Number of found documents: 421
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A new set-up for total reaction cross section measuring
Sobolev, Yuri, G.; Ivanov, M. P.; Kugler, Andrej; Penionzhkevich, Y. E.
2012 - English
The experimental method and set-up based on 4 P n-gamma-technique for direct and model-independent measuring of the total reaction cross section sigma(R) have been presented. The excitation function sigma(R)(E) for He-6+Au-197 reaction at the Coulomb barrier energy region has been measured. The measured data are compared with the summarized cross section which has been prepared by summing of measured cross sections of main reaction channels: 1n-transfer and Au-197(He-6, xn)Tl203-xn with x = 2 divided by 7 evaporation reaction channels.\n\n Keywords: cross section; reaction; measurement Available at various institutes of the ASCR
A new set-up for total reaction cross section measuring

The experimental method and set-up based on 4 P n-gamma-technique for direct and model-independent measuring of the total reaction cross section sigma(R) have been presented. The excitation function ...

Sobolev, Yuri, G.; Ivanov, M. P.; Kugler, Andrej; Penionzhkevich, Y. E.
Ústav jaderné fyziky, 2012

Odlišení stop průchozích částic v detektoru stop v pevné fázi
Pachnerová Brabcová, Kateřina; Ambrožová, Iva
2011 - Czech
Keywords: cosmic-ray; Liulin detector; solar energetic particles Available at various institutes of the ASCR
Odlišení stop průchozích částic v detektoru stop v pevné fázi

Pachnerová Brabcová, Kateřina; Ambrožová, Iva
Ústav jaderné fyziky, 2011

Detectability of changes in cosmic-ray counting rate measured with the Liulin detector
Malušek, Alexandr; Kubančák, Ján; Ambrožová, Iva
2011 - English
Keywords: cosmic-ray; Liulin detector; solar energetic particles; částice; změny Available at various institutes of the ASCR
Detectability of changes in cosmic-ray counting rate measured with the Liulin detector

Malušek, Alexandr; Kubančák, Ján; Ambrožová, Iva
Ústav jaderné fyziky, 2011

Urban Structure Analysis
Vašata, D.; Exner, Pavel; Šeba, Petr
2011 - English
The built-up land represents an important type of overall landscape. We analyse the structure of built-up land in largest cities in the Czech Republic and selected cities in the USA using the framework of statistical physics. To do this, both the variance of the built-up area and the number variance of built-up landed plots in circles are calculated. In both cases the variance as a function of a circle radius follows a power law. The obtained value of the exponents are comparable to exponents typical for critical systems. The study is based on cadastral data in the Czech Republic and building footprints GIS data in the USA. Keywords: Urban structure; critical systems; self-organized criticality Available at various institutes of the ASCR
Urban Structure Analysis

The built-up land represents an important type of overall landscape. We analyse the structure of built-up land in largest cities in the Czech Republic and selected cities in the USA using the ...

Vašata, D.; Exner, Pavel; Šeba, Petr
Ústav jaderné fyziky, 2011

Spectator invariance test in the study of the Li-6,Li-7 fusion reactions via the Trojan Horse Method
Pizzone, R. G.; Lamia, L.; Bertulani, C. A.; Mukhamedzhanov, A.; Spitaleri, C.; Blokhinstev, L.; Burjan, Václav; Cherubini, S.; Hons, Zdeněk; Kiss, G. G.; Kroha, Václav; La Cognata, M.; Li, C.; Mrázek, Jaromír; Piskoř, Štěpán; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Tumino, A.
2011 - English
Fusion reactions play a crucial role for several astrophysical scenarios. At the low energies typical of such environments direct measurements of reaction cross sections are very difficult, and even sometimes impossible. In such cases the use of indirect methods can give a substantial help. The Trojan Horse Method (THM) is based on the quasi-free break-up of a nucleus, which can be described in terms of a cluster structure. In such applications the independence of THM results with different break-up schemes, was tested using the quasi free(3)He(Li-6,alpha alpha)H and He-3(Li-7,alpha alpha)H-2 reactions. Results were then compared with the direct behaviours obtained from available data as well as with the cross sections extracted from previous indirect investigations of the same binary reactions using a different nuclide as a Trojan Horse nucleus. Keywords: fusion reactions; indirect methods; cross section Available at various institutes of the ASCR
Spectator invariance test in the study of the Li-6,Li-7 fusion reactions via the Trojan Horse Method

Fusion reactions play a crucial role for several astrophysical scenarios. At the low energies typical of such environments direct measurements of reaction cross sections are very difficult, and even ...

