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Wyświetlanie 1-13 z 13
Tytuł:
A study about the measurement method of the homogeneity of radioactivity along an iridium-192 wire used in brachytherapy
Autorzy:
Costa, O. L.
Calvo, W. A. P.
Zeituni, C. A.
Rostelato, M. E. C. M.
Moura, J. A.
Feher, A.
Souza, C. D.
Somessari, S. L.
Powiązania:
https://bibliotekanauki.pl/articles/148238.pdf
Data publikacji:
2014
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
iridium-192
iridium wire
low dose rate brachytherapy
quality control
cancer treatment
radioactive sources production
Opis:
The Nuclear and Energy Research Institute has produced, since 1998, iridium-192 wires used in low dose rate brachytherapy. In the paper the authors studied the influence of wire profile on the homogeneity distribution of radioactivity of iridium-192 along the wire. The authors propose the improvements in the quality control procedure that will provide more accurate measurement data and suggest changes in control devices.
Źródło:
Nukleonika; 2014, 59, 1; 37-39
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design, construction and performance of a pressure chamber for water retention curve determination through traditional and nuclear methods
Autorzy:
Pires, L.
Bacchi, O.
Powiązania:
https://bibliotekanauki.pl/articles/146181.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
soil water potential
gamma-ray attenuation
soil water content
soil physics
radioisotope application
Opis:
We present in this work a detailed design of a small low-pressure chamber outfitted with a ceramic porous plate for evaluating the soil water retention curve (SWRC) in the water potential range from 0 to -100 kPa. The chamber is made of acrylic and permits the use of one unique soil sample each time. The use of this chamber allows quick measurements of soil moisture using nuclear (based on gamma-ray attenuation) and conventional methods and SWRC determinations made with the designed chamber are in agreement with those obtained using a commercial low-pressure chamber. The chamber was designed especially for testing the use of the nuclear method as an auxiliary tool for SWRC determinations but it can be easily adapted for routine investigations and a practical alternative for the conventional SWRC method.
Źródło:
Nukleonika; 2006, 51, 4; 225-230
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time of soil water thermodynamic equilibrium during retention curve establishment using gamma-ray beam attenuation
Autorzy:
Pires, L.
Bacchi, O.
Reichardt, K.
Powiązania:
https://bibliotekanauki.pl/articles/148674.pdf
Data publikacji:
2005
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
gamma-ray attenuation
time of equilibrium
pressure chamber
soil water retention curve
Opis:
The soil water retention curve (SWRC) represents a fundamental part of the characterization of the soil hydraulic properties. The establishment of SWRC is usually time-consuming and presents several problems such as the difficulty of a correct judgment of the time of equilibrium. This work presents a new methodology that involves gammaray beam attenuation technique associated with the traditional pressure chambers, having as objective the more precise judgment of the time to attain equilibrium. The gamma-ray source used has an activity of 3.7 GBq consisting of 241Am, with peak energy of 59.54 keV. For the determination of retention curves using the gamma-ray attenuation technique, an acrylic pressure chamber was projected and constructed to be positioned between the source and detector with the gamma-ray beam crossing the center of the chamber and the soil sample during water extraction. The proposed technique allowed, through a specifically elaborated software for data acquisition, to evaluate with precision the exact instant of the equilibrium and, consequently, to obtain the right moment to change the chamber pressure to a new desired level, leading to a reduction of the time required for the whole retention curve determination. The results obtained show that the gamma-ray attenuation technique can be very useful as an auxiliary tool to evaluate SWRC, utilizing the Richards chamber.
Źródło:
Nukleonika; 2005, 50, 4; 173-177
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gamma-ray beam attenuation to assess the influence of soil texture on structure deformation
Autorzy:
Pires, L.
Bacchi, O.
Dias, N.
Powiązania:
https://bibliotekanauki.pl/articles/147480.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
gamma-ray attenuation
soil physical properties
soil structure deformation
soil sampling
soil porosity
Opis:
Gamma-ray beam attenuation is a non-invasive technique that permits analysis of soil porosity without disturbing the region of interest of the core sample. The technique has as additional advantage to allow measurements point by point on a millimetric scale in contrast to other methodologies that are invasive and analyze the soil properties in the bulk sample volume. Soil porosity can be used as an important parameter to quantify soil structural damages, which affect soil aeration, water movement and retention. In this study, porosities of three soils different in texture were measured at various positions in order to analyze the impact of the sampling procedure on the structure of each particular soil texture. The gamma-ray attenuation system consisted of an 241Am radioactive source having an activity of 3.7 GBq, collimated with cylindrical lead collimators of 2 mm diameter. The results obtained show the presence of dense regions near the edges of samples and that different soil textures can suffer distinct deformations at sampling.
