Ne (216)
Ano (4)
Použitá omezení
(2)
Počet nalezených dokumentů:
220
Publikováno od
do
Ultra-low intensity proton beams for radiation response related experiments at the U-120M cyclotron
Matlocha, Tomáš; Křížek, Filip
2018 - anglický
The U-120M cyclotron at the Nuclear Physics Institute (NPI) of the Czech Academy of Sciences in Rez is used for radiation hardness tests of electronics for high-energy physics experiments. These tests are usually carried out with proton fluxes of the order of 105–109 proton cm-2 s -1. Some tests done for the upgrade of the Inner Tracking System of the ALICE experiment at CERN, however, required proton beam intensities several orders of magnitude lower. This paper presents a method which has been developed to achieve the proton beam flux of the order of 1 proton cm-2 s -1. The method is mainly based on reduction of the discharge current in the cyclotron internal Penning type ion source. Influence of this new operation mode on the lifetime of ion source cathodes is discussed.
Klíčová slova:
ultra-low intensity proton flux; penning ion source; negative hydrogen yield resonance; cyclotron irraditation facility; radiation hardness tests
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Ultra-low intensity proton beams for radiation response related experiments at the U-120M cyclotron
The U-120M cyclotron at the Nuclear Physics Institute (NPI) of the Czech Academy of Sciences in Rez is used for radiation hardness tests of electronics for high-energy physics experiments. These tests ...
Measurements and usage of cross sections of various (n,chi n) threshold reactions
Chudoba, Petr; Vrzalová, Jitka; Svoboda, Ondřej; Krása, Antonín; Kugler, Andrej; Majerle, Mitja; Suchopár, Martin; Wagner, Vladimír
2017 - anglický
Current trend in nuclear reactor physics is a transition from technologies using thermal neutrons to technologies utilizing fast neutrons. Unfortunately focus was put mainly on the thermal neutrons for a long time and lead to very good knowledge about this low energy region, but very scarce coverage of the high energy region. This means that there is a gap in the knowledge of excitation functions for higher energies. This gap spreads from 20 MeV up to 1 GeV and higher. This is exactly the energy region needed for description of advanced nuclear systems such as accelerator driven systems (ADS). Our group from Nuclear Physics Institute (NPI) of the CAS is a member of an international collaboration Energy & Transmutation of Radioactive Waste (E&T RAW). This collaboration focuses on ADS for many years. In order to measure neutron field within ADS models it is necessary to know excitation functions of reactions used to monitor the neutron field. In many cases there are almost no experimental data for suitable reactions. Worse and quite common case is that there are no data at all. Therefore we are also focusing on measurements of these data in order to fill the databases as well as to allow further improvements of codes for nuclear data calculations.
Klíčová slova:
cross section; NPI; E&T RAW
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Measurements and usage of cross sections of various (n,chi n) threshold reactions
Current trend in nuclear reactor physics is a transition from technologies using thermal neutrons to technologies utilizing fast neutrons. Unfortunately focus was put mainly on the thermal neutrons ...
Trojan horse method with neutrons induced reactions: The 17O(n,alpha)14C reaction
Guardo, G. L.; Spitaleri, C.; Lamia, L.; Gulino, M.; Tang, X.; Bucher, B.; Burjan, Václav; Couder, M.; Davies, P.; deBoer, R.; Fang, X.; Kroha, Václav; La Cognata, M.; Ma, C.; Mrázek, Jaromír; Mukhamedzhanov, A.; Notani, M.; O'Brien, S.; Pizzone, R. G.; Rapisarda, G. G.; Roberson, D.; Sergi, M. L.; Tan, W.; Wiescher, M.
2017 - anglický
The experimental study of the 17O(n,alpha)14C reaction has been performed in the energy range 0-350 keV. This reaction could play an important role in explaining heavy elements (s-process) nucleosynthesis in various astrophysical scenario. To over-come the practical problems arising from the neutrons production, a new application of the Trojan Horse Method has been recently suggested.
Klíčová slova:
reaction study; nucleosynthesis; Trojan Horse Method
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Trojan horse method with neutrons induced reactions: The 17O(n,alpha)14C reaction
The experimental study of the 17O(n,alpha)14C reaction has been performed in the energy range 0-350 keV. This reaction could play an important role in explaining heavy elements (s-process) ...
