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Wyszukujesz frazę "gamma spectroscopy" wg kryterium: Temat


Wyświetlanie 1-7 z 7
Tytuł:
The Mössbauer spectrometer MsAa-4
Autorzy:
Górnicki, R.
Ruebenbauer, K.
Powiązania:
https://bibliotekanauki.pl/articles/147400.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
gamma-ray spectroscopy
Mössbauer spectroscopy
spectrometers
Opis:
A description of the Mossbauer spectrometer MsAa-4 is given. The spectrometer has a modular design and it could be used as the gamma-ray spectrometer as well. It has almost entirely digital design to assure stability and repeatability. It is powered via the rechargeable battery to make it immune to the power failures. All settings are performed remotely over the Ethernet link used also to transfer data and spectrometer functions. External CAN bus could be used to attach auxiliary equipment. The status of the external equipment could be used to control spectrometer functions. Internal digital oscilloscope monitors vital functions of the spectrometer over the Ethernet link. Driving software operates under Microsoft Windows registered trademark systems and it is fully compatible with the Mosgraf-2009 data processing suite.
Źródło:
Nukleonika; 2013, 58, 1; 17-21
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Natural radioactivity in building materials in Iran
Autorzy:
Mehdizadeh, S.
Faghihi, R.
Sina, S.
Powiązania:
https://bibliotekanauki.pl/articles/147658.pdf
Data publikacji:
2011
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
gamma spectroscopy
absorbed dose rate
annual effective dose
hazard index
Opis:
This work presents a comprehensive study of natural radioactivity in building materials used in Iran. For this purpose, 177 samples of five types of building material, i.e. cement, gypsum, cement blocks, gravel and brick, were gathered from different regions of the country and analyzed by gamma spectroscopy to quantify radioactivity concentrations using a high purity germanium (HPGe) detector and a spectroscopy system. According to the results of this investigation, cement samples had maximum values of the mean Ra-226 and Th-232 concentrations, 39.6 and 28.9 Bq/kg, respectively, while the lowest value for mean concentration of these two radionuclides were found in gypsum samples 8.1 and 2.2 Bq/kg, respectively. The highest (851.4 Bq/kg) and lowest (116.2 Bq/kg) value of K-40 mean concentration were found in brick and gypsum samples, respectively. The absorbed dose rate and the annual effective dose were also calculated from the radioactivity content of the radionuclides. The results show that the maximum values of dose rate and annual effective dose equivalent were 53.72 nGy/h and 0.37 mSv/y in brick samples. The radium equivalent activities Req calculated were below the permissible level of 370 Bq/kg for all building materials. The values of hazard indexes were below the recommended levels, therefore, it is concluded that the buildings constructed from such materials are safe for the inhabitants. The results of this study are consistent with the results of other investigations in different parts of the world.
Źródło:
Nukleonika; 2011, 56, 4; 363-368
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:
Gamma Induced Positron Annihilation: History, Current, and Future Developments
Autorzy:
Selim, F.
Powiązania:
https://bibliotekanauki.pl/articles/1030020.pdf
Data publikacji:
2017-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
gamma induced positron spectroscopy
positron transient measurements
thermal neutron capture
proton capture
electron accelerator
Van de Graaff accelerator
Opis:
Positron annihilation spectroscopy is often performed using radioactive sources for bulk measurements or positron beams for depth resolved measurements. Both have many advantages and great capabilities for a variety of applications. In the recent history, we have shown that positron annihilation spectroscopy can be carried out directly using high energy photons without the need for positron source or positron beam. This approach brings unique capabilities for some specific applications and promotes the use of positron annihilation spectroscopy in new areas of materials science and probably in industrial applications. Some of the important applications include developing new nondestructive highly penetrating sensitive probe for structural and engineering materials. It can also greatly advance positron applications in bulk semiconductors, electronic and photonic materials as well as in polymers, ceramics, and liquids. The recently developed γ-induced positron spectroscopy in HZDR in Dresden provides an example of an excellent facility for many of these applications. When incorporated with pulsed accelerators, γ-induced positron annihilation spectroscopy may trigger novel studies of transient states in matter and explore several solid-state processes that take place on short time scale. In this article I will review the history and development of the technique and its incorporation in a wide range of accelerators including table top electron accelerators, pulsed electron accelerators, and Van de Graaff accelerators. Then I will introduce a design for a new γ-induced positron annihilation spectroscopy facility based on using small nuclear research reactors or neutron generators. The paper presents all the possible approaches for γ-induced positron annihilation spectroscopy and discusses its potential and limitations to guide the efforts in further development of the technique and illustrate the unique aspects that the technique can bring to positron science and applications.
Źródło:
Acta Physica Polonica A; 2017, 132, 5; 1450-1455
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Radicals initiated by gamma rays in selected amino acids and collagen
Autorzy:
Przybytniak, Grażyna.
