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Wyszukujesz frazę "neutron" wg kryterium: Temat


Tytuł:
Progress in the development of the semi-empirical calibration of neutron probes based on Monte Carlo modeling
Autorzy:
Woźnicka, Urszula
Powiązania:
https://bibliotekanauki.pl/articles/1841776.pdf
Data publikacji:
2020
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
neutron well logging
calibration of the borehole neutron probe
general neutron parameter of neutron transport
Opis:
The method of the semi-empirical calibration of a neutron well logging probe was developed by Jan Andrzej Czubek on the concept of the general neutron parameter (GNP) and tested positively at the neutron calibration station in Zielona Góra, Poland. The neutron probe responses in a wide range of neutron parameters (and thus lithology, porosity and saturation) were also computed using the Monte Carlo method. The obtained simulation results made it possible to determine the calibration curves using the Czubek concept in a wider range than by means of the original method. The very good compatibility of both methods confirms the applicability of the GNP as well as the Monte Carlo numerical experiments, which allow for a significant extension of the semi-empirical calibration in complex well geometries taking into account e.g., casing or invaded zones.
Źródło:
Geology, Geophysics and Environment; 2020, 46, 3; 251-254
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
MTS-6 detectors calibration by using ²³⁹Pu-Be neutron source
Autorzy:
Wrzesień, Małgorzata
Albiniak, Łukasz
Al-Hameed, Hiba
Powiązania:
https://bibliotekanauki.pl/articles/2164008.pdf
Data publikacji:
2017-10-17
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
thermoluminescence
calibration
thermoluminescent detectors
neutron
neutron source
MTS
Opis:
Background Thermoluminescent detectors, type MTS-6, containing isotope ⁶Li (lithium) are sensitive in the range of thermal neutron energy; the ²³⁹Pu-Be (plutonium-and-beryllium) source emits neutrons in the energy range from 1 to 11 MeV. These seemingly contradictory elements may be combined by using the paraffin moderator, a determined density of thermal neutrons in the paraffin block and a conversion coefficient neutron flux to kerma, not forgetting the simultaneous registration of the photon radiation inseparable from the companion neutron radiation. The main aim of this work is to present the idea of calibration of thermoluminescent detectors that consist of a ⁶Li isotope, by using ²³⁹Pu-Be neutron radiation source. Material and Methods In this work, MTS-6 and MTS-7 thermoluminescent detectors and a plutonium-and-beryllium (²³⁹Pu-Be) neutron source were used. Paraffin wax fills the block, acting as a moderator. The calibration idea was based on the determination of dose equivalent rate based on the average kerma rate calculated taking into account the empirically determined function describing the density of thermal neutron flux in the paraffin block and a conversion coefficient neutron flux to kerma. Results The calculated value of the thermal neutron flux density was 1817.5 neutrons/cm²/s and the average value of kerma rate determined on this basis amounted to 244 μGy/h, and the dose equivalent rate 610 μSv/h. The calculated value allowed for the assessment of the length of time of exposure of the detectors directly in the paraffin block. Conclusions The calibration coefficient for the used batch of detectors is (6.80±0.42)×10⁻⁷ Sv/impulse. Med Pr 2017;68(6):705–710
Źródło:
Medycyna Pracy; 2017, 68, 6; 705-710
0465-5893
2353-1339
Pojawia się w:
Medycyna Pracy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of thermal neutron detection capability of a CdZnTe detector in a mixed gamma-neutron radiation field
Autorzy:
Yücel, H.
Narttürk, R. B.
Zümrüt, S.
Gedik, G.
Karadag, M.