Pizzone, R. G.; Lamia, L.; Bertulani, C. A.; Mukhamedzhanov, A.; Spitaleri, C.; Blokhinstev, L.; Burjan, Václav; Cherubini, S.; Hons, Zdeněk; Kiss, G. G.; Kroha, Václav; La Cognata, M.; Li, C.; Mrázek, Jaromír; Piskoř, Štěpán; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Tumino, A.
Ústav jaderné fyziky, 2011

Program zabezpečování jakosti pro činnosti dle §59 odst. 1 písm a), e) a f) vyhlášky č. 307/2002 Sb., ve znění vyhlášky č. 499/2005 Sb
Kubančák, Ján; Malušek, Alexandr
2011 - Czech
Práce slouží jako nezbytný dokument potřebný a) pro získání povolení od Státního úřadu pro jadernou bezpečnost k výkonu služeb osobní dozimetrie leteckých posádek a b) k samotné realizaci služby osobní dozimetrie pro členy posádek společností registrovaných v ČR. Je vytvořen ve formě programu zajištění jakosti, kterého součástí jsou metodiky nezbytné pro vykonávání služby. Work poses document which is necessary a) to obtain the permission from the State Office for the Nuclear Safety of the Czech Republic to provide personal aircrew dosimetry service and b) to realize the service itself for aircrew of the companies registered in the Czech Republic. It is written as a quality assurance program which is based on methodology developed in the NPI for this purpose. Keywords: aircrew dosimetry; cosmic radiation; CERF Available at various institutes of the ASCR
Program zabezpečování jakosti pro činnosti dle §59 odst. 1 písm a), e) a f) vyhlášky č. 307/2002 Sb., ve znění vyhlášky č. 499/2005 Sb

Práce slouží jako nezbytný dokument potřebný a) pro získání povolení od Státního úřadu pro jadernou bezpečnost k výkonu služeb osobní dozimetrie leteckých posádek a b) k samotné realizaci služby ...

Kubančák, Ján; Malušek, Alexandr
Ústav jaderné fyziky, 2011

Characterization of the Nanostructured Nickel Oxide Layers Prepared by Ion Beam Sputtering
Horák, Pavel; Bejšovec, Václav; Lavrentiev, Vasyl; Khun, J.; Vrňata, M.
2011 - English
Nanostructured nickel oxide layers (thickness cca 100 nm) were prepared by bombardment of nickel foil with ion beam created from a mixture of argon and oxygen. Different volume ratios of argon:oxygen mixture were used, ranging from 4:1 to 1:3. Composition of the resulting layers was analyzed by RBS, morphology by AFM and main crystal orientation of the sample by XRD. The electrophysical properties (resistivity, concentration of charge carriers) were measured by four point Van der Pauw technique and Hall measurement respectively. Prepared samples were characterized in as-deposited state and after annealing with varying temperature of treatment. Chemical composition (i.e. stoichiometry) of the as-deposited samples with different argon: oxygen ratio was related to their electrophysical parameters. Hall measurements are showing majority charge carriers to be electrons - surface concentration (0.5 - 2.3) x 10(21) m(-2) - suggesting prevailing metallic conductivity. Resistivity of the sample is increasing with higher amount of oxygen in gas mixture. The as-deposited layer is almost amorphous with no visible grains on AFM. Keywords: Nickel oxide; Ion Beam Sputtering; Van der Pauw Fulltext is available at external website.
Characterization of the Nanostructured Nickel Oxide Layers Prepared by Ion Beam Sputtering

Nanostructured nickel oxide layers (thickness cca 100 nm) were prepared by bombardment of nickel foil with ion beam created from a mixture of argon and oxygen. Different volume ratios of argon:oxygen ...