Źródło:
Nukleonika; 2006, 51, 2; 125-129
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gamma-ray computed tomography as a tool to evaluate porosity changes along depth for surface crusted soils
Autorzy:
Pires, L. F.
Bacchi, O. O. S.
Reichardt, K.
Dias, N. M. P.
Powiązania:
https://bibliotekanauki.pl/articles/146838.pdf
Data publikacji:
2007
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
gamma-ray attenuation
soil density
soil structure
soil surface sealing
241 Am
applied nuclear physics
gamma tomography
Opis:
Assessment of changes in porosity (ö) along depth for soils with surface crusting is difficult because conventional soil physical investigation tools are destructive and usually require a long period of time for preparation and analysis of the samples. Computed tomography (CT) has frequently been used as a method to evaluate soil structure in a nondestructive, sensitive, and rapid manner. CT data can be used for measuring at a millimetric scale changes in ö along depth for soils with surface crusting. The main objective of this work was to investigate the sensibility of the gamma-ray CT to assess soil structural changes along depth in samples presenting structural crust. CT images were taken with a first generation scanner of 1.14 mm resolution along eight different soil layers within the 0 28 mm depth. Porosity increased along depth up to the 14 17.5 mm layer. Through the analysis of the ö distribution of each layer it was possible to show that the sealed surface layer presented ö values of approximately 30%, while the other layers were greater than 30% up to 60% (macropore regions). The sealing crust thickness was estimated to be in the range of 2.3 3.5 mm.
Źródło:
Nukleonika; 2007, 52, 3; 125-131
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Remediation of polluted waters and wastewater by radiation processing
Autorzy:
Sampa, M. H. O.
Takács, E.
Gehringer, P.
Rela, P. R.
Ramirez, T.
Amro, H.
Trojanowicz, M.
Botelho, M. L.
Han, B.
Solpan, D.
Cooper, W. J.
Emmi, S. S.
Wojnárovits, L.
Powiązania:
https://bibliotekanauki.pl/articles/147644.pdf
Data publikacji:
2007
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron beam
wastewater treatment
pesticides
dyes
degradation
radiation technology
Opis:
Application of radiation processing for drinking water, wastewater, and groundwater treatment is a cost effective process which may insure adequate availability of that resource worldwide. This paper summarizes the results of a Coordinated Research Project (organized by the IAEA) with participants from 10 countries with the purpose of describing the degradation mechanism of organic impurities, and establishing optimal treatment conditions. Decoloration, disinfection, microbiological and toxicological experiments are also mentioned. These experiments led to pilot plants and also to a large scale industrial realization of radiation technology.
Źródło:
Nukleonika; 2007, 52, 4; 137-144
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the pulse plasma stream
Autorzy:
Evtikhin, V. A.
Lyublinsky, I. E.
Vertkov, A. V.
Ivanov, L. I.
Ivanov, Y. P.
Krokhin, O. N.
Nikulin, V. Y.
Polukhin, S. N.
Safronova, T. V.
Tikhomirov, A. A.
Powiązania:
https://bibliotekanauki.pl/articles/148327.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
interaction of plasma with matter
lithium capillary porous system
plasma dynamics
plasma focus
thermonuclear reactor
Opis:
In this report we present a first series of tests of the lithium Capillary Porous System (CPS). We suppose that such a system can be used as a first wall in a thermonuclear reactor. The main goal of the presented work was to study the behavior of the lithium CPS in the condition simulating the influence of plasma in various operating regimes of the thermonuclear reactor. The tests were conducted in a Plasma Focus (PF) installation. The preliminary analysis of the received results confirms the high resistance of the lithium CPS to the pulse influence of plasma flows.
Źródło:
Nukleonika; 2001, 46, suppl. 1; 113-115
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reconstruction of hit time and hit position of annihilation quanta in the J-PET detector using the Mahalanobis distance
Autorzy:
Sharma, N. G.
Silarski, M.
Bednarski, T.
Białas, P.
Czerwiński, E.
Gajos, A.
Gorgol, M.
Jasińska, B.
Kamińska, D.
Kapłon, Ł.
Korcyl, G.
Kowalski, P.
Kozik, T.
Krzemień, W.
Kubicz, E.
Niedźwiecki, S.
Pałka, M.
Raczyński, L.
Rudy, Z.
Rundel, O.
Słomski, A.
Strzelecki, A.
Wieczorek, A.
Wiślicki, W.
Zieliński, M.
Zgardzińska, B.
Moskal, P.
