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Tytuł:
Factors affecting the precision of measurements with the usage of proportional counters
Autorzy:
Bochenek, M.
Koperny, S.
Kowalski, T. Z.
Powiązania:
https://bibliotekanauki.pl/articles/146131.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
proportional counter
gas gain
count rate effect
Opis:
In all measurements with the usage of proportional counters the pulse height and its distribution are measured. From this one can calculate energy losses and their distribution along the particle track position in 2D. The pulse height at the output of electronic circuit, co-working with the proportional counters, depends on: gas gain, energy deposited inside a counter and parameters of the readout electronics. However, it is only the first approximation. Careful studies show that output pulse height depends on the place of radiation absorption along and across the counter. The measured effect is as high as a few percent across and along the counter. Those effects were observed for both cylindrical and rectangular geometry. The pulse height depends not only on the registered count rate but also on the speed of its change. All the above effects are a few percentage effects, but can strongly affect the correctness of measurement made with the usage of proportional counters.
Źródło:
Nukleonika; 2008, 53, suppl. 2; 29-32
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modern micropattern gas detectors
Autorzy:
Bochenek, M.
Koperny, S.
Kowalski, T. Z.
Powiązania:
https://bibliotekanauki.pl/articles/148102.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
microstructure detector
microstrip
GEM
MICROMEGAS
capillary plate
Opis:
In all measurement systems of radiation, the detector is the most important part. We can say that it is the heart of these systems. Gas detectors are still the most popular type of detector. Modern technologies allow manufacturing gas detectors having a very good energy and position (2D) resolution, high efficiency, large effective area, small count rate effect, radiation hardness, good signal-to-noise ratio and not complicated structure. These detectors are very fast and can stably work for a long period of time. One advantage of gas detectors is the possibility to read not only charge, but also UV light generated in the detector. In this paper we want to make a review of construction, mechanical properties, performance and possible applications of the following so-called micropattern gas detectors (MPGD): microstrip gas chamber (MSGC), gas electron multiplier (GEM), MICRO-MEsh GAseous Structure (MICROMEGAS) and capillary plate detector (CP).
Źródło:
Nukleonika; 2008, 53, suppl. 2; 25-28
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Algorithms for digital γ-ray spectroscopy
Autorzy:
Guzik, Z.
Krakowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/147770.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
data acquisition
digital spectrometry
digital signal processing (DSP)
gamma spectroscopy
Z-transform
Opis:
The data processing in modern nuclear spectroscopy is dominated by digital methods. In this paper we present a full set of algorithms necessary for energy reconstruction, baseline restoration, trigger generation and selection of events (acceptation) which are based on digital signal processing (DSP) techniques. All algorithms were fully evaluated using mathematical apparatus of Z-transform. The energy reconstruction algorithm is based on trapezoidal shaping. The baseline restoration makes the use of a digital moving average, while trigger generation algorithm utilize a digital form of RC-CR2 filter with protection windowing. The evaluated algorithms has been implemented and used in the demonstrator build for national borders protection.
Źródło:
Nukleonika; 2013, 58, 2; 333-338
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Target preparation of RbCl on a copper substrate by sedimentation method for the cyclotron production of no-carrier-added 85Sr for endotherapy
Autorzy:
Sadeghi, M.
Alipoor, Z.
Kakavand, T.
Powiązania:
https://bibliotekanauki.pl/articles/148632.pdf
Data publikacji:
2010
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
rubidium chloride
target
sedimentation
radionuclide
Opis:
85Sr was produced via the 85Rb(p,n)85Sr reaction. Rubidium chloride deposition on copper substrate was carried out via the sedimentation method in order to produce strontium-85. Optimum conditions were achieved as a result of several repeated experiments with different amount of ethyl cellulose (EC) and acetone. 520 mg of RbCl, 208 mg of EC 4 mL of acetone were used to prepare a layer of enriched rubidium chloride of 11.69 cm2 area and 62.2 mg/cm2 thickness. Target quality control was done by a SEM photomicrograph and a thermal shock test. The deposited target was irradiated at a 20 ěA current and a 15 MeV proton beam for 30 min. No degradation was observed. The RbCl surface following bombardment was white, except the central area that was light brown and also without any crack or peeling off.