Horák, Pavel; Bejšovec, Václav; Lavrentiev, Vasyl; Khun, J.; Vrňata, M.
Ústav jaderné fyziky, 2011

High accuracy O-18(p, alpha)N-15 reaction rate in the 8 . 10(6)-5 . 10(9) K temperature range
La Cognata, M.; Spitaleri, C.; Mukhamedzhanov, A.; Banu, A.; Cherubini, S.; Coc, A.; Crucilla, V.; Goldberg, V.; Gulino, M.; Irgaziev, B.; Kiss, G. G.; Lamia, L.; Mrázek, Jaromír; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Tabacaru, G.; Trache, L.; Tribble, R. E.; Trzaska, W.; Tumino, A.
2011 - English
The O-18(p, alpha)N-15 reaction is of great importance in several astrophysical scenarios, as it influences the production of key isotopes such as F-19, O-18 and N-15. In this work, a high accuracy O-18(p, alpha) N-15 reaction rate is proposed, based on the simultaneous fit of direct measurements and of the results of a new Trojan Horse experiment. In particular, we have focused on the study of the broad 660 keV 1/2(+) resonance. Since Gamma similar to 100 - 300 keV, it strongly influences the nearly-zero-energy region of the cross section by means of the low-energy tail of the resonant contribution and dominates the cross section at higher energies. Here we provide a factor of 2 larger reaction rate above T similar to 0.510(9) K based over our new improved determination of its resonance parameters. Keywords: nuclear reactions; nycleosynthesis; abundances Available at various institutes of the ASCR
High accuracy O-18(p, alpha)N-15 reaction rate in the 8 . 10(6)-5 . 10(9) K temperature range

The O-18(p, alpha)N-15 reaction is of great importance in several astrophysical scenarios, as it influences the production of key isotopes such as F-19, O-18 and N-15. In this work, a high accuracy ...

La Cognata, M.; Spitaleri, C.; Mukhamedzhanov, A.; Banu, A.; Cherubini, S.; Coc, A.; Crucilla, V.; Goldberg, V.; Gulino, M.; Irgaziev, B.; Kiss, G. G.; Lamia, L.; Mrázek, Jaromír; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Tabacaru, G.; Trache, L.; Tribble, R. E.; Trzaska, W.; Tumino, A.
Ústav jaderné fyziky, 2011

Vertex Couplings in quantum Graphs: Approximations by Scaled Schrödinger Operators
Exner, Pavel
2011 - English
We review recent progress in understanding the physical meaning of quantum graph models through analysis of their vertex coupling approximations. Keywords: quantum graphs; vertex coupling; tube networks Available at various institutes of the ASCR
Vertex Couplings in quantum Graphs: Approximations by Scaled Schrödinger Operators

We review recent progress in understanding the physical meaning of quantum graph models through analysis of their vertex coupling approximations.

Exner, Pavel
Ústav jaderné fyziky, 2011

Výpočet dynamiky chování microtronu MT 25 a jeho rychlá simulace
Krist, Pavel; Bíla, J.; Chvátil, David
2011 - Czech
Článek se zabývá návrhem matematického modelu, který je vyvíjen z důvodu nastavení a testování fuzzy řídicího systému mikrotronu MT 25. Mikrotron MT 25 je cyklický urychlovač elektronů. Tento typ urychlovače je doposud řízen pouze manuálně operátorem. Matematický model je založen na výpočtu pohybu elektronů v urychlovací dutině a ve vakuové komoře urychlovače. Simulace urychlovače je pak provedena v prostředí Matlab – Simulink. This paper presents the design of a mathematical model and its fast simulation developed for the setup of the control system of the MT 25 microtron, which is a cyclic electron accelerator. This type of accelerator has been controlled manually until now. The mathematical model is based on calculations of the electron motion in the accelerating cavity and vacuum chamber. The simulation diagram was created in Matlab – Simulink. Keywords: Microtron; electron accelerator; electron source; LaB6; beam simulation Available at various institutes of the ASCR
Výpočet dynamiky chování microtronu MT 25 a jeho rychlá simulace

Článek se zabývá návrhem matematického modelu, který je vyvíjen z důvodu nastavení a testování fuzzy řídicího systému mikrotronu MT 25. Mikrotron MT 25 je cyklický urychlovač elektronů. Tento typ ...

Krist, Pavel; Bíla, J.; Chvátil, David
Ústav jaderné fyziky, 2011

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