydrogen content with or without heat treatment of the three edible palm oils available on the market were compared with a brand cooking oil (frytol). The average total hydrogen content in the local oil samples prior to heating was measured to be 11.62 w% which compared well with acceptable value of 12 w% for palm oils in the sub-region. After heat treatment, the frytol oil (produced through bleaching process) had the least loss of hydrogen content of 0.26% in comparison with palm kernel oil of 0.44% followed by dzomi of 1.96% and by amidze of 3.22%. (author)

  11. Calculation of total counting efficiency of a NaI(Tl) detector by hybrid Monte-Carlo method for point and disk sources

    Energy Technology Data Exchange (ETDEWEB)

    Yalcin, S. [Education Faculty, Kastamonu University, 37200 Kastamonu (Turkey)], E-mail: yalcin@gazi.edu.tr; Gurler, O.; Kaynak, G. [Department of Physics, Faculty of Arts and Sciences, Uludag University, Gorukle Campus, 16059 Bursa (Turkey); Gundogdu, O. [Department of Physics, School of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2007-10-15

    This paper presents results on the total gamma counting efficiency of a NaI(Tl) detector from point and disk sources. The directions of photons emitted from the source were determined by Monte-Carlo techniques and the photon path lengths in the detector were determined by analytic equations depending on photon directions. This is called the hybrid Monte-Carlo method where analytical expressions are incorporated into the Monte-Carlo simulations. A major advantage of this technique is the short computation time compared to other techniques on similar computational platforms. Another advantage is the flexibility for inputting detector-related parameters (such as source-detector distance, detector radius, source radius, detector linear attenuation coefficient) into the algorithm developed, thus making it an easy and flexible method to apply to other detector systems and configurations. The results of the total counting efficiency model put forward for point and disc sources were compared with the previous work reported in the literature.

  12. Calculation of total counting efficiency of a NaI(Tl) detector by hybrid Monte-Carlo method for point and disk sources

    International Nuclear Information System (INIS)

    Yalcin, S.; Gurler, O.; Kaynak, G.; Gundogdu, O.

    2007-01-01

    This paper presents results on the total gamma counting efficiency of a NaI(Tl) detector from point and disk sources. The directions of photons emitted from the source were determined by Monte-Carlo techniques and the photon path lengths in the detector were determined by analytic equations depending on photon directions. This is called the hybrid Monte-Carlo method where analytical expressions are incorporated into the Monte-Carlo simulations. A major advantage of this technique is the short computation time compared to other techniques on similar computational platforms. Another advantage is the flexibility for inputting detector-related parameters (such as source-detector distance, detector radius, source radius, detector linear attenuation coefficient) into the algorithm developed, thus making it an easy and flexible method to apply to other detector systems and configurations. The results of the total counting efficiency model put forward for point and disc sources were compared with the previous work reported in the literature

  13. Tower counts

    Science.gov (United States)

    Woody, Carol Ann; Johnson, D.H.; Shrier, Brianna M.; O'Neal, Jennifer S.; Knutzen, John A.; Augerot, Xanthippe; O'Neal, Thomas A.; Pearsons, Todd N.

    2007-01-01

    Counting towers provide an accurate, low-cost, low-maintenance, low-technology, and easily mobilized escapement estimation program compared to other methods (e.g., weirs, hydroacoustics, mark-recapture, and aerial surveys) (Thompson 1962; Siebel 1967; Cousens et al. 1982; Symons and Waldichuk 1984; Anderson 2000; Alaska Department of Fish and Game 2003). Counting tower data has been found to be consistent with that of digital video counts (Edwards 2005). Counting towers do not interfere with natural fish migration patterns, nor are fish handled or stressed; however, their use is generally limited to clear rivers that meet specific site selection criteria. The data provided by counting tower sampling allow fishery managers to determine reproductive population size, estimate total return (escapement + catch) and its uncertainty, evaluate population productivity and trends, set harvest rates, determine spawning escapement goals, and forecast future returns (Alaska Department of Fish and Game 1974-2000 and 1975-2004). The number of spawning fish is determined by subtracting subsistence, sport-caught fish, and prespawn mortality from the total estimated escapement. The methods outlined in this protocol for tower counts can be used to provide reasonable estimates ( plus or minus 6%-10%) of reproductive salmon population size and run timing in clear rivers. 

  14. The total neutron cross-sections of 151Eu, 153Eu and Eu below 1 eV

    International Nuclear Information System (INIS)

    Adib, M.; Maayouf, R.M.A.; Abdel-Kawy, A.; Ashry, A.; Hamouda, I.

    1981-01-01

    Total neutron cross-section measurements have been carried out for natural Eu and its stable isotopes in the energy range from 3 meV to 1 eV. The measurements were performed using two time-of-flight spectrometers installed in front of two of the horizontal channels of the ET-RR-1 reactor. The following results have been obtained: sigmasub(a) ( 151 Eu) = (9180 +- 150) b at 0.0253 eV, sigmasub(s) ( 153 Eu) = (375 +- 20) b at 0.0253 eV, sigmasub(d) (Eu) = (4600 +- 120) b at 0.0253 eV. The contribution of the resonance to the total neutron cross-sections, in the thermal region, was calculated using the single-level Breit-Wigner formula. (orig.)

  15. Total neutron cross-sections of /sup 151/Eu, /sup 153/Eu and Eu below 1 eV

    Energy Technology Data Exchange (ETDEWEB)

    Adib, M.; Maayouf, R.M.A.; Abdel-Kawy, A.; Ashry, A.; Hamouda, I.

    1981-01-01

    Total neutron cross-section measurements have been carried out for natural Eu and its stable isotopes in the energy range from 3 meV to 1 eV. The measurements were performed using two time-of-flight spectrometers installed in front of two of the horizontal channels of the ET-RR-1 reactor. The following results have been obtained: sigmasub(a) (/sup 151/Eu) = (9180 +- 150) b at 0.0253 eV, sigmasub(s) (/sup 153/Eu) = (375 +- 20) b at 0.0253 eV, sigmasub(d) (Eu) = (4600 +- 120) b at 0.0253 eV. The contribution of the resonance to the total neutron cross-sections, in the thermal region, was calculated using the single-level Breit-Wigner formula.

  16. Neutron total cross section measurements in the energy region from 47 keV to 20 MeV

    International Nuclear Information System (INIS)

    Poenitz, W.P.; Whalen, J.F.

    1983-05-01

    Neutron total cross sections were measured for 26 elements. Data were obtained in the energy range from 47 keV to 20 MeV for 11 elements in the range of light-mass fission products. Previously reported measurements for eight heavy and actinide isotopes were extended to 20 MeV. Data were also obtained for Cu (47 keV to 1.4 MeV) and for Sc, Zn, Nd, Hf, and Pt (1.8 to 20 MeV). The present work is part of a continuing effort to provide accurate neutron total cross sections for evaluations and for optical-model parameteriztions. The latter are required for the derivation of other nuclear-data information of importance to applied programs. 37 references

  17. The total neutron cross section of 58Fe in the energy range 7 to 325 keV

    International Nuclear Information System (INIS)

    Hong, L.D.; Beer, H.; Kaeppeler, F.

    1976-08-01

    The total neutron cross section of 58 Fe has been determined in the energy range 7-325 keV by a transmission measurement using enriched 58 Fe samples. The data have been shape fitted by means of an R-matrix multi-level formalism to extract resonance parameters for s- and l > 0 wave resonances. The s-wave strength function was determined to S 0 = (4.3 +- 1.9) c 10 -4 . (orig.) [de

  18. Estimation of 242Cm neutron cross sections for total file creation

    International Nuclear Information System (INIS)

    Bakhanovich, L.A.; Klepatskij, A.B.; Maslov, V.M.; Porodzinskij, Yu.V.; Sukhovitskij, E.Sh.

    1989-01-01

    Description of evaluation of 242 Cm neutron cross sections in 10 -5 eV-20 MeV energy range is given. Due to the lack of experimental data the evaluation is largely based on the application of theoretical models and systematics. The data obtained are compared to evaluations by other authors. 10 refs.; 2 figs.; 2 tabs

  19. Study of the fluctuations of the partial and total radiative widths by neutron capture resonance method; Etude des fluctuations des largeurs radiatives partielles et totales par la capture des neutrons de resonance

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, V D [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-06-01

    Radiative capture experiments by neutron time-of-flight methods have been made for following studies: distribution of partial radiative widths, effects of correlation between different radiative transitions, fluctuations of total radiative widths {gamma}{sub {gamma}} from resonance to resonance, variation of {gamma}{sub {gamma}} with number of mass and the search for the existence of potential capture. Also, some other experiments with the use of neutron capture gamma-rays spectra have been investigated. (author) [French] Par la capture des neutrons de resonance dont les energies sont selectionnees a l'aide de la technique du temps de vol, differents types d'experiences ont ete realisees concernant les etudes des distributions des largeurs radiatives partielles, des effets de correlation entre differentes voies de desexcitation, de la fluctuation des largeurs radiatives totales {gamma}{sub {gamma}} de resonance a resonance, de la variation de la quantite {gamma}{sub {gamma}} en fonction du nombre de masse et de la mise en evidence de l'existence du processus de capture potentielle. Quelques autres applications de l'emploi du spectre de rayons gamma ont egalement ete presentees. (auteur)

  20. Study of the fluctuations of the partial and total radiative widths by neutron capture resonance method; Etude des fluctuations des largeurs radiatives partielles et totales par la capture des neutrons de resonance

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, V.D. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-06-01

    Radiative capture experiments by neutron time-of-flight methods have been made for following studies: distribution of partial radiative widths, effects of correlation between different radiative transitions, fluctuations of total radiative widths {gamma}{sub {gamma}} from resonance to resonance, variation of {gamma}{sub {gamma}} with number of mass and the search for the existence of potential capture. Also, some other experiments with the use of neutron capture gamma-rays spectra have been investigated. (author) [French] Par la capture des neutrons de resonance dont les energies sont selectionnees a l'aide de la technique du temps de vol, differents types d'experiences ont ete realisees concernant les etudes des distributions des largeurs radiatives partielles, des effets de correlation entre differentes voies de desexcitation, de la fluctuation des largeurs radiatives totales {gamma}{sub {gamma}} de resonance a resonance, de la variation de la quantite {gamma}{sub {gamma}} en fonction du nombre de masse et de la mise en evidence de l'existence du processus de capture potentielle. Quelques autres applications de l'emploi du spectre de rayons gamma ont egalement ete presentees. (auteur)

  1. Comparative analysis of dose rates in bricks determined by neutron activation analysis, alpha counting and X-ray fluorescence analysis for the thermoluminescence fine grain dating method

    Science.gov (United States)

    Bártová, H.; Kučera, J.; Musílek, L.; Trojek, T.

    2014-11-01

    In order to evaluate the age from the equivalent dose and to obtain an optimized and efficient procedure for thermoluminescence (TL) dating, it is necessary to obtain the values of both the internal and the external dose rates from dated samples and from their environment. The measurements described and compared in this paper refer to bricks from historic buildings and a fine-grain dating method. The external doses are therefore negligible, if the samples are taken from a sufficient depth in the wall. However, both the alpha dose rate and the beta and gamma dose rates must be taken into account in the internal dose. The internal dose rate to fine-grain samples is caused by the concentrations of natural radionuclides 238U, 235U, 232Th and members of their decay chains, and by 40K concentrations. Various methods can be used for determining trace concentrations of these natural radionuclides and their contributions to the dose rate. The dose rate fraction from 238U and 232Th can be calculated, e.g., from the alpha count rate, or from the concentrations of 238U and 232Th, measured by neutron activation analysis (NAA). The dose rate fraction from 40K can be calculated from the concentration of potassium measured, e.g., by X-ray fluorescence analysis (XRF) or by NAA. Alpha counting and XRF are relatively simple and are accessible for an ordinary laboratory. NAA can be considered as a more accurate method, but it is more demanding regarding time and costs, since it needs a nuclear reactor as a neutron source. A comparison of these methods allows us to decide whether the time- and cost-saving simpler techniques introduce uncertainty that is still acceptable.

  2. Measurements of the total neutron cross-sections of U and UO2 below 2 eV at different temperatures

    International Nuclear Information System (INIS)

    Adib, M.; Maayouf, R.M.A.; Abdel-Kawy, A.; Ashry, A.; Abbas, Y.; Abu-Zahra, A.; Hamouda, I.

    1982-11-01

    The total neutron cross-sections of natural uranium and its oxide are measured using two time of flight spectrometers, installed in front of two of the ET-RR-1 reactor horizontal channels, and also by a neutron diffraction spectrometer. The measurements were carried out at room temperature in the energy range from 2 eV-0.002 eV and at 210 deg. C, for neutron energies below 0.005 eV. The coherent scattering cross-section of U was deduced both from the Bragg cut-offs observed in the behaviour of the total neutron cross-section of both U and UO 2 at cold neutron energies and the neutron diffraction pattern obtained at room temperature. (author)

  3. Total Count of Salmonella typhimurium Coupled on Water Soluble CdSe Quantum Dots by Fluorescence Detection

    Science.gov (United States)

    Feliciano Crespo, Raquel; Perales Perez, Oscar Juan; Ramirez, C.

    2018-05-01

    Health diseases due to the ingestion of water or food contaminated with pathogenic microorganisms are a main health problem around the world. The traditional methods for detecting foodborne pathogens are time-consuming (on the order of days). The development of methods that can help to detect and identify foodborne pathogens with high sensitivity and specificity have been proposed to overcome the limitations of traditional methods. Accordingly, this research is focused on the development of an experimental protocol for a high-sensitivity detection and quantification of bacterial pathogens with reduced detection times. This will lead to the development of a portable and low-cost technology with the opportunity to make onsite detection of pathogenic species. The proposed approach has modified the route reported in the literature; the method proposed is expected to be sensitive enough to detect a low limit of 102 CFU/mL counts of bacteria. The fluorescence-based method was tested in presence of Salmonella typhimurium (ATCC 14020) and Escherichia coli (ATCC 25922). CdSe water-soluble quantum dots (QDs) were synthesized in aqueous phase in presence of thioglycolic acid (TGA) as a capping agent. As-synthesized QDs were characterized by x-ray diffraction, near infrared and Fourier transform infrared spectroscopy, UV-Vis and photoluminescence techniques. Results of the CdSe/TGA-bacteria coupling and the determination of the corresponding quantification profiles (calibration curves) will be presented and discussed.

  4. Ultracold neutrons

    International Nuclear Information System (INIS)

    Steenstrup, S.

    Briefly surveys recent developments in research work with ultracold neutrons (neutrons of very low velocity, up to 10 m/s at up to 10 -7 eV and 10 -3 K). Slow neutrons can be detected in an ionisation chamber filled with B 10 F 3 . Very slow neutrons can be used for investigations into the dipole moment of neutrons. Neutrons of large wave length have properties similar to those of light. The limit angle for total reflection is governed by the wave length and by the material. Total reflection can be used to filter ultracold neutrons out of the moderator material of a reactor. Total reflection can also be used to store ultracold neutrons but certain problems with storage have not yet been clarified. Slow neutrons can be made to lose speed in a neutron turbine, and come out as ultracold neutrons. A beam of ultracold neutrons could be used in a neutron microscope. (J.S.)

  5. Gas detectors for thermal neutron at high counting rates; Etude des detecteurs a gaz pour neutrons thermiques fonctionnant en collection de courant

    Energy Technology Data Exchange (ETDEWEB)

    Mai, V Q [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1965-09-01

    After reminding of the current pulse formation theory in a cylindrical shape counter with and without gas multiplication, one gives the schemes of pulse amplifier and level discriminator which have allowed to verify the above calculations and to make clear the part at high counting rates of the space charge in proportional counters. The theory of that phenomenon is given in chapter V I at last, one gives the results obtained in a nuclear reactor with a counting-channel built with the above electronics circuits. (author) [French] Apres avoir rappele la theorie de la formation de l'impulsion de courant dans un compteur a geometrie cylindrique, fonctionnant sans et avec multiplication de charge, on etudie l'amplificateur et le discriminateur qui ont permis de verifier experimentalement les calculs precedents et de mettre en evidence l'action de la charge d'espace dans les compteurs proportionnels fonctionnant a tres fort taux de comptage. Une theorie de ce phenomene est donnee au chapitre VI; on indique enfin les resultats obtenus dans un reacteur avec une chaine de comptage utilisant les circuits electroniques precedents. (auteur)

  6. Propidium iodide (PI) stains Nissl bodies and may serve as a quick marker for total neuronal cell count.

    Science.gov (United States)

    Niu, Junfei; Li, Chunman; Wu, Haihui; Feng, Xianling; Su, Qingning; Li, Shihe; Zhang, Lihong; Yew, David Tai Wai; Cho, Eric Yu Pang; Sha, Ou

    2015-03-01

    Propidium iodide (PI) reacts with both DNA and RNA and is a commonly used fluorescent reagent for nucleic acid staining. The aim of the study was to compare the cellular staining patterns of PI with that of Nissl staining in rat nervous tissues and to report a modified staining method that selectively labels Nissl bodies in neurons. Cryosections and paraffin sections of different tissues of normal Sprague-Dawley rats, including trigeminal ganglia, dorsal root ganglia, spinal cord, liver, and small intestine, were stained by either PI or the hematoxylin and eosin method. Some sections were treated with RNase or DNase before the above staining, and some were double stained with PI and a Nissl stain. The sections were observed by light, fluorescence or confocal microscopy. Results showed strong PI signals detected as patterns of granules in the neuronal cytoplasm of all nervous tissues, whereas the staining of neuronal nuclei was weaker. In contrast, nuclei of neuroglial cells were strongly stained by PI, while the cytoplasm was not obviously stained. Pretreatment of the neural tissue with RNase abolished the PI signals. Furthermore, the PI positive granules in neuronal cytoplasm co-localized with Nissl bodies stained by the fluorescent Nissl stain. When the tissue was pretreated with DNase, PI only stained the cytoplasmic granules of neurons, but not that of glial cells. Our results show that PI stains Nissl bodies and may serve as an economical and convenient neuron marker for neuronal cell counting when specific neural markers such as antibodies are not readily available. Copyright © 2015. Published by Elsevier GmbH.

  7. Determination of Total Arsenic in Seaweed Products by Neutron Activation Analysis

    OpenAIRE

    Salim, N; Santoso, M; Damayanti, S; Kartawinata, T.G

    2013-01-01

    Seaweed products are widely consumed as food nowadays. Seaweeds are known to contain arsenic due to their capability to accumulate arsenic from the environment. Arsenic is a known toxic element which naturally occurs in the environment. Ingestion of high levels of arsenic will cause several adverse health effects. Arsenic in food occurs at trace concentrations which require sensitive and selective analysis methods to perform elemental analysis on. Validated neutron activation analysis was use...

  8. The Structure of Ethylbenzene, Styrene and Phenylacetylene Determined by Total Neutron Scattering

    OpenAIRE

    Szala‐Bilnik, Joanna; Falkowska, Marta; Bowron, Daniel T.; Hardacre, Christopher; Youngs, Tristan G. A.

    2017-01-01

    Abstract Organic solvents such as phenylacetylene, styrene and ethylbenzene are widely used in industrial processes, especially in the production of rubber or thermoplastics. Despite their important applications detailed knowledge about their structure is limited. In this paper the structures of these three aromatic solvents were investigated using neutron diffraction. The results show that many of their structural characteristics are similar, although the structure of phenylacetylene is more...

  9. Total cross-sections assessment of neutron reaction with stainless steel SUS-310 contained in various nuclear data files

    International Nuclear Information System (INIS)

    Suwoto

    2002-01-01

    The integral testing of neutron cross-sections for Stainless Steel SUS-310 contained in various nuclear data files have been performed. The shielding benchmark calculations for Stainless Steel SUS-310 has been analysed through ORNL-Broomstick Experiment calculation which performed by MAERKER, R.E. at ORNL - USA ( 1) . Assessment with JENDL-3.1, JENDL-3.2, ENDF/B-IV, ENDF/B-VI nuclear data files and data from GEEL have also been carried out. The overall calculation results SUS-310 show in a good agreement with the experimental data, although, underestimate results appear below 3 MeV for all nuclear data files. These underestimation tendencies clearly caused by presented of iron nuclide which more than half in Stainless Steel compound. The total neutron cross-sections of iron nuclide contained in various nuclear data files relatively lower on that energy ranges

  10. Estimation of DMFT, Salivary Streptococcus Mutans Count, Flow Rate, Ph, and Salivary Total Calcium Content in Pregnant and Non-Pregnant Women: A Prospective Study.

    Science.gov (United States)

    Kamate, Wasim Ismail; Vibhute, Nupura Aniket; Baad, Rajendra Krishna

    2017-04-01

    Pregnancy, a period from conception till birth, causes changes in the functioning of the human body as a whole and specifically in the oral cavity that may favour the emergence of dental caries. Many studies have shown pregnant women at increased risk for dental caries, however, specific salivary caries risk factors and the particular period of pregnancy at heightened risk for dental caries are yet to be explored and give a scope of further research in this area. The aim of the present study was to assess the severity of dental caries in pregnant women compared to non-pregnant women by evaluating parameters like Decayed, Missing, Filled Teeth (DMFT) index, salivary Streptococcus mutans count, flow rate, pH and total calcium content. A total of 50 first time pregnant women in the first trimester were followed during their second trimester, third trimester and postpartum period for the evaluation of DMFT by World Health Organization (WHO) scoring criteria, salivary flow rate by drooling method, salivary pH by pH meter, salivary total calcium content by bioassay test kit and salivary Streptococcus mutans count by semiautomatic counting of colonies grown on Mitis Salivarius (MS) agar supplemented by 0.2U/ml of bacitracin and 10% sucrose. The observations of pregnant women were then compared with same parameters evaluated in the 50 non-pregnant women. Paired t-test and Wilcoxon sign rank test were performed to assess the association between the study parameters. Evaluation of different caries risk factors between pregnant and non-pregnant women clearly showed that pregnant women were at a higher risk for dental caries. Comparison of caries risk parameters during the three trimesters and postpartum period showed that the salivary Streptococcus mutans count had significantly increased in the second trimester , third trimester and postpartum period while the mean pH and mean salivary total calcium content decreased in the third trimester and postpartum period. These

  11. Estimation of DMFT, Salivary Streptococcus Mutans Count, Flow Rate, Ph, and Salivary Total Calcium Content in Pregnant and Non-Pregnant Women: A Prospective Study

    Science.gov (United States)

    Vibhute, Nupura Aniket; Baad, Rajendra Krishna

    2017-01-01

    Introduction Pregnancy, a period from conception till birth, causes changes in the functioning of the human body as a whole and specifically in the oral cavity that may favour the emergence of dental caries. Many studies have shown pregnant women at increased risk for dental caries, however, specific salivary caries risk factors and the particular period of pregnancy at heightened risk for dental caries are yet to be explored and give a scope of further research in this area. Aim The aim of the present study was to assess the severity of dental caries in pregnant women compared to non-pregnant women by evaluating parameters like Decayed, Missing, Filled Teeth (DMFT) index, salivary Streptococcus mutans count, flow rate, pH and total calcium content. Materials and Methods A total of 50 first time pregnant women in the first trimester were followed during their second trimester, third trimester and postpartum period for the evaluation of DMFT by World Health Organization (WHO) scoring criteria, salivary flow rate by drooling method, salivary pH by pH meter, salivary total calcium content by bioassay test kit and salivary Streptococcus mutans count by semiautomatic counting of colonies grown on Mitis Salivarius (MS) agar supplemented by 0.2U/ml of bacitracin and 10% sucrose. The observations of pregnant women were then compared with same parameters evaluated in the 50 non-pregnant women. Paired t-test and Wilcoxon sign rank test were performed to assess the association between the study parameters. Results Evaluation of different caries risk factors between pregnant and non-pregnant women clearly showed that pregnant women were at a higher risk for dental caries. Comparison of caries risk parameters during the three trimesters and postpartum period showed that the salivary Streptococcus mutans count had significantly increased in the second trimester, third trimester and postpartum period while the mean pH and mean salivary total calcium content decreased in the third

  12. Total and (n, 2n) neutron cross section measurements on 241Am

    International Nuclear Information System (INIS)

    Sage, C.

    2009-01-01

    Neutron induced reaction cross sections on 241 Am have been measured at the IRMM in Geel, Belgium, in the frame of a collaboration between the EC Joint Research Centres IRMM and ITU and French laboratories from CNRS and CEA. Raw material coming from the Atalante facility of CEA Marcoule has been transformed into suitable AmO 2 samples embedded in Al 2 O 3 and Y 2 O 3 matrices. The irradiations for the 241 Am(n, 2n) 240 Am reaction cross section measurement were carried out at the 7 MV Van de Graaff accelerator using the activation technique with quasi mono-energetic neutrons from 8 to 21 MeV produced via the D(d, n) 3 He and the T(d, n) 4 He reactions. The cross section was determined relative to the 27 Al(n, α) 24 Na standard cross section and was investigated for the first time above 15 MeV. The induced activity was measured off-line by standard γ-ray spectrometry using a high purity Ge detector. A special effort was made for the estimation of the uncertainties and the correlations between our experimental points. A different sample of the same isotope 241 Am has been measured in transmission and capture experiments in the resolved resonance region at the neutron ToF facility GELINA. The transmission measurement was performed in two campaigns, with an upgrade of the whole data acquisition system in between, followed by an investigation of its new performances. A preliminary analysis of the resonance parameters tends to confirm the recent evaluation to a higher value for the cross section at the bottom of the first resonances. A new design of C 6 D 6 detectors for capture measurements has been studied, but the data reduction and analysis of the measurement are not part of this work. (author) [fr

  13. Total alpha and beta determination by liquid scintillation counting in water samples from a Brazilian intercomparison exercise

    International Nuclear Information System (INIS)

    Dias, Fabiana F.; Taddei, Maria Helena T.; Pontedeiro, Elizabeth May Braga Dulley

    2009-01-01

    This paper describes CNEN/LAPOC's participation in the Brazilian Intercomparison Exercise (PNI) for simultaneous determination of total radioactivity in water samples, which took place in August and December 2008. The Proficiency Test (PT) also involved a short description of the nuclear analytical technique employed, emphasizing sources of uncertainty. A Liquid Scintillation System (Packard TRICARB 2700) was used with appropriate corrections applied to final results, expressed as Bq L -1 . Participation and PT data provide independent information on performance of a Laboratory and have an important role in method validation; especially because it allows the assessment of method performance over an entire range of concentrations and matrices. PT is also an important tool to demonstrate equivalence of measurements, if not their metrological comparability, and to promote education and improvement of Lab practices. (author)

  14. Examination of total cross section resonance structure of niobium and silicon in neutron transmission experiments

    Science.gov (United States)

    Andrianova, Olga; Lomakov, Gleb; Manturov, Gennady

    2017-09-01

    The neutron transmission experiments are one of the main sources of information about the neutron cross section resonance structure and effect in the self-shielding. Such kind of data for niobium and silicon nuclides in energy range 7 keV to 3 MeV can be obtained from low-resolution transmission measurements performed earlier in Russia (with samples of 0.027 to 0.871 atom/barn for niobium and 0.076 to 1.803 atom/barn for silicon). A significant calculation-to-experiment discrepancy in energy range 100 to 600 keV and 300 to 800 keV for niobium and silicon, respectively, obtained using the evaluated nuclear data library ROSFOND, were found. The EVPAR code was used for estimation the average resonance parameters in energy range 7 to 600 keV for niobium. For silicon a stochastic optimization method was used to modify the resolved resonance parameters in energy range 300 to 800 keV. The improved ROSFOND evaluated nuclear data files were tested in calculation of ICSBEP integral benchmark experiments.