Theranostic Mercury Part 1: A New Hg/Au Separation by a Resin Based Method
Walther, M.; Lebeda, Ondřej; Preusche, S.; Pietzsch, H.-J.; Steinbach, J.
2017 - anglický
The development of a fast and efficient method for Mercury/Gold separation is described as a necessary precondition for large scale production of theranostic mercury Hg-197(m). To achieve this, the application of so called LN resin (LaNthanides) was studied. The results confirm the applicability of this resin for Au/Hg separation by high efficiency, high separation factor and reproducibility.
Klíčová slova:
cyclotron; Hg-197(m); LaNthanides
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Theranostic Mercury Part 1: A New Hg/Au Separation by a Resin Based Method
The development of a fast and efficient method for Mercury/Gold separation is described as a necessary precondition for large scale production of theranostic mercury Hg-197(m). To achieve this, the ...
On the scientific utilisation of low power research reactors
Mikula, Pavol; Strunz, Pavel
2017 - anglický
In our contribution we focus our attention on the scientific utilisation of the beam tubes at the low power research reactor LVR-15. Namely, it will be reported about the neutron scattering instrumentation development and the educational possibilities at the low power neutron sources. The feasibility of carrying out the methodology and instrumental development research at the low power neutron sources will be demonstrated on designs of several high resolution and good luminosity neutron scattering instruments exploiting Bragg diffraction optics. Some of them have been already realized e.g. for small angle neutron scattering studies or residual strain/stress measurements. As the mentioned instrumental development and testing can be carried out at the low power neutron sources, due to the much lower safety requirements in comparison with the medium and high flux sources, they offer excellent educational and training programmes in neutron scattering or imaging for students.
Klíčová slova:
low power reactor; research with thermal neutrons; LVR-15
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
On the scientific utilisation of low power research reactors
In our contribution we focus our attention on the scientific utilisation of the beam tubes at the low power research reactor LVR-15. Namely, it will be reported about the neutron scattering ...
Ion beams provided by small accelerators for material synthesis and characterization
Macková, Anna; Havránek, Vladimír
2017 - anglický
The compact, multipurpose electrostatic tandem accelerators are extensively used for production of ion beams with energies in the range from 400 keV to 24 MeV of almost all elements of the periodic system for the trace element analysis by means of nuclear analytical methods. The ion beams produced by small accelerators have a broad application, mainly for material characterization (Rutherford Back-Scattering spectrometry, Particle Induced X ray Emission analysis, Nuclear Reaction Analysis and Ion-Microprobe with 1 um lateral resolution among others) and for high-energy implantation. Material research belongs to traditionally progressive fields of technology. Due to the continuous miniaturization, the underlying structures are far beyond the analytical limits of the most conventional methods. Ion Beam Analysis (IBA) techniques provide this possibility as they use probes of similar or much smaller dimensions (particles, radiation). Ion beams can be used for the synthesis of new progressive functional nanomaterials for optics, electronics and other applications. Ion beams are extensively used in studies of the fundamental energetic ion interaction with matter as well as in the novel nanostructure synthesis using ion beam irradiation in various amorphous and crystalline materials in order to get structures with extraordinary functional properties. IBA methods serve for investigation of materials coming from material research, industry, micro- and nano-technology, electronics, optics and laser technology, chemical, biological and environmental investigation in general. Main research directions in laboratories employing small accelerators are also the preparation and characterization of micro- and nano-structured materials which are of interest for basic and oriented research in material science, and various studies of biological, geological, environmental and cultural heritage artefacts are provided too.
Klíčová slova:
Ion beams; Electrostatic accelerators; Electronics; Nanostructures; Optics and optical physics
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Ion beams provided by small accelerators for material synthesis and characterization
The compact, multipurpose electrostatic tandem accelerators are extensively used for production of ion beams with energies in the range from 400 keV to 24 MeV of almost all elements of the periodic ...
The activation of W and Zr by deuterons at energies up to 20 MeV
Šimečková, Eva; Štefánik, Milan; Bém, Pavel; Mrázek, Jaromír; Novák, Jan
2017 - anglický
The proton and deuteron induced reactions are of a great interest for the assessment of induced radioactivity of accelerator components, target and beam stoppers. In order to investigate the important nuclides, we have carried up the irradiation experiments with the variable-energy cyclotron U-120 M of the NPI CAS ež. The production cross sections of the nuclides 179,181,182m,182,183,184m,184,186Re and 187W from reaction on natural W were investigated by deuteron beams of 20 MeV energy. A part of preliminary results of deuteron activation of natural Zr is also shown. The stacked-foil technique was utilized. The comparison of present results to data of other authors and to predictions of evaluated data libraries is discussed.