Powiązania:
https://bibliotekanauki.pl/articles/146914.pdf
Data publikacji:
2018
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
neutron detection
CdZnTe
prompt gamma ray
thermal neutron
cadmium
neutron sensitivity
241Am-Be source
Opis:
The aim of this study was to investigate the thermal neutron measurement capability of a CdZnTe detector irradiated in a mixed gamma-neutron radiation fi eld. A CdZnTe detector was irradiated in one of the irradiation tubes of a 241Am-Be source unit to determine the sensitivity factors of the detector in terms of peak count rate (counts per second [cps]) per neutron flux (in square centimeters per second) [cps/neutron•cm–2•s–1]. The CdZnTe detector was covered in a 1-mm-thick cadmium (Cd) cylindrical box to completely absorb incoming thermal neutrons via 113Cd(n,γ) capture reactions. To achieve, this Cd-covered CdZnTe detector was placed in a well-thermalized neutron fi eld (f-ratio = 50.9 ± 1.3) in the irradiation tube of the 241Am-Be neutron source. The gamma-ray spectra were acquired, and the most intense gamma-ray peak at 558 keV (0.74 γ/n) was evaluated to estimate the thermal neutron fl ux. The epithermal component was also estimated from the bare CdZnTe detector irradiation because the epithermal neutron cutoff energy is about 0.55 eV at the 1-mm-thick Cd filter. A high-density polyethylene moderating cylinder box can also be fi tted into the Cd fi lter box to enhance thermal sensitivity because of moderation of the epithermal neutron component. Neutron detection sensitivity was determined from the measured count rates from the 558 keV photopeak, using the measured neutron fluxes at different irradiation positions. The results indicate that the CdZnTe detector can serve as a neutron detector in mixed gamma-neutron radiation fields, such as reactors, neutron generators, linear accelerators, and isotopic neutron sources. New thermal neutron filters, such as Gd and Tb foils, can be tested instead of the Cd filter due to its serious gamma-shielding effect.
Źródło:
Nukleonika; 2018, 63, 3; 59-64
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diagnostics and scaling of fusion-produced neutrons in PF experiments
Autorzy:
Schmidt, H.
Powiązania:
https://bibliotekanauki.pl/articles/146622.pdf
Data publikacji:
2011
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
neutron emission
plasma focus
scaling laws
neutron diagnostics
nuclear fusion
Opis:
Neutrons from a plasma focus (PF) device operated in a deuterium gas, measured as a function of time, location and direction of emission, reveal quite a number of important parameters on fusion reactions occurring in the dense high-current phase of the experiment. In addition the determination of the energy spectra of the emitted neutrons is important for understanding the mechanisms taking place for the neutron production. Results of neutron measurements in large experiments such as the former POSEIDON experiment in Stuttgart and the PF-1000 experiment in Warsaw are presented. The neutron diagnostic methods that had been utilized include nuclear track detectors, plastic scintillators coupled to photomultipliers, activation measurements, time-of-flight methods as well as pinholes for spatial resolution of the neutron source. The well known scaling law according to which the neutron yield scales roughly as the square of the energy input or the fourth power of the current is discussed. Reasons for strong deviation from this law for high energies - known as the saturation effect - are still a subject of debate.
Źródło:
Nukleonika; 2011, 56, 2; 107-112
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Neutron and fast ion emission from PF-1000 facility equipped with new large electrodes
Autorzy:
Szydlowski, M.
Scholz, M.
Karpinski, L.
Sadowski, M.
Tomaszewski, K.
Paduch, M.
Powiązania:
https://bibliotekanauki.pl/articles/147301.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
fast ion beam
neutron emission anisotropy
neutron yield
plasma focus
Opis:
A PF-1000 facility was operated for the first time at an energy level of up to 1 MJ. The maximal emission of 2×1011 neutrons/shot was registered. Relatively low emission anisotropy was observed. Fast ion beams were generated only from shots performed at a low filling pressure (1-2 Torr).
Źródło:
Nukleonika; 2001, 46, suppl. 1; 61-64
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Large Sample Neutron Activation Analysis: correction for neutron and gamma attenuation
Autorzy:
Tzika, F.
Stamatelatos, I.
Kalef-Ezra, J.
Bode, P.