  15. Fission Fragment Mass Distributions and Total Kinetic Energy Release of 235-Uranium and 238-Uranium in Neutron-Induced Fission at Intermediate and Fast Neutron Energies

    Energy Technology Data Exchange (ETDEWEB)

    Duke, Dana Lynn [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-12

    This Ph.D. dissertation describes a measurement of the change in mass distributions and average total kinetic energy (TKE) release with increasing incident neutron energy for fission of 235U and 238U. Although fission was discovered over seventy-five years ago, open questions remain about the physics of the fission process. The energy of the incident neutron, En, changes the division of energy release in the resulting fission fragments, however, the details of energy partitioning remain ambiguous because the nucleus is a many-body quantum system. Creating a full theoretical model is difficult and experimental data to validate existing models are lacking. Additional fission measurements will lead to higher-quality models of the fission process, therefore improving applications such as the development of next-generation nuclear reactors and defense. This work also paves the way for precision experiments such as the Time Projection Chamber (TPC) for fission cross section measurements and the Spectrometer for Ion Determination in Fission (SPIDER) for precision mass yields.

  16. Experiments and Simulations of the Use of Time-Correlated Thermal Neutron Counting to Determine the Multiplication of an Assembly of Highly Enriched Uranium

    Energy Technology Data Exchange (ETDEWEB)

    David L. Chichester; Mathew T. Kinlaw; Scott M. Watson; Jeffrey M. Kalter; Eric C. Miller; William A. Noonan

    2014-11-01

    A series of experiments and numerical simulations using thermal-neutron time-correlated measurements has been performed to determine the neutron multiplication, M, of assemblies of highly enriched uranium available at Idaho National Laboratory. The experiments used up to 14.4 kg of highly-enriched uranium, including bare assemblies and assemblies reflected with high-density polyethylene, carbon steel, and tungsten. A small 252Cf source was used to initiate fission chains within the assembly. Both the experiments and the simulations used 6-channel and 8-channel detector systems, each consisting of 3He proportional counters moderated with polyethylene; data was recorded in list mode for analysis. 'True' multiplication values for each assembly were empirically derived using basic neutron production and loss values determined through simulation. A total of one-hundred and sixteen separate measurements were performed using fifty-seven unique measurement scenarios, the multiplication varied from 1.75 to 10.90. This paper presents the results of these comparisons and discusses differences among the various cases.

  17. Some hematological parameters and the prognostic values of CD4, CD8 and total lymphocyte counts and CD4/CD8 cell count ratio in healthy HIV sero-negative, healthy HIV sero-positive and AIDS subjects in Port Harcourt, Nigeria

    Directory of Open Access Journals (Sweden)

    Blessing Didia

    2008-12-01

    Full Text Available OBJECTIVE: The present study attempts to determine normal values of CD4, CD8, CD4/CD8 ratio, total WBC and differential counts, hematocrit and total lymphocyte count (TLC in healthy HIV sero-negative and sero-positive subjects, and to assess the prognostic significance of these parameters in these subjects as compared to AIDS subjects.METHODS: A total of 300 subjects (147 M, 153 F aged between 17 and 71 years were recruited into the study. Subjects were separated according to sex and divided into three groups: Group A: healthy HIV sero-negative subjects; Group B: healthy HIV sero-positive newly diagnosed ART-naïve subjects; and Group C: AIDS subjects. CD4 and CD8 counts were determined by flow cytometry; hematocrit was determined using Hawksley micro-capillary tubes; total WBC and differential counts were determined manually with the improved Neubauer counting chamber; and TLC was obtained by multiplying the percentage of lymphocytes by the total WBC count.RESULTS: For male subjects, significant differences were found in CD4 count, CD4/CD8 count ratio, hematocrit, total WBC and TLC, whereas for female subjects, significant differences were found only in CD4 and CD4/CD8 count ratio in the three groups of subjects. In both sexes, however, these parameters were found to be highest in healthy HIV sero-negative subjects and lowest in AIDS subjects, with HIV sero-positive subjects having intermediate values. CONCLUSION: The results confirm previous reports that the CD4 count and CD4/CD8 count ratio are fairly reliable indicators of the progression of HIV infection. In addition, the results also apparently suggest that the prognostic value of CD8 count is limited and that of TLC possibly sex-dependent. The results could be of importance in our environment since previous reports have been relatively scarce.

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

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  19. The total neutron cross-sections of 151Eu, 153Eu and Eu below 1 eV

    International Nuclear Information System (INIS)

    Adib, M.; Maayouf, R.M.A.; Abdel-Kawy, A.; Ashry, A.; Hamouda, I.

    1980-12-01

    Total neutron cross-section measurements have been carried out for natural Eu and its stable isotopes in the energy range from 3 meV-1 eV. The measurements were performed using two time-of-flight spectrometers installed in front of two of the horizontal channels of the ET-RR-1 reactor. The following results have been obtained: sigmasub(α)( 151 Eu) = 9180+-150 b at 0.0253 eV; sigmasub(α)( 153 Eu) = 375+-20 b at 0.0253 eV; sigmasub(α)(Eu) = 4600+-120 b at 0.0253 eV

  20. The effect of post-wash total progressive motile sperm count and semen volume on pregnancy outcomes in intrauterine insemination cycles: a retrospective study.

    Science.gov (United States)

    Ok, Elvan Koyun; Doğan, Omer Erbil; Okyay, Recep Emre; Gülekli, Bülent

    2013-01-01

    The purpose of this study was to determine the impact of post-wash total progressive motile sperm count (TPMSC) and semen volume on pregnancy outcomes in intrauterine insemination (IUI) cycles. The retrospective study included a total of 156 cycles (141 couples) and was performed in our center over a 24-month period. The semen parameters were recorded for each man and each insemination. The semen samples were re-evaluated after the preparation process. Post-wash TPMSC values were divided into four groups; Group 1: 10×10(6). Post-wash inseminated semen volume was divided into three groups; Group 1: 0.3 mL; Group 2: 0.4 mL; Group 3: 0.5 mL. The effect of post-wash total progressive motile sperm and semen volume on pregnancy outcomes was evaluated. The pregnancy rates per cycle and per couple were 27.56% and 30.49%, respectively. There was not a significant relationship between the inseminated semen volume and pregnancy rate (p>0.05). However, a significant linear-by-linear association was documented between the TPMSC and pregnancy rate (p=0.042). Our findings suggest that the post-wash inseminated semen volume should be between 0.3-0.5 mL. An average post-wash total motile sperm count of 10×10(6) may be a useful threshold value for IUI success, but more studies are needed to determine a cut-off value for TPMSC.

  1. The Structure of Ethylbenzene, Styrene and Phenylacetylene Determined by Total Neutron Scattering.

    Science.gov (United States)

    Szala-Bilnik, Joanna; Falkowska, Marta; Bowron, Daniel T; Hardacre, Christopher; Youngs, Tristan G A

    2017-09-20

    Organic solvents such as phenylacetylene, styrene and ethylbenzene are widely used in industrial processes, especially in the production of rubber or thermoplastics. Despite their important applications detailed knowledge about their structure is limited. In this paper the structures of these three aromatic solvents were investigated using neutron diffraction. The results show that many of their structural characteristics are similar, although the structure of phenylacetylene is more ordered and has a smaller solvation sphere than either ethylbenzene or styrene. Two regions within the first coordination sphere, in which the surrounding molecules show different preferable orientations with respect to the central molecule, were found for each liquid. Additionally, the localisation of the aliphatic chains reveals that they tend to favour closer interactions with each other than to the aromatic rings of the adjacent molecules. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Evaluation of 40K in vegetables collected Malaysia by determination total potassium using neutron activation analysis

    International Nuclear Information System (INIS)

    Shafaei, M.A.; Saion, E.; Naghavi, K.; Wood, K.; Rezaee, Kh.

    2011-01-01

    Some vegetables of important nutritive requirements have been collected from Kuala Lumpur region capital of Malaysia. The vegetables were analyzed in order to determine activity concentration level of potassium using neutron activation analysis (NAA). The NAA results obtained showed the activity concentration of 40 K varied from 379 Bq/kg (Egg-plant) to 1585 Bq/kg (Spinach Red). These results are compared to other researches and are clear that the concentrations of K are relatively high in the Malaysia in compared to rather than vegetables of Pakistan and Jamaican. However, they are seen not to pose any serious internal health burden due to ingestion given the realities of vegetables choice by individuals in the study area. (author)

  3. Total neutron cross sections at energies around 20 MeV

    International Nuclear Information System (INIS)

    Morales, J.R.; Romero, J.L.; Martens, P.

    1990-09-01

    The results for measurements of total cross sections on C, Al, Mg, Cu, Ge and Pb at 17.6 and 19.8 MeV are reported. A detailed comparison is presented with previous data and with the global optical model by the Ohio group. We also discuss plans for total non elastic cross section measurements. 31 refs, 12 figs, 2 tabs

  4. Studies on fission with ALADIN. Precise and simultaneous measurement of fission yields, total kinetic energy and total prompt neutron multiplicity at GSI

    International Nuclear Information System (INIS)

    Martin, Julie-Fiona; Taieb, Julien; Chatillon, Audrey; Belier, Gilbert; Boutoux, Guillaume; Ebran, Adeline; Gorbinet, Thomas; Grente, Lucie; Laurent, Benoit; Pellereau, Eric; Alvarez-Pol, Hector; Ayyad, Yassid; Benlliure, Jose; Cortina Gil, Dolores; Caamano, Manuel; Fernandez Dominguez, Beatriz; Paradela, Carlos; Ramos, Diego; Rodriguez-Sanchez, Jose-Luis; Vargas, Jossitt; Audouin, Laurent; Tassan-Got, Laurent; Aumann, Thomas; Casarejos, Enrique; Farget, Fanny; Rodriguez-Tajes, Carme; Heinz, Andreas; Jurado, Beatriz; Kelic-Heil, Aleksandra; Kurz, Nikolaus; Nociforo, Chiara; Pietri, Stephane; Rossi, Dominic; Schmidt, Karl-Heinz; Simon, Haik; Voss, Bernd; Weick, Helmut

    2015-01-01

    A novel technique for fission studies, based on the inverse kinematics approach, is presented. Following pioneering work in the nineties, the SOFIA Collaboration has designed and built an experimental set-up dedicated to the simultaneous measurement of isotopic yields, total kinetic energies and total prompt neutron multiplicities, by fully identifying both fission fragments in coincidence, for the very first time. This experiment, performed at GSI, permits to study the fission of a wide variety of fissioning systems, ranging from mercury to neptunium, possibly far from the valley of stability. A first experiment, performed in 2012, has provided a large array of unprecedented data regarding the nuclear fission process. An excerpt of the results is presented. With this solid starter, further improvements of the experimental set-up are considered, which are consistent with the expected developments at the GSI facility, in order to measure more fission observables in coincidence. The completeness reached in the SOFIA data, permits to scrutinize the correlations between the interesting features of fission, offering a very detailed insight in this still unraveled mechanism. (orig.)

  5. Studies on fission with ALADIN. Precise and simultaneous measurement of fission yields, total kinetic energy and total prompt neutron multiplicity at GSI

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Julie-Fiona; Taieb, Julien; Chatillon, Audrey; Belier, Gilbert; Boutoux, Guillaume; Ebran, Adeline; Gorbinet, Thomas; Grente, Lucie; Laurent, Benoit; Pellereau, Eric [CEA DAM Bruyeres-le-Chatel, Arpajon (France); Alvarez-Pol, Hector; Ayyad, Yassid; Benlliure, Jose; Cortina Gil, Dolores; Caamano, Manuel; Fernandez Dominguez, Beatriz; Paradela, Carlos; Ramos, Diego; Rodriguez-Sanchez, Jose-Luis; Vargas, Jossitt [Universidad de Santiago de Compostela, Santiago de Compostela (Spain); Audouin, Laurent; Tassan-Got, Laurent [CNRS/IN2P3, IPNO, Orsay (France); Aumann, Thomas [Technische Universitaet Darmstadt, Darmstadt (Germany); Casarejos, Enrique [Universidad de Vigo, Vigo (Spain); Farget, Fanny; Rodriguez-Tajes, Carme [CNRS/IN2P3, GANIL, Caen (France); Heinz, Andreas [Chalmers University of Technology, Gothenburg (Sweden); Jurado, Beatriz [CNRS/IN2P3, CENBG, Gradignan (France); Kelic-Heil, Aleksandra; Kurz, Nikolaus; Nociforo, Chiara; Pietri, Stephane; Rossi, Dominic; Schmidt, Karl-Heinz; Simon, Haik; Voss, Bernd; Weick, Helmut [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2015-12-15

    A novel technique for fission studies, based on the inverse kinematics approach, is presented. Following pioneering work in the nineties, the SOFIA Collaboration has designed and built an experimental set-up dedicated to the simultaneous measurement of isotopic yields, total kinetic energies and total prompt neutron multiplicities, by fully identifying both fission fragments in coincidence, for the very first time. This experiment, performed at GSI, permits to study the fission of a wide variety of fissioning systems, ranging from mercury to neptunium, possibly far from the valley of stability. A first experiment, performed in 2012, has provided a large array of unprecedented data regarding the nuclear fission process. An excerpt of the results is presented. With this solid starter, further improvements of the experimental set-up are considered, which are consistent with the expected developments at the GSI facility, in order to measure more fission observables in coincidence. The completeness reached in the SOFIA data, permits to scrutinize the correlations between the interesting features of fission, offering a very detailed insight in this still unraveled mechanism. (orig.)

  6. The estimation of total body fat by inelastic neutron scattering - a geometrical feasibility study

    International Nuclear Information System (INIS)

    Lizos, F.; Kotzasarlidoou, M.; Makridou, A.; Giannopoulou, K.

    2012-01-01

    A rough quantitative representation of the basic elements in a human body is shown. It deals with a hypothetical, normal adult weighting 70 kg. It is possible to measure two basic quantities, the FFM, standing for Fat Free Mass and the FM, standing for Fat Mass. The present simulation deals with the most important aspect of the estimation of storage fat in the human body and in order to accomplish such a task, it is considered a representation of the human body, containing a uniform distribution of triacylglycerols, in a shape of cylindrical phantom. The whole process is analyzed and simulated by a geometrical model and with the aid of a computer program which takes into consideration the different attenuation for neutrons and photons, the amount of gamma radiation reaching the detector is also calculated. The net result is the determination of sensitivity for a particular set-up and by relating the out coming data to the amount of carbon; the quantity of fat is estimated. In addition, the non-uniformity is calculated, from the computer programs expressing the consistency of the system. In order to determine the storage fat, a simulation model that will enable to represent the detection of the carbon atoms in triacylglycerols was built

  7. Neutron total cross-sections and resonance parameters of Mo and Ta

    Indian Academy of Sciences (India)

    Linear accelerator; total cross-sections; resonance parameters; SAMMY code. ... Centre for Atomic Research, Kalpakkam 603 102, India; Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784, Korea; Department of Physics, Kyungpook National University, Daegu 702-701, Korea ...

  8. The neutron total cross-section measurement of 56Fe and 57Fe by using Japan Proton Accelerator Research Complex facility

    International Nuclear Information System (INIS)

    Kim, Eun Ae; Shvetsov, Valery; Cho, Moo Hyun; Won, Nam Kung; Kim, Kwang Soo; Yang, Sung Chul; Lee, Man Woo; Kim, Guin Yun; Yi, Kyoung Rak; Choi, Hong Yub; Ro, Tae Ik; Mizumoto, Motoharu; Katabuchi, Tatsuya; Igashira, Masayuki

    2012-01-01

    The measurement of neutron cross section using Time-Of-Flight (TOF) method gives significant information for the nuclear data research. In the present work, the neutron total cross section of 56 Fe and 57 Fe has been measured in the energy range between 10 eV and 100 keV by using the neutron beam produced from 3-GeV proton synchrotron accelerator. The 3-GeV proton synchrotron accelerator is located at Japan Proton Accelerator Research Complex (J-PARC) facility in Tokai village. In this study, the neutron total cross section data measured by 6 Li glass scintillator detector was compared with the evaluated values of ENDF/B-VII.0

  9. The neutron total cross-section measurement of {sup 56}Fe and {sup 57}Fe by using Japan Proton Accelerator Research Complex facility

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun Ae; Shvetsov, Valery; Cho, Moo Hyun [Pohang University of Science and Technology, Pohang (Korea, Republic of); Won, Nam Kung [Pohang Accelerator Laboratory, Pohang (Korea, Republic of); Kim, Kwang Soo; Yang, Sung Chul; Lee, Man Woo; Kim, Guin Yun [Kyungpook National University, Daegu (Korea, Republic of); Yi, Kyoung Rak; Choi, Hong Yub; Ro, Tae Ik [Dong-A University, Pusan (Korea, Republic of); Mizumoto, Motoharu; Katabuchi, Tatsuya; Igashira, Masayuki [Tokyo Institute of Technology, Tokyo (Japan)

    2012-05-15

    The measurement of neutron cross section using Time-Of-Flight (TOF) method gives significant information for the nuclear data research. In the present work, the neutron total cross section of {sup 56}Fe and {sup 57}Fe has been measured in the energy range between 10 eV and 100 keV by using the neutron beam produced from 3-GeV proton synchrotron accelerator. The 3-GeV proton synchrotron accelerator is located at Japan Proton Accelerator Research Complex (J-PARC) facility in Tokai village. In this study, the neutron total cross section data measured by {sup 6}Li glass scintillator detector was compared with the evaluated values of ENDF/B-VII.0

  10. Neutron reflectometry

    International Nuclear Information System (INIS)

    Van Well, A.A.

    1999-01-01

    Neutron research where reflection, refraction, and interference play an essential role is generally referred to as 'neutron optics'. The neutron wavelength, the scattering length density and the magnetic properties of the material determine the critical angle for total reflection. The theoretical background of neutron reflection, experimental methods and the interpretation of reflection data are presented. (K.A.)

  11. Total mesophilic counts underestimate in many cases the contamination levels of psychrotrophic lactic acid bacteria (LAB) in chilled-stored food products at the end of their shelf-life.

    Science.gov (United States)

    Pothakos, Vasileios; Samapundo, Simbarashe; Devlieghere, Frank

    2012-12-01

    The major objective of this study was to determine the role of psychrotrophic lactic acid bacteria (LAB) in spoilage-associated phenomena at the end of the shelf-life of 86 various packaged (air, vacuum, modified-atmosphere) chilled-stored retail food products. The current microbiological standards, which are largely based on the total viable mesophilic counts lack discriminatory capacity to detect psychrotrophic LAB. A comparison between the total viable counts on plates incubated at 30 °C (representing the mesophiles) and at 22 °C (indicating the psychrotrophs) for 86 food samples covering a wide range - ready-to-eat vegetable salads, fresh raw meat, cooked meat products and composite food - showed that a consistent underestimation of the microbial load occurs when the total aerobic mesophilic counts are used as a shelf-life parameter. In 38% of the samples, the psychrotrophic counts had significantly higher values (+0.5-3 log CFU/g) than the corresponding total aerobic mesophilic counts. A total of 154 lactic acid bacteria, which were unable to proliferate at 30 °C were isolated. In addition, a further 43 with a poor recovery at this temperature were also isolated. This study highlights the potential fallacy of the total aerobic mesophilic count as a reference shelf-life parameter for chilled food products as it can often underestimate the contamination levels at the end of the shelf-life. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Total β-decay energies of neutron-rich zinc isotopes, A=75-80

    International Nuclear Information System (INIS)

    Lund, E.; Aleklett, K.; Fogelberg, B.; Sangariyavanish, A.

    1984-01-01

    The present investigation involves improved measurements of the Qsub(β)-values of 75-78 Zn and determinations of the total decay energies of sup(79,80)Zn which are not reported in the literature before. Also 81 Zn was detected but at the time for the experiment the ion-source was not efficient enough to yield sufficient activity for an accurate Qsub(β)-determination. (orig./HSI)

  13. The use of computed neutron coincidence counting with time interval analysis for the analysis of Fork-measurements on a fresh MOX-LWR fuel assembly under water

    Energy Technology Data Exchange (ETDEWEB)

    Baeten, P.; Bruggeman, M.; Carchon, R

    1998-06-01

    The objective of this study was to investigate the influence of different important parameters on measurement results for various fork-detectors. Computed Neutron Coincidence Counting (CNCC) with Time Interval Analysis (TIA) was used for this study. The performance of the electronics for the different fork-detectors was studied by investigating the deadtime perturbed zone of the Rossi-alpha distribution in TIA. The measurement revealed anomalies in the performance of the electronics of the IAEA BWR and LANL fork-detector. The IAEA PWR fork-detector functioned well and the deadtime parameter was calculated. The optimal setting for the pre delay was investigated and it was found that a pre delay of 10 micro seconds should be considered as an optimum between excluding from analysis data in the deadtime perturbed zone and keeping a high signal-to-noise ratio. For the shift register electronics used with the fork-detectors, a pre delay of only 4.5 micro seconds was used. The study of the pre delay and the deadtime showed that the calculated triples-rate is strongly dependent on these parameters. An accurate determination of the triple-rate in this type of measurements has proven to be quite difficult and requires proper operation of the electronics, a correct pre delay and an accurate deadtime correction formalism. By varying the boron concentration in water, the change of the decay time of the Rossi-alpha distribution was clearly observed. This change is due to the variation of the thermal multiplication. The variation of this decay time with the boron concentration proves that Boehnel's model for fast neutron multiplication is not valid under these measurement conditions and that a model for fast and thermal multiplication should be used in order to obtain unbiased measurement results. CNCC with TIA has proved to be a valuable tool in which parameter settings can be varied a posterori and the optimal setting can be determined for each measurement. Moreover, the

  14. The use of computed neutron coincidence counting with time interval analysis for the analysis of Fork-measurements on a fresh MOX-LWR fuel assembly under water

    International Nuclear Information System (INIS)

    Baeten, P.; Bruggeman, M.; Carchon, R.

    1998-06-01

    The objective of this study was to investigate the influence of different important parameters on measurement results for various fork-detectors. Computed Neutron Coincidence Counting (CNCC) with Time Interval Analysis (TIA) was used for this study. The performance of the electronics for the different fork-detectors was studied by investigating the deadtime perturbed zone of the Rossi-alpha distribution in TIA. The measurement revealed anomalies in the performance of the electronics of the IAEA BWR and LANL fork-detector. The IAEA PWR fork-detector functioned well and the deadtime parameter was calculated. The optimal setting for the pre delay was investigated and it was found that a pre delay of 10 micro seconds should be considered as an optimum between excluding from analysis data in the deadtime perturbed zone and keeping a high signal-to-noise ratio. For the shift register electronics used with the fork-detectors, a pre delay of only 4.5 micro seconds was used. The study of the pre delay and the deadtime showed that the calculated triples-rate is strongly dependent on these parameters. An accurate determination of the triple-rate in this type of measurements has proven to be quite difficult and requires proper operation of the electronics, a correct pre delay and an accurate deadtime correction formalism. By varying the boron concentration in water, the change of the decay time of the Rossi-alpha distribution was clearly observed. This change is due to the variation of the thermal multiplication. The variation of this decay time with the boron concentration proves that Boehnel's model for fast neutron multiplication is not valid under these measurement conditions and that a model for fast and thermal multiplication should be used in order to obtain unbiased measurement results. CNCC with TIA has proved to be a valuable tool in which parameter settings can be varied a posterori and the optimal setting can be determined for each measurement. Moreover, the

  15. Chromium Fractions Changes Compared With Total-Cr As Determined by Neutron Activation Analysis Technique

    International Nuclear Information System (INIS)

    Abdel-Sabour, M.F.; Abdou, F.M.; Elwan, I.M.; Al-Salama, Y.J.

    2003-01-01

    Fifteen soil samples were chosen from different locations (five different locations at north greater Cairo, Egypt to represent different soils (alluvial and sandy) as well as different source of contaminated wastewater (sewage and industrial effluent). Using sequential extraction technique (extracting the soil with different solutions, which is designed to separate metal fractions), Cr was separated into six operationally defined fractions water soluble, exchangeable, carbonate bound, Fe-Mn oxides bound, organic bound and residual fractions. Result of soil total-Cr indicated the serious accumulation of Cr in soils subjected to prolonged irrigation with contaminated wastewater. As it could seen, total-Cr in the tested contaminated soils exceeds the permissible levels (75-100)ppm Cr by several order of magnitude particularly at the surface and subsurface layers. The highest accumulation of total Cr down to depth 60 cm was observed in case of soil E. Data showed that values of total Cr determined by NAA method were always higher than the relevant values determined either by AAS or those calculated after the sequential extraction method. T-test analysis showed the significant difference between NAA and either AAS or sequential extraction methods. Although T-test analysis showed that were significant differences between total content in soils as determined by destructive (AAS or SUM) and non-destructive (NAA) analytical techniques however, strong liner relation between NAA and other tested methods was obtained. Chromium distribution between different extractants shows that the greatest amounts are found in the residual and Occluded in Fe and Mn-Oxides fractions followed by carbonate or organic fractions. In most cases the proportion of all tested Cr-forms has increased in contaminated soil layers with higher enrichment in organically bound Cr, occluded in Fe and Mn oxides, carbonate exchangeable and soluble fractions. Results indicate that soil properties have a

  16. Slow neutron total cross-section, transmission and reflection calculation for poly- and mono-NaCl and PbF{sub 2} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Mansy, Muhammad S., E-mail: mmansy88@asrt.sci.eg [Reactor Physics Department, Nuclear Research Centre, Atomic Energy Authority, Cairo (Egypt); Radioactive Waste Management Unit, Hot Labs Centre, Atomic Energy Authority, Cairo (Egypt); Adib, M.; Habib, N. [Reactor Physics Department, Nuclear Research Centre, Atomic Energy Authority, Cairo (Egypt); Bashter, I.I. [Physics Department, Faculty of Science, Zagazig University (Egypt); Morcos, H.N.; El-Mesiry, M.S. [Reactor Physics Department, Nuclear Research Centre, Atomic Energy Authority, Cairo (Egypt)

    2016-10-01

    Highlights: • Slow neutron cross-section calculation for poly- and mono-crystalline materials. • Monochromatic features of PbF{sub 2} and NaCl mono-crystals. • Characterization of poly- and mono-crystal filters used in neutron diffraction. • Computer code developed calculates neutron cross-section, transmission & reflection. - Abstract: A detailed study about the calculation of total neutron cross-section, transmission and reflection from crystalline materials was performed. The developed computer code is approved to be sufficient for the required calculations, also an excellent agreement has been shown when comparing the code results with the other calculated and measured values. The optimal monochromator and filter parameters were discussed in terms of crystal orientation, mosaic spread, and thickness. Calculations show that 30 cm thick of PbF{sub 2} poly-crystal is an excellent cold neutron filter producing neutron wavelengths longer than 0.66 nm needed for the investigation of magnetic structure experiments. While mono-crystal filter PbF{sub 2} cut along its (1 1 1), having mosaic spread (η = 0.5°) and thickness 10 cm can only transmit thermal neutrons of the desired wavelengths and suppress epithermal and γ-rays forming unwanted background, when it is cooled to liquid nitrogen temperature. NaCl (2 0 0) and PbF{sub 2} (1 1 1) monochromator crystals having mosaic spread (η = 0.5°) and thickness 10 mm shows high neutron reflectivity for neutron wavelengths (λ = 0.114 nm and λ = 0.43 nm) when they used as a thermal and cold neutron monochromators respectively with very low contamination from higher order reflections.