Klíčová slova:
CANAM accelerators; proton and duteron induced reactions; cross section
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
The activation of W and Zr by deuterons at energies up to 20 MeV
The proton and deuteron induced reactions are of a great interest for the assessment of induced radioactivity of accelerator components, target and beam stoppers. In order to investigate the important ...
Performance of self-developing radiography films in LVR-15's neutron beams
Šoltés, J.; Viererbl, L.; Klupák, V.; Vinš, M.; Michalcová, Božena
2017 - anglický
In the search for a suitable detector for demonstration neutron radiography measurements on the zero-power VR-1 training reactor at the Czech Technical University in Prague, some options were considered. Due to the reactor's low power and spatial limitations, an easy and practical solution had to be found. Self-developing films represent a flexible detection tool in x-ray imaging. Therefore, the goal of this study was to evaluate their potential for neutron detection. For this purpose, bare and converter covered films were studied in the thermal and epithermal neutron beams at the LVR-15 research reactor in Rez, Czech Republic.
Klíčová slova:
neutron radiography; self-developing film; reactor LVR-15
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Performance of self-developing radiography films in LVR-15's neutron beams
In the search for a suitable detector for demonstration neutron radiography measurements on the zero-power VR-1 training reactor at the Czech Technical University in Prague, some options were ...
Neutron Diffraction and Acoustic Emission Measurement During Loading and Unloading of Magnesium Aluminium Binary Alloys
Čapek, Jan; Máthis, K.
2017 - anglický
The neutron diffraction and acoustic emission were measured during compression loading-unloading tests in randomly textured cast magnesium and magnesium 2 and 9 wt% aluminium binary alloys. The anelastic behavior and the change of twinned volume related to the detwinning phenomena can be observed during the unloading. The decrease of twinned volume fraction during unloading is most pronounced for Mg 9 wt% Al.
Klíčová slova:
magnesium alloys; twinning; detwinning; neutron diffraction; acoustic emission
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Neutron Diffraction and Acoustic Emission Measurement During Loading and Unloading of Magnesium Aluminium Binary Alloys
The neutron diffraction and acoustic emission were measured during compression loading-unloading tests in randomly textured cast magnesium and magnesium 2 and 9 wt% aluminium binary alloys. The ...
Top-Quark p(T)-Spectra at LHC and Flavor Independence of z-Scaling
Tokarev, M. V.; Zborovský, Imrich
2017 - anglický
New results of analysis of top-quark differential cross sections obtained by the CMS and ATLAS Collaborations in pp collisions at the LHC in the framework of z-scaling approach are presented. The spectra are measured over a wide range of collision energy root s = 7, 8, 13 TeV and transverse momentum p(T) = 30-1000 GeV/c of top-quark using leptonic and jet decay modes. The LHC data on transverse momentum of the top-quark spectra are compared with the Tevatron data obtained by the Dempty set Collaboration in p (p) over bar collisions at root s = 1.96 GeV. Flavour independence of the scaling function psi(z) in pp and p (p) over bar interactions over a wide collision energy range root s = 19 - 13000 GeV is verified. This property of psi(z) was found for different hadrons from pi-meson up to. particle. The flavour independence of psi(z) is used as indication on self-similarity of to p-quark production. A tendency to saturation of psi(z) at low z for top-quark is demonstrated. We anticipate that data on low-and high-p(T) inclusive spectra of top-quark production at LHC energies could be of interest for verification of the self-similarity over a wide range of masses and different flavour content of produced particles.
Klíčová slova:
LHC; pp collisions
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Top-Quark p(T)-Spectra at LHC and Flavor Independence of z-Scaling
New results of analysis of top-quark differential cross sections obtained by the CMS and ATLAS Collaborations in pp collisions at the LHC in the framework of z-scaling approach are presented. The ...
NUŠL poskytuje centrální přístup k informacím o šedé literatuře vznikající v ČR v oblastech vědy, výzkumu a vzdělávání. Více informací o šedé literatuře a NUŠL najdete na webu služby.
Vaše náměty a připomínky posílejte na email nusl@techlib.cz
Provozovatel
Zahraniční báze