Źródło:
Nukleonika; 2010, 55, 3; 303-306
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Laser ablated carbon plume : experiment and modelling
Autorzy:
Moscicki, T.
Hoffman, J.
Szymanski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/146429.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
laser ablation
plasma plume
Opis:
Laser ablation of graphite is studied both theoretically and experimentally. Plasma temperature and electron density in the early phase of expansion into vacuum are measured as a function of distance from the target. The experimental results agree well with the theoretical simulations. The simulation of ablation shows that plasma plume considerably affects the ablation rate.
Źródło:
Nukleonika; 2012, 57, 2; 283-286
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron beam decomposition of pollutant model compounds in aqueous systems
Autorzy:
Ting, T. -M.
Dahlan, K. Z. M.
Powiązania:
https://bibliotekanauki.pl/articles/147660.pdf
Data publikacji:
2011
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
absorbed dose
concentration of solute
ionizing radiation
organic decomposition
Opis:
In this study, factors that limit the utilization of electron beam irradiation for decomposition of pollutants were investigated. Potassium hydrogen phthalate (KHP) was used as the model pollutant compound. The accumulated chemical oxygen demand (COD) removal below 2.4 kGy (applied for concentration at 85, 170, 255, 425 and 850 mg/l) was less than 10 per cent, whereas the accumulated COD removal at 215 kGy (applied for concentration at 85, 170, 255, 425 and 850 mg/l) was 198 per cent. At a lower concentration of KHP, 85 mg/l, the accumulated COD removal (for dose ranging from 0.5 to 215 kGy) was 236per cent. As the concentration of KHP increases to 850 mg/l, almost no COD removal was recorded (for dose ranging from 0.5 to 215 kGy). The results show that the removal efficiency and effectiveness of pollutants were influenced by the solute concentration and irradiation dose. When the concentration of KHP increases to a certain level, water radical species were not sufficient to form KHP radicals and, therefore, reduce the decomposition of KHP molecules. Removal of phthalate as measured by COD was restricted at a very high concentration, 850 mg/l. This indicates that the by-products have scavenged the radicals rapidly. This also suggests that, the limitation of radiolytic products of water to decompose KHP at higher concentration. A large quantity of KHP molecules would also stabilize the KHP radicals and resulting in lower removal of KHP. Similar removal trend was also observed for the actual industrial wastewater.
Źródło:
Nukleonika; 2011, 56, 4; 349-355
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Seasonal variability of the soil CO2 flux and its isotopic composition in southern Poland
Autorzy:
Gorczyca, Z.
Rozanski, K.
Kuc, T.
Michalec, B.
Powiązania:
https://bibliotekanauki.pl/articles/148390.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
carbon-14
carbon-13
isotopic composition
soil CO2
oxygen-18
Opis:
The flux and isotopic composition of soil CO2 has been monitored at three sites located in the southern Poland, during the time period: January 1998 - December 2000. The sites represent typical ecosystems appearing in central Europe: mixed forest, cultivated agricultural field and grassland. To monitor the flux and isotopic composition of soil CO2, the method based on the inverted cup principle was used. The flux of soil CO2 reveals distinct seasonal fluctuations, with maximum values up to ca. 20 mmolźm-2 h-1 during summer and around ten times lower values during winter. Also significant differences among the monitored sites were detected, the CO2 flux being the highest for the mixed forest site and ca. two times lower for the grassland site. The 13C content of the soil CO2 flux is nearly constant throughout the year, with d13C values essentially reflecting the isotopic composition of the soil organic matter and the vegetation type. The 18O content of the soil CO2 flux shows a remarkable seasonality, with distinctly less negative d18O values recorded during summer. This seasonality is highly reduced in the CO2 sampled from different depths of the soil. The radiocarbon content of the CO2 flux turned out to be non-distinguishable, within the uncertainty of the measurements, from current 14C levels in atmospheric carbon dioxide. However, significant reduction of the radiocarbon content was measured in the soil CO2 sampled at 80 cm, when compared to the uppermost layer, reflecting increasing age of soil organic matter with depth.