  17. RBC count

    Science.gov (United States)

    ... by kidney disease) RBC destruction ( hemolysis ) due to transfusion, blood vessel injury, or other cause Leukemia Malnutrition Bone ... slight risk any time the skin is broken) Alternative Names Erythrocyte count; Red blood cell count; Anemia - RBC count Images Blood test ...

  18. Determination of trace elements in total particulate matter of cigarette smoke by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Mishra, U.C.; Shaikh, G.N.

    1985-01-01

    Cigarette smoke contains many trace elements hazardous for human body. Tobacco samples were analyzed for their trace element contents and the results were reported earlier. This paper presents results on the trace element content analyzed in cigarette smoke using an automatic smoking machine developed in laboratory to simulate actual smoking pattern. The trace element levels in the total particulate matter samples of the cigarette smoke collected on filter papers were measured and compared with those of cigarette smoke condensate reported in the literature. Both methods of collection give comparable results. (author)

  19. Measurement of Neutron Total Cross Sections in Support of the APT Program

    International Nuclear Information System (INIS)

    Abfalterer, W.P.; Haight, R.C.; Morgan, G.L.; Bateman, F.B.; Dietrich, F.S.; Finlay, R.W.

    1998-01-01

    The authors have completed a new set of total cross section measurements of 37 samples spanning the periodic table. The authors employed the same technique as in a previous measurement, with refinements intended to allow measurements on separated isotopes, and with improved systematic error control. The goal of the new measurement was 1% statistical accuracy in 1% energy bins with systematic errors less than 1%. This was achieved for all but the smallest samples, for which the statistical accuracy was as large as 2% in 1% bins

  20. Dependence of two-neutron momentum densities on total pair momentum

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Joseph A [Los Alamos National Laboratory; Wiringa, R B [ANL; Schiavilla, R [JEFFERSON LAB; Pieper, Steven C [ANL

    2008-01-01

    Two-nucleon momentum distributions are calculated for the ground states of {sup 3}He and {sup 4}He as a function of the nucleons' relative and total momenta. We use variational Monte Carlo wave functions derived from a realistic Hamiltonian with two- and three-nucleon potentials. The momentum distribution of pp pairs is found to be much smaller than that of pn pairs for values of the relative momentum in the range (300--500) MeV/c and vanishing total momentum. Howeer, as the totalmomentum increases to 400 MeV/c, the ratio of pp to pn pairs in this relative momentum range grows and approaches the limit 1/2 for {sup 3}He and 1/4 for {sup 4}He, corresponding to the ratio of pp to pn pairs in these nuclei. This behavior should be easily observable in two-nucleon knock-out processes, such as A(e, e'pN).

  1. Alteration of sensitivity of intratumor quiescent and total cells to γ-rays following thermal neutron irradiation with or without 10B-compound

    International Nuclear Information System (INIS)

    Masunaga, Shin-ichiro; Ono, Koji; Suzuki, Minoru; Sakurai, Yoshinori; Kobayashi, Tooru; Takagaki, Masao; Kinashi, Yuko; Akaboshi, Mitsuhiko

    2000-01-01

    Purpose: Changes in the sensitivity of intratumor quiescent (Q) and total cells to γ-rays following thermal neutron irradiation with or without 10 B-compound were examined. Methods and Materials: 5-Bromo-2'-deoxyuridine (BrdU) was injected to SCC VII tumor-bearing mice intraperitoneally 10 times to label all the proliferating (P) tumor cells. As priming irradiation, thermal neutrons alone or thermal neutrons with 10 B-labeled sodium borocaptate (BSH) or dl-p-boronophenylalanine (BPA) were administered. The tumor-bearing mice then received a series of γ-ray radiation doses, 0 through 24 h after the priming irradiation. During this period, no BrdU was administered. Immediately after the second irradiation, the tumors were excised, minced, and trypsinized. Following incubation of tumor cells with cytokinesis blocker, the micronucleus (MN) frequency in cells without BrdU labeling (= Q cells at the time of priming irradiation) was determined using immunofluorescence staining for BrdU. The MN frequency in the total (P + Q) tumor cells was determined from the tumors that were not pretreated with BrdU before the priming irradiation. To determine the BrdU-labeled cell ratios in the tumors at the time of the second irradiation, each group also included mice that were continuously administered BrdU until just before the second irradiation using mini-osmotic pumps which had been implanted subcutaneously 5 days before the priming irradiation. Results: In total cells, during the interval between the two irradiations, the tumor sensitivity to γ-rays relative to that immediately after priming irradiation decreased with the priming irradiation ranking in the following order: thermal neutrons only > thermal neutrons with BSH > thermal neutrons with BPA. In contrast, in Q cells, during that time the sensitivity increased in the following order: thermal neutrons only 10 B-compound, especially BPA, in thermal neutron irradiation causes the recruitment from the Q to P population

  2. Beta strength distributions in neutron-deficient Kr and Sr isotopes using a total absorption spectrometer

    CERN Document Server

    Maréchal, F

    2003-01-01

    Far from the line of stability, beta -decay studies are often a primary source of information on nuclear structure. The measured beta -strength distribution for a given decay can be used to verify the accuracy of our theoretical description of the parent nucleus ground state and the states populated in the daughter nucleus. Total absorption spectrometers based on large NaI crystals are well suited tools to determine the beta -strength distribution over the whole Q /sub EC/ decay window. The newly built spectrometer TAgS, dedicated to such studies, is presented and its performances and possibilities are discussed in the light of experiments performed at the ISOLDE /CERN mass separator. The resulting information on ground state deformations for the /sup 74/Kr and /sup 76/Sr isotopes are discussed. (22 refs).

  3. Slow neutron total cross-section, transmission and reflection calculation for poly- and mono-NaCl and PbF2 crystals

    Science.gov (United States)

    Mansy, Muhammad S.; Adib, M.; Habib, N.; Bashter, I. I.; Morcos, H. N.; El-Mesiry, M. S.

    2016-10-01

    A detailed study about the calculation of total neutron cross-section, transmission and reflection from crystalline materials was performed. The developed computer code is approved to be sufficient for the required calculations, also an excellent agreement has been shown when comparing the code results with the other calculated and measured values. The optimal monochromator and filter parameters were discussed in terms of crystal orientation, mosaic spread, and thickness. Calculations show that 30 cm thick of PbF2 poly-crystal is an excellent cold neutron filter producing neutron wavelengths longer than 0.66 nm needed for the investigation of magnetic structure experiments. While mono-crystal filter PbF2 cut along its (1 1 1), having mosaic spread (η = 0.5°) and thickness 10 cm can only transmit thermal neutrons of the desired wavelengths and suppress epithermal and γ-rays forming unwanted background, when it is cooled to liquid nitrogen temperature. NaCl (2 0 0) and PbF2 (1 1 1) monochromator crystals having mosaic spread (η = 0.5°) and thickness 10 mm shows high neutron reflectivity for neutron wavelengths (λ = 0.114 nm and λ = 0.43 nm) when they used as a thermal and cold neutron monochromators respectively with very low contamination from higher order reflections.

  4. Count-to-count time interval distribution analysis in a fast reactor; Estudio de la distribucion de intervalos de tiempo entre detecciones consecutivas de neutrones en un reactor rapido

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Navarro Gomez, A

    1973-07-01

    The most important kinetic parameters have been measured at the zero power fast reactor CORAL-I by means of the reactor noise analysis in the time domain, using measurements of the count-to-count time intervals. (Author) 69 refs.

  5. Low serum albumin and total lymphocyte count as predictors of 30 day hospital readmission in patients 65 years of age or older

    Directory of Open Access Journals (Sweden)

    Robert Robinson

    2015-08-01

    Full Text Available Introduction. Hospital readmission within 30 days of discharge is a target for health care cost savings through the medicare Value Based Purchasing initiative. Because of this focus, hospitals and health systems are investing considerable resources into the identification of patients at risk of hospital readmission and designing interventions to reduce the rate of hospital readmission. Malnutrition is a known risk factor for hospital readmission.Materials and Methods. All medical patients 65 years of age or older discharged from Memorial Medical Center from January 1, 2012 to March 31, 2012 who had a determination of serum albumin level and total lymphocyte count on hospital admission were studied retrospectively. Admission serum albumin levels and total lymphocyte counts were used to classify the nutritional status of all patients in the study. Patients with a serum albumin less than 3.5 grams/dL and/or a TLC less than 1,500 cells per mm3 were classified as having protein energy malnutrition. The primary outcome investigated in this study was hospital readmission for any reason within 30 days of discharge.Results. The study population included 1,683 hospital discharges with an average age of 79 years. The majority of the patients were female (55.9% and had a DRG weight of 1.22 (0.68. 219 patients (13% were readmitted within 30 days of hospital discharge. Protein energy malnutrition was common in this population. Low albumin was found in 973 (58% patients and a low TLC was found in 1,152 (68% patients. Low albumin and low TLC was found in 709 (42% of patients. Kaplan–Meier analysis shows any laboratory evidence of PEM is a significant (p < 0.001 predictor of hospital readmission. Low serum albumin (p < 0.001 and TLC (p = 0.018 show similar trends. Cox proportional-hazards regression analysis showed low serum albumin (Hazard Ratio 3.27, 95% CI [2.30–4.63] and higher DRG weight (Hazard Ratio 1.19, 95% CI [1.03–1.38] to be significant

  6. Neutron measuring device

    International Nuclear Information System (INIS)

    Hatayama, Akiyoshi; Seki, Eiji; Kita, Yoshio; Nishitani, Takeo.

    1993-01-01

    The device of the present invention concerns measurement for neutrons in a tokamak type thermonuclear device and it can measure total amount of generated neutrons accurately throughout the operation period even if an error is caused in counted values by plasma disruption. That is, the device comprises (1) a means for detecting presence or absence of occurrence of plasma disruption and the time for the initiation of the occurrence, (2) a first data processing means for processing detection signals, (3) a means for detecting neutrons generated in plasmas and (4) a second data processing means for calculating integrated values for the number of neutrons generated from the start to the completion of electric discharge when no disruption occurs and calculating integrated values for the number of generated neutrons from the start of electric discharge to the time at the initiation of occurrence of the disruption when disruption is present. In the thus constituted device, even if an error is caused by frequent occurrence of plasma disruption, total time integrated amount of neutrons generated in the plasmas can be measured accurately. (I.S.)

  7. Yield of Prompt Gamma Radiation in Slow-Neutron Induced Fission of 235U as a Function of the Total Fragment Kinetic Energy

    Energy Technology Data Exchange (ETDEWEB)

    Albinsson, H [Chalmers Univ. of Technology, Goeteborg (SE)

    1971-07-01

    Fission gamma radiation yields as functions of the total fragment kinetic energy were obtained for 235U thermal-neutron induced fission. The fragments were detected with silicon surface-barrier detectors and the gamma radiation with a Nal(Tl) scintillator. In some of the measurements mass selection was used so that the gamma radiation could also be measured as a function of fragment mass. Time discrimination between the fission gammas and the prompt neutrons released in the fission process was employed to reduce the background. The gamma radiation emitted during different time intervals after the fission event was studied with the help of a collimator, the position of which was changed along the path of the fission fragments. Fission-neutron and gamma-ray data of previous experiments were used for comparisons of the yields, and estimates were made of the variation of the prompt gamma-ray energy with the total fragment kinetic energy

  8. Total body calcium by neutron activation analysis in normals and osteoporotic populations: a discriminator of significant bone mass loss

    International Nuclear Information System (INIS)

    Ott, S.M.; Murano, R.; Lewellen, T.K.; Nelp, W.B.; Chesnut, C.M.

    1983-01-01

    Measurements of total body calcium by neutron activation (TBC) in 94 normal individuals and 86 osteoporotic patients are reported. The ability of TBC to discriminate normal from osteoporotic females was evaluated with decision analysis. Bone mineral content (BMC) by single-photon absorptiometry was also measured. TBC was higher in males (range 826 to 1363 gm vs 537 to 1054 in females) and correlated with height in all normals. In females over age 55 there was a negative correlation with age. Thus, for normals an algorithm was derived to allow comparison between measured TBC and that predicted by sex, age, and height (TBCp). In the 28 normal females over age 55, the TBC was 764 +/- 115 gm vs. 616 +/- 90 in the osteoporotics. In 63 of the osteoporotic females an estimated height, from tibial length, was used to predict TBC. In normals the TBC/TBCp ratio was 1.00 +/- 0.12, whereas in osteoporotic females it was 0.80 +/- 0.12. A receiver operating characteristic curve showed better discrimination of osteoporosis with TBC/TBCp than with wrist BMC. By using Bayes' theorem, with a 25% prevalence of osteoporosis (estimate for postmenopausal women), the posttest probability of disease was 90% when the TBC/TBCp ratio was less than 0.84. The authors conclude that a low TBC/TBCp ratio is very helpful in determining osteoporosis

  9. Total Absorption Spectroscopy Study of the Beta Decay of 60Mn to Constrain the Neutron Capture Rate of 60Fe

    Science.gov (United States)

    Richman, Debra; Spyrou, Artemis; Dombos, Alex; Couture, Aaron; e15034 Collaboration

    2017-09-01

    Interest in 60Fe, a long lived radioisotope synthesized in massive stars, has recently peaked. The signature of its decay allows us to probe astrophysical processes, events such as the early formation of the solar system and nucleosynthesis. To understand these observations a complete understanding of the creation, destruction and nuclear properties of 60Fe in the astrophysical environment are required. Using the beta decay of 60Mn in conjunction with total absorption spectroscopy (TAS), made possible by the high efficiency gamma ray calorimeter SuN (Summing NaI detector) at the National Superconducting Cyclotron Laboratory (NSCL), to study the distribution of beta-decay intensity over the daughter-nucleus 60Fe, provides information about the structure of the daughter and improves the predictive power of astrophysical models. In addition to the ongoing TAS analysis, The Beta-Oslo method will be used to extract the nuclear level density and gamma-strength function of 60Fe providing much needed constraints on the neutron capture reaction rate responsible for the creation of this nucleus.

  10. The recovery of bone marrow derived GM-CFU in baboons unilaterally exposed to a total body LD50/30d mixed neutron-gamma irradiation

    International Nuclear Information System (INIS)

    Herodin, F.; Orfeuvre, H.; Janodet, D.; Mestries, J.C.; Fatome, M.

    1990-01-01

    The unilateral exposure of baboons to a total body LD 50/30d mixed neutron/gamma irradiation was characterized to be non uniform in dose distribution. The pattern of recovery of granulocyte-macrophage progenitors in bone marrow samples collected from entrance and exit sides respectively is consistent with this observed heterogeneity [fr

  11. The calorically restricted low-fat nutrient-dense diet in Biosphere 2 significantly lowers blood glucose, total leukocyte count, cholesterol, and blood pressure in humans.

    Science.gov (United States)

    Walford, R L; Harris, S B; Gunion, M W

    1992-12-01

    Biosphere 2 is a 3.15-acre space containing an ecosystem that is energetically open (sunlight, electric power, and heat) but materially closed, with air, water, and organic material being recycled. Since September 1991, eight subjects (four women and four men) have been sealed inside, living on food crops grown within. Their diet, low in calories (average, 1780 kcal/day; 1 kcal = 4.184 kJ), low in fat (10% of calories), and nutrient-dense, conforms to that which in numerous animal experiments has promoted health, retarded aging, and extended maximum life span. We report here medical data on the eight subjects, comparing preclosure data with data through 6 months of closure. Significant changes included: (i) weight, 74 to 62 kg (men) and 61 to 54 kg (women); (ii) mean systolic/diastolic blood pressure (eight subjects), 109/74 to 89/58 mmHg (1 mmHg = 133 Pa); (iii) total serum cholesterol, from 191 +/- 11 to 123 +/- 9 mg/dl (mean +/- SD; 36% mean reduction), and high density lipoprotein, from 62 +/- 8 to 38 +/- 5 (risk ratio unchanged); (iv) triglyceride, 139 to 96 mg/dl (men) and 78 to 114 mg/dl (women); (v) fasting glucose, 92 to 74 mg/dl; (vi) leukocyte count, 6.7 to 4.7 x 10(9) cells per liter. We conclude that drastic reductions in cholesterol and blood pressure may be instituted in normal individuals in Western countries by application of a carefully chosen diet and that a low-calorie nutrient-dense regime shows physiologic features in humans similar to those in other animal species.

  12. Neutrons production of very low energy by filtration through graphite and measurement of total cross sections; Production de neutrons de tres basse energie par filtration a travers du graphite et mesure de sections efficaces totales

    Energy Technology Data Exchange (ETDEWEB)

    Ertaud, A; Beauge, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1953-07-01

    In this report, we done on the reactor of Chatillon analogous experiences to those of Fermi in Argonne. The temperature of the neutrons filtered ba a more or less thickness of graphite is measured by the method of absorption. This method permits the production and the study of a very low energy neutron beam. (M.B.) [French] Dans ce rapport, nous avons repris sur la pile de Chatillon des experiences analogues a celles de FERMI a Argonne. La temperature des neutrons filtree par une epaisseur plus ou moins grande de graphite est mesuree par la methode d'absorption. Cette methode permettant la production et l'etude d'un faisceau de neutron de tres basse energie. (M.B.)

  13. Determination of human and Sprague-Dawley rat trimethylseleonium ion and total selenium urine concentrations from endogenous body selenium pool by neutron activation analysis

    International Nuclear Information System (INIS)

    Blotcky, A.J.; Claassen, J.P.; Rack, E.P.

    1992-01-01

    This study determined trimethylselenonium ion [TMSe,(CH 3 ) 3 Se + ] and total organic selenium cationic species urinary excretion values for healthy human subjects and Sprague-Dawley rats fed regular diets. The only source of TMSe was from the endogenous selenium body pool. Total selenium concentration in urine was determined by instrumental neutron activation analysis. TMSe and total selenium cationic species concentrations and percent of total selenium urine excretion were determined by chemical neutron activation analysis and coupled anion-cation exchange chromatography and anion-exchange chromatography, respectively. Within experimental error, mean values for TMSe and cationic species as percent selenium were comparable for both human subjects and Sprague-Dawley rats. This study suggested that TMSe excreated in urine by healthy human subjects and Sprague-Dawley rats fed a normal diet is not a minor but a general metabolite of selenium ingested in a normal diet. (author) 27 refs.; 1 fig.; 2 tabs

  14. Counting carbohydrates

    Science.gov (United States)

    Carb counting; Carbohydrate-controlled diet; Diabetic diet; Diabetes-counting carbohydrates ... Many foods contain carbohydrates (carbs), including: Fruit and fruit juice Cereal, bread, pasta, and rice Milk and milk products, soy milk Beans, legumes, ...

  15. Neutron spectrometry with artificial neural networks

    International Nuclear Information System (INIS)

    Vega C, H.R.; Hernandez D, V.M.; Manzanares A, E.; Rodriguez, J.M.; Mercado S, G.A.; Iniguez de la Torre Bayo, M.P.; Barquero, R.; Arteaga A, T.

    2005-01-01

    An artificial neural network has been designed to obtain the neutron spectra from the Bonner spheres spectrometer's count rates. The neural network was trained using 129 neutron spectra. These include isotopic neutron sources; reference and operational spectra from accelerators and nuclear reactors, spectra from mathematical functions as well as few energy groups and monoenergetic spectra. The spectra were transformed from lethargy to energy distribution and were re-bin ned to 31 energy groups using the MCNP 4C code. Re-binned spectra and UTA4 response matrix were used to calculate the expected count rates in Bonner spheres spectrometer. These count rates were used as input and the respective spectrum was used as output during neural network training. After training the network was tested with the Bonner spheres count rates produced by a set of neutron spectra. This set contains data used during network training as well as data not used. Training and testing was carried out in the Mat lab program. To verify the network unfolding performance the original and unfolded spectra were compared using the χ 2 -test and the total fluence ratios. The use of Artificial Neural Networks to unfold neutron spectra in neutron spectrometry is an alternative procedure that overcomes the drawbacks associated in this ill-conditioned problem. (Author)

  16. Evaluation of apoptosis and micronucleation induced by reactor neutron beams with two different cadmium ratios in total and quiescent cell populations within solid tumors

    International Nuclear Information System (INIS)

    Masunaga, Shin-ichiro; Ono, Koji; Sakurai, Yoshinori; Takagaki, Masao; Kobayashi, Tooru; Kinashi, Yuko; Suzuki, Minoru

    2001-01-01

    Purpose: Response of quiescent (Q) and total tumor cells in solid tumors to reactor neutron beam irradiation with two different cadmium (Cd) ratios was examined in terms of micronucleus (MN) frequency and apoptosis frequency, using four different tumor cell lines. Methods and Materials: C57BL mice bearing EL4 tumors, C3H/He mice bearing SCC VII or FM3A tumors, and Balb/c mice bearing EMT6/KU tumors received 5-bromo-2'-deoxyuridine (BrdU) continuously for 5 days via implanted mini-osmotic pumps to label all proliferating (P) cells. Thirty min after i.p. injection of sodium borocaptate- 10 B (BSH), or 3 h after oral administration of p-boronophenylalanine- 10 B (BPA), the tumors were irradiated with neutron beams. The tumors without 10 B-compound administration were irradiated with neutron beams or γ-rays. This neutron beam irradiation was performed using neutrons with two different Cd ratios. The tumors were then excised, minced, and trypsinized. The tumor cell suspensions thus obtained were incubated with cytochalasin-B (a cytokinesis blocker), and the MN frequency in cells without BrdU labeling (=Q cells) was determined using immunofluorescence staining for BrdU. Meanwhile, for apoptosis assay, 6 h after irradiation, tumor cell suspensions obtained in the same manner were fixed, and the apoptosis frequency in Q cells was also determined with immunofluorescence staining for BrdU. The MN and apoptosis frequencies in total (P+Q) tumor cells were determined from the tumors that were not pretreated with BrdU. Results: Without 10 B-compounds, the sensitivity difference between total and Q cells was reduced by neutron beam irradiation. Under our particular neutron beam irradiation condition, relative biological effectiveness (RBE) of neutrons was larger in Q cells than in total cells, and the RBE values were larger for low Cd-ratio than high Cd-ratio neutrons. With 10 B-compounds, both frequencies were increased for each cell population, especially for total cells. BPA

  17. Fission fragment yields and total kinetic energy release in neutron-induced fission of235,238U,and239Pu

    Science.gov (United States)

    Tovesson, F.; Duke, D.; Geppert-Kleinrath, V.; Manning, B.; Mayorov, D.; Mosby, S.; Schmitt, K.

    2018-03-01

    Different aspects of the nuclear fission process have been studied at Los Alamos Neutron Science Center (LANSCE) using various instruments and experimental techniques. Properties of the fragments emitted in fission have been investigated using Frisch-grid ionization chambers, a Time Projection Chamber (TPC), and the SPIDER instrument which employs the 2v-2E method. These instruments and experimental techniques have been used to determine fission product mass yields, the energy dependent total kinetic energy (TKE) release, and anisotropy in neutron-induced fission of U-235, U-238 and Pu-239.

  18. Total cross-section measurements on aluminium, carbon, fluorine and hydrogen for d, d reaction neutrons using the coincidence method (1963); Mesure de la section efficace totale de l'aluminium, du carbone, du fluor et de l'hydrogene pour des neutrons de la reaction d, d par la methode des coincidences (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosino, G; Sorriaux, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The experiment described consists in the measurement of the total cross-section of various materials: aluminium, carbon, fluorine and hydrogen, for mono-energetic 2.77 MeV neutrons obtained from the d,d reaction. The measurement is carried out by transmission. The neutrons are detected by means of a plastic scintillator mounted on a 56 AVP photomultiplier, and are isolated from all secondary phenomena (background noise, scattered neutrons) by coincidence with helium 3. which particles are associated to the neutrons from the reaction {sup 2}{sub 1}D ({sup 2}{sub 1}D, n) {sup 3}{sub 2}H The helium 3 particles are detected by a PN junction diode used with inverted polarisation. An absorption exponential has been traced out using measurements made on seven aluminium bars. The accuracy of the total cross-section measurements is about 10{sup -2}. (authors) [French] L'experience exposee dans ce rapport consiste en la mesure des sections efficaces totales de differents materiaux: aluminium, carbone, fluor et hydrogene, pour des neutrons monoenergetiques de 2,77 MeV, obtenus par la reaction d,d. La mesure est faite par transmission. Les neutrons sont detectes par un scintillateur plastique monte sur un photomultiplicateur 56 AVP, et sont separes de tout phenomene secondaire (bruit de fond, neutrons diffuses) par coincidence avec les helium 3, particules associees aux neutrons de la reaction {sup 2}{sub 1}D ({sup 2}{sub 1}D, n) {sup 3}{sub 2}H Les helium 3 sont detectes par une diode a jonction PN utilisee en polarisation inverse. Une exponentielle d'absorption a ete tracee a partir de mesures faites sur sept barreaux d'aluminium. La precision des mesures des sections efficaces totales est de l'ordre de 10{sup -2}. (auteurs)

  19. High sensitivity neutron bursts detecting system

    International Nuclear Information System (INIS)

    Shyam, A.; Kaushik, T.C.; Srinivasan, M.; Kulkarni, L.V.

    1993-01-01

    Technique and instrumentation to detect multiplicity of fast neutrons, emitted in sharp bursts, has been developed. A bank of 16 BF 3 detectors, in an appropriate thermalising assembly, efficiency ∼ 16%, is used to detect neutron bursts. The output from this setup, through appropriate electronics, is divided into two paths. The first is directly connected to a computer controlled scalar. The second is connected to another similar scalar through a delay time unit (DTU). The DTU design is such that once it is triggered by a count pulse than it does not allow any counts to be recorded for a fixed dead time set at ∼ 100 μs. The difference in counts recorded directly and through DTU gives the total number of neutrons produced in bursts. This setup is being used to study lattice cracking, anomalous effects in solid deuterium systems and various reactor physics experiments. (author). 3 refs., 1 fig

  20. A measurement of ΔσL(np), the difference between neutron-proton total cross sections in pure longitudinal spin states

    International Nuclear Information System (INIS)

    Beddo, M.E.

    1990-10-01

    A measurement off Δσ L (np), the difference between neutron-proton total cross sections in pure longitudinal spin states, is described. The results will help determine the isospin-zero (I = 0) scattering amplitudes, which are not well known above laboratory energies of 500 MeV, whereas the isospin-one (I = 1) amplitudes are fairly well-determined to 1 GeV. Data points were taken at the Los Alamos Meson Physics Facility (LAMPF) at Los Alamos, New Mexico, for five neutron beam energies: 484, 568, 634,720 and 788 MeV; they are the first in this energy range. Polarized neutrons were produced by charge-exchange of polarized protons on a liquid deuterium target (LD 2 ). Large-volume neutron counters detected the neutrons that passed through a polarized proton target. The counters subtended a range of solid angles large enough to allow extrapolation of the scattered neutrons to 0 degree. Two modifications to the LAMPF accelerator system which were made for this work are described. They included a ''beam buncher,'' which modified the normal rf-time structure of the proton beam and allowed for the selection of peak-energy neutrons by time-of-flight means, and a computerized beam steering program, which reduced systematic effects due to beam motion at the LD 2 target. The experimental values of Δσ L (np) are found to be consistent with other np data, including preliminary data from SIN and Saclay, but not with some results from Argonne which used a polarized proton beam and a polarized deuteron target. The I = 0 component was extracted from Δσ L (np) using existing pp data (I = 1), with the unexpected result that Δσ L (I = 0) was found to be essentially identical in shape to Δσ L (I = 1). The significance of this is not yet understood

  1. Predictive models for the effect of storage temperature on Vibrio parahaemolyticus viability and counts of total viable bacteria in Pacific oysters (Crassostrea gigas).