Powiązania:
https://bibliotekanauki.pl/articles/147265.pdf
Data publikacji:
2004
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
neutron activation analysis
neutron self-shielding
gamma-ray attenuation
MCNP code
Opis:
A Large Sample Neutron Activation Analysis (LSNAA) facility is under development at the GRR-1 research reactor, NCSR "Demokritos". The LSNAA facility design incorporates sample irradiation in the reactor graphite thermal neutron column and subsequent measurement of the activity induced in a gamma spectroscopy system with gamma ray transmission measurement options included. The Monte Carlo neutron and photon transport code MCNP-4C was used to model the facility. Appropriate correction factors accounting for neutron field perturbation during sample irradiation and high-purity germanium detector efficiency for the volume source were derived. The results of the computations were experimentally verified by measurements for a set of known materials. The LSNAA facility will be used to perform multi-element, non-destructive, contamination-free analysis of large volume samples with high sensitivity and excellent sampling. End-users of the facility will be archaeological, environmental, bio-medical research laboratories and industry.
Źródło:
Nukleonika; 2004, 49, 3; 115-121
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Feasibility of Monte Carlo modelling for the neutron-neutron logging tool response in specific geological models
Autorzy:
Wiącek, U.
Woźnicka, U.
Powiązania:
https://bibliotekanauki.pl/articles/184592.pdf
Data publikacji:
2016
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Monte Carlo calculations
neutron well logging
NNTE density tool
neutron parameters
Opis:
Neutron well logging is one of the basic methods for the determination of the characteristic parameters of rock samples. The neutron source and neutron detectors are elements of Neutron-Neutron Thermal-Epithermal logging tool (NNTE) of significant importance. A neutron source creates the neutron field in the nearest environment. Detectors placed at specified distances from the source register neutrons from this space. A signal of a Neutron-Neutron Thermal-Epithermal tool in specific geological conditions was numerically calculated by means of the Monte Carlo (MC) codes. The main aim of this paper is to show the potential for using the Monte Carlo N-Particle Transport Code (MCNP) software in nuclear well logging prospection methods. The results of this MC modelling are presented in this paper.
Źródło:
Geology, Geophysics and Environment; 2016, 42, 3; 365-383
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic neutron radiography studies of drying of kaolin clay cylinders
Autorzy:
Fijał-Kirejczyk, I.
Milczarek, J. J.
Banaszak, J.
Trzciński, A.
Żołądek, J.
Powiązania:
https://bibliotekanauki.pl/articles/148084.pdf
Data publikacji:
2009
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
drying
kaolin
neutron radiography
Opis:
The results of neutron radiography studies on convective drying of kaolin cylinders are presented. The sample shrinkage and loss of water during drying was easily observed on registered neutron radiograms. The saturation of the sample with water was estimated in terms of the neutron effective macroscopic cross-section. The results are comparable to those of gravimetric measurements and are discussed within the framework of simple theories of drying. The effect of the scattered neutrons is discussed in terms of the results of the MC simulations.
Źródło:
Nukleonika; 2009, 54, 2; 123-128
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development and Experimental Validation of a Correlation Monitor Tool Based on the Endogenous Pulsed Neutron Source Technique
Autorzy:
Arkani, M.
Khalafi, H.
Vosoughi, N.
Khakshournia, S.
Powiązania:
https://bibliotekanauki.pl/articles/221446.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
endogenous pulsed neutron source experiment
neutron noise fluctuation
zero power reactor noise
Esfahan heavy-water zero power reactor
neutron correlation
Opis:
A correlation measuring tool for an endogenous pulsed neutron source experiment is developed in this work. Paroxysmal pulses generated by a bursts of neutron chains are detected by a 10-kbit embedded shift register with a time resolution of 100 ns. The system is implemented on a single reprogrammable device making it a compact, cost-effective instrument, easily adaptable for any case study. The system was verified experimentally in the Esfahan heavy-water zero power reactor (EHWZPR). The results obtained by the measuring tool are validated by the Feynman-α experiment, and a good agreement is seen within the boundaries of statistical uncertainties. The theory of the methods is briefly initiated in the text. Also, the system structure is described, the experimental results and their uncertainties are discussed, and neutron statistics in EHWZPR is examined experimentally.