Powiązania:
https://bibliotekanauki.pl/articles/146937.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
J-PET detector
Mahalanobis distance
time resolution
threshold levels
Opis:
The J-PET detector being developed at the Jagiellonian University is a positron emission tomograph composed of the long strips of polymer scintillators. At the same time, it is a detector system that will be used for studies of the decays of positronium atoms. The shape of photomultiplier signals depends on the hit time and hit position of the gamma quantum. In order to take advantage of this fact, a dedicated sampling front-end electronics that enables to sample signals in voltage domain with the time precision of about 20 ps and novel reconstruction method based on the comparison of examined signal with the model signals stored in the library has been developed. As a measure of the similarity, we use the Mahalanobis distance. The achievable position and time resolution depend on the number and values of the threshold levels at which the signal is sampled. A reconstruction method as well as preliminary results are presented and discussed.
Źródło:
Nukleonika; 2015, 60, No. 4, part 1; 765-769
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Searches for discrete symmetries violation in ortho-positronium decay using the J-PET detector
Autorzy:
Kamińska, D.
Gajos, A.
Czerwiński, E.
Bednarski, T.
Białas, P.
Gorgol, M.
Jasińska, B.
Kapłon, Ł.
Korcyl, G.
Kowalski, P.
Kozik, T.
Krzemień, W.
Kubicz, E.
Niedźwiecki, S.
Pałka, M.
Raczyński, L.
Rudy, Z.
Rundel, O.
Sharma, N. G.
Silarski, M.
Słomski, A.
Strzelecki, A.
Wieczorek, A.
Wiślicki, W.
Zieliński, M.
Zgardzińska, B.
Moskal, P.
Powiązania:
https://bibliotekanauki.pl/articles/147408.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
discrete symmetries
J-PET
ortho-positronium
Opis:
In this paper, we present prospects for using the Jagiellonian positron emission tomograph (J-PET) detector to search for discrete symmetries violations in a purely leptonic system of the positronium atom. We discuss tests of CP and CPT symmetries by means of ortho-positronium decays into three photons. No zero expectation values for chosen correlations between ortho-positronium spin and momentum vectors of photons would imply the existence of physics phenomena beyond the standard model. Previous measurements resulted in violation amplitude parameters for CP and CPT symmetries consistent with zero, with an uncertainty of about 10−3. The J-PET detector allows to determine those values with better precision, thanks to the unique time and angular resolution combined with a high geometrical acceptance. Achieving the aforementioned is possible because of the application of polymer scintillators instead of crystals as detectors of annihilation quanta.
Źródło:
Nukleonika; 2015, 60, No. 4, part 1; 729-732
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of unicellular microorganisms Saccharomyces cerevisiae by means of positron annihilation lifetime spectroscopy
Autorzy:
Kubicz, E.
Jasińska, B.
Zgardzińska, B.
Bednarski, T.
Białas, P.
Czerwiński, E.
Gajos, A.
Gorgol, M.
Kamińska, D.
Kapłon, Ł.
Kochanowski, A.
Korcyl, G.
Kowalski, P.
Kozik, T.
Krzemień, W.
Niedźwiecki, S.
Pałka, M.
Raczyński, L.
Rajfur, Z.
Rudy, Z.
Rundel, O.
Sharma, N. G.
Silarski, M.
Słomski, A.
Strzelecki, A.
Wieczorek, A.
Wiślicki, W.
Zieliński, M.
Moskal, P.
Powiązania:
https://bibliotekanauki.pl/articles/147902.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
environmental scanning electron microscopy (ESEM)
free volume
inverted microscopy
positron annihilation
positronium
yeasts
Opis:
Results of positron annihilation lifetime spectroscopy (PALS) and microscopic studies on simple microorganisms, brewing yeasts, are presented. Lifetime of ortho-positronium (o-Ps) were found to change from 2.4 to 2.9 ns (longer-lived component) for lyophilized and aqueous yeasts, respectively. Also hygroscopicity of yeasts in time was examined, allowing to check how water – the main component of the cell – affects PALS parameters, thus lifetime of o-Ps were found to change from 1.2 to 1.4 ns (shorter-lived component) for the dried yeasts. The time sufficient to hydrate the cells was found below 10 hours. In the presence of liquid water, an indication of reorganization of yeast in the molecular scale was observed. Microscopic images of the lyophilized, dried, and wet yeasts with best possible resolution were obtained using inverted microscopy (IM) and environmental scanning electron microscopy (ESEM) methods. As a result, visible changes to the surface of the cell me mbrane were observed in ESEM images.
Źródło:
Nukleonika; 2015, 60, No. 4, part 1; 749-753
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
PALS investigations of free volumes thermal expansion of J-PET plastic scintillator synthesized in polystyrene matrix
Autorzy:
Wieczorek, A.
Zgardzińska, B.
Jasińska, B.
Gorgol, M.
Bednarski, T.