    Science.gov (United States)

    Fernandez-Piquer, Judith; Bowman, John P; Ross, Tom; Tamplin, Mark L

    2011-12-01

    Vibrio parahaemolyticus is an indigenous bacterium of marine environments. It accumulates in oysters and may reach levels that cause human illness when postharvest temperatures are not properly controlled and oysters are consumed raw or undercooked. Predictive models were produced by injecting Pacific oysters (Crassostrea gigas) with a cocktail of V. parahaemolyticus strains, measuring viability rates at storage temperatures from 3.6 to 30.4°C, and fitting the data to a model to obtain parameter estimates. The models were evaluated with Pacific and Sydney Rock oysters (Saccostrea glomerata) containing natural populations of V. parahaemolyticus. V. parahaemolyticus viability was measured by direct plating samples on thiosulfate-citrate-bile salts-sucrose (TCBS) agar for injected oysters and by most probable number (MPN)-PCR for oysters containing natural populations. In parallel, total viable bacterial counts (TVC) were measured by direct plating on marine agar. Growth/inactivation rates for V. parahaemolyticus were -0.006, -0.004, -0.005, -0.003, 0.030, 0.075, 0.095, and 0.282 log₁₀ CFU/h at 3.6, 6.2, 9.6, 12.6, 18.4, 20.0, 25.7, and 30.4°C, respectively. The growth rates for TVC were 0.015, 0.023, 0.016, 0.048, 0.055, 0.071, 0.133, and 0.135 log₁₀ CFU/h at 3.6, 6.2, 9.3, 14.9, 18.4, 20.0, 25.7, and 30.4°C, respectively. Square root and Arrhenius-type secondary models were generated for V. parahaemolyticus growth and inactivation kinetic data, respectively. A square root model was produced for TVC growth. Evaluation studies showed that predictive growth for V. parahaemolyticus and TVC were "fail safe." The models can assist oyster companies and regulators in implementing management strategies to minimize V. parahaemolyticus risk and enhancing product quality in supply chains.

  2. [Increase in prevalence of childhood asthma in Budapest between 1995 and 2003: correlation with air pollution data and total pollen count].

    Science.gov (United States)

    Endre, László; Láng, Sarolta; Vámos, Adrienn; Bobvos, János; Páldy, Anna; Farkas, Ildikó; Collinsné Horváth, Zsuzsa; Varró, Mihály János

    2007-02-04

    According to the data of the Hungarian pulmonological network, the prevalence of asthma in the last 15 years has increased (almost linearly) in Hungary. In 2004 it was 1.8%. There are only a few data about the prevalence of childhood asthma. The aim of the authors was to measure the prevalence of bronchial asthma in childhood in Budapest in 1995, 1999 and 2003, using questionnaires directed to district pediatricians. There were only two questions in these questionnaires: how many children are in their districts, and how many are suffering from asthma? Besides of this survey the dust, CO, NO(2) and SO(2) concentrations in the air were measured on-line at 8 points in Budapest, while ozone level measurements were also made at 2 stations. The counts of pollen and of fungal elements in the air were calculated separately for Buda and for Pest. In 1995, replies were received from 118 pediatricians in 11 districts, who were responsible for the supervision of 104,060 children, out of these 1.88+/-0.87% had been diagnosed as having asthma. In 1999 replies were sent by 153 physicians in 22 of the 23 districts, who had a total of 142,679 children under their care. These included 3228 asthmatics, i.e. a prevalence of 2.26+/-0.95%. In 2003 the authors received answers from all of the 23 districts of Budapest. The 204 pediatricians were responsible for the supervision of 176 049 children. The number of patients with the diagnosis of asthma was 4712 (corresponding for a prevalence of 2.68+/-1.3%). The increase between 1995 and 1999, and between 1999 and 2003 was highly significant (p Budapest did not deteriorate in the period in question, and the concentration of pollen grains of plants causing allergy did not increase compared to previous years. On the basis of the results of more than 100 thousand children, the authors conclude that between 1995 and 2003 the proportion of asthmatic children increased by 50% in Budapest, while the air pollution did not deteriorate and the pollen

  3. Clean Hands Count

    Medline Plus

    Full Text Available ... starting stop Loading... Watch Queue Queue __count__/__total__ It’s YouTube. Uninterrupted. Loading... Want music and videos with ... ads? Get YouTube Red. Working... Not now Try it free Find out why Close Clean Hands Count ...

  4. Auto-counting of high density overlapping tracks and neutron spectrum measurement using CR-39 detectors and in-house image analysis program

    International Nuclear Information System (INIS)

    Paul, Sabyasachi; Tripathy, S.P.; Sahoo, G.S.; Joshi, D.S.; Bandyopadhyay, T.

    2014-01-01

    An effort is made in this work to overcome the difficulty of counting highly dense and overlapping tracks in solid polymeric track detectors (SPTD) such as CR-39. A program is developed to automatically count the track density which is found to be faster and more precise compared to other commonly used image analysing software. The results obtained by the present methodology are compared with those obtained using other software. (author)

  5. Count-doubling time safety circuit

    International Nuclear Information System (INIS)

    Keefe, D.J.; McDowell, W.P.; Rusch, G.K.

    1981-01-01

    There is provided a nuclear reactor count-factor-increase time monitoring circuit which includes a pulse-type neutron detector, and means for counting the number of detected pulses during specific time periods. Counts are compared and the comparison is utilized to develop a reactor scram signal, if necessary

  6. Count-doubling time safety circuit

    Science.gov (United States)

    Rusch, Gordon K.; Keefe, Donald J.; McDowell, William P.

    1981-01-01

    There is provided a nuclear reactor count-factor-increase time monitoring circuit which includes a pulse-type neutron detector, and means for counting the number of detected pulses during specific time periods. Counts are compared and the comparison is utilized to develop a reactor scram signal, if necessary.

  7. Neutron leakage measurements from a medical linear accelerator

    International Nuclear Information System (INIS)

    Palta, J.R.; Hogstrom, K.R.; Tannanonta, C.

    1984-01-01

    The McCall method has been used to measure neutron leakage from the Mevatron 77, 18- and 15-MV photon beams. Gold foil activation has been used employing a beta counting technique for the 18-MV beam and a gamma counting technique for both the 18- and 15-MV beam. The two counting techniques were used to evaluate their relative merit. The measurements were made at various locations in the patient-treatment plane for different field sizes. The results show that the thermal-neutron dose equivalent contributes only about 1%--2% of the total neutron dose equivalent. At 100 cm, the neutron dose equivalent for the 18-MV beam is approximately six times that of the 15-MV beam, slightly exceeding the 0.1% of the useful beam criteria used by some of the regulatory agencies. In light of the uncertainty in fluence to dose equivalent conversion factors, the increased dose equivalent above 0.1% is insignificant

  8. Clean Hands Count

    Medline Plus

    Full Text Available ... stop Loading... Watch Queue Queue __count__/__total__ It’s YouTube. Uninterrupted. Loading... Want music and videos with zero ads? Get YouTube Red. Working... Not now Try it free Find ...

  9. Experimental investigation of decay properties of neutron deficient $^{116-118}$Ba isotopes and test of $^{112-115}$Ba beam counts

    CERN Multimedia

    We propose to study decay of neutron deficient isotopes $^{116-118}$Ba using Double Sided Silicon Strip Detector (DSSSD). To study delayed-proton and $\\alpha$-decay branching ratios of $^{116-118}$Ba are of special interest because of their vicinity to the proton drip line. The nuclear life-times and properties of the proton unstable states of Cs isotopes, populated through decay of $^{116-118}$Ba isotopes will be measured. In addition to that we propose beam development of $^{112-115}$Ba to study exotic decay properties of these neutron deficient nuclei and to search for super-allowed $\\alpha$-decay in future.

  10. Adequação da contagem de células somáticas e da contagem bacteriana total em leite cru refrigerado aos parâmetros da legislação Suitability of somatic cell count and total bacterial count in raw refrigerated milk to legislation standards

    Directory of Open Access Journals (Sweden)

    G.A. Bozo

    2013-04-01

    Full Text Available O objetivo deste trabalho foi adequar a qualidade do leite cru refrigerado de cinco propriedades leiteiras aos parâmetros microbiológicos e de contagem de células somáticas (CCS estabelecidos pela legislação estadual do Paraná. As propriedades leiteiras estudadas foram monitoradas durante sete meses após a implantação de boas práticas de ordenha e de recomendações quanto ao tratamento de mastites e à manutenção e higienização de equipamentos de ordenha. Antes da adoção das recomendações, a contagem bacteriana total (CBT média era de 1,36 x 10(6UFC/mL e a CCS média, de 1,87 x 10(6/mL. Todas as propriedades atingiram os padrões estabelecidos para CBT, com redução média de 93,4%. A redução de CCS foi, em média, 74,3%. Apenas três propriedades atingiram os valores estabelecidos para CCS. As demais atingiram valores muito próximos ao limite. A adequação aos padrões de CBT e CCS gerou aumento na renda mensal, em razão do pagamento por qualidade do produto, entre R$120,00 e R$828,00, de acordo com a produção de cada propriedade.The aim of this work was to adequate raw refrigerated milk quality of five dairy farms to microbiological and somatic cell count (SCC standards established by Paraná state legislation. The dairy farms were monitored during seven months after the implementation of good milking practices and recommendations regarding mastitis treatment, and milking equipment maintenance and hygiene. Before the adoption of recommendations, the average total bacterial count (TBC was 1.36 x 10(6CFU/mL and average SCC was 1.87 x 10(6/mL. All farms reached established standards for TBC, originating an average reduction of 93.4%. Average SCC reduction was 74.3%. Only three farms reached established values for SCC. The remaining reached values near the limits. The suitability of TBC and SCC produced an increase in the monthly income due to payment quality reward of the dairy product, between R$120.00 and R$828

  11. Counting cormorants

    DEFF Research Database (Denmark)

    Bregnballe, Thomas; Carss, David N; Lorentsen, Svein-Håkon

    2013-01-01

    This chapter focuses on Cormorant population counts for both summer (i.e. breeding) and winter (i.e. migration, winter roosts) seasons. It also explains differences in the data collected from undertaking ‘day’ versus ‘roost’ counts, gives some definitions of the term ‘numbers’, and presents two...

  12. Certification of total arsenic in blood and urine standard reference materials by radiochemical neutron activation analysis and inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Paul, R.L.; Clay Davis, W.; Lee Yu; Murphy, K.E.; Bryan, C.E.; Vetter, T.W.; Guthrie, W.F.; Leber, D.D.; Gulchekhra Shakirova; Graylin Mitchell

    2014-01-01

    Radiochemical neutron activation analysis (RNAA) was used to measure arsenic at four levels in standard reference material (SRM) 955c Toxic Elements in Caprine Blood and at two levels in SRM 2668 Toxic Elements in Frozen Human Urine for the purpose of providing mass concentration values for certification. Samples were freeze-dried prior to analysis followed by neutron irradiation for 3 h at a fluence rate of 1 × 10 14 cm -2 s -1 . After sample dissolution in perchloric and nitric acids, arsenic was separated from the matrix either by retention on hydrated manganese dioxide (urine) or by extraction into zinc diethyldithiocarbamate in chloroform (blood). 76 As was quantified by gamma-ray spectroscopy. Differences in chemical yield and counting geometry between samples and standards were monitored by measuring the count rate of a 77 As tracer added before sample dissolution. RNAA results were combined with inductively coupled plasma-mass spectrometry values from National Institute of Standards and Technology and collaborating laboratories to provide certified values of 10.81 ± 0.54 and 213.1 ± 0.73 μg/L for SRM 2668 Levels I and II, and certified values of 21.66 ± 0.73, 52.7 ± 1.1, and 78.8 ± 4.9 μg/L for SRM 955c Levels II-IV, respectively. Because of discrepancies between values obtained by different methods for SRM 955c Level I, an information value of <5 μg/L was assigned for this material. (author)

  13. The Determination of Uranium in Urine by Delayed Neutron Counting; Dosage de l'Uranium dans l'Urine par Comptage des Neutrons Differes; Opredelenie soderzhaniya urana v moche putem scheta zapazdyvayushchikh nejtronov; Determinacion del Uranio Contenido en la Orina por Recuento de Neutrones Retardados

    Energy Technology Data Exchange (ETDEWEB)

    Brookes, I. R. [Atomic Weapons Research Establishment, Aldermaston, Berks. (United Kingdom)

    1965-10-15

    For this method {sup 235}U is assayed by counting delayed neutrons emitted following the fission of {sup 235}U in the sample with thermal neutrons. The three groups of neutrons of interest have half-lives of 55.72, 22.72 and 6.22 s. A 100-ml sample of urine is evaporated to dryness on a water bath. The residue is transferred with about 4-5 ml of water to a 1-oz polythene bottle which is then heat sealed. The sample bottle is put into a ''rabbit'' and sent through a pneumatic tube system to the HERALD reactor core where it is irradiated in a thermal flux of 3.94 x 10{sup 12} n cm{sup 2}/s. The sample automatically returns to the laboratory after 60 s irradiation where the sample bottle is transferred to the counter. This counter is switched on 25 s after the sample has left the reactor and counts the sample for 1 min. Blank samples consist of urine from persons occupationally unexposed to uranium and the calibration standard is a known amount of {sup 235}U (as natural uranium). The limit of detection is 0.020 pCi of 93% enriched uranium (0.007 of the maximum permissible body- burden) and 0.036 {mu}g of natural uranium per 100 ml of urine. The limit of detection is governed by the magnitude of the blank count. The main component of the blank is the response of the counter to {gamma}-radiation from activation products in irradiated urine. The counting and irradiation cycle takes about 3 Vulgar-Fraction-One-Half min and 50 samples at one time may be evaporated and bottled in the working day. Interference from {sup 239}Pu is likely to be negligible for the purposes of urine analysis. (author) [French] U methode decrite consiste a doser l'uranium-235 d'un echantillon en comptant les neutrons differes emis lors de la fission de {sup 235}U par neutrons thermiques. Les trois groupes de neutrons qui presentent un interet ont des periodes de 55,72, 22, 72 et 6, 22 s. On fait evaporer 100 ml d'urine au bain-marie. Le residu est transvase avec 4 a 5 ml d'eau dans un flacon en

  14. Neutron total cross-section of hydrogenous and deuterated 1- and 2-propanol and n-butanol measured using the VESUVIO spectrometer

    Science.gov (United States)

    Rodríguez Palomino, L. A.; Dawidowski, J.; Márquez Damián, J. I.; Cuello, G. J.; Romanelli, G.; Krzystyniak, M.

    2017-10-01

    This work presents the total cross sections of a set of normal and deuterated alcohols (hydrogenous 1- and 2-propanol and n-butanol, 1-propanol(OD) and fully deuterated 2-propanol and n-butanol), measured at spectrometer VESUVIO (ISIS spallation neutron source, United Kingdom). Granada's Synthetic Model was applied to describe those systems and a satisfactory agreement with the measured total cross section was achieved in the range of energies from 10-3 to 100 eV. The input parameters of the model were determined from the essential features of the vibrational spectra of the atoms that compose the systems, which were studied using Molecular Dynamics.

  15. Uranium analysis by neutron induced fissionography method using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Akyuez, T.; Tretyakova, S. P.; Guezel, T.; Akyuz, S.

    1999-01-01

    In this study total twenty samples (eight reference materials and twelve sediment samples) were analysed for their uranium content which is in the range of 1-17 μg/g, by neutron induced fissionography (NIF) method using solid state nuclear track detectors (SSNTDs) in comparison with the results of neutron activation analysis (NAA), delayed neutron counting (DNC) technique or fluorometric method. It is found that NIF method using SSNTDs is very sensitive for analysis of uranium

  16. Uranium analysis by neutron induced fissionography method using solid state nuclear track detectors

    CERN Document Server

    Akyuez, T; Guezel, T; Akyuz, S

    1999-01-01

    In this study total twenty samples (eight reference materials and twelve sediment samples) were analysed for their uranium content which is in the range of 1-17 mu g/g, by neutron induced fissionography (NIF) method using solid state nuclear track detectors (SSNTDs) in comparison with the results of neutron activation analysis (NAA), delayed neutron counting (DNC) technique or fluorometric method. It is found that NIF method using SSNTDs is very sensitive for analysis of uranium.

  17. High-sensitivity measurements for low-level TRU wastes using advanced passive neutron techniques

    International Nuclear Information System (INIS)

    Menlove, H.O.; Eccleston, G.W.

    1992-01-01

    In recent years, both passive- and active-neutron nondestructive assay (NDA) systems have been used to measure the uranium and plutonium content in 200-ell drums. Because of the heterogeneity of the wastes, representative sampling is not possible and NDA methods are preferred over destructive analysis. Active-neutron assay systems are used to measure the fissile isotopes such as 235 U, 23 Pu, and 241 Pu; the isotopic ratios are used to infer the total plutonium content and thus the specific disintegration rate. The active systems include 14-MeV-neutron (DT) generators with delayed-neutron counting, (D,T) generators with the differential die-away technique, and 252 Cf delayed-neutron shufflers. Passive assay systems (for example, segmented gamma-ray scanners)5 have used gamma-ray sessions, while others (for example, passive drum counters) used passive-neutron signals. We have developed a new passive-neutron measurement technique to improve the accuracy and sensitivity of the NDA of plutonium scrap and waste. This new 200-ell-drum assay system combines the classical NDA method of counting passive-neutron totals and coincidences from plutonium with the new features of ''add-a-source'' (AS) and multiplicity counting to improve the accuracy of matrix corrections and statistical techniques that improve the low-level detectability limits. This paper describes the improvements we have made in passive-neutron assay systems and compares the accuracies and detectability limits of passive- and active-neutron assay systems

  18. Effect of liposome entrapped Cu/Zn bovine superoxide dismutase in rat after total body (neutron-gamma) irradiation

    International Nuclear Information System (INIS)

    Lamproglou, I.; Martin, S.; Lambert, F.; Fontanille, P.; Fessi, H.; Puisieux, F.; Colas-Linhart, N.; Bok, B.; Fatome, M.; Martin, C.

    1998-01-01

    Our purpose was, to study in rat the effects of (neutron-gamma) exposure and of LIPSOD treatment (liposomal Cu/Zn super-oxide dismutase) on cognitive functions. Our data demonstrate that whole-body irradiation induces in Sprague-Dawley rats some cognitive dysfunction. Treatment using LIPSOD corrects in a significantly way this trend. Moreover, in sham-irradiated rats, this treatment shows an inhibitory effect. (authors)

  19. A measurement of. Delta. sigma. sub L (np), the difference between neutron-proton total cross sections in pure longitudinal spin states

    Energy Technology Data Exchange (ETDEWEB)

    Beddo, M.E.

    1990-10-01

    A measurement off {Delta}{sigma}{sub L}(np), the difference between neutron-proton total cross sections in pure longitudinal spin states, is described. The results will help determine the isospin-zero (I = 0) scattering amplitudes, which are not well known above laboratory energies of 500 MeV, whereas the isospin-one (I = 1) amplitudes are fairly well-determined to 1 GeV. Data points were taken at the Los Alamos Meson Physics Facility (LAMPF) at Los Alamos, New Mexico, for five neutron beam energies: 484, 568, 634,720 and 788 MeV; they are the first in this energy range. Polarized neutrons were produced by charge-exchange of polarized protons on a liquid deuterium target (LD{sub 2}). Large-volume neutron counters detected the neutrons that passed through a polarized proton target. The counters subtended a range of solid angles large enough to allow extrapolation of the scattered neutrons to 0{degree}. Two modifications to the LAMPF accelerator system which were made for this work are described. They included a beam buncher,'' which modified the normal rf-time structure of the proton beam and allowed for the selection of peak-energy neutrons by time-of-flight means, and a computerized beam steering program, which reduced systematic effects due to beam motion at the LD{sub 2} target. The experimental values of {Delta}{sigma}{sub L}(np) are found to be consistent with other np data, including preliminary data from SIN and Saclay, but not with some results from Argonne which used a polarized proton beam and a polarized deuteron target. The I = 0 component was extracted from {Delta}{sigma}{sub L}(np) using existing pp data (I = 1), with the unexpected result that {Delta}{sigma}{sub L}(I = 0) was found to be essentially identical in shape to {Delta}{sigma}{sub L}(I = 1). The significance of this is not yet understood.

  20. Wide range neutron detection system

    International Nuclear Information System (INIS)

    Todt, W.H. Sr.

    1978-01-01

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

  1. A method to compare calculated and experimental 14 MeV neutron attenuation coefficient and to determine the total removal cross-section

    International Nuclear Information System (INIS)

    Elay, A.G.

    1978-01-01

    A method to compare calculated and experimental neutron attenuation coefficients (chi) when samples are o, different geometries but the same material is proposed. The best Σ (total removal cross section) is determined by using the fact that the logarithm of the attenuation coefficient varies linearly with respect to Σ i.e. lg chi = + asub(s) Σ, where asub(s) is a parameter that characterises all the geometrical experimental conditions of the neutron source, the sample and the relative source-to-sample geometry. In order to increase the precision, samples of different geometries but the same material were used. Values of chi are determined experimentally and asub(s) calculated for these geometries. The graph of lg chi as a function of asub(s) together with a simple fit to a straight line is sufficient to determine Σ (the slope of the line). (T.G.)

  2. Comparative analysis of dose rates in bricks determined by neutron activation analysis, alpha counting and X-ray fluorescence analysis for the thermoluminescence fine grain dating method

    Czech Academy of Sciences Publication Activity Database

    Bártová, H.; Kučera, Jan; Musílek, L.; Trojek, T.

    2014-01-01

    Roč. 104, NOV (2014), s. 393-397 ISSN 0969-806X. [1st International Conference on Dosimetry and its Applications (ICDA). Prague, 23.6.2013-28.6.2013] R&D Projects: GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : Alpha coutning * neutron activation analysis * X-ray fluorescence * thermoluminescence dating * dose rate Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.380, year: 2014

  3. Active method of neutron time correlation coincidence measurement to authenticate mass and enrichment of uranium metal

    International Nuclear Information System (INIS)

    Zhang Songbai; Wu Jun; Zhu Jianyu; Tian Dongfeng; Xie Dong

    2011-01-01

    The active methodology of time correlation coincidence measurement of neutron is an effective verification means to authenticate uranium metal. A collimated 252 Cf neutron source was used to investigate mass and enrichment of uranium metal through the neutron transport simulation for different enrichments and different masses of uranium metal, then time correlation coincidence counts of them were obtained. By analyzing the characteristic of time correlation coincidence counts, the monotone relationships were founded between FWTH of time correlation coincidence and multiplication factor, between the total coincidence counts in FWTH for time correlation coincidence and mass of 235 U multiplied by multiplication factor, and between the ratio of neutron source penetration and mass of uranium metal. Thus the methodology to authenticate mass and enrichment of uranium metal was established with time correlation coincidence by active neutron investigation. (authors)

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

    International Nuclear Information System (INIS)

    Rassow, J.

    1984-01-01

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

  5. In vivo neutron activation at the Sloan-Kettering Institute

    International Nuclear Information System (INIS)

    Bigler, R.E.

    1986-01-01

    A medical cyclotron (Model CS-15, The Cyclotron Corporation, Berkeley, CA) with a multi-layer neutron collimator designed for partial body neutron irradiations and a low-background patient counting facility have been established for measurement of bone calcium and sodium; and soft tissue, exchangeable sodium and chlorine. The cyclotron also provides total-body calcium by the 37 Ar method of Palmer. (author)

  6. The neutron production rate measurement of an indigenously developed compact D-D neutron generator

    Directory of Open Access Journals (Sweden)

    Das Basanta Kumar

    2013-01-01

    Full Text Available One electrostatic accelerator based compact neutron generator was developed. The deuterium ions generated by the ion source were accelerated by one accelerating gap after the extraction from the ion source and bombarded to a target. Two different types of targets, the drive - in titanium target and the deuteriated titanium target were used. The neutron generator was operated at the ion source discharge potential at +Ve 1 kV that generates the deuterium ion current of 200 mA at the target while accelerated through a negative potential of 80 kV in the vacuum at 1.3×10-2 Pa filled with deuterium gas. A comparative study for the neutron yield with both the targets was carried out. The neutron flux measurement was done by the bubble detectors purchased from Bubble Technology Industries. The number of bubbles formed in the detector is the direct measurement of the total energy deposited in the detector. By counting the number of bubbles the total dose was estimated. With the help of the ICRP-74 neutron flux to dose equivalent rate conversion factors and the solid angle covered by the detector, the total neutron flux was calculated. In this presentation the operation of the generator, neutron detection by bubble detector and estimation of neutron flux has been discussed.

  7. Use of the method of neutrons moderation to the adjustment of the concrete dosage through the total humidity of the arid s

    International Nuclear Information System (INIS)

    Howland, J.; Morejon, D.; Simeon, G.; Gracia, R.; Desdin, L.; O'Reilly, V.

    1997-01-01

    The method of neutrons moderation to the fast determination was applied of the content of humidity in the fine and thick arid s. The measure values of humidity were employed in the adjustment of the Dosification of concrete by the total humidity of the arid. The obtained results indicate that the employment of this fitting method allows to get higher values of resistance to the compression and also reduces the dispersions in the concretes production. This method would permit a considerable saving of cement in comparison with the traditional method. (author) [es

  8. Non-destructive isotopic uranium assay by multiple delayed neutron measurements

    International Nuclear Information System (INIS)

    Papadopoulos, N.N.; Tsagas, N.F.

    1991-01-01

    The high accuracy and precision required in nuclear safeguards measurements can be achieved by an improved neutron activation technique based on multiple delayed fission neutron counting under various experimental conditions. For the necessary ultrahigh counting statistics required, cyclic activation of multiple subsamples has been applied. The home-made automated flexible analytical system with neutron flux and spectrum differentiation by irradiation position adjustment and cadmium screening, permits the non-destructive determination of the U235 abundance and the total U element concentration needed in nuclear safeguards sample analysis, with a high throughout and a low operational cost. Careful experimental optimization led to considerable improvement of the results

  9. Determination of the total amount of organically bound chlorine, bromine and iodine in environmental samples by instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gether, J; Lunde, G [Central Institute for Industrial Research, Oslo (Norway); Steinnes, E [Institutt for Atomenergi, Kjeller (Norway)

    1979-07-01

    The determination of chlorine, bromine and iodine present as non-polar, hydrophobic hydrocarbons in environmental samples is reported. The organohalogen compounds are seprated from water into an organic phase by on-site liquid-liquid extraction, and form biological material by procedures based on lipid phase extraction and codistillation. After removal of inorganic halides by washing with water and concentration of the sample by evaporation of the solvent, the resulting extracts are analyzed for their chlorine, bromine and iodine contents by instrumental neutron activation analysus. Strict attention is paid to the possibility of contamination in every step of the procedure. Background values in routine analysis are approximately 100-200 ng of chlorine, <5 ng of bromine and <3 ng of iodine.