Źródło:
Nukleonika; 2003, 48, 4; 187-196
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computations of fuel management in MARIA reactor with highly poisoned beryllium matrix
Autorzy:
Andrzejewski, K. J.
Kulikowska, T. A.
Marcinkowska, Z. E.
Powiązania:
https://bibliotekanauki.pl/articles/147704.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
criticality
excess reactivity
beryllium poisoning
isotope transmutation
nuclear reactor
Opis:
The high-flux research reactor MARIA has been operated in Poland since 1975. Its core consists of loop type fuel channels placed in a beryllium block matrix. Irradiation of beryllium by neutrons results in a build-up of 6Li, and 3He isotopes with large thermal neutron absorption cross-sections. In addition, tritium is formed and decays into 3He which complicates the transmutation chains. Thus, the fuel management of the reactor depends on the beryllium poisoning. The isotopic transmutations in beryllium have to be computed in parallel to the fuel depletion. In this paper a comparison of the measured and computed results is given during: reactor operation in the period up to January 2004, modernization break in the reactor operation from January 2004 to February 2005 and reactor operation from February 2005. The measured and computed effects comprise: reactivity effects due to the fuel burn-up and beryllium poisoning by 6Li, and 3He.
Źródło:
Nukleonika; 2008, 53, 4; 173-179
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interaction of diatomic molecules with nickel ions inside the channels of high silica zeolites : an EPR and DFT study
Autorzy:
Mazur, T.
Podolska, K.
Pietrzyk, P.
Sojka, Z.
Powiązania:
https://bibliotekanauki.pl/articles/147105.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron paramagnetic resonance (EPR) spectroscopy
g-tensor
nickel
zeolite
small molecule activation
Opis:
Interaction of CO, NO, and O2 diatomics with NiII and NiI ions dispersed in ZSM-5 zeolite was investigated by electron paramagnetic resonance (EPR) spectroscopy and density functional theory (DFT) modelling. The resulting adducts NiI-CO, NiII-NO, and NiI-O2 were identified based on g-tensor parameters, obtained by computer fitting of the powder EPR spectra, and next ascertained by parallel relativistic DFT calculations of the corresponding g-tensor values. The structures of the NiI-CO, NiII-NO, and NiI-O2 complexes were obtained by geometry optimization with the Kohn- -Sham method. Binding of the diatomics was discussed in terms of the spin-pairing and electron density transfer events. Interaction of CO with NiI cations led to the pronounced change in the coordination and electronic structure of the NiI center, however, no redox processes were observed in agreement with the “innocent” nature of CO as a ligand. On the contrary, strong electron and spin density redistribution was observed upon NO and O2 interaction (“non-innocent ligands”) leading to the formation of the bound nitrosonium NOδ+ and superoxo O2 – species, respectively.
Źródło:
Nukleonika; 2013, 58, 3; 351-357
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
DNA damage in subpopulations of human lymphocytes irradiated with doses in the range of 0-1 Gy of X-radiation
Autorzy:
Wojewódzka, M.
Machaj, E. K.
Goździk, A.
Iwaneńko, T.
Ołdak, T.
Kruszewski, M.
Pojda, Z.