Sadło, Jarosław
Dąbrowska, Małgorzata
Zimek, Zbigniew
Powiązania:
https://bibliotekanauki.pl/articles/146293.pdf
Data publikacji:
2019
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
amino acid
collagen
EPR spectroscopy
gamma rays
aminokwas
kolagen
spektroskopia EPR
promienie gamma
Opis:
Calf skin collagen and three amino acids essential for its structure, namely glycine, L-proline and 4-hydroxyl-L-proline, were irradiated with gamma rays up to a dose of 10 kGy. Conversion of radicals over time or after thermal annealing to selected temperatures was monitored by X-band electron paramagnetic resonance (EPR) spectroscopy. Some experimental spectra were compared with signals simulated based on literature data from the electron nuclear double resonance (ENDOR) studies. The following phenomena were confi rmed in the tested amino acids: abstraction of hydrogen atom (glycine, proline, hydroxyproline, collagen), deamination (glycine, hydroxyproline), decarboxylation (hydroxyproline). Chain scission at glycine residues, radiation-induced decomposition of side groups and oxidative degradation were observed in irradiated collagen. The decay of radicals in collagen saturated with water occurred at lower temperatures than in macromolecules having only structural water. The paramagnetic centres were the most stable in an oxygen-free atmosphere (vacuum). Radical processes deteriorated the structure of collagen; hence, radiation sterilization of skin grafts requires careful pros and cons analysis.
Źródło:
Nukleonika; 2019, 64, 1; 11-17
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mössbauer studies of single crystal gamma-Mn-Fe
Autorzy:
Szymański, K.
Olszewski, W.
Dobrzyński, L.
Satuła, D.
Jankowska-Kisielińska, J.
Powiązania:
https://bibliotekanauki.pl/articles/147239.pdf
Data publikacji:
2004
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
gamma-Mn-Fe alloys
iron alloys
manganese alloys
Mössbauer spectroscopy
Opis:
Mössbauer measurements were performed on single crystals gamma-Mn60Fe37Cu3 in an external field of 1.3 T at room temperature. The hyperfine field distribution can be described as a vector sum of the external and internal fields. In addition, anisotropic response of magnetic moments was detected. The anisotropy, due to Fe atoms, has Fe-rich surroundings.
Źródło:
Nukleonika; 2004, 49,suppl.3; 75-78
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron paramagnetic resonance studies on silver atoms and clusters in regularly interstratified clay minerals
Autorzy:
Yamada, H.
Sadlo, J.
Tamura, K.
Shimomura, S.
Turek, J.
Michalik, J.
Powiązania:
https://bibliotekanauki.pl/articles/147360.pdf
Data publikacji:
2004
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
EPR spectroscopy
regularly interstratified clay minerals
silver atoms
gamma irradiation
Opis:
The formation and stabilization of reduced silver species in the regularly interstratified clay minerals, trioctahedral smectite/chlorite (tri-Sm/Ch) and dioctahedral smectite/mica (di-Sm/M), have been studied by electron paramagnetic resonance (EPR) spectroscopy. Both minerals loaded with Ag+ cations after degassing and dehydration were g-irradiated at 77 K and monitored by EPR as the temperature increased. Some samples were exposed to water or methanol vapor after dehydration. In both hydrated and dehydrated samples only the doublets assigned to Ag0 atoms were observed with no evidence of the formation of Ag clusters. However, the EPR parameters of silver atoms in both matrices are different. In tri-Sm/Ch the narrow anisotropic EPR lines overlap with the broader isotropic lines, whereas in di-Sm/M only broad lines are recorded. The hyperfine splitting - Aiso(Ag0) is larger in tri-Sm/Ch than in di-Sm/M. Also the stability of Ag0 in both clay minerals is distinctly different. Ag0 doublet in di-Sm/M disappears completely above 230 K, whereas in tri-Sm/Ch it is still recorded at 310 K. It is proposed, basing on the EPR results that Ag0 atoms appear at different sites in both matrices: - in tri-Sm/Ch in the middle of smectite interlayer and in hexagonal cavities in the silicate sheets of tetrahedron layer and in di-Sm/M in hexagonal cavities only. When samples had been exposed to methanol before irradiation, the silver clusters become stabilized in the interlayer sites. In tri- Sm/Ch matrix the silver dimer Ag2+ formed by g-irradiation at 77 K is transformed to tetrameric cluster, Ag43+ at 150 K. In di-Sm/M the radiation-induced silver agglomeration proceeds in a similar way, but with a slower rate and Ag tetramer is formed only above 190 K. In both clay minerals, Ag43+ clusters decay above 250 K.
Źródło:
Nukleonika; 2004, 49, 4; 131-136
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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