  10. 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)

  11. Use of a total traffic count metric to investigate the impact of roadways on asthma severity: a case-control study

    Directory of Open Access Journals (Sweden)

    deVos Annemarie JBM

    2011-06-01

    Full Text Available Abstract Background This study had two principal objectives: (i to investigate the relationship between asthma severity and proximity to major roadways in Perth, Western Australia; (ii to demonstrate a more accurate method of exposure assessment for traffic pollutants using an innovative GIS-based measure that fully integrates all traffic densities around subject residences. Methods We conducted a spatial case-control study, in which 'cases' were defined as individuals aged under 19 years of age with more severe asthma (defined here as two or more emergency department contacts with asthma in a defined 5-year period versus age- and gender-matched 'controls' with less severe asthma (defined here as one emergency department contact for asthma. Traffic exposures were measured using a GIS-based approach to determine the lengths of the roads falling within a buffer area, and then multiplying them by their respective traffic counts. Results We examined the spatial relationship between emergency department contacts for asthma at three different buffer sizes: 50 metres, 100 metres and 150 metres. No effect was noted for the 50 metre buffer (OR = 1.07; 95% CI: 0.91-1.26, but elevated odds ratios were observed with for crude (unadjusted estimates OR = 1.21 (95% CI: 1.00-1.46 for 100 metre buffers and OR = 1.25 (95% CI: 1.02-1.54 for 150 metre buffers. For adjusted risk estimates, only the 150 metre buffer yielded a statistically significant finding (OR = 1.24; 95% CI:1.00-1.52. Conclusions Our study revealed a significant 24% increase in the risk of experiencing multiple emergency department contacts for asthma for every log-unit of traffic exposure. This study provides support for the hypothesis that traffic related air pollution increases the frequency of health service contacts for asthma. This study used advanced GIS techniques to establish traffic-weighted buffer zones around the geocoded residential location of subjects to provide an accurate

  12. The Effects of Total Motile Sperm Count on Spontaneous Pregnancy Rate and Pregnancy After IUI Treatment in Couples with Male Factor and Unexplained Infertility.

    Science.gov (United States)

    Hajder, Mithad; Hajder, Elmira; Husic, Amela

    2016-02-01

    Male infertility factor is defined if the total number of motile spermatozoa (TMSC) 3,10(6) / ejaculate and a spontaneous pregnancy, group (B) with TMSCl 3 x 10(6) / ejaculate and couples who have not achieved pregnancy. From a total of 98 pairs of men's and unexplained infertility, 42 of them (42.8%) achieved spontaneous pregnancy, while 56 (57.2%) pairs did not achieve spontaneous pregnancy. TMSC was significantly higher (42.4 ± 28.4 vs. 26.2 ± 24, p 20 x 10(6) / ejaculate (RR = 1.7, 95% CI: 1.56-1.82, 5 x 10(6) / ejaculate are indicated for treatment with IUI. TMSC can be used as the method of choice for diagnosis and treatment of male infertility.

  13. Increased count, motility, and total motile sperm cells collected across three consecutive ejaculations within 24 h of oocyte retrieval: implications for management of men presenting with low numbers of motile sperm for assisted reproduction.

    Science.gov (United States)

    Said, Al-Hasen; Reed, Michael L

    2015-07-01

    The purpose of this study was to quantitate changes in seminal volume, sperm count, motility, qualitative forward progression, and total motile sperm cells per ejaculate, across three consecutive ejaculates collected from individuals within 24 h preceding an IVF cycle. Men presenting with oligoasthenozoospermia or asthenozoospemia attempted three ejaculates within 24 h preceding IVF. Ejaculate 1 was produced the afternoon prior to oocyte retrieval, and ejaculates 2 and 3 were produced the morning of oocyte retrieval with 2-3 h between collections. Ejaculates 1 and 2 were extended 1:1 v/v with room temperature rTYBS. Test tubes were placed into a beaker of room temperature water, then placed at 4 °C for gradual cooling. Ejaculate 3 was not extended, but pooled with ejaculates 1 and 2 and processed for intracytoplasmic sperm injection (ICSI). Out of 109 oocyte retrievals, 28 men were asked to attempt multiple consecutive ejaculations. Among this population, 25/28 (89.3 %) were successful, and 3/28 men (10.7 %) could only produce two ejaculates. Mean volumes for ejaculates 1, 2, and 3 were significantly different from each other (p sperm counts, motility, qualitative forward progression, and total motile cells per ejaculate for the ejaculates1, 2, and 3 demonstrated the following: ejaculates 2 and 3 were not significantly different, but counts, motility, and total motile sperm were improved over ejaculate 1 (p sperm in this population by 8-fold compared to the first ejaculate alone, facilitating avoidance of sperm cryopreservation and additional centrifugation steps that could affect sperm viability and/or function.

  14. Compton suppression gamma-counting: The effect of count rate

    Science.gov (United States)

    Millard, H.T.

    1984-01-01

    Past research has shown that anti-coincidence shielded Ge(Li) spectrometers enhanced the signal-to-background ratios for gamma-photopeaks, which are situated on high Compton backgrounds. Ordinarily, an anti- or non-coincidence spectrum (A) and a coincidence spectrum (C) are collected simultaneously with these systems. To be useful in neutron activation analysis (NAA), the fractions of the photopeak counts routed to the two spectra must be constant from sample to sample to variations must be corrected quantitatively. Most Compton suppression counting has been done at low count rate, but in NAA applications, count rates may be much higher. To operate over the wider dynamic range, the effect of count rate on the ratio of the photopeak counts in the two spectra (A/C) was studied. It was found that as the count rate increases, A/C decreases for gammas not coincident with other gammas from the same decay. For gammas coincident with other gammas, A/C increases to a maximum and then decreases. These results suggest that calibration curves are required to correct photopeak areas so quantitative data can be obtained at higher count rates. ?? 1984.

  15. Effects of mixed neutrontotal-body irradiation on physical activity performance of rhesus monkeys

    International Nuclear Information System (INIS)

    Franz, C.G.

    1985-01-01

    Behavioral incapacitation for a physical activity task and its relationship to emesis and survival time following exposure to ionizing radiation were evaluated in 39 male rhesus monkeys (Macaca mulatta). Subjects were trained to perform a shock avoidance activity task for 6 hr on a 10-min work/5-min rest schedule in a nonmotorized physical activity wheel. Following stabilization of performance, each subject received a single, pulsed dose of mixed neutron-γ, whole-body radiation (n/γ = 3.0) ranging between 1274 and 4862 rad. Performance testing was started 45 sec after exposure. A dose-response function for early transient incapacitation (ETI) during the first 2 hr after irradiation was fitted, and the median effective dose (ED 50 ) was calculated to be 1982 rad. Analysis done on the relationship of dose to ETI, emesis, and survival time found (a) a significant relationship between the radiation dose and the number and duration of ETIs; (b) no correlation between emesis and dose, survival time, or ETI; (c) no relation between survival time and ETI at any dose; and (d) no significant difference in survival time for dose groups between 1766 +/- 9 (SEM) and 2308 +/- 23 rad

  16. Counting probe

    International Nuclear Information System (INIS)

    Matsumoto, Haruya; Kaya, Nobuyuki; Yuasa, Kazuhiro; Hayashi, Tomoaki

    1976-01-01

    Electron counting method has been devised and experimented for the purpose of measuring electron temperature and density, the most fundamental quantities to represent plasma conditions. Electron counting is a method to count the electrons in plasma directly by equipping a probe with the secondary electron multiplier. It has three advantages of adjustable sensitivity, high sensitivity of the secondary electron multiplier, and directional property. Sensitivity adjustment is performed by changing the size of collecting hole (pin hole) on the incident front of the multiplier. The probe is usable as a direct reading thermometer of electron temperature because it requires to collect very small amount of electrons, thus it doesn't disturb the surrounding plasma, and the narrow sweep width of the probe voltage is enough. Therefore it can measure anisotropy more sensitively than a Langmuir probe, and it can be used for very low density plasma. Though many problems remain on anisotropy, computer simulation has been carried out. Also it is planned to provide a Helmholtz coil in the vacuum chamber to eliminate the effect of earth magnetic field. In practical experiments, the measurement with a Langmuir probe and an emission probe mounted to the movable structure, the comparison with the results obtained in reverse magnetic field by using a Helmholtz coil, and the measurement of ionic sound wave are scheduled. (Wakatsuki, Y.)

  17. Directional epithermal neutron detector

    International Nuclear Information System (INIS)

    Givens, W.W.; Mills, W.R. Jr.

    1986-01-01

    A borehole tool for epithermal neutron die-away logging of subterranean formations surrounding a borehole is described which consists of: (a) a pulsed source of fast neutrons for irradiating the formations surrounding a borehole, (b) at least one neutron counter for counting epithermal neutrons returning to the borehole from the irradiated formations, (c) a neutron moderating material, (d) an outer thermal neutron shield providing a housing for the counter and the moderating material, (e) an inner thermal neutron shield dividing the housing so as to provide a first compartment bounded by the inner thermal neutron shield and a first portion of the outer thermal neutron shield and a second compartment bounded by the inner thermal neutron shield and a second portion of the outer thermal neutron shield, the counter being positioned within the first compartment and the moderating material being positioned within the second compartment, and (f) means for positioning the borehole tool against one side of the borehole wall and azimuthally orienting the borehole tool such that the first chamber is in juxtaposition with the borehole wall, the formation epithermal neutrons penetrating into the first chamber through the first portion of the outer thermal neutron shield are detected by the neutron counter for die-away measurement, thereby maximizing the directional sensitivty of the neutron counter to formation epithermal neutrons, the borehole fluid epithermal neutrons penetrating into the second chamber through the second chamber through the second portion of the outer thermal neutron shield are largely slowed down and lowered in energy by the moderating material and absorbed by the inner thermal neutron shield before penetrating into the first chamber, thereby minimizing the directional sensitivity of the neutron counter to borehole fluid epithermal neutrons

  18. Effect of Medications for Gastric Acid-Related Symptoms on Total Motile Sperm Count and Concentration: A Case-Control Study in Men of Subfertile Couples from the Netherlands.

    Science.gov (United States)

    Huijgen, Nicole A; Goijen, Hedwig J; Twigt, John M; Mulders, Annemarie G M G J; Lindemans, Jan; Dohle, Gert R; Laven, Joop S E; Steegers-Theunissen, Régine P M

    2017-03-01

    Gastric acid-related symptoms are highly prevalent in the general population (21-40%), and more than 11% of individuals use medication for the treatment of these symptoms. The uptake of micronutrients is dependent on the gastrointestinal potential of hydrogen (pH). We hypothesized that medication affecting gastrointestinal pH reduces the availability of B vitamins, thereby deranging one-carbon metabolism and detrimentally affecting spermatogenesis. This explorative nested case-control study in men of subfertile couples investigated associations between medication used for gastric acid-related symptoms and semen parameters. We included 40 men using medication for gastric acid-related symptoms and 843 men not using medication. Semen analyses were performed between 70 days before and 21 days after the visit. The use of medication was associated with a twofold higher risk of a low total motile sperm count [TMSC sperm concentration (β -0.320, p = 0.028). Red blood cell folate was positively associated with TMSC (β 0.257, p = 0.026), sperm count (β 1.679, p = 0.013) and ejaculate volume (β 0.120, p = 0.023), and total homocysteine (tHcy) was negatively associated with sperm count (β -0.077, p = 0.021). Here we delineate associations between the use of medication for gastric acid-related symptoms and poor semen quality in men of subfertile couples. The use of medication for gastric acid-related symptoms is associated with a twofold higher risk of a low TMSC and a decreased sperm concentration. Although these findings warrant further research on causality, the associations between folate, tHcy and semen quality emphasize the importance of preconception counselling in male subfertility.

  19. Clean Hands Count

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  1. Clean Hands Count

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  13. Clean Hands Count

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    Full Text Available ... is starting stop Loading... Watch Queue Queue __count__/__total__ It’s YouTube. Uninterrupted. Loading... Want music and videos ... empower patients to play a role in their care by asking or reminding healthcare providers to clean ...

  14. Clean Hands Count

    Medline Plus

    Full Text Available ... Queue __count__/__total__ It’s YouTube. Uninterrupted. Loading... Want music and videos with zero ads? Get YouTube Red. ... 043 views 1:36 Wash 'Em - Hand Hygiene Music Video - Duration: 5:46. Jefferson Health 411,292 ...

  15. Obtaining of total and thermal neutron flux in the carousel facility of the TRIGA MARK IPR-R1 reactor using the Monte Carlo transport method

    International Nuclear Information System (INIS)

    Guerra, Bruno Teixeira

    2011-01-01

    The IPR-R1 is a reactor type TRIGA, Mark-I model, manufactured by the General Atomic Company and installed at Nuclear Technology Development Centre (CDTN) of Brazilian Nuclear Energy Commission (CNEN), in Belo Horizonte, Brazil. It is a light water moderated and cooled, graphite-reflected, open-pool type research reactor. IPR-R1 works at 100 kW but it will be briefly licensed to operate at 250 kW. It presents low power, low pressure, for application in research, training and radioisotopes production. The fuel is an alloy of zirconium hydride and uranium enriched at 20% in 235 U. The goal this work is modelling of the IPR-R1 Research Reactor TRIGA using the codes MCNPX2.6.0 (Monte Carlo N-Particle Transport extend) and MCNP5 to the calculating the neutron flux in the carousel facility. In each simulation the sample was placed in a different position, totaling forty positions around of the reactor core. The comparison between the results obtained with experimental values from other work showing a relatively good agreement. Moreover, this methodology is a theoretical tool in validating of the experimental values and necessary for determining neutron flux which can not be accessible experimentally. (author)

  16. Total Cross-Sections of U, UO{sub 2} and ThO{sub 2} for Thermal and Subthermal Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Beshai, S F [IAEA-fellow from Atomic Energy Establishment (Egypt)

    1966-03-15

    The total neutron cross-sections of U, UO{sub 2} and ThO{sub 2} have been measured from 0.0045 eV to 0.028 eV, using the time-of-flight technique. The samples were measured at 20 deg C. ThO{sub 2} was also measured at 750 deg C. The neutron source was the reactor Rl, Stockholm. The experimental results presented as graphs in the report show in detail the influence of Bragg scattering. The results further show that the increase of the temperature for the ThO{sub 2} sample gives an increase in the cross-section. The work also contains some calculations of the position in energy of Bragg edges for the three materials. These calculations show a very good agreement with the experiments. For uranium metal some calculations have been carried out also for the height ({sigma}{sup g}{sub hkl}) of the edges The agreement with the experiments is reasonable.

  17. An attempt of application of short lived 44K activity induced in the 44Ca(n,p)44K reaction using 14 MeV neutrons for total body calcium assessment in human subject

    International Nuclear Information System (INIS)

    Haratym, Z.; Kempisty, T.; Mikolajewski, S.; Rurarz, E.

    1999-01-01

    The status of in vivo neutron activation analysis techniques for the measurement of total body calcium in human subject is reviewed. Relevant data on the nuclear characteristics of calcium isotopes during interaction with neutrons ranging from slow up to 14 MeV neutrons are presented. Physical aspects of the measurement of in vivo total body calcium (TBCa) using 44 K activity induced in the 44 Ca(n,p) 44 K(T 1/2 =22.3 min) reaction by 14 MeV neutrons are discussed. The measurement of delayed γ-ray emitted during decay of activities induced in enriched 44 Ca, nat Ca, phantom filled with water solution of natural calcium and skeletal arm are considered. Results of measurements on the phantom and skeletal arm indicate a possibility to measure the TBCa using the 44 K activity. (author)

  18. ENDF/B-IV representation of the 238U total neutron cross section in the resolved resonance energy region

    International Nuclear Information System (INIS)

    de Saussure, G.; Olsen, D.K.; Perez, R.B.

    1976-01-01

    The ENDF/B-IV prescription fails to represent correctly the 238 U total (and scattering) cross section between the levels of the resolved range. It is shown how this representation can be improved by properly accounting for the contribution of levels outside the resolved region to the cross section at energies inside the resolved region, and by substituting the more precise multilevel Breit-Wigner formula for the presently used single-level formula. The importance of computing accurately the minima in the total cross section is illustrated by comparing values of the self-shielded capture resonance integral computed with ENDF/B-IV and with a more accurate cross section model

  19. Counting Possibilia

    Directory of Open Access Journals (Sweden)

    Alfredo Tomasetta

    2010-06-01

    Full Text Available Timothy Williamson supports the thesis that every possible entity necessarily exists and so he needs to explain how a possible son of Wittgenstein’s, for example, exists in our world:he exists as a merely possible object (MPO, a pure locus of potential. Williamson presents a short argument for the existence of MPOs: how many knives can be made by fitting together two blades and two handles? Four: at the most two are concrete objects, the others being merely possible knives and merely possible objects. This paper defends the idea that one can avoid reference and ontological commitment to MPOs. My proposal is that MPOs can be dispensed with by using the notion of rules of knife-making. I first present a solution according to which we count lists of instructions - selected by the rules - describing physical combinations between components. This account, however, has its own difficulties and I eventually suggest that one can find a way out by admitting possible worlds, entities which are more commonly accepted - at least by philosophers - than MPOs. I maintain that, in answering Williamson’s questions, we count classes of physically possible worlds in which the same instance of a general rule is applied.

  20. 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

  1. Measurements of streaming neutrons on nuclear ship 'Mutsu' by a two-detector-method

    International Nuclear Information System (INIS)

    Kobayashi, Iwao; Yamazaki, Hiroshi; Ryufuku, Hiroshi.

    1976-01-01

    Streaming neutrons escaping through an air gap located between the pressure vessel and the primary shield of the Nuclear Ship ''Mutsu'' were measured by applying the two-detector-method. The two detectors consisted of a single BF 3 counter provided alternatively with different covering arrangements - (a) 3mm thick steel tube + layers of polyethylene sheeting with total thickness of 30mm + 1mm thick Cd plate and (b) same covering as (a) + polyethylene boxing 20mm thick. In order to derive from the count rates obtained with the detectors described above the absolute values of neutron flux and dose equivalent rate, the detectors were calibrated in laboratory by comparison with a reference detector system in neutron field created around a 252 Cf source and TCA, a light-water moderated critical assembly. The conversion from measured counts to neutron flux and neutron dose equivalent rate was estimated to incur errors of +-15 and +-40%, respectively. (auth.)

  2. Hygrothermal degradation of (3-glycidoxypropyl)trimethoxysilane films studied by neutron and X-ray reflectivity and attenuated total reflection infrared spectroscopy

    International Nuclear Information System (INIS)

    Tallant, David Robert; Garcia, Manuel Joseph; Majewski, Jaroslaw; Kent, Michael Stuart; Yim, Hyun

    2005-01-01

    Thin films of organosilanes have great technological importance in the areas of adhesion promotion, durability, and corrosion resistance. However, it is well-known that water can degrade organosilane films, particularly at elevated temperatures. In this work, X-ray and neutron reflectivity (XR and NR) were combined with attenuated total reflection infrared (ATR-IR) spectroscopy to study the chemical and structural changes within thin films of (3-glycidoxypropyl)trimethoxysilane (GPS) after exposure for various periods of time to air saturated with either D 2 O or H 2 O at 80 C. For NR and XR, ultrathin (∼100 (angstrom)) films were prepared by spin-coating. Both D 2 O and H 2 O provide neutron scattering contrast with GPS. Variations in the neutron scattering length density (SLD) profiles (a function of mass density and atomic composition) with conditioning time were measured after drying the samples out and also swelled with H 2 O or D 2 O vapor at room temperature. For samples that were dried out prior to measurement, little or no change was observed for H 2 O conditioning up to 3.5 days, but large changes were observed after 30 days of conditioning. The range of conditioning time for this structural change was narrowed to between 4 and 10 days with XR. The SLD profiles indicated that the top portion of the GPS film was transformed into a thick low-density layer after conditioning, but the bottom portion showed little structural change. A previous NR study of as-prepared GPS films involving swelling with deuterated nitrobenzene showed that the central portion of the film has much lower cross-link density than the region nearest the substrate. The present data show that the central portion also swells to a much greater extent with water and hydrolyzes more rapidly. The chemical degradation mechanism was identified by IR as hydrolysis of siloxane bonds. For ATR-IR, GPS films were prepared by dip-coating, which resulted in a greater and more variable thickness than

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  4. Categorical counting.

    Science.gov (United States)

    Fetterman, J Gregor; Killeen, P Richard

    2010-09-01

    Pigeons pecked on three keys, responses to one of which could be reinforced after a few pecks, to a second key after a somewhat larger number of pecks, and to a third key after the maximum pecking requirement. The values of the pecking requirements and the proportion of trials ending with reinforcement were varied. Transits among the keys were an orderly function of peck number, and showed approximately proportional changes with changes in the pecking requirements, consistent with Weber's law. Standard deviations of the switch points between successive keys increased more slowly within a condition than across conditions. Changes in reinforcement probability produced changes in the location of the psychometric functions that were consistent with models of timing. Analyses of the number of pecks emitted and the duration of the pecking sequences demonstrated that peck number was the primary determinant of choice, but that passage of time also played some role. We capture the basic results with a standard model of counting, which we qualify to account for the secondary experiments. Copyright 2010 Elsevier B.V. All rights reserved.

  5. Estimation of total as well as bioaccessible levels and average daily dietary intake of iodine from Japanese edible seaweeds by epithermal neutron activation analysis

    International Nuclear Information System (INIS)

    Fukushima, M.; Chatt, A.

    2012-01-01

    An epi-thermal instrumental neutron activation analysis (EINAA) method in conjunction with Compton suppression spectrometry (EINAA-CSS) was used for the determination of total iodine in eight different species of edible seaweeds from Japan. This method gave an absolute detection limit of about 2 μg. The accuracy of the method was evaluated using various reference materials and found to be generally in agreement within ±6% of the certified values. The longitudinal distributions of iodine at different growing stages in Japanese sea mustard and tangle seaweeds were investigated. For a 150-cm-high tangle, the highest concentration (5,360 mg/kg) of iodine was found at the root, then decreased slowly to 780 mg/kg in the middle portion (60-75 cm), and increased to 2,300 mg/kg at the apex. On the other hand, for a 190-cm-high sea mustard the highest levels of iodine were found both at the roots (164 mg/kg) and apex (152 mg/kg) with lower values (98 mg/kg) in the middle section. In order to estimate the bioaccessible fraction of iodine, seaweeds were digested by an in vitro enzymolysis method, dietary fibre separated from residue, and both fractions analyzed by EINAA-CSS. The average daily dietary intakes of total (0.14 mg) as well as bioaccessible fraction (0.12 mg) of iodine from the consumption of sea mustards were estimated. (author)

  6. Effect Of Soil Contamination Due To Wastewater Irrigation On Total Co As Determined By Neutron Activation And Other Conventional Analytical Techniques In Some Soils Of Egypt

    International Nuclear Information System (INIS)

    Abdel-Sabour, M. F.; Al-Salama, Y. J.

    2004-01-01

    Fifteen soil samples were chosen from different locations (five different locations at north greater Cairo, Egypt) to represent different soils (alluvial and sandy) as well as different sources of contaminated wastewater (sewage and industrial effluent). Using sequential extraction technique (extracting the soil with different solutions, which is designed to separate metal fractions), Co was separated into six operationally defined fractions: water soluble, exchangeable, carbonate bound, Fe-Mn oxides bound, organic bound and residual fractions. Moreover, total-Co in soils as determined by three analytical methods (sum of sequential extracting, Atomic Absorption Spectrometry (AAS) and neutron activation analysis (NAA) techniques) were compared. Cobalt distribution between different extractants shows that the greatest amounts are found in the residual and Occluded in Fe and Mn-Oxides fractions followed by carbonate or organic fractions. In most cases the proportion of all tested Co-forms has increased in contaminated soil layers with higher enrichment in organically bound Co, occluded in Fe and Mn oxides, carbonate exchangeable and soluble fractions. Results indicate that soil properties have a significant role on Co fractions in soil. In the mean time, soil properties are affected by pollution factors such as source of pollution and load of pollution on the studied soil. Data showed that values of total Co determined by NAA method were always higher than the relevant values determined by AAS or those calculated after the sequential extraction method. (Authors)

  7. [Corrected count].

    Science.gov (United States)

    1991-11-27

    The data of the 1991 census indicated that the population count of Brazil fell short of a former estimate by 3 million people. The population reached 150 million people with an annual increase of 2%, while projections in the previous decade expected an increase of 2.48% to 153 million people. This reduction indicates more widespread use of family planning (FP) and control of fertility among families of lower social status as more information is being provided to them. However, the Ministry of Health ordered an investigation of foreign family planning organizations because it was suspected that women were forced to undergo tubal ligation during vaccination campaigns. A strange alliance of left wing politicians and the Roman Catholic Church alleges a conspiracy of international FP organizations receiving foreign funds. The FP strategies of Bemfam and Pro-Pater offer women who have little alternative the opportunity to undergo tubal ligation or to receive oral contraceptives to control fertility. The ongoing government program of distributing booklets on FP is feeble and is not backed up by an education campaign. Charges of foreign interference are leveled while the government hypocritically ignores the grave problem of 4 million abortions a year. The population is expected to continue to grow until the year 2040 and then to stabilize at a low growth rate of .4%. In 1980, the number of children per woman was 4.4 whereas the 1991 census figures indicate this has dropped to 3.5. The excess population is associated with poverty and a forsaken caste in the interior. The population actually has decreased in the interior and in cities with 15,000 people. The phenomenon of the drop of fertility associated with rural exodus is contrasted with cities and villages where the population is 20% less than expected.

  8. Neutron capture in borehole logging

    International Nuclear Information System (INIS)

    Randall, R.R.

    1981-01-01

    The use is described of a pulsed source of fast neutrons and a radiation detector to measure the thermal neutron population decay rate in a well logging instrument. The macroscopic neutron absorption cross-section is calculated by taking the natural logarithm of the ratio of the detected radiation counts occurring within two measurement intervals of fixed duration and starting at a fixed time after a neutron burst. (U.K.)

  9. Measurement of the #betta#sub(μ) and anti #betta#sub(μ)-nucleon charged current total cross sections, and the ratio of #betta#sub(μ) neutron to #betta#sub(μ) proton charged current total cross-section

    International Nuclear Information System (INIS)

    Allasia, D.; Bisi, V.; Gamba, D.; Marzari-Chiesa, A.; Ramello, L.; Riccati, L.; Romero, A.; Bobisut, F.; Calimani, E.; Ciampolillo, S.; Huzita, H.; Loreti, M.; Sconza, A.; Bolognese, T.; Faccini-Turluer, M.L.; Louedec, C.; Mosca, L.; Vignaud, D.; Bonarelli, R.; Capiluppi, P.; Derkaoui, J.; Giacomelli, G.; Mandrioli, G.; Rossi, A.M.; Serra-Lugaresi, P.; Frodesen, A.G.; Halsteinslid, A.; Hornaes, A.

    1983-04-01

    This report contains an investigation performed by the Amsterdam-Bergen-Bologna-Padova-Pisa-Saclay-Torino collaboration. The total #betta#sub(μ)- and anti #betta#sub(μ)-nucleon charged current cross sections have been measured in BEBC filled with deuterium and exposed to the wide band neutrino and antineutrino beams at the CERN-SPS. Assuming a linear energy dependence for the cross sections, sigma = a Esub((anti #betta#)), the authors obtained the coefficients asub(#betta#N) = 0.60 +- 0.04 and asub(anti #betta#N) = 0.30 +- 0.02 (in units of 10 - 38 cm 2 /GeV), where the quoted error is mainly systematic. The ratio of the cross sections is sigmasub(anti #betta#N)/sigmasub(#betta#N) = 0.50 +- 0.03. They also determined the ratio of the charged current cross section for neutrino interactions on neutrons and protons R = sigmasub(#betta#n)/sigmasub(#betta#p) = 2.10 +- 0.08 (stat.) +- 0.22 (syst.). The dependence of R on the variables x, y and Esub(#betta#) is discussed. (Auth.)