Źródło:
Metrology and Measurement Systems; 2017, 24, 3; 441-461
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Compensated ionization chamber for (n,α) reaction measurements at a spallation neutron source
Autorzy:
Andrzejewski, J.
Yu, M.
Gledenov, M.
Korejwo, A.
Sobczak, K.
Szałański, P.
Powiązania:
https://bibliotekanauki.pl/articles/146570.pdf
Data publikacji:
2007
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
ionization chamber
pulsed neutron source
Opis:
The new spallation neutron facility n_TOF (neutron time-of-flight) at CERN opens wide possibilities in measurements of neutron induced reaction cross sections. The facility with its excellent energy resolution of neutrons, low repetition rate and most important – with a very high instantaneous luminosity, makes up an extra challenge for experimenters faced by doing measurements at a high peak intensity spallation source. Our proposition is directed to the use of a compensated ionization chamber for the (n, alpha) reaction cross section measurements we plan to carry out in a wide range of neutron energy. First experience gained with using such a kind of detector at ORELA (the Oak Ridge Electron Linear Accelerator) neutron source (ORNL) was very optimistic.
Źródło:
Nukleonika; 2007, 52, 2; 51-57
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fast Neutron Activation Analysis of gold by inelastic scattering, 197Au(n,ngamma)197Aum, by means of Plasma Focus device
Autorzy:
Verri, G.
Mezzetti, F.
Da Re, A.
Rapezzi, L.
Gribkov, V.
Powiązania:
https://bibliotekanauki.pl/articles/146754.pdf
Data publikacji:
2000
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
activation
gold
neutron
plasma focus
Opis:
The application of a Fast Neutron Activation Analysis (FNAA) technique on samples of pure gold, irradiated by a plasma focus of 7 kJ, has been investigated. The reaction was the inelastic scattering of neutrons, 197Au(n,n'gamma)197Aum. To avoid problems connected with peculiar features of the neutron emission from this kind of source, a preliminary standardisation of the method has been carried out. The results obtained have a practical interest in view of possible applications to the technology of extraction of minerals.
Źródło:
Nukleonika; 2000, 45, 3; 189-191
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Antiferromagnet-ferromagnet transitions in La1-xBaxCoO3-δ induced by pressure and magnetic field
Autorzy:
Troyanchuk, I.
Bushinsky, M.
Tereshko, N.
Fedotova, V.
Powiązania:
https://bibliotekanauki.pl/articles/118516.pdf
Data publikacji:
2014
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
cobaltites
przejścia fazowe
struktura kryształów
dyfrakcja neutronów neutron
phase transition
crystal structure
neutron diffraction
Opis:
Magnetic properties of the anion deficient cobaltites La1-xBaxCoO3-δ (x ≥ 0.5) have been studied. Magnetic field induces very large changes in resistivity accompanied by large magnetic hysteresis. It is found that an applied pressure transforms antiferromagnetic state into ferromagnetic one. It is assumed that a ground magnetic state strongly depends on unit cell volume and transition is associated with the cobalt ions spin state crossover. It is suggested that the antiferromagnetic state corresponds to high spin state of cobalt ions whereas ferromagnetic one is due to intermediate spin state of cobalt ions.
Zbadano wpływ naprężenia na podstawowy antyferromagnetyczny stan w anionzubożonym La1-xBaxCoO3-δ Ustalono że tak oddziaływanie ciśnienia jak zewnętrznego pola magnetycznego indukuje przejście ze stanu antyferromagnetycznego w stan ferromagnetyczny. Obserwowana wartość momenty magnetycznego dla La0.5Ba0.5CoO2.8 przy 65 kbar jest równa 1.9μB/Co. Otrzymane wyniki są zgodne z modelem, w którym siła dynamiczna antiferromagnetyczno-ferromagnetycznego przejścia ze stanu HS w stan LS jest spowodowany przez ciśnienie lub pole magnetyczne. Oddziaływanie magnetyczne pomiędzy jonami Co w stanie HS jest ferromagnetyczne, a w stanie IS – antyferromagnetyczne. Oba typy oddziaływań mogą być związane z superoddziaływaniem z atomami tlenu.