Powiązania:
https://bibliotekanauki.pl/articles/147760.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
alkaline comet assay
biodosimetry
micronucleus test
histone gammaH2AX foci immunofluorescence assay
T lymphocytes
B lymphocytes
ionizing radiation
DNA damage
Opis:
We compared three methods usually applied in biological dosimetry for estimation of radiation-induced DNA damage in human T and B lymphocytes: alkaline comet assay, micronucleus (MN) test and formation of histone gamma-H2AX foci. Human peripheral blood lymphocytes were fractionated using T cells and B cells isolation kits. Cells were irradiated with doses in the range of 0-1 Gy of X-rays. Induction of DNA damage was assessed by the standard alkaline comet assay, MN test and histone gammaH2AX foci immunofluorescence assay. Notwithstanding different end-points measured by the applied methods, all tests revealed a similar induction of DNA damage in B lymphocytes as compared with T lymphocytes. The results indicated that all three tests detect DNA damage with similar sensitivity, the lowest dose being approximately 0.3 Gy. The difference between irradiated and control cells was expressed as the ratio of the value obtained for irradiated cells (1 Gy) to that for control cells. The highest ratio was obtained for formation of gammaH2AX foci and was 6.2 for T and 13.8 for B lymphocytes, whereas those for comet assay and micronucleus test were 3.5; 3.6 and 5.6; 4.8, respectively.
Źródło:
Nukleonika; 2008, 53, 4; 145-149
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of two methods for the determination of nitrogen and oxygen isotope composition of dissolved nitrates
Autorzy:
Chmura, W. M.
Różański, K.
Kuc, T.
Gorczyca, Z.
Powiązania:
https://bibliotekanauki.pl/articles/146460.pdf
Data publikacji:
2009
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
nitrates
isotope composition
denitrification
nitrogen-15
oxygen-18
Opis:
Two methods of sample preparation for isotopic analyses of nitrates dissolved in water are presented: (i) chemical conversion of NO3– to N2 and CO2, and (ii) bacterial reduction of NO3– to N2O, followed by the measurement of nitrogen and oxygen isotope composition of these gases. Both methods have been successfully used for routine isotope analyses of dissolved nitrates in different types of water. The chemical conversion method, requiring ca. 300 mi mol of NO3– yields relatively good precision, in the order of 0.3‰ for delta15N, and 0.6‰ for delta18 O. The bacterial reduction method was modified in this study to accommodate samples of intermediate size (ca. 30 mmol of NO3–) to provide sufficient amount of N2O gas for isotope analysis using conventional IRMS. The method demonstrated satisfactory results, although sample preparation was more complicated and required access to microbiological laboratory.
Źródło:
Nukleonika; 2009, 54, 1; 17-23
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metallurgical quality evaluation of the wind turbine main shaft 42CrMo4 steel: microscopic and Mössbauer studies
Autorzy:
Siemiątkowski, Z.
Gzik-Szumiata, M.
Szumiata, T.
Rucki, M.
Martynowski, R.
Powiązania:
https://bibliotekanauki.pl/articles/146538.pdf
Data publikacji:
2017
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
metallurgical forging
wind turbine
Mössbauer spectrometry
Opis:
In this paper, the results of the complex examination of the 42CrMo4 steel samples are presented. The samples were taken from the metallurgical forging prepared for the production of the wind turbine main shaft. The samples underwent Mössbauer spectroscopic analysis, as well as the measurement of its mechanical characteristics such as hardness and strength are analysed. Conversion electron Mössbauer spectrometry confirmed phase purity and isotropy of the investigated 42CrMo4 steel. The method provided accurate results, proving Mössbauer spectrometry to be an effective tool for the wind turbine main shaft analysis.
Źródło:
Nukleonika; 2017, 62, 2; 171-176
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of gamma radiation and physicochemical treatment to improve the bioactive properties of chitosan extracted from shrimp shell
Autorzy:
Aktar, J.
Hasan, Z.
Afroz, T.
or-Rashid, H.
Pramanik, K.