  10. Study of the environmental neutron spectrum at Zacatecas city

    International Nuclear Information System (INIS)

    Vega C, H.R.

    2003-01-01

    The environmental neutron spectrum has been measured at Zacatecas City in Mexico. Neutron spectrum was unfolded from count rates obtained with a multisphere neutron spectrometer with a Li I(Eu) scintillator. With the spectrum information the ambient dose equivalent and the isotropic effective dose were calculated. A model based upon the geomagnetic latitude and the altitude above sea level, that allows to estimate the neutron fluence rate is proposed, the model results are compared with total neutron fluences measured at several locations worldwide. Environmental neutron spectrum shows peaks at 1 and 100 MeV as well as a relevant amount of low energy neutrons. The neutron fluence rate was 65 ± 3 cm -2 -h -1 , producing 13.7 ± 0.6 n Sv-h -1 due to ambient dose equivalent rate and an isotropic effective dose rate of 14.1 ± 0.6 n Sv-h -1 . Neutron fluence rates predicted with the model are in agreement with those reported in the literature. (Author)

  11. Study of the environmental neutron spectrum at Zacatecas city

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R. [Universidad Autonoma de Zacatecas, Cuerpo Academico de Radiobiologia, A.P. 336, 98000 Zacatecas (Mexico)

    2003-07-01

    The environmental neutron spectrum has been measured at Zacatecas City in Mexico. Neutron spectrum was unfolded from count rates obtained with a multisphere neutron spectrometer with a Li I(Eu) scintillator. With the spectrum information the ambient dose equivalent and the isotropic effective dose were calculated. A model based upon the geomagnetic latitude and the altitude above sea level, that allows to estimate the neutron fluence rate is proposed, the model results are compared with total neutron fluences measured at several locations worldwide. Environmental neutron spectrum shows peaks at 1 and 100 MeV as well as a relevant amount of low energy neutrons. The neutron fluence rate was 65 {+-} 3 cm{sup -2}-h{sup -1}, producing 13.7 {+-} 0.6 n Sv-h{sup -1} due to ambient dose equivalent rate and an isotropic effective dose rate of 14.1 {+-} 0.6 n Sv-h{sup -1}. Neutron fluence rates predicted with the model are in agreement with those reported in the literature. (Author)

  12. Assessment of the efficiency of SimPlate™ total plate count color indicator (TPC CI to quantify mesophilic aerobic microorganisms in pasteurized milk Avaliação da eficiência do SimPlate™ Total Plate Count Color Indicator (TPC CI para enumeração de microrganismos aeróbios mesófilos em leite pasteurizado

    Directory of Open Access Journals (Sweden)

    Luís Augusto Nero

    2002-01-01

    Full Text Available The SimPlate™ TPC CI system is a rapid method to count mesophilic aerobic microorganisms (MAM in foods, based on the use of resazurine to indicate bacterial growth. Its efficiency in pasteurized milk was evaluated using 142 pasteurized milk samples (38 type A, 43 type B and 61 type C collected in Londrina, PR. The standard plating method, using Plate Count Agar (PCA was used for comparison. The plates of both systems were incubated at 35ºC and read after 24h and 48h. The occurrence of false-positive and false-negative wells and the predominant microorganisms in them were also evaluated. The results were compared by simple correlation and mean variance analyses. The correlation (r and mean variance values were 0.6811 and 0.7583 for the results obtained after 24h, respectively, and 0.9126 and 0.0842 for the results obtained after 48h, respectively. These results indicate that the performance of the system increases when the plates are incubated for 48h. When the three types of milk were evaluated separately, these values were 0.9285 and 0.0817 for type A milk, 0.9231 and 0.0466 for type B milk and 0.7209 and 0.1082 for type C milk. These results indicate that the better the quality of the milk the better the performance of SimPlate™ TPC CI. False-negative wells, found more frequently in samples with high MAM counts, were caused by Gram positive microorganisms, poorly detected by the SimPlate™ TPC CI system because they grew slowly and had low reduction capacity. The results indicated a higher efficiency of the SimPlate™ TPC CI system in the reading at 48h.O sistema SimPlate™ TPC CI é um método rápido para enumeração de microrganismos aeróbios mesófilos (MAM em alimentos que utiliza a resazurina como substância indicadora de crescimento bacteriano. Para avaliar sua eficiência em leite pasteurizado, 142 amostras (38 de leite tipo A, 43 de leite tipo B e 61 de leite tipo C foram colhidas em Londrina, PR, e analisadas pelo Sim

  13. Recuento de bacterias totales en leche cruda de tambos que caracterizan la zona noroeste de Santa Fe y sur de Santiago del Estero Total bacterial count in raw milk of dairy farms that characterize the northwest zone of Santa Fe and south of Santiago del Estero

    Directory of Open Access Journals (Sweden)

    G.R. Revelli

    2004-09-01

    Full Text Available Un total de 6.998 muestras de leche cruda de pool de tanque, correspondientes a 55 establecimientos lecheros asociados a la Cooperativa Tambera Nueva Alpina Ltda., fueron recolectadas entre los años 1993 y 2002. Se realizó el Recuento de Microorganismos Aerobios Mesófilos Totales, obteniéndose como resultado un valor medio de 1,2 x 105± 2,4 x 105UFC/ml que caracteriza la zona. El año de finalización de la experiencia, se observó un 97% de los tambos evaluados con promedios £ 1,0 x 105UFC/ml. Solamente un 3% sobrepasa este límite, no encontrándose establecimientos con niveles superiores a 1,5 x 105UFC/ml. Al relacionar este indicador con parámetros composicionales, las correlaciones más significativas resultaron para: Recuento de Bacterias Totales vs Acidez (r = 0,292; P A total of 6.998 raw milk samples of bulk tank, belonging to 55 dairy farms associated to the Cooperativa Tambera Nueva Alpina Ltda., were collected between the years 1993 and 2002. The Total Mesophilic Aerobic Microorganisms Count was analyzed, obtaining a medium value of 1.2 x 105± 2.4 x 105CFU/ml that characterizes the zone. The final year of experience, observed a 97% of dairy farms evaluated with averages £ 1,0 x 105CFU/ml. Only a 3% it surpasses this limit, not being found establishments with levels over 1.5 x 105CFU/ml. Relating this indicators with compositionals parameters, the most significant correlation resulted for: Total Bacterial Count vs Acidity (r = 0.292; P < 0.001 and Total Bacterial Count vs Freezing Point (r = 0.157; P < 0.001. The microbiological quality in raw milk of dairy farms belonging to the northwest zone of Santa Fe and south of Santiago del Estero showed a significant improvement during this time.

  14. Microcomputerized neutron moisture gauge

    International Nuclear Information System (INIS)

    Liu Shengkang; Mei Yu

    1987-01-01

    A microcomputerized neutron moisture gauge is introduced. This gauge consists of a neutron moisture sensor and instruments. It is developed from the neutron moisture gauge for concrete mixer. A TECH-81 single card microcomputer is used for count, computation and display. It has the function of computing compensated quantity of sand. It can acquire the data from several neutron sensors by the multichanneling sampling, therefore it can measure moisture values of sand in several hoppers simultaneously. The precision of the static state calibration curve is 0.24% wt. The error limits of the dynamic state check is < 0.50% wt

  15. Prototype Neutron Energy Spectrometer

    International Nuclear Information System (INIS)

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

    2010-01-01

    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.

  16. 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.

  17. Pulsed neutron uranium borehole logging with prompt fission neutrons

    International Nuclear Information System (INIS)

    Bivens, H.M.; Smith, G.W.; Jensen, D.H.

    1976-01-01

    The gross count natural gamma log normally used for uranium borehole logging is seriously affected by disequilibrium. Methods for the direct measurement of uranium, such as neutron logging, which are not affected by disequilibrium have been the object of considerable effort in recent years. This paper describes a logging system for uranium which uses a small accelerator to generate pulses of 14 MeV neutrons to detect and assay uranium by the measurement of prompt fission neutrons in the epithermal energy range. After an initial feasibility study, a prototype logging probe was built for field evaluation which began in January 1976. Physical and operational characteristics of the prototype probe, the neutron tube-transformer assembly, and the neutron tube are described. In logging operations, only the epithermal prompt fission neutrons detected between 250 microseconds to 2500 microseconds following the excitation neutron pulse are counted. Comparison of corrected neutron logs with the conventional gross count natural gamma logs and the chemical assays of cores from boreholes are shown. The results obtained with this neutron probe clearly demonstrate its advantages over the gross count natural gamma log, although at this time the accuracy of the neutron log assay is not satisfactory under some conditions. The necessary correction factors for various borehole and formation parameters are being determined and, when applied, should improve the assay accuracy

  18. Neutron stars

    International Nuclear Information System (INIS)

    Irvine, J.M.

    1978-01-01

    The subject is covered in chapters entitled: introduction (resume of stellar evolution, gross characteristics of neutron stars); pulsars (pulsar characteristics, pulsars as neutron stars); neutron star temperatures (neutron star cooling, superfluidity and superconductivity in neutron stars); the exterior of neutron stars (the magnetosphere, the neutron star 'atmosphere', pulses); neutron star structure; neutron star equations of state. (U.K.)

  19. Multielement analysis of environmental samples by total-reflection X-ray fluorescence sprectrometry, neutron activation analysis and inductively coupled plasma optical emission spectroscopy

    International Nuclear Information System (INIS)

    Michaelis, W.

    1986-01-01

    In environmental research and protection trace elements have to be determined over a wide range of atomic number, down to very low concentrations, and in quite different matrices. This challenge requires the availability of complementary analytical methods characterized by a high detection power and few sources of systematic errors. Besides, the capacity of multielement detection is often desired since it facilitates the talking of many problems in which numerous trace elements are of direct concern. Total-reflection X-ray fluorescence, neutron activation analysis and inductively coupled plasma optical emission spectroscopy, in principle fulfill these requirements quite well. However, each method has its domain, and the application to certain sample species may be less promising. Under this aspect, the paper summarizes some recent developments and investigations, including intercomparisons as far as possible. Various matrices are considered : rainwater and airborne particulates, soil samples, river sediments and suspended particulate matter, river water filtrates, ozean water, and organic matrices. Capabilities and limitations are discussed. Sample preparation techniques are described if they are new or essential for achieving the results given. (orig.) [de

  20. Determination of the Jet Neutron Rate and Fusion Power using the Magnetic Proton Recoil Neutron Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Sjoestrand, Henrik

    2003-01-01

    In this thesis a new independent method has been developed to enable precise measurements of neutron yields and rates from fusion plasmas and thereby determining the fusion power and fusion energy. The new method, together with the associated diagnostics, can provide information of great importance to present and future high fusion yield experiments, such as the Joint European Torus (JET) tokamak and the International Thermonuclear Experiment Reactor (ITER). The method has been applied to data from high fusion rate experiments from the tritium campaign at JET. By using the count-rate from the Magnetic Proton Recoil (MPR) neutron spectrometer the number of neutrons in the spectrometer's line of sight has been calculated. To be able to do this, all relevant factors between the plasma and the instrument have been evaluated. The number of neutrons in the MPR line of sight has been related to the total number of produced neutrons in the plasma by using information on the neutron emission profile. The achieved results have been compared with other JET neutron diagnostic data and the agreement is shown to be very good.

  1. Assessment of uncertainties in Neutron Multiplicity Counting

    International Nuclear Information System (INIS)

    Peerani, P.; Marin Ferrer, M.

    2008-01-01

    This paper describes a methodology for a complete and correct assessment of the errors coming from the uncertainty of each individual component on the final result. A general methodology accounting for all the main sources of error (both type-A and type-B) will be outlined. In order to better illustrate the method, a practical example applying it to the uncertainty estimation for a special case of multiplicity counter, the SNMC developed at JRC, will be given

  2. Total Diet Study. Mg and Mn content estimation of a Market Basket of Sao Paulo state (Brazil) by Instrumental Neutron Activation

    International Nuclear Information System (INIS)

    Roseane Pagliaro Avegliano; Vera Akiko Maihara

    2014-01-01

    Total Diet Studies (TDS) have been carried out to estimate dietary intakes of the essential and toxic elements for a large-scale population over a specific period of time. In this study, the TDS was based on the evaluation of food representing a Market Basket (MB), which reflected the dietary habits of the Sao Paulo State population, corresponding to 72 % of the average food consumption for the state of Sao Paulo. In the present Total Diet Study, magnesium and manganese concentrations were determined in 30 of the most consumed food groups of a MB of Sao Paulo State, Brazil. Instrumental Neutron Activation Analysis (INAA) has been successfully used on a regularly basis in several areas of nutrition and foodstuffs. Element concentrations were determined by INAA in freeze-dried samples and ranged in mg kg -1 . Mg 41.4 (fats)-5287 (coffee) and Mn 0.12 (prime grade beef)-32.9 (coffee). The average daily Mg and Mn intake was calculated by multiplying the concentration of each element in each table-ready food group by the respective weight (g day -1 ) of the food group in the MB and adding the products from all food groups. The results of daily dietary intakes in this study were: Mg 174.8 and Mn 1.34 mg day -1 . Theses values were lower than the adequate intake (AI) proposed by the Food and Nutrition Board of the Institute of Medicine (USA National Academy) for adults. The low levels of Mg and Mn intakes presented in this TDS are probably due to the fact that MB of this study represented only 72 % of the weight of the most consumed household foods of Sao Paulo State. (author)

  3. Point-by-point model description of average prompt neutron data as a function of total kinetic energy of fission fragments

    International Nuclear Information System (INIS)

    Tudora, A.

    2013-01-01

    The experimental data of average prompt neutron multiplicity as a function of total kinetic energy of fragments <ν>(TKE) exhibit, especially in the case of 252 Cf(SF), different slopes dTKE/dν and different behaviours at low TKE values. The Point-by-Point (PbP) model can describe these different behaviours. The higher slope dTKE/dν and the flattening of <ν> at low TKE exhibited by a part of experimental data sets is very well reproduced when the PbP multi-parametric matrix ν(A,TKE) is averaged over a double distribution Y(A,TKE). The lower slope and the almost linear behaviour over the entire TKE range exhibited by other data sets is well described when the same matrix ν(A,TKE) is averaged over a single distribution Y(A). In the case of average prompt neutron energy in SCM as a function of TKE, different dTKE/dε slopes are also obtained by averaging the same PbP matrix ε(A,TKE) over Y(A,TKE) and over Y(A). The results are exemplified for 3 fissioning systems benefiting of experimental data as a function of TKE: 252 Cf(SF), 235 U(n th ,f) and 239 Pu(n th ,f). In the case of 234 U(n,f) for the first time it was possible to calculate <ν>(TKE) and <ε>(TKE) at many incident energies by averaging the PbP multi-parametric matrices over the experimental Y(A,TKE) distributions recently measured at IRMM for 14 incident energies in the range 0.3- 5 MeV. The results revealed that the slope dTKE/dν does not vary with the incident energy and the flattening of <ν> at low TKE values is more pronounced at low incident energies. The average model parameters dependences on TKE resulted from the PbP treatment allow the use of the most probable fragmentation approach, having the great advantage to provide results at many TKE values in a very short computing time compared to PbP and Monte Carlo treatments. (author)

  4. Neutron spectrum unfolding using neural networks

    International Nuclear Information System (INIS)

    Vega C, H.R.; Hernandez D, V.M.; Manzanares A, E.

    2004-01-01

    An artificial neural network has been designed to obtain the neutron spectra from the Bonner spheres spectrometer's count rates. The neural network was trained using a large set of neutron spectra compiled by the International Atomic Energy Agency. These include spectra from iso- topic neutron sources, reference and operational neutron spectra obtained from accelerators and nuclear reactors. The spectra were transformed from lethargy to energy distribution and were re-binned to 31 energy groups using the MCNP 4C code. Re-binned spectra and UTA4 matrix were used to calculate the expected count rates in Bonner spheres spectrometer. These count rates were used as input and correspondent spectrum was used as output during neural network training. The network has 7 input nodes, 56 neurons as hidden layer and 31 neurons in the output layer. After training the network was tested with the Bonner spheres count rates produced by twelve neutron spectra. The network allows unfolding the neutron spectrum from count rates measured with Bonner spheres. Good results are obtained when testing count rates belong to neutron spectra used during training, acceptable results are obtained for count rates obtained from actual neutron fields; however the network fails when count rates belong to monoenergetic neutron sources. (Author)

  5. Prototype Stilbene Neutron Collar

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, M. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shumaker, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Snyderman, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Verbeke, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wong, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-26

    A neutron collar using stilbene organic scintillator cells for fast neutron counting is described for the assay of fresh low enriched uranium (LEU) fuel assemblies. The prototype stilbene collar has a form factor similar to standard He-3 based collars and uses an AmLi interrogation neutron source. This report describes the simulation of list mode neutron correlation data on various fuel assemblies including some with neutron absorbers (burnable Gd poisons). Calibration curves (doubles vs 235U linear mass density) are presented for both thermal and fast (with Cd lining) modes of operation. It is shown that the stilbene collar meets or exceeds the current capabilities of He-3 based neutron collars. A self-consistent assay methodology, uniquely suited to the stilbene collar, using triples is described which complements traditional assay based on doubles calibration curves.

  6. PROMETHEE: An Alpha Low Level Waste Assay System Using Passive and Active Neutron Measurement Methods

    International Nuclear Information System (INIS)

    Passard, Christian; Mariani, Alain; Jallu, Fanny; Romeyer-Dherbey, Jacques; Recroix, Herve; Rodriguez, Michel; Loridon, Joel; Denis, Caroline; Toubon, Herve

    2002-01-01

    The development of a passive-active neutron assay system for alpha low level waste characterization at the French Atomic Energy Commission is discussed. Less than 50 Bq[α] (about 50 μg Pu) per gram of crude waste must be measured in 118-l 'European' drums in order to reach the requirements for incinerating wastes. Detection limits of about 0.12 mg of effective 239 Pu in total active neutron counting, and 0.08 mg of effective 239 Pu coincident active neutron counting, may currently be detected (empty cavity, measurement time of 15 min, neutron generator emission of 1.6 x 10 8 s -1 [4π]). The most limiting parameters in terms of performances are the matrix of the drum - its composition (H, Cl...), its density, and its heterogeneity degree - and the localization and self-shielding properties of the contaminant

  7. The Ratio of Regulatory (FOXP3+) to Total (CD3+) T Cells Determined by Epigenetic Cell Counting and Cardiovascular Disease Risk: A Prospective Case-cohort Study in Non-diabetics.

    Science.gov (United States)

    Barth, Sebastian Dietmar; Kaaks, Rudolf; Johnson, Theron; Katzke, Verena; Gellhaus, Katharina; Schulze, Janika Josephin; Olek, Sven; Kühn, Tilman

    2016-09-01

    Experimental and clinical evidence indicate that inflammatory processes in atherogenesis and the development of cardiovascular complications are promoted by a loss of regulatory T cell (Treg)-mediated immunological tolerance to plaque antigens. Yet, the association between alterations of systemic Treg frequency and cardiovascular disease incidence remains uncertain. A nested case-cohort study was conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Heidelberg, comprising a random subcohort (n=778) and primary cases of myocardial infarction (MI, n=276) and ischemic stroke (n=151). Pre-diagnostic FOXP3+ Treg and total CD3+ T-lymphocyte (tTL) frequencies in blood were measured by epigenetic-based, quantitative real-time PCR-assisted cell counting. Multivariate, Prentice-weighted Cox regression analyses revealed that lower Treg/tTL ratios were not associated with the risk of either MI (lowest vs. highest sex-specific quartile; hazard ratio: 0.72, 95% confidence interval: 0.46 to 1.13; P trend =0.51) or stroke (HR: 0.90, 95% CI: 0.51 to 1.60; P trend =0.78). There were no correlations of Treg/tTL ratios with C-reactive protein, HbA1c, and various lipid parameters. Among middle-aged adults from the general population, imbalances in the relative frequency of Tregs within the total T cell compartment do not confer an increased risk of MI or stroke. Copyright © 2016 Forschungsgesellschaft für Arbeitsphysiologie und Arbeitschutz e.V. Published by Elsevier B.V. All rights reserved.

  8. TU-F-CAMPUS-T-01: Dose and Energy Spectra From Neutron Induced Radioactivity in Medical Linear Accelerators Following High Energy Total Body Irradiation

    International Nuclear Information System (INIS)

    Keehan, S; Taylor, M; Franich, R; Smith, R; Dunn, L; Kron, T

    2015-01-01

    Purpose: To assess the risk posed by neutron induced activation of components in medical linear accelerators (linacs) following the delivery of high monitor unit 18 MV photon beams such as used in TBI. Methods: Gamma spectroscopy was used to identify radioisotopes produced in components of a Varian 21EX and an Elekta Synergy following delivery of photon beams. Dose and risk estimates for TBI were assessed using dose deliveries from an actual patient treatment. A 1 litre spherical ion chamber (PTW, Germany) has been used to measure the dose at the beam exit window and at the total body irradiation (TBI) treatment couch following large and small field beams with long beam-on times. Measurements were also made outside of the closed jaws to quantify the benefit of the attenuation provided by the jaws. Results: The radioisotopes produced in the linac head have been identified as 187 W, 56 Mn, 24 Na and 28 Al, which have half-lives from between 2.3 min to 24 hours. The dose at the beam exit window following an 18 MV 2197 MU TBI beam delivery was 12.6 µSv in ten minutes. The dose rate at the TBI treatment couch 4.8 m away is a factor of ten lower. For a typical TBI delivered in six fractions each consisting of four beams and an annual patient load of 24, the annual dose estimate for a staff member at the treatment couch for ten minutes is 750 µSv. This can be further reduced by a factor of about twelve if the jaws are closed before entering the room, resulting in a dose estimate of 65 µSv. Conclusion: The dose resulting from the activation products for a representative TBI workload at our clinic of 24 patients per year is 750 µSv, which can be further reduced to 65 µSv by closing the jaws

  9. Neutron energy measurement for practical applications

    Science.gov (United States)

    Roshan, M. V.; Sadeghi, H.; Ghasabian, M.; Mazandarani, A.

    2018-03-01

    Industrial demand for neutrons constrains careful energy measurements. Elastic scattering of monoenergetic α -particles from neutron collision enables neutron energy measurement by calculating the amount of deviation from the position where collision takes place. The neutron numbers with specific energy is obtained by counting the number of α -particles in the corresponding location on the charged particle detector. Monte Carlo simulation and COMSOL Multiphysics5.2 are used to account for one-to-one collision of neutrons with α -particles.

  10. Application of neutron activation analysis to the determination of total mercury and other elements of interest in soil and sediment samples from Serra do Navio and Vila Nova River Basin, Amapa, Brazil

    International Nuclear Information System (INIS)

    Goncalves, Cristina

    1997-01-01

    In this work it is presented a survey on total mercury determination by a radiochemical method in sediment and soil samples from two regions, in the state of Amapa: Serra do Navio (background area) and Vila Nova river basin (gold mining area). The method consisted in leaching of the irradiated samples with acqua regia in a Parr bomb, and heating in microwave oven, for one minute. Then the solvent extraction technique was applied, using bismuth diethyldithiocarbamate (Bi(DDC) 3 ) as extractant agent. The organic phase, containing 197 Hg and 203 Hg radioisotopes, was measured in a gamma spectrometer with hyper pure Ge detector. This method eliminated the interference of the 279.54 keV photopeak of 75 Se on 279.2 keV photopeak of 203 Hg, besides improving counting statistics of both Hg radioisotopes. The elements As, Ba, Br, Ce, Co, Cr, Cs, Eu, Fe, Hf, Ho, K, La, Lu, Mg, Mn, Na, Nd, Rb, Sb, Sc, Se, Sm, Ta, Tb, Th, Ti, U, V, W, Yb, Zn and Zr were also determined by the instrumental neutron activation analysis. Two irradiation series were carried out to quantify these elements in soil and sediment samples; a short term irradiation allowed to evaluate Mg, Mn, Na, Ti and V levels, and by long term irradiation, the other elements were determined. Precision and accuracy of radiochemical procedure were verified by means of analysis of the reference materials Buffalo River Sediment and Lake Sediment, for sediments and GXR-5, for soils. For the instrumental analysis, the reference materials Buffalo River Sediment, Soil 7, JB-1 and Oyster Tissue were used. The samples were also submitted to X ray diffraction, in Instituto de Geoscience-USP, to observe mercury behaviour with mineralogy. Aluminium concentration was determined by X ray fluorescence method, in the Department of Materials, IPEN/CNEN-SP, making possible enrichment factor calculation so that mercurial contamination in the gold mining area (Vila Nova river basin) could be evaluated. The mercury levels obtained in this

  11. Neutron-activation analysis of routine mineral-processing samples

    International Nuclear Information System (INIS)

    Watterson, J.; Eddy, B.; Pearton, D.

    1974-01-01

    Instrumental neutron-activation analysis was applied to a suite of typical mineral-processing samples to establish which elements can be rapidly determined in them by this technique. A total of 35 elements can be determined with precisions (from the counting statistics) ranging from better than 1 per cent to approximately 20 per cent. The elements that can be determined have been tabulated together with the experimental conditions, the precision from the counting statistics, and the estimated number of analyses possible per day. With an automated system, this number can be as high as 150 in the most favourable cases [af

  12. Tritium and neutron measurements from deuterated Pd-Si

    International Nuclear Information System (INIS)

    Claytor, T.N.; Tuggle, D.G.; Menlove, H.O.; Seeger, P.A.; Doty, W.R.; Rohwer, R.K.

    1990-01-01

    Evidence has been found for tritium and neutron production in palladium and silicon stacks when pulsed with a high electric current. These palladium-silicon stacks consist of alternating layers of pressed palladium and silicon powder. A pulsed high electric current is thought to promote non equilibrium conditions important for tritium and neutron production. More than 2000 hours of neutron counting time has been accumulated in a underground, low background, environment with high efficiency counters (21%). Neutron emission has occurred as infrequent burst or as low level emission lasting for up to 20 hours. In eight of 30 cells, excess tritium greater than 3 sigma has been observed. In each of these measurements, with the powder system, the ratio of tritium detected to total integrated total neutrons inferred has been anomalously high. Recent cells have shown reproducible tritium generation at a level of about 0.5 nCi/hr. Several hydrogen and air control cells have been run with no anomalous excess tritium or neutron emission above background. A significant amount of the total palladium inventory (18%) has been checked for tritium contamination by three independent means. 12 refs., 6 figs., 2 tabs

  13. Black and grey neutron detectors

    International Nuclear Information System (INIS)

    Gabbard, F.

    1977-01-01

    Recent progress in the development and use of ''black'' and ''grey'' detectors is reviewed. Such detectors are widely used for counting neutrons in (p,n) and (α,n) experiments and in neutron cross section measurements. Accuracy of each detector is stressed. 19 figures

  14. Measurement of natural background neutron

    CERN Document Server

    Li Jain, Ping; Tang Jin Hua; Tang, E S; Xie Yan Fong

    1982-01-01

    A high sensitive neutron monitor is described. It has an approximate counting rate of 20 cpm for natural background neutrons. The pulse amplitude resolution, sensitivity and direction dependence of the monitor were determined. This monitor has been used for natural background measurement in Beijing area. The yearly average dose is given and compared with the results of KEK and CERN.

  15. Neutron Beam Filters

    International Nuclear Information System (INIS)

    Adib, M.