Źródło:
Zeszyty Naukowe Wydziału Elektroniki i Informatyki Politechniki Koszalińskiej; 2014, 6; 51-60
1897-7421
Pojawia się w:
Zeszyty Naukowe Wydziału Elektroniki i Informatyki Politechniki Koszalińskiej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Correction of the electric resistivity distribution of Si wafers using selective neutron transmutation doping (SNTD) in MARIA nuclear research reactor
Autorzy:
Tarchalski, M.
Kordyasz, A. J.
Pytel, K.
Dorosz, D.
Powiązania:
https://bibliotekanauki.pl/articles/146646.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
silicon wafer
thermal neutron doping
silicon resistivity homogeneity
silicon resistivity heterogeneity
neutron transmutation doping (NTD)
selective neutron transmutation doping (SNTD)
MARIA nuclear research reactor
Opis:
The result of the electric resistivity distribution modification in silicon wafers, by means of selective neutron transmutation doping (SNTD) method in the MARIA nuclear research reactor at Świerk/Otwock (Poland) is presented. Silicon wafer doping system has been fully designed for the MARIA reactor, where irradiation took place. The silicon wafer resistivity distribution after SNTD has been measured by the capacity voltage (C-V) method. In this article we show first results of this correction technique. The result of the present investigation is that the planar resolution of the correction process is about 4 mm. It is the full width at half maximum (FWHM) of the resistivity distribution produced by thermal neutrons irradiation of Si wafer through a 3 mm hole in the Cd-mask.
Źródło:
Nukleonika; 2012, 57, 3; 363-367
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interferometry of the plasma focus equipped with forehead cathode
Autorzy:
Kubeš, P.
Klír, D.
Rezac, K.
Paduch, M.
Pisarczyk, T.
Scholz, M.
Chodukowski, T.
Kalinowska, Z.
Hitschfel, J.
Kortanek, J.
Kravárik, J.
Ivanova-Stanik, I.
Bienkowska, B.
Karpinski, L.
Zielinska, E.
Sadowski, M. J.
Tomaszewski, K.
Powiązania:
https://bibliotekanauki.pl/articles/147512.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
interferometry
neutron diagnostics
plasma focus discharge
Opis:
The PF-1000 plasma-focus facility in Warsaw, equipped with Mather-type coaxial electrodes working with a deuterium filling, was modified by the addition of a cathode disk in front of the anode front-plate at a distance of 3 cm. The plasma was diagnosed with temporal resolved interferometry and neutron diagnostics. The modified electrode configuration showed an increase of the current in the pinch phase and a decrease of the total neutron yield. The lower total neutron yield is caused by a lower energy of deuterons producing the observed neutrons and by a decrease of the velocity of transformations of the structures in the pinch column.
Źródło:
Nukleonika; 2012, 57, 2; 189-192
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Joint detection of gravitational waves from binary black hole and binary neutron star mergers by LIGO and Virgo
Autorzy:
Królak, Andrzej
Patil, Mandar
Powiązania:
https://bibliotekanauki.pl/articles/690922.pdf
Data publikacji:
2018
Wydawca:
Copernicus Center Press
Tematy:
gravitational waves
neutron stars
black holes
Opis:
Advanced Virgo detector joined advanced LIGO twin detectors on 1st August 2017 in the quest to look for the gravitational waves. The global network of three detectors was operational for 25 days until the LIGO shut down on 25th August 2017. Two gravitational wave events were registered during this period. One of them was the binary black hole merger dubbed as GW170814 and other one is binary neutron star merger referred to as GW170817. Electromagnetic counterpart associated with binary neutron star merger was promptly identified which marks the beginning of multi-messenger astronomy. This article describes these events emphasizing on the crucial role played by the Virgo and focusing on some methodological issues.
Źródło:
Zagadnienia Filozoficzne w Nauce; 2018, 64; 95-115
0867-8286
2451-0602
Pojawia się w:
Zagadnienia Filozoficzne w Nauce
Dostawca treści:
Biblioteka Nauki
Artykuł

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