Powiązania:
https://bibliotekanauki.pl/articles/148197.pdf
Data publikacji:
2017
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
chitosan
gamma radiation
degree of deacetylation
antimicrobial activity
Opis:
The aim of this study is to exploit a suitable chitosan extraction method from the chitin of indigenous shrimp shells by employing different physicochemical treatments and to improve different bioactive properties of this extracted chitosan (CS) by applying gamma radiation. Chitin was prepared from shrimp shell by pretreatment (deproteination, demineralization and oxidation). Chitosan was extracted from chitin by eight different methods varying different physicochemical parameters (reagent concentration, temperature and time) and assessed with respect to the degree of deacetylation, requirement of time and reagents. The method where chitin was repeatedly treated with 121°C for 30 min with 20 M NaOH, produced the highest degree of deacetylation (DD) value (92%) as measured by potentiometric titration, with the least consumption of time and chemicals, and thus, selected as the best suitable extraction method. For further quality improvement, chitosan with highest DD value was irradiated with different doses (i.e., 5, 10, 15, 20 and 50 kGy) of gamma radiation from cobalt-60 gamma irradiator. As the radiation dose was increased, the molecular weight of the wet irradiated chitosan, as measured by the viscosimetric method, decreased from 1.16 × 105 to 1.786 × 103 , 1.518 × 103 , 1.134 × 103 , 1.046 × 103 and 8.23 × 102 dalton, respectively. The radiation treatment of chitosan samples increased the antimicrobial activity signifi cantly in concentration dependent manner on both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria, as determined by the well-diffusion method. Four to fi ve percent wet chitosan treated with a radiation dose range of 5.0–10.0 kGy rendered the highest antimicrobial activity with least energy and time consumption. Solubility, water binding capacity (WBC) and fat binding capacity (FBC) also improved due to irradiation of chitosan.
Źródło:
Nukleonika; 2017, 62, 4; 245-251
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thoron emanation and exhalation of Slovenian soils determined by a PIC detector-equipped radon monitor
Autorzy:
Jónás, J.
Sas, Z.
Vaupotic, J.
Kocsis, E.
Somlai, J.
Kovács, T.
Powiązania:
https://bibliotekanauki.pl/articles/146850.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
emanation
exhalation
gamma spectrometry
PIC detector
soil
thorium
thoron
Opis:
The health risk from thoron (Rn-220) is usually ignored owing to its short half-life (55.6 s), but the generated thoron decay products can cause a significant dose contribution. In this study, altogether 51 Slovenian soil samples were investigated using an accumulation chamber technique to obtain information about thoron exhalation features. The obtained (massic) thoron exhalation results varied between 6.9 and 149 mBq•kg–1•s–1 (average: 55.2 mBq•kg –1•s–1). The Th-232 content was determined using HPGe gamma spectrometry. The Th-232 activity concentration ranged between 9.3 and 161.7 Bq•kg–1 (average: 64.6 Bq•kg –1). The thoron emanation features were also calculated from the obtained results (2.9 to 21.2% with an average of 8.6%). The thoron exhalation and emanation properties were compared with the radon exhalation and emanation features determined in a previous study. It was found that there was no correlation between the radon and thoron emanation features, according to the obtained data. This can be explained by the different Ra-224 and Ra-226 distributions in the soil grains. As a result, the thoron emanation factor cannot be predicted from radon emanation and vice versa.
Źródło:
Nukleonika; 2016, 61, 3; 379-384
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Validation of the method for determination of plutonium isotopes in urine samples and its application in a nuclear facility at Otwock
Autorzy:
Rzemek, K.
Czerwiński, A.
Dymecka, M.
Ośko, J.
Pliszczyński, T.
Haratym, Z.
Powiązania:
https://bibliotekanauki.pl/articles/147900.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
alpha radioactive elements
internal contamination
plutonium
urine
Opis:
The studies aimed at determining low activities of alpha radioactive elements are widely recognized as essential for the human health, because of their high radiotoxicity in case of internal contamination. Some groups of workers of nuclear facility at Otwock are potentially exposed to contamination with plutonium isotopes. For this reason, the method for determination of plutonium isotopes has been introduced and validated in Radiation Protection Measurements Laboratory (LPD) of the National Centre for Nuclear Research (NCBJ). In this method the plutonium is isolated from a sample by coprecipitation with phosphates and separated on a AG 1-X2 Resin. After electrodeposition, the sample is measured by alpha spectrometry. Validation was performed in order to assess parameters such as: selectivity, accuracy (trueness and precision) and linearity of the method. The results of plutonium determination in urine samples of persons potentially exposed to internal contamination are presented in this work.
Źródło:
Nukleonika; 2015, 60, 1; 181-186
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł

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