    2011-01-01

    The purpose of filters is to transmit neutrons with selected energy, while remove unwanted ones from the incident neutron beam. This reduces the background, and the number of spurious. The types of commonly used now-a-day neutron filters and their properties are discussed in the present work. There are three major types of neutron filters. The first type is filter of selective thermal neutron. It transmits the main reflected neutrons from a crystal monochromate, while reject the higher order contaminations accompanying the main one. Beams coming from the moderator always contain unwanted radiation like fast neutrons and gamma-rays which contribute to experimental background and to the biological hazard potential. Such filter type is called filter of whole thermal neutron spectrum. The third filter type is it transmits neutrons with energies in the resonance energy range (En . 1 KeV). The main idea of such neutron filter technique is the use of large quantities of a certain material which have the deep interference minima in its total neutron cross-section. By transmitting reactor neutrons through bulk layer of such material, one can obtain the quasimonochromatic neutron lines instead of white reactor spectrum.

  16. Measurements of the total neutron cross-section of cerium and thulium in the energy range from 1.8 MeV to 1.8 eV

    International Nuclear Information System (INIS)

    Adib, M.; Maayouf, R.M.A.; Abdel-Kawy, A.; Abu-Elnour, F.; Hamouda, I.

    1979-01-01

    Total neutron cross-section measurements have been carried out for cerium and thulium in the energy range from 1.8 meV to 1.8 eV. The measurements were performed using the time-of-flight spectrometer installed in front of one of the horizontal channels of the ET-RR-1 reactor. The obtained total neutron cross-sections were analyzed using the single level Breit-Wigner formula and the magnetic form factor. The potential scattering cross-section of Ce was found to be (3.14 +- 0.3) barns. Its coherent scattering amplitude was determined from the Bragg reflections observed in the total neutron cross-section of CeO 2 and found to be (4,8 +- 0.2) fm. The potential scattering and absorption cross-sections of Tm, at E = 0.025 eV, were found to be (7.5 +- 0.7) barns and (89.1 +- 4.1) barns respectively. (orig.) [de

  17. Neutron-induced mutation experiments and total radiation-induced genetic damage in entire genomes of Drosophila melanogaster. Final report, November 1, 1967-August 31, 1980

    International Nuclear Information System (INIS)

    Abrahamson, S.

    1981-02-01

    Neutron-induced mutation experiments with Drosophila oogonia were conducted at the University of Wisconsin, with irradiations being carried out at the RARAF facility at Brookhaven National Laboratory. X-linked recessive lethals and specific locus mutations were studied. Using the α value of the weighted linear regression equation for lethal data, RBE's relative to X-rays were calculated for the energies of neutrons studied. They are: 15 MeV to 2.0; 6 MeV to 2.9; 2 MeV to 3.2; .66 MeV to 4.0; .43 MeV to 4.8. The dose/frequency response curves for lethal data of all neutron energies studied was suggestive of a quadratic component. All data best fit a linear hypothesis, however. Control data for specific locus mutations was used to estimate the number of loci on the X-chromosome which are capable of mutating to lethals. Neutron-induced data for specific locus mutation was inconclusive due to the high error inherent in the frequencies obtained

  18. Experimental validation of GADRAS's coupled neutron-photon inverse radiation transport solver

    International Nuclear Information System (INIS)

    Mattingly, John K.; Mitchell, Dean James; Harding, Lee T.

    2010-01-01

    Sandia National Laboratories has developed an inverse radiation transport solver that applies nonlinear regression to coupled neutron-photon deterministic transport models. The inverse solver uses nonlinear regression to fit a radiation transport model to gamma spectrometry and neutron multiplicity counting measurements. The subject of this paper is the experimental validation of that solver. This paper describes a series of experiments conducted with a 4.5 kg sphere of α-phase, weapons-grade plutonium. The source was measured bare and reflected by high-density polyethylene (HDPE) spherical shells with total thicknesses between 1.27 and 15.24 cm. Neutron and photon emissions from the source were measured using three instruments: a gross neutron counter, a portable neutron multiplicity counter, and a high-resolution gamma spectrometer. These measurements were used as input to the inverse radiation transport solver to evaluate the solver's ability to correctly infer the configuration of the source from its measured radiation signatures.

  19. Parameters affecting temporal resolution of Time Resolved Integrative Optical Neutron Detector (TRION)

    International Nuclear Information System (INIS)

    Mor, I; Vartsky, D; Bar, D; Feldman, G; Goldberg, M B; Brandis, M; Dangendorf, V; Tittelmeier, K; Bromberger, B; Weierganz, M

    2013-01-01

    The Time-Resolved Integrative Optical Neutron (TRION) detector was developed for Fast Neutron Resonance Radiography (FNRR), a fast-neutron transmission imaging method that exploits characteristic energy-variations of the total scattering cross-section in the E n = 1–10 MeV range to detect specific elements within a radiographed object. As opposed to classical event-counting time of flight (ECTOF), it integrates the detector signal during a well-defined neutron Time of Flight window corresponding to a pre-selected energy bin, e.g., the energy-interval spanning a cross-section resonance of an element such as C, O and N. The integrative characteristic of the detector permits loss-free operation at very intense, pulsed neutron fluxes, at a cost however, of recorded temporal resolution degradation This work presents a theoretical and experimental evaluation of detector related parameters which affect temporal resolution of the TRION system

  20. Determining random counts in liquid scintillation counting

    International Nuclear Information System (INIS)

    Horrocks, D.L.

    1979-01-01

    During measurements involving coincidence counting techniques, errors can arise due to the detection of chance or random coincidences in the multiple detectors used. A method and the electronic circuits necessary are here described for eliminating this source of error in liquid scintillation detectors used in coincidence counting. (UK)

  1. Advances in passive neutron instruments for safeguards use

    International Nuclear Information System (INIS)

    Menlove, H.O.; Krick, M.S.; Langner, D.G.; Miller, M.C.; Stewart, J.E.

    1994-01-01

    Passive neutron and other nondestructive assay techniques have been used extensively by the International Atomic Energy Agency to verify plutonium metal, powder, mixed oxide, pellets, rods, assemblies, scrap, and liquids. Normally, the coincidence counting rate is used to measure the 240 Pu-effective mass and gamma-ray spectrometry or mass spectrometry is used to verify the plutonium isotopic ratios. During the past few years, the passive neutron detectors have been installed in plants and operated in the unattended/continuous mode. These radiation data with time continuity have made it possible to use the totals counting rate to monitor the movement of nuclear material. Monte Carlo computer codes have been used to optimize the detector designs for specific applications. The inventory sample counter (INVS-III) has been designed to have a higher efficiency (43%) and a larger uniform counting volume than the original INVS. Data analyses techniques have been developed, including the ''known alpha'' and ''known multiplication'' methods that depend on the sample. For scrap and other impure or poorly characterized samples, we have developed multiplicity counting, initially implemented in the plutonium scrap multiplicity counter. For large waste containers such as 200-L drums, we have developed the add-a-source technique to give accurate corrections for the waste-matrix materials. This paper summarizes recent developments in the design and application of passive neutron assay systems

  2. Soil-Carbon Measurement System Based on Inelastic Neutron Scattering

    International Nuclear Information System (INIS)

    Orion, I.; Wielopolski, L.

    2002-01-01

    Increase in the atmospheric CO 2 is associated with concurrent increase in the amount of carbon sequestered in the soil. For better understanding of the carbon cycle it is imperative to establish a better and extensive database of the carbon concentrations in various soil types, in order to develop improved models for changes in the global climate. Non-invasive soil carbon measurement is based on Inelastic Neutron Scattering (INS). This method has been used successfully to measure total body carbon in human beings. The system consists of a pulsed neutron generator that is based on D-T reaction, which produces 14 MeV neutrons, a neutron flux monitoring detector and a couple of large NaI(Tl), 6'' diameter by 6'' high, spectrometers [4]. The threshold energy for INS reaction in carbon is 4.8 MeV. Following INS of 14 MeV neutrons in carbon 4.44 MeV photons are emitted and counted during a gate pulse period of 10 μsec. The repetition rate of the neutron generator is 104 pulses per sec. The gamma spectra are acquired only during the neutron generator gate pulses. The INS method for soil carbon content measurements provides a non-destructive, non-invasive tool, which can be optimized in order to develop a system for in field measurements

  3. A neutron spectrum unfolding code based on iterative procedures

    International Nuclear Information System (INIS)

    Ortiz R, J. M.; Vega C, H. R.

    2012-10-01

    In this work, the version 3.0 of the neutron spectrum unfolding code called Neutron Spectrometry and Dosimetry from Universidad Autonoma de Zacatecas (NSDUAZ), is presented. This code was designed in a graphical interface under the LabVIEW programming environment and it is based on the iterative SPUNIT iterative algorithm, using as entrance data, only the rate counts obtained with 7 Bonner spheres based on a 6 Lil(Eu) neutron detector. The main features of the code are: it is intuitive and friendly to the user; it has a programming routine which automatically selects the initial guess spectrum by using a set of neutron spectra compiled by the International Atomic Energy Agency. Besides the neutron spectrum, this code calculates the total flux, the mean energy, H(10), h(10), 15 dosimetric quantities for radiation protection porpoises and 7 survey meter responses, in four energy grids, based on the International Atomic Energy Agency compilation. This code generates a full report in html format with all relevant information. In this work, the neutron spectrum of a 241 AmBe neutron source on air, located at 150 cm from detector, is unfolded. (Author)

  4. Radon counting statistics - a Monte Carlo investigation

    International Nuclear Information System (INIS)

    Scott, A.G.

    1996-01-01

    Radioactive decay is a Poisson process, and so the Coefficient of Variation (COV) of open-quotes nclose quotes counts of a single nuclide is usually estimated as 1/√n. This is only true if the count duration is much shorter than the half-life of the nuclide. At longer count durations, the COV is smaller than the Poisson estimate. Most radon measurement methods count the alpha decays of 222 Rn, plus the progeny 218 Po and 214 Po, and estimate the 222 Rn activity from the sum of the counts. At long count durations, the chain decay of these nuclides means that every 222 Rn decay must be followed by two other alpha decays. The total number of decays is open-quotes 3Nclose quotes, where N is the number of radon decays, and the true COV of the radon concentration estimate is 1/√(N), √3 larger than the Poisson total count estimate of 1/√3N. Most count periods are comparable to the half lives of the progeny, so the relationship between COV and count time is complex. A Monte-Carlo estimate of the ratio of true COV to Poisson estimate was carried out for a range of count periods from 1 min to 16 h and three common radon measurement methods: liquid scintillation, scintillation cell, and electrostatic precipitation of progeny. The Poisson approximation underestimates COV by less than 20% for count durations of less than 60 min

  5. Absolute nuclear material assay using count distribution (LAMBDA) space

    Science.gov (United States)

    Prasad, Manoj K [Pleasanton, CA; Snyderman, Neal J [Berkeley, CA; Rowland, Mark S [Alamo, CA

    2012-06-05

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  6. Water table and the neutron moisture meter

    Energy Technology Data Exchange (ETDEWEB)

    Visvalingam, M [Hull Univ. (UK). Geography Dept.

    1975-12-01

    Measurements with a neutron moisture meter at Westlands, near Hull, showed count rates at capillary saturation to be within the error limits of count rates at full saturation. However, the saturation profiles in themselves were interesting as they indicated not only the zonation of the soil but also differences in drainable porosity when compared to count-rate profiles at the end of November.

  7. Pulsed neutron activation calibration technique

    International Nuclear Information System (INIS)

    Kehler, P.

    1979-01-01

    A pulsed neutron activation (PNA) for measurement of two-phase flow consists of a pulsed source of fast neutron to activate the oxygen in a steam-water mixture. Flow is measured downstream by an NaI detector. Measured counts are sorted by a multiscaler into different time channels. A counts vs. time distribution typical for two-phase flow with slip between the two phases is obtained. Proper evaluation for the counts/time distribution leads to flow-regime independent equations for the average of the inverse transil time and the average density. After calculation of the average mass flow velocity, the true mass flow is derived

  8. An alternative method for the measurement of neutron flux

    Indian Academy of Sciences (India)

    dose rate. We have used a 241AmBe neutron source for neutron irradiation, and the neutron dose rate and count rate were ... neutron sources, e.g., for the characterization of superheated droplet detectors (SDD). [1–6]. The SDD is a .... Grants Commission (UGC) for the financial assistance provided for this work. References.

  9. Polarized neutrons

    International Nuclear Information System (INIS)

    Williams, W.G.

    1988-01-01

    The book on 'polarized neutrons' is intended to inform researchers in condensed matter physics and chemistry of the diversity of scientific problems that can be investigated using polarized neutron beams. The contents include chapters on:- neutron polarizers and instrumentation, polarized neutron scattering, neutron polarization analysis experiments and precessing neutron polarization. (U.K.)

  10. Clean Hands Count

    Medline Plus

    Full Text Available ... Like this video? Sign in to make your opinion count. Sign in 131 2 Don't like this video? Sign in to make your opinion count. Sign in 3 Loading... Loading... Transcript The ...

  11. The Big Pumpkin Count.

    Science.gov (United States)

    Coplestone-Loomis, Lenny

    1981-01-01

    Pumpkin seeds are counted after students convert pumpkins to jack-o-lanterns. Among the activities involved, pupils learn to count by 10s, make estimates, and to construct a visual representation of 1,000. (MP)

  12. Neutron Signal and Noise Separation of the {sup 6}Li-ZnS(Ag) scintillator (BC702) Using Flash ADC

    Energy Technology Data Exchange (ETDEWEB)

    Shin, S. G.; Kye, Y. U. [POSTECH, Pohang (Korea, Republic of); Cho, M. H.; Namkung, W. [Pohang Accelerator Laboratory, Pohang (Korea, Republic of); Kim, G. N. [Kyungpook National Univ., Daegu (Korea, Republic of); Lee, M. W. [Dongnam Inst. of radiological and Medical Science, Daejeon (Korea, Republic of)

    2013-10-15

    This study will apply to nuclear data experiments and improve the quality of nuclear data measured at PNF. We also briefly discuss the future plan to apply our research to different kinds of neutron detectors. The parameters to separate the neutron signals and noises of the {sup 6}Li.ZnS(Ag) scintillator are determined through the upper processes. Three kinds of noise are determined by the parameters as shown in figure.5. The signals at the green (pedestal), red (gamma flash), and blue (gamma flash with big signal area) region are subtracted from the total amount of the counted signals. These algorithms will be applied to next neutron TOF experiments. Two additional neutron detectors will be introduced for neutron TOF experiment. These will measure the neutron flux to get the normalization factor. We will also conduct signal and noise separation of these neutron detectors. Neutron total cross-sections have been measured by using the time-of-flight (TOF) method at Pohang Neutron Facility (PNF). A {sup 6}Li.ZnS(Ag) scintillator BC702 from Bicron (Newbury, OH) with a diameter of 127 mm and a thickness of 6.35 mm mounted on an EMI-93090 photomultiplier was used as a detector for the neutron TOF spectrum measurement. This detector is sensitive to thermal and epithermal neutrons and insensitive to gamma radiation. However, it is required to more accurately separate neutron signal and noise. In the present work, we studied neutron signal and noise separation of the BC702 scintillator to measure the accurate neutron TOF data.

  13. Study of the effect of the energy spectrum and of the total flux on the damage produced by neutrons in solids; Contribution a l'etude de l'influence du spectre et du flux integre sur les dommages crees par les neutrons dans les solides

    Energy Technology Data Exchange (ETDEWEB)

    Dulieu, P C [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1967-01-01

    In the first part are studied the general relationships between the physical effects produced by neutrons in solids, and the total flux and neutron energy spectrum; some examples are given. The second part, describes the application to a silicon damage detector whose principle is to use the damage produced in a PIN Junction for measuring the neutron flux (intermediate and fast) received by the detector. Chapter I is devoted to the experimental determination of the energy given to the atoms by a primary in the silicon. The results and conclusions drawn from this determination make it possible to consider, in chapter II, the calculation of the detectors response characteristics.Chapter III deals with the measurement of the detectors response function and it is noted that good agreement is obtained between the calculation and experimental results. The whole of the second part constitutes a test of the methods presented in the first part. (author) [French] Dans la premiere partie, nous etudions les relations generales qui lient les effets physiques engendres par les neutrons dans les solides au flux integre et au spectre des neutrons et nous donnons des exemples d'utilisation. La deuxieme partie est une application au detecteur de dommages en silicium, dont le principe est d'utiliser les dommages crees dans une jonction PIN pour mesurer les flux de neutrons (intermediaires et rapides) recus par le detecteur. Le chapitre I est consacre a la determination experimentale de l'energie cedee aux atomes par un primaire dans le silicium. Les resultats et les conclusions que l'on peut tirer de cette determination permettent d'aborder, au chapitre II, le calcul de la fonction de reponse du detecteur. Le chapitre III porte sur la mesure de la fonction de reponse du detecteur et on constate qu'il y a un bon accord entre le calcul et l'experience. L'ensemble de la deuxieme partie constitue un test des methodes exposees dans la premiere partie. (auteur)

  14. Neutron diagnostics on TFTR utilizing the Campbelling technique

    International Nuclear Information System (INIS)

    England, A.C.; Hendel, H.W.; Neischmidt, E.B.

    1986-01-01

    The authors report modified commercial neutron counting equipment installed on a tokamak fusion test reactor (TFTR) which utilizes the Campbelling theorem to monitor the neutron source strength at very high neutron count rates. Campbelling utilizes the large amplitude fluctuation from neutron events in the detectors to discriminate against small amplitude noise events. Source strengths yielding equivalent count rates a factor of five higher than possible in the conventional count rate mode have been obtained to date. The concept of Campbelling is discussed and the particular application to TFTR is illustrated

  15. Radiation counting statistics

    Energy Technology Data Exchange (ETDEWEB)

    Suh, M. Y.; Jee, K. Y.; Park, K. K.; Park, Y. J.; Kim, W. H

    1999-08-01

    This report is intended to describe the statistical methods necessary to design and conduct radiation counting experiments and evaluate the data from the experiment. The methods are described for the evaluation of the stability of a counting system and the estimation of the precision of counting data by application of probability distribution models. The methods for the determination of the uncertainty of the results calculated from the number of counts, as well as various statistical methods for the reduction of counting error are also described. (Author). 11 refs., 8 tabs., 8 figs.

  16. Radiation counting statistics

    Energy Technology Data Exchange (ETDEWEB)

    Suh, M. Y.; Jee, K. Y.; Park, K. K. [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-08-01

    This report is intended to describe the statistical methods necessary to design and conduct radiation counting experiments and evaluate the data from the experiments. The methods are described for the evaluation of the stability of a counting system and the estimation of the precision of counting data by application of probability distribution models. The methods for the determination of the uncertainty of the results calculated from the number of counts, as well as various statistical methods for the reduction of counting error are also described. 11 refs., 6 figs., 8 tabs. (Author)

  17. Radiation counting statistics

    International Nuclear Information System (INIS)

    Suh, M. Y.; Jee, K. Y.; Park, K. K.; Park, Y. J.; Kim, W. H.

    1999-08-01

    This report is intended to describe the statistical methods necessary to design and conduct radiation counting experiments and evaluate the data from the experiment. The methods are described for the evaluation of the stability of a counting system and the estimation of the precision of counting data by application of probability distribution models. The methods for the determination of the uncertainty of the results calculated from the number of counts, as well as various statistical methods for the reduction of counting error are also described. (Author). 11 refs., 8 tabs., 8 figs

  18. Temporal trends in sperm count

    DEFF Research Database (Denmark)

    Levine, Hagai; Jørgensen, Niels; Martino-Andrade, Anderson

    2017-01-01

    a predefined protocol 7518 abstracts were screened and 2510 full articles reporting primary data on SC were reviewed. A total of 244 estimates of SC and TSC from 185 studies of 42 935 men who provided semen samples in 1973-2011 were extracted for meta-regression analysis, as well as information on years.......006, respectively). WIDER IMPLICATIONS: This comprehensive meta-regression analysis reports a significant decline in sperm counts (as measured by SC and TSC) between 1973 and 2011, driven by a 50-60% decline among men unselected by fertility from North America, Europe, Australia and New Zealand. Because......BACKGROUND: Reported declines in sperm counts remain controversial today and recent trends are unknown. A definitive meta-analysis is critical given the predictive value of sperm count for fertility, morbidity and mortality. OBJECTIVE AND RATIONALE: To provide a systematic review and meta-regression...

  19. Background subtraction system for pulsed neutron logging of earth boreholes

    International Nuclear Information System (INIS)

    Hopkinson, E.C.

    1977-01-01

    A neutron generator in well logging instrument is pulsed 100 times having a time between pulses of 1400 microseconds. This is followed by an off period of four cycles wherein 2800 microseconds is allowed for capture radiation to decay to an insignificant level and the remaining 2800 microseconds is used to measure background radiation. This results in the neutron source being disabled four pulses after every hundred pulses of operation, or approximately a 4 percent loss of neutron output. A first detector gate is open from 400 to 680 microseconds and a second detector gate is open from 700 to 980 microseconds. During the 100 cycles, each of the gates is thus open for 280 microseconds times 100 for a total of 28,000 microseconds. By scaling the gate count rate by a factor of 10, the background is subtracted directly

  20. Determination of the separate lipid and protein profile structures derived from the total membrane profile structure or isolated sarcoplasmic reticulum via x-ray and neutron diffraction

    International Nuclear Information System (INIS)

    Herbette, L.; Blasie, J.K.

    1984-01-01

    Sarcoplasmic reticulum (SR) membranes were prepared to contain biosynthetically deuterated SR phospholipids utilizing specific and general phospholipid exchange proteins (PLEP). Functional measurements and freeze fracture on SR dispersions and x-ray diffraction of hydrated oriented membrane multilayers revealed that the exchanged SR membranes were very similar to unexchanged SR membranes. Low resolution (28-A) neutron diffraction studies utilizing SR membranes exchanged with either protonated or perdeuterated SR phospholipids allowed direct determination of the lipid profile within the isolated SR membrane at two different unit cell repeat distances. These lipid profile structures were found to be highly asymmetric regarding the conformation of the fatty acid chain extents and compositional distribution of phospholipid molecules in the inner vs. outer monolayer of the SR membrane bilayer. The relatively high resolution (11-A) electron-density profile from x-ray diffraction was decomposed by utilizing the asymmetry in the number of phospholipid molecules residing in the inner vs. outer monolayer of the SR lipid bilayer as obtained from the neutron diffraction study. To our knowledge, this represents the first direct determination of a lipid bilayer profile structure within an isolated membrane system

  1. Neutron flux monitoring device

    International Nuclear Information System (INIS)

    Goto, Yasushi; Mitsubori, Minehisa; Ohashi, Kazunori.

    1997-01-01

    The present invention provides a neutron flux monitoring device for preventing occurrence of erroneous reactor scram caused by the elevation of the indication of a start region monitor (SRM) due to a factor different from actual increase of neutron fluxes. Namely, judgement based on measured values obtained by a pulse counting method and a judgment based on measured values obtained by a Cambel method are combined. A logic of switching neutron flux measuring method to be used for monitoring, namely, switching to an intermediate region when both of the judgements are valid is adopted. Then, even if the indication value is elevated based on the Cambel method with no increase of the counter rate in a neutron source region, the switching to the intermediate region is not conducted. As a result, erroneous reactor scram such as 'shorter reactor period' can be avoided. (I.S.)

  2. Electron volt neutron spectrometers

    International Nuclear Information System (INIS)

    Pietropaolo, A.; Senesi, R.

    2011-01-01

    The advent of pulsed neutron sources has made available intense fluxes of epithermal neutrons (500 meV ≤E≤100 eV ). The possibility to open new investigations on condensed matter with eV neutron scattering techniques, is related to the development of methods, concepts and devices that drive, or are inspired by, emerging studies at this energy scale. Electron volt spectrometers have undergone continuous improvements since the construction of the first prototype instruments, but in the last decade major breakthroughs have been accomplished in terms of resolution and counting statistics, leading, for example, to the direct measurement of the proton 3-D Born–Oppenheimer potential in any material, or to quantitatively probe nuclear quantum effects in hydrogen bonded systems. This paper reports on the most effective methods and concepts for energy analysis and detection, as well as devices for the optimization of electron volt spectrometers for different applications. This is set in the context of the progress made up to date in instrument development. Starting from early stages of development of the technique, particular emphasis will be given to the Vesuvio eV spectrometer at the ISIS neutron source, the first spectrometer where extensive scientific, as well as research and development programmes have been carried out. The potential offered by this type of instrumentation, from single particle excitations to momentum distribution studies, is then put in perspective into the emerging fields of eV spectroscopy applied to cultural heritages and neutron irradiation effects in electronics. - Highlights: ► Neutron spectrometers at eV energies. ► Methods and techniques for eV neutrons counting at spallation sources. ► Scattering, imaging and radiation hardness tests with multi-eV neutrons.

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

    International Nuclear Information System (INIS)

    Rochau, G.E.

    1980-01-01

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

  4. An accurate and portable solid state neutron rem meter

    Energy Technology Data Exchange (ETDEWEB)

    Oakes, T.M. [Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO (United States); Bellinger, S.L. [Department of Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS (United States); Miller, W.H. [Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO (United States); Missouri University Research Reactor, Columbia, MO (United States); Myers, E.R. [Department of Physics, University of Missouri, Kansas City, MO (United States); Fronk, R.G.; Cooper, B.W [Department of Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS (United States); Sobering, T.J. [Electronics Design Laboratory, Kansas State University, KS (United States); Scott, P.R. [Department of Physics, University of Missouri, Kansas City, MO (United States); Ugorowski, P.; McGregor, D.S; Shultis, J.K. [Department of Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS (United States); Caruso, A.N., E-mail: carusoan@umkc.edu [Department of Physics, University of Missouri, Kansas City, MO (United States)

    2013-08-11

    Accurately resolving the ambient neutron dose equivalent spanning the thermal to 15 MeV energy range with a single configuration and lightweight instrument is desirable. This paper presents the design of a portable, high intrinsic efficiency, and accurate neutron rem meter whose energy-dependent response is electronically adjusted to a chosen neutron dose equivalent standard. The instrument may be classified as a moderating type neutron spectrometer, based on an adaptation to the classical Bonner sphere and position sensitive long counter, which, simultaneously counts thermalized neutrons by high thermal efficiency solid state neutron detectors. The use of multiple detectors and moderator arranged along an axis of symmetry (e.g., long axis of a cylinder) with known neutron-slowing properties allows for the construction of a linear combination of responses that approximate the ambient neutron dose equivalent. Variations on the detector configuration are investigated via Monte Carlo N-Particle simulations to minimize the total instrument mass while maintaining acceptable response accuracy—a dose error less than 15% for bare {sup 252}Cf, bare AmBe, an epi-thermal and mixed monoenergetic sources is found at less than 4.5 kg moderator mass in all studied cases. A comparison of the energy dependent dose equivalent response and resultant energy dependent dose equivalent error of the present dosimeter to commercially-available portable rem meters and the prior art are presented. Finally, the present design is assessed by comparison of the simulated output resulting from applications of several known neutron sources and dose rates.

  5. Analysis of coal by neutron activation

    International Nuclear Information System (INIS)

    Burtner, D.R.