Białas, P.
Czerwiński, E.
Gajos, A.
Kamińska, D.
Kapłon, Ł.
Kochanowski, A.
Korcyl, G.
Kowalski, P.
Kozik, T.
Krzemień, W.
Kubicz, E.
Niedźwiecki, S.
Pałka, M.
Raczyński, L.
Rudy, Z.
Rundel, O.
Sharma, N. G.
Silarski, M.
Silarski, A.
Strzelecki, A.
Wiślicki, W.
Zieliński, M.
Moskal, P.
Powiązania:
https://bibliotekanauki.pl/articles/147132.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
free volume
positron annihilation
polystyrene
positronium
scintillator
Opis:
The polystyrene doped with 2,5-diphenyloxazole as a primary fluor and 2-(4-styrylphenyl)benzoxazole as a wavelength shifter prepared as a plastic scintillator was investigated using positronium probe in wide range of temperatures from 123 to 423 K. Three structural transitions at 260, 283, and 370 K were found in the material. In the o-Ps intensity dependence on temperature, the significant hysteresis is observed. Heated to 370 K, the material exhibits the o-Ps intensity variations in time.
Źródło:
Nukleonika; 2015, 60, No. 4, part 1; 777-781
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Processing optimization with parallel computing for the J-PET scanner
Autorzy:
Krzemień, W.
Bała, M.
Bednarski, T.
Białas, P.
Czerwiński, E.
Gajos, A.
Gorgol, M.
Jasińska, B.
Kamińska, D.
Kapłon, Ł.
Korcyl, G.
Kowalski, P.
Kozik, T.
Kubicz, E.
Niedźwiecki, S.
Pałka, M.
Raczyński, L.
Rudy, Z.
Rundel, O.
Sharma, N. G.
Silarski, M.
Słomski, A.
Stola, K.
Strzelecki, A.
Trybek, D.
Wieczorek, A.
Wiślicki, W.
Zieliński, M.
Zgardzińska, B.
Moskal, P.
Powiązania:
https://bibliotekanauki.pl/articles/148285.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
data aquisition system (DAQ)
parallel computing
TOF-PET
Opis:
The Jagiellonian Positron Emission Tomograph (J-PET) collaboration is developing a prototype time of flight (TOF)-positron emission tomograph (PET) detector based on long polymer scintillators. This novel approach exploits the excellent time properties of the plastic scintillators, which permit very precise time measurements. The very fast fi eld programmable gate array (FPGA)-based front-end electronics and the data acquisition system, as well as low- and high-level reconstruction algorithms were specially developed to be used with the J-PET scanner. The TOF-PET data processing and reconstruction are time and resource demanding operations, especially in the case of a large acceptance detector that works in triggerless data acquisition mode. In this article, we discuss the parallel computing methods applied to optimize the data processing for the J-PET detector. We begin with general concepts of parallel computing and then we discuss several applications of those techniques in the J-PET data processing.
Źródło:
Nukleonika; 2015, 60, No. 4, part 1; 745-748
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Progress in stellarator research at IPP-Kharkov
Autorzy:
Moiseenko, V. E.
Lozin, O. V.
Shapoval, A. M.
Dreval, M. B.
Kulyk, Y. S.
Mironov, Y. K.
Romanov, V. S.
Pashnev, V. K.
Sorokovoy, E. L.
Petrushenya, A. A.
Ozherel’ev, F. I.
Kozulya, M. M.
Konovalov, V. G.
Maznichenko, S. M.
Garkusha, I. E.
Powiązania:
https://bibliotekanauki.pl/articles/146173.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
stellarator
radio-frequency heating
low frequency modes
magnetic diagnostics
Opis:
A new antenna of ‘crankshaft’ type has been installed in the Uragan-2M device in order to increase the plasma density and heating below the ion cyclotron frequency. Antenna operation is modelled by 1D code, which solves boundary problem for time-harmonic Maxwell’s equations in radially non-uniform plasma cylinder. In recent experiments with this antenna, the SXR, CV, OV and OII emission measurements indicate that the light impurity radiation barrier is overcame at this device. Plasma with a temperature of ~50 eV exists during a short period of a few milliseconds. Then the radiation collapse comes owing to strong infl ux of impurities to the plasma column. A new magnetic diagnostics has been installed at Uragan-3M. Using it the poloidal magnetic fi eld is measured and the shift of toroidal current in major radius is registered. A miniature pinhole camera array for spatially and temporally resolved measurements of soft X-ray (SXR) plasma emission has been recently installed on the U-3M. Different shapes of the SXR emission profi le has been observed in different discharge conditions.
Źródło:
Nukleonika; 2016, 61, 2; 91-97
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-13 z 13

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