    1983-01-01

    The development of a thermal-neutron activation analysis procedure for determining elemental concentrations in whole coal samples, and the goal of combining this technique with other nuclear methods for determining a total mass balance in these and similar complex materials, is described. Problems of applying a fast-neutron activation analysis method for nitrogen are discussed, as well as an efficient procedure for drying and packaging coal samples. A thermal-neutron activation analysis (TNAA) procedure was developed for determining up to 27 elements in coal samples from the US, China, Nigeria, and Brazil. The comparator form of TNAA was applied, using a unique multielement standard, which contained 48 elements. The difference in net photopeak counts between sample and standard, due to γ-ray attenuation, was reduced by preparing this standard in an organic matrix, which simulates the composition and physical structure of the coal material. The simultaneous irradiation of several aliquots of this standard enabled high precision and accuracy to be attained. An accurate value for oxygen, determined by fast-neutron activation analysis, is used to correct for this effect in the nitrogen determination method

  6. Spark counting technique with an aluminium oxide film

    International Nuclear Information System (INIS)

    Kawai, H.; Koga, T.; Morishima, H.; Niwa, T.; Nishiwaki, Y.

    1980-01-01

    Automatic spark counting of etch-pits on a polycarbonate film produced by nuclear fission fragments is now used for neutron monitoring in several countries. A method was developed using an aluminium oxide film instead of a polycarbonate as the neutron detector. Aluminium oxide films were prepared as follows: A cleaned aluminium plate as an anode and a nickel plate as a cathode were immersed in dilute sulfuric acid solution and electric current flowed between the electrodes at 12degC for 10-30 minutes. Electric current density was about 10 mA/cm 2 . The aluminium plate was then kept in boiling water for 10-30 minutes for sealing. The thickness of the aluminium oxide layer formed was about 1μm. The aluminium plate attached to a plate of suitable fissionable material, such as uranium or thorium, was irradiated with neutrons and set in a usual spark counter for fission track counting. One electrode was the aluminium plate and the other was an aluminized polyester sheet. Sparked pulses were counted with a usual scaler. The advantage of using spark counting with an aluminium oxide film for neutron monitoring is rapid measurement of neutron exposure, since chemical etching which is indispensable for spark counting with a polycarbonate detector film, is not needed. (H.K.)

  7. Optimization of a neutron detector design using adjoint transport simulation

    International Nuclear Information System (INIS)

    Yi, C.; Manalo, K.; Huang, M.; Chin, M.; Edgar, C.; Applegate, S.; Sjoden, G.

    2012-01-01

    A synthetic aperture approach has been developed and investigated for Special Nuclear Materials (SNM) detection in vehicles passing a checkpoint at highway speeds. SNM is postulated to be stored in a moving vehicle and detector assemblies are placed on the road-side or in chambers embedded below the road surface. Neutron and gamma spectral awareness is important for the detector assembly design besides high efficiencies, so that different SNMs can be detected and identified with various possible shielding settings. The detector assembly design is composed of a CsI gamma-ray detector block and five neutron detector blocks, with peak efficiencies targeting different energy ranges determined by adjoint simulations. In this study, formulations are derived using adjoint transport simulations to estimate detector efficiencies. The formulations is applied to investigate several neutron detector designs for Block IV, which has its peak efficiency in the thermal range, and Block V, designed to maximize the total neutron counts over the entire energy spectrum. Other Blocks detect different neutron energies. All five neutron detector blocks and the gamma-ray block are assembled in both MCNP and deterministic simulation models, with detector responses calculated to validate the fully assembled design using a 30-group library. The simulation results show that the 30-group library, collapsed from an 80-group library using an adjoint-weighting approach with the YGROUP code, significantly reduced the computational cost while maintaining accuracy. (authors)

  8. Neutron Multiplicity Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Frame, Katherine Chiyoko [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-06-28

    Neutron multiplicity measurements are widely used for nondestructive assay (NDA) of special nuclear material (SNM). When combined with isotopic composition information, neutron multiplicity analysis can be used to estimate the spontaneous fission rate and leakage multiplication of SNM. When combined with isotopic information, the total mass of fissile material can also be determined. This presentation provides an overview of this technique.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-11

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

  10. Neutron Detector Signal Processing to Calculate the Effective Neutron Multiplication Factor of Subcritical Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Talamo, Alberto [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Gohar, Yousry [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

    2016-06-01

    This report describes different methodologies to calculate the effective neutron multiplication factor of subcritical assemblies by processing the neutron detector signals using MATLAB scripts. The subcritical assembly can be driven either by a spontaneous fission neutron source (e.g. californium) or by a neutron source generated from the interactions of accelerated particles with target materials. In the latter case, when the particle accelerator operates in a pulsed mode, the signals are typically stored into two files. One file contains the time when neutron reactions occur and the other contains the times when the neutron pulses start. In both files, the time is given by an integer representing the number of time bins since the start of the counting. These signal files are used to construct the neutron count distribution from a single neutron pulse. The built-in functions of MATLAB are used to calculate the effective neutron multiplication factor through the application of the prompt decay fitting or the area method to the neutron count distribution. If the subcritical assembly is driven by a spontaneous fission neutron source, then the effective multiplication factor can be evaluated either using the prompt neutron decay constant obtained from Rossi or Feynman distributions or the Modified Source Multiplication (MSM) method.

  11. Neutron Detector Signal Processing to Calculate the Effective Neutron Multiplication Factor of Subcritical Assemblies

    International Nuclear Information System (INIS)

    Talamo, Alberto; Gohar, Yousry

    2016-01-01

    This report describes different methodologies to calculate the effective neutron multiplication factor of subcritical assemblies by processing the neutron detector signals using MATLAB scripts. The subcritical assembly can be driven either by a spontaneous fission neutron source (e.g. californium) or by a neutron source generated from the interactions of accelerated particles with target materials. In the latter case, when the particle accelerator operates in a pulsed mode, the signals are typically stored into two files. One file contains the time when neutron reactions occur and the other contains the times when the neutron pulses start. In both files, the time is given by an integer representing the number of time bins since the start of the counting. These signal files are used to construct the neutron count distribution from a single neutron pulse. The built-in functions of MATLAB are used to calculate the effective neutron multiplication factor through the application of the prompt decay fitting or the area method to the neutron count distribution. If the subcritical assembly is driven by a spontaneous fission neutron source, then the effective multiplication factor can be evaluated either using the prompt neutron decay constant obtained from Rossi or Feynman distributions or the Modified Source Multiplication (MSM) method.

  12. Platelet Count and Plateletcrit

    African Journals Online (AJOL)

    strated that neonates with late onset sepsis (bacteremia after 3 days of age) had a dramatic increase in MPV and. PDW18. We hypothesize that as the MPV and PDW increase and platelet count and PCT decrease in sick children, intui- tively, the ratio of MPV to PCT; MPV to Platelet count,. PDW to PCT, PDW to platelet ...

  13. EcoCount

    Directory of Open Access Journals (Sweden)

    Phillip P. Allen

    2014-05-01

    Full Text Available Techniques that analyze biological remains from sediment sequences for environmental reconstructions are well established and widely used. Yet, identifying, counting, and recording biological evidence such as pollen grains remain a highly skilled, demanding, and time-consuming task. Standard procedure requires the classification and recording of between 300 and 500 pollen grains from each representative sample. Recording the data from a pollen count requires significant effort and focused resources from the palynologist. However, when an adaptation to the recording procedure is utilized, efficiency and time economy improve. We describe EcoCount, which represents a development in environmental data recording procedure. EcoCount is a voice activated fully customizable digital count sheet that allows the investigator to continuously interact with a field of view during the data recording. Continuous viewing allows the palynologist the opportunity to remain engaged with the essential task, identification, for longer, making pollen counting more efficient and economical. EcoCount is a versatile software package that can be used to record a variety of environmental evidence and can be installed onto different computer platforms, making the adoption by users and laboratories simple and inexpensive. The user-friendly format of EcoCount allows any novice to be competent and functional in a very short time.

  14. Counting It Twice.

    Science.gov (United States)

    Schattschneider, Doris

    1991-01-01

    Provided are examples from many domains of mathematics that illustrate the Fubini Principle in its discrete version: the value of a summation over a rectangular array is independent of the order of summation. Included are: counting using partitions as in proof by pictures, combinatorial arguments, indirect counting as in the inclusion-exclusion…

  15. Wide range neutron flux monitor

    International Nuclear Information System (INIS)

    Endo, Yorimasa; Fukushima, Toshiki.

    1983-01-01

    Purpose: To provide a wide range neutron-flux monitor adapted such that the flux monitoring function and alarming function can automatically by shifted from pulse counting system to cambel method system. Constitution: A wide range neutron-flux monitor comprises (la) pulse counting system and (lb) cambel-method system for inputting detection signals from neutron detectors and separating them into signals for the pulse measuring system and the cambel measuring system, (2) overlap detection and calculation circuit for detecting the existence of the overlap of two output signals from the (la) and (lb) systems, and (3) trip circuit for judging the abnormal state of neutron detectors upon input of the detection signals. (Seki, T.)

  16. Neutron resonance parameters of CM isotopes

    International Nuclear Information System (INIS)

    Belanova, T.S.; Kolesov, A.G.; Poruchikov, V.A.

    1977-01-01

    The total neutron cross sections of isotopes 244, 245, 246, 248 Curium have been measured on reactor CM-2 using the time-of-flight method. Single-level Breit-Wigner resonance parameters: energy E 0 , neutron width 2g GITAn, total width GITA, total neutron cross section in resonance sigma 0 have been obtained by the shape and area methods

  17. Multiplicity counting from fission detector signals with time delay effects

    Science.gov (United States)

    Nagy, L.; Pázsit, I.; Pál, L.

    2018-03-01

    In recent work, we have developed the theory of using the first three auto- and joint central moments of the currents of up to three fission chambers to extract the singles, doubles and triples count rates of traditional multiplicity counting (Pázsit and Pál, 2016; Pázsit et al., 2016). The objective is to elaborate a method for determining the fissile mass, neutron multiplication, and (α, n) neutron emission rate of an unknown assembly of fissile material from the statistics of the fission chamber signals, analogous to the traditional multiplicity counting methods with detectors in the pulse mode. Such a method would be an alternative to He-3 detector systems, which would be free from the dead time problems that would be encountered in high counting rate applications, for example the assay of spent nuclear fuel. A significant restriction of our previous work was that all neutrons born in a source event (spontaneous fission) were assumed to be detected simultaneously, which is not fulfilled in reality. In the present work, this restriction is eliminated, by assuming an independent, identically distributed random time delay for all neutrons arising from one source event. Expressions are derived for the same auto- and joint central moments of the detector current(s) as in the previous case, expressed with the singles, doubles, and triples (S, D and T) count rates. It is shown that if the time-dispersion of neutron detections is of the same order of magnitude as the detector pulse width, as they typically are in measurements of fast neutrons, the multiplicity rates can still be extracted from the moments of the detector current, although with more involved calibration factors. The presented formulae, and hence also the performance of the proposed method, are tested by both analytical models of the time delay as well as with numerical simulations. Methods are suggested also for the modification of the method for large time delay effects (for thermalised neutrons).

  18. Study of the effect of the energy spectrum and of the total flux on the damage produced by neutrons in solids; Contribution a l'etude de l'influence du spectre et du flux integre sur les dommages crees par les neutrons dans les solides

    Energy Technology Data Exchange (ETDEWEB)

    Dulieu, P.C. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1967-01-01

    In the first part are studied the general relationships between the physical effects produced by neutrons in solids, and the total flux and neutron energy spectrum; some examples are given. The second part, describes the application to a silicon damage detector whose principle is to use the damage produced in a PIN Junction for measuring the neutron flux (intermediate and fast) received by the detector. Chapter I is devoted to the experimental determination of the energy given to the atoms by a primary in the silicon. The results and conclusions drawn from this determination make it possible to consider, in chapter II, the calculation of the detectors response characteristics.Chapter III deals with the measurement of the detectors response function and it is noted that good agreement is obtained between the calculation and experimental results. The whole of the second part constitutes a test of the methods presented in the first part. (author) [French] Dans la premiere partie, nous etudions les relations generales qui lient les effets physiques engendres par les neutrons dans les solides au flux integre et au spectre des neutrons et nous donnons des exemples d'utilisation. La deuxieme partie est une application au detecteur de dommages en silicium, dont le principe est d'utiliser les dommages crees dans une jonction PIN pour mesurer les flux de neutrons (intermediaires et rapides) recus par le detecteur. Le chapitre I est consacre a la determination experimentale de l'energie cedee aux atomes par un primaire dans le silicium. Les resultats et les conclusions que l'on peut tirer de cette determination permettent d'aborder, au chapitre II, le calcul de la fonction de reponse du detecteur. Le chapitre III porte sur la mesure de la fonction de reponse du detecteur et on constate qu'il y a un bon accord entre le calcul et l'experience. L'ensemble de la deuxieme partie constitue un test des methodes exposees dans la premiere partie

  19. Neutron detection technique

    International Nuclear Information System (INIS)

    Oblath, N.S.; Poon, A.W.P.

    2000-01-01

    The Sudbury Neutrino Observatory (SNO) has the ability to measure the total flux of all active flavors of neutrinos using the neutral current reaction, whose signature is a neutron. By comparing the rates of the neutral current reaction to the charged current reaction, which only detects electron neutrinos, one can test the neutrino oscillation hypothesis independent of solar models. It is necessary to understand the neutron detection efficiency of the detector to make use of the neutral current reaction. This report demonstrates a coincidence technique to identify neutrons emitted from the 252 Cf neutron calibration source. The source releases on average four neutrons when a 252 Cf nucleus spontaneously fissions. Each neutron is detected as a separate event when the neutron is captured by a deuteron, releasing a gamma ray of approximately 6.25 MeV. This gamma ray is in turn detected by the photomultiplier tube (PMT) array. By investigating the time and spatial separation between neutron-like events, it is possible to obtain a pure sample of neutrons for calibration study. Preliminary results of the technique applied to two calibration runs are presented

  20. Study of neutron fields around an intense neutron generator.

    Science.gov (United States)

    Kicka, L; Machrafi, R; Miller, A

    2017-12-01

    Neutron fields in the vicinity of the newly built neutron facility, at the University of Ontario Institute of Technology (UOIT), have been investigated in a series of Monte Carlo simulations and measurements. The facility hosts a P-385 neutron generator based on a deuterium-deuterium fusion reaction. The neutron fluence at different locations around the neutron generator facility has been simulated using MCNPX 2.7E Monte Carlo particle transport program. To characterize neutron fields, three neutron sources were modeled with distributions corresponding to different incident deuteron energies of 90kV, 110kV, and 130kV. Measurements have been carried out to determine the dose rate at locations adjacent to the generator using bubble detectors (BDs). The neutron intensity was evaluated and the total dose rates corresponding to different applied acceleration potentials were estimated at various locations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Proposals of counting method for bubble detectors and their intercomparisons

    International Nuclear Information System (INIS)

    Ramalho, Eduardo; Silva, Ademir X.; Bellido, Luis F.; Facure, Alessandro; Pereira, Mario

    2009-01-01

    The study of neutron's spectrometry and dosimetry has become significantly easier due to relatively new devices called bubble detectors. Insensitive to gamma rays and composed by superheated emulsions, they still are subjects of many researches in Radiation Physics and Nuclear Engineering. In bubble detectors, either exposed to more intense neutron fields or for a long time, when more bubbles are produced, the statistical uncertainty during the dosimetric and spectrometric processes is reduced. A proposal of this nature is set up in this work, which presents ways to perform counting processes for bubble detectors and an updated proceeding to get the irradiated detectors' images in order to make the manual counting easier. Twelve BDS detectors were irradiated by RDS111 cyclotron from IEN's (Instituto de Engenharia Nuclear) and photographed using an assembly specially designed for this experiment. Counting was proceeded manually in a first moment; simultaneously, ImagePro was used in order to perform counting automatically. The bubble counting values, either manual or automatic, were compared and the time to get them and their difficult levels as well. After the bubble counting, the detectors' standardizes responses were calculated in both cases, according to BDS's manual and they were also compared. Among the results, the counting on these devices really becomes very hard at a large number of bubbles, besides higher variations in counting of many bubbles. Because of the good agreement between manual counting and the custom program, the last one revealed a good alternative in practical and economical levels. Despite the good results, the custom program needs of more adjustments in order to achieve more accuracy on higher counting on bubble detectors for neutron measurement applications. (author)

  2. Discrimination of the wall effect in a thin counter with micro-gap structure for neutron position sensing

    Energy Technology Data Exchange (ETDEWEB)

    Sakae, Takeji; Manabe, Tohru; Kitamura, Yasunori; Nohtomi, Akihiro [Kyushu Univ., Fukuoka (Japan); Sakamoto, Sigeyasu

    1996-07-01

    Simulation by the Monte Carlo method is applied to estimate the wall effect in a thermal neutron counter having a new function for discriminating the effect. The counter is designed to have paralleled electrodes with micro-gap structure. A resistive anode is used for position sensing on the center of a set of the three electrode. The structure can be made by simple arrangement of anode and cathode wires on an insulator plane. The calculation shows discrimination of the wall effect can be achieved by coincident counting of two or three elements included in the counter. By using the coincident counting, the thickness of the neutron counter can be made into 1 mm with the information of the total energy created in the neutron detection. (author)

  3. Computer-automated neutron activation analysis system

    International Nuclear Information System (INIS)

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

    1983-01-01

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

  4. Measurements and analysis of the {sup 127}I and {sup 129}I neutron capture and total cross sections; Mesure et analyses des sections efficaces neutroniques totales et de capture radiative des iodes 127 et 129 de 0.5 eV a 100keV

    Energy Technology Data Exchange (ETDEWEB)

    Noguere, G

    2005-07-01

    Most of the experimental work on the interaction of neutrons with matter has focused on materials important to reactor physics and reactor structures. By comparison, the corresponding data for minor actinides or long-lived fission products are poor. A significant demand has developed for improved neutron cross-section data of these little-studied nuclides due to the surge of interest in the transmutation of nuclear waste. With 400 kg of {sup 129}I produced yearly in the reactors of the EU countries and a very long {beta}{sup -} half-life of 1.57 x 10{sup 7} years, iodine requires disposal strategies that will isolate this isotope from the environment for long periods of time. Therefore, {sup 129}I is potentially a key long-lived fission product for transmutation applications, since {sup 129}I transmutes in {sup 130}I after a single neutron capture and decays to {sup 130}Xe with a 12.36 h half-life. Accurate capture cross sections would help to reduce uncertainties in waste management concepts. For that purpose, Time-Of-Flight measurements covering the [0.5 eV-100 keV] energy range have been carried out at the 150 MeV pulsed neutron source GELINA of the Institute for Reference Materials and Measurements (IRMM). Two types of experiments have been performed at the IRMM, namely capture and transmission experiments. They are respectively related to the neutron capture and total cross sections. Since the PbI{sub 2} samples used in this work contain natural and radioactive iodine, extensive measurements of {sup 129}I have been carried out under the same experimental conditions as for the {sup 129}I. The data reduction process was performed with the AGS system, and the resonance parameters were extracted with the SAMMY and REFIT shape analysis codes. In a last step, the parameters have been converted into ENDF-6 format and processed with the NJOY code to produce point-wise and multigroup cross sections, as well as MCNP and ERANOS libraries. (author)

  5. Determination of neutron dose from criticality accidents with bioassays for sodium-24 in blood and phosphorus-32 in hair

    International Nuclear Information System (INIS)

    Feng, Y.; Miller, L.F.; Brown, K.S.; Casson, W.H.; Mei, G.T.; Thein, M.

    1993-06-01

    A comprehensive review of accident neutron dosimetry using blood and hair analysis was performed and is summarized in this report. Experiments and calculations were conducted at Oak Ridge National Laboratory (ORNL) and the University of Tennessee (UT) to develop measurement techniques for the activity of 24 Na in blood and 32 P in hair for nuclear accident dosimetry. An operating procedure was established for the measurement of 24 Na in blood using an HPGe detector system. The sensitivity of the measurement for a 20-mL sample is 0.01-0.02 Gy of total neutron dose for hard spectra and below 0.005 Gy for soft spectra based on a 30- to 60-min counting time. The operating procedures for direct counting of hair samples are established using a liquid scintillation detector. Approximately 0.06-0.1 Gy of total neutron dose can be measured from a 1-g hair sample using this procedure. Detailed procedures for chemical dissolution and ashing of hair samples are also developed. A method is proposed to use blood and hair analysis for assessing neutron dose based on a collection of 98 neutron spectra. Ninety-eight blood activity-to-dose conversion factors were calculated. The calculated results for an uncollided fission spectrum compare favorably with previously published data for fission neutrons. This nuclear accident dosimetry system makes it possible to estimate an individual's neutron dose within a few hours after an accident if the accident spectrum can be approximated from one of 98 tabulated neutron spectrum descriptions. If the information on accident and spectrum description is not available, the activity ratio of 32 P in hair and 24 Na in blood can provide information related to the neutron spectrum for dose assessment

  6. Clean Hands Count

    Medline Plus

    Full Text Available ... Clean Hands Count Centers for Disease Control and Prevention (CDC) Loading... Unsubscribe from Centers for Disease Control and Prevention (CDC)? Cancel Unsubscribe Working... Subscribe Subscribed Unsubscribe 65K ...

  7. Clean Hands Count

    Medline Plus

    Full Text Available ... Clean Hands Count Centers for Disease Control and Prevention (CDC) Loading... Unsubscribe from Centers for Disease Control and Prevention (CDC)? Cancel Unsubscribe Working... Subscribe Subscribed Unsubscribe 66K ...

  8. Housing Inventory Count

    Data.gov (United States)

    Department of Housing and Urban Development — This report displays the data communities reported to HUD about the nature of their dedicated homeless inventory, referred to as their Housing Inventory Count (HIC)....

  9. Scintillation counting apparatus

    International Nuclear Information System (INIS)

    Noakes, J.E.

    1978-01-01

    Apparatus is described for the accurate measurement of radiation by means of scintillation counters and in particular for the liquid scintillation counting of both soft beta radiation and gamma radiation. Full constructional and operating details are given. (UK)

  10. Allegheny County Traffic Counts

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Traffic sensors at over 1,200 locations in Allegheny County collect vehicle counts for the Pennsylvania Department of Transportation. Data included in the Health...

  11. Counting Knights and Knaves

    Science.gov (United States)

    Levin,Oscar; Roberts, Gerri M.

    2013-01-01

    To understand better some of the classic knights and knaves puzzles, we count them. Doing so reveals a surprising connection between puzzles and solutions, and highlights some beautiful combinatorial identities.

  12. Clean Hands Count

    Medline Plus

    Full Text Available ... why Close Clean Hands Count Centers for Disease Control and Prevention (CDC) Loading... Unsubscribe from Centers for Disease Control and Prevention (CDC)? Cancel Unsubscribe Working... Subscribe Subscribed ...

  13. Neutron diagnostics on TFTR utilizing the Campbelling technique

    International Nuclear Information System (INIS)

    England, A.C.; Hendel, H.W.; Nieschmidt, E.B.

    1986-01-01

    Modified commercial equipment installed on the tokamak fusion test reactor (TFTR) at Princeton Plasma Physics Laboratory (PPPL) utilizes Campbell's mean square voltage theorem to monitor the neutron source strength at neutron count rates orders of magnitude above the capability of the count rate mode. Campbelling uses the large amplitude fluctuations from neutron fission events in the detectors to discriminate against small amplitude γ ray and other noise events. Source strengths yielding equivalent count rates a factor of 5 greater than possible in the conventional count rate mode have been obtained to date. The concept of Campbelling is discussed and the particular application to TFTR is illustrated. Fundamental advantages are the extended useful range of the detectors by a factor of --10 4 and gamma rejection by a factor of --10 3 . Some results are shown and the neutron source strengths obtained are compared to those from conventional counting circuits and from other detectors whose outputs have not yet suffered counting losses

  14. The Kruskal Count

    OpenAIRE

    Lagarias, Jeffrey C.; Rains, Eric; Vanderbei, Robert J.

    2001-01-01

    The Kruskal Count is a card trick invented by Martin J. Kruskal in which a magician "guesses" a card selected by a subject according to a certain counting procedure. With high probability the magician can correctly "guess" the card. The success of the trick is based on a mathematical principle related to coupling methods for Markov chains. This paper analyzes in detail two simplified variants of the trick and estimates the probability of success. The model predictions are compared with simula...

  15. Neutron radiography with ultracold neutrons

    International Nuclear Information System (INIS)

    Bates, J.C.

    1981-01-01

    The neutron transmission factor of very thin films may be low if the neutron energy is comparable to the pseudo-potential of the film material. Surprisingly, perhaps, it is relatively easy to obtain neutrons with such low energies in sufficient numbers to produce neutron radiographs. (orig.)

  16. Optimising polarised neutron scattering measurements--XYZ and polarimetry analysis

    International Nuclear Information System (INIS)

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

    2002-01-01

    The analytic optimisation of neutron scattering measurements made using XYZ polarisation analysis and neutron polarimetry techniques is discussed. Expressions for the 'quality factor' and the optimum division of counting time for the XYZ technique are presented. For neutron polarimetry the optimisation is identified as analogous to that for measuring the flipping ratio and reference is made to the results already in the literature

  17. Optimising polarised neutron scattering measurements--XYZ and polarimetry analysis

    CERN Document Server

    Cussen, L D

    2002-01-01

    The analytic optimisation of neutron scattering measurements made using XYZ polarisation analysis and neutron polarimetry techniques is discussed. Expressions for the 'quality factor' and the optimum division of counting time for the XYZ technique are presented. For neutron polarimetry the optimisation is identified as analogous to that for measuring the flipping ratio and reference is made to the results already in the literature.

  18. Neutron response study using PADC

    International Nuclear Information System (INIS)

    El-Badry, B.A; Hegazy, T.M; Morsy, A.A.; Zaki, M.F.

    2007-01-01

    The results of an experimental work aimed at improving the performances of the Cr-39 nuclear track detector for neutron dosimetry applications. So, a set of Cr-39 plastic detectors was exposed to 252 Cf neutron source, which has the emission rate of 0.68 x 10 8 s ( -1), and neutron dose equivalent rate 1m apart from the source is equal to 3.8 mrem/h. The detection of fast neutrons performed with Cr-39 detector foils, subsequent chemical etching and evaluation of the etched tracks by an automatic track counting system was studied. It is found that the track density grows with the increase of neutron dose and etching time. These results. are compared with previous work. It is found that there is a matching and good agreement with their investigations

  19. On the absolute calibration of a DT fusion neutron yield diagnostic

    Directory of Open Access Journals (Sweden)

    Ruiz C.L.

    2013-11-01

    Full Text Available Recent advances in Inertial Confinement Fusion (ICF experiments at Lawrence Livermore National Laboratory's National Ignition Facility (NIF have underscored the need for accurate total yield measurements of DT neutrons because yield measurements provide a measure of the predicted performance of the experiments. Future gas-puff DT experiments at Sandia National Laboratory's Z facility will also require similar measurements. For ICF DT experiments, the standard technique for measuring the neutron (14.1 MeV yield, counts the activity (counts/minute induced in irradiated copper samples. This activity occurs by the 63Cu(n,2n62Cu reaction where 62Cu decays by positrons (β+ with a half-life of 9.67 minutes. The calibrations discussed here employ the associated-particle method (APM, where the α (4He particles from the T(d,n4He reaction are measured to infer neutron fluxes on a copper sample. The flux induces 62Cu activity, measured in a coincidence counting system. The method leads to a relationship between a DT neutron yield and copper activity known as the F-factor. The goal in future experiments is to apply this calibration to measure the yield at NIF with a combined uncertainty approaching 5%.

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

    International Nuclear Information System (INIS)

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

    1987-01-01

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