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442
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Neutron Diffraction and Acoustic Emission Measurement During Loading and Unloading of Magnesium Aluminium Binary Alloys
Čapek, Jan; Máthis, K.
2017 - English
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.
Keywords:
magnesium alloys; twinning; detwinning; neutron diffraction; acoustic emission
Available at various institutes of the ASCR
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 - English
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.
Keywords:
LHC; pp collisions
Available at various institutes of the ASCR
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 ...
Effect of the eta eta channel and interference phenomena in the two-pion transitions of charmonia and bottomonia
Surovtsev, Yu .S.; Bydžovský, Petr; Gutsche, T.; Kaminski, R.; Lyubovitskij, V. E.; Nagy, M.
2017 - English
The basic shape of di-pion mass spectra in the two-pion transitions of both charmonia and bottomonia states is explained by a unified mechanism based on contributions of the pi pi, K (K) over bar, and eta eta coupled channels including their interference. The role of the individual f(0) resonances in shaping the di-pion mass distributions in the charmonia and bottomonia decays is considered.
Keywords:
resonance; charmonia; bottomonia
Available at various institutes of the ASCR
Effect of the eta eta channel and interference phenomena in the two-pion transitions of charmonia and bottomonia
The basic shape of di-pion mass spectra in the two-pion transitions of both charmonia and bottomonia states is explained by a unified mechanism based on contributions of the pi pi, K (K) over bar, and ...
Fragmentation from heavy ion beams in HIMAC BIO room calculated with PHITS and measured with Liulin
Ploc, Ondřej; Dachev, T.; Uchihori, Y.; Kitamura, H.; Sihver, L.
2017 - English
The Heavy Ion Medical Accelerator in Chiba (HIMAC), at the National Institutes for Quantum and Radiological Science and Technology, is not only an excellent cancer-treatment facility but also a facility to perform experiments related to radiation therapy, space radiation protection and basic nuclear physics. HIMAC BIO is an irradiation room used for experiments related to both radiobiology and physics. When performing such experiments, it is essential to know the experimental setup, as well as the beam characteristics, in details. The advantage of HIMAC BIO is that both narrow and broad parallel heavy ion beams (up to. 10 cm), with flat circular profile at the isocenter, can be used for experiments. Such beam is obtained by using scatterers, ridge filters, beam degraders, etc., similar to what is used during radiation therapy. However, these components decrease the energies of the primary beams and are sources of secondary particles. To be able to draw correct conclusions from the experimental results, and to be able to compare the measurements with simulations, it is crucial to know the real energy of the primary ions and the detailed beam composition at the location of the biological samples and the physical detectors. The energies of the primary ions are calculated from Bragg curve measurements with a Markus ionization chamber before each experiment. However, the exact beam composition including the fluence and energies of the secondary fragments and neutrons are usually unknown. The purpose ofdetailed information about the components in the beam line at the HIMAC BIO room to facilitate accurate particle and heavy ion transport simulations of the beam characteristics. The main sources of secondary particles have been investigated, and the beam composition was calculated with the 3-dimensional general purpose Monte Carlo this paper is to provide PHITS and compared with measurements using a Liulin exposed to various monoenergetic and SOBP heavy ion beams.
Keywords:
HIMAC BIO; cosmic rays; dosimetry
Available at various institutes of the ASCR
Fragmentation from heavy ion beams in HIMAC BIO room calculated with PHITS and measured with Liulin
The Heavy Ion Medical Accelerator in Chiba (HIMAC), at the National Institutes for Quantum and Radiological Science and Technology, is not only an excellent cancer-treatment facility but also a ...
Proton and deuteron activation measurements at the NPI and future plans in SPIRAL2/NFS
Šimečková, Eva; Bém, Pavel; Mrázek, Jaromír; Štefánik, Milan; Běhal, Radomír; Glagolev, Vadim
2017 - English
The proton- and deuteron-induced reactions are of a great interest for the assessment of induced radioactivity of accelerator components, target and beam stoppers as well as isotope production for medicine. In the present work, the deuteron-induced reaction cross sections on zinc were investigated by stacked-foil activation technique with deuteron beam of 20 MeV energy from the cyclotron U-120M of NPI CAS ež. Also the proton activation cross section measurement of iron is presented. The comparison of present results to data of other authors and to predictions of evaluated data libraries is discussed. The investigation shall continue for higher proton and deuteron energy interval 20-35 MeV at SPIRAL2/NFS facility using a charged particle irradiation chamber with pneumatic transport system to measure isotopes and isomers with half-lives in minutes-regions.
Keywords:
SPIRAL2/NFS; CANAM accelerators; cross section
Available at various institutes of the ASCR
Proton and deuteron activation measurements at the NPI and future plans in SPIRAL2/NFS
The proton- and deuteron-induced reactions are of a great interest for the assessment of induced radioactivity of accelerator components, target and beam stoppers as well as isotope production for ...
Position-Sensitive Coincidence Detection of Nuclear Reaction Products at the Prague Van-de-Graaff Accelerator
Granja, Carlos; Kraus, V.; Pugatch, V.; Kohout, Z.
2017 - English
In low-energy nuclear reactions of astrophysical interest or fusion studies the spatial-and time-correlated detection of two and more reaction products can be a valuable tool in studies of reaction mechanisms, resolving reaction channels and measuring angular distributions of reaction products. For this purpose we constructed a configurable array of position-sensitive detectors based on the hybrid semiconductor pixel detector Timepix. Additional analog-signal electronics provide self-trigger together with extended multi-device control and synchronized readout electronics by a customized control and coincidence unit. The instrumentation, developed and used for detection of fission fragments in spontaneous and neutron induced fission as well as in charged particle detection in neutron induced reactions, is being implemented for low-energy light-ion induced nuclear reactions. Application and demonstration of the technique with two Timepix detectors on p+p elastic scattering at the Van-de-Graaff (VdG) accelerator in Prague is given.
Keywords:
Van-de-Graaff; Timepix
Available at various institutes of the ASCR
Position-Sensitive Coincidence Detection of Nuclear Reaction Products at the Prague Van-de-Graaff Accelerator
In low-energy nuclear reactions of astrophysical interest or fusion studies the spatial-and time-correlated detection of two and more reaction products can be a valuable tool in studies of reaction ...
Numerical modeling of surface elastic wave scattering in polycrystalline materials
Grabec, Tomáš; Ryzy, M.; Verres, I. A.
2017 - English
Grain-boundary scattering of acoustic waves in polycrystalline materials is studied with analytical and numerical methods in the presented paper. In particular, the attenuation of Surface Acoustic Waves (SAWs) propagating through a polycrystalline microstructure is investigated. A three dimensional timedomain finite-element method (FEM) is utilized for the numerical simulation, whereby the granular microstructure is modeled by Voronoi tessellation. The resulting frequency-dependent attenuation coefficients are compared to an explicit analytical model.
Keywords:
grain boundary scattering; elastic wave; numerical modeling; polycrystalline material
Available at various institutes of the ASCR
Numerical modeling of surface elastic wave scattering in polycrystalline materials
Grain-boundary scattering of acoustic waves in polycrystalline materials is studied with analytical and numerical methods in the presented paper. In particular, the attenuation of Surface Acoustic ...
Residual stress determination by neutron diffraction in low-carbon steel wires with accumulated shear deformation
Rogante, M.; Mikula, Pavol; Strunz, Pavel; Zavdoveev, A.
2017 - English
Modern methods of severe plastic deformation (SPD) currently allow obtaining the ultrafine-grained (UFG) structure nearly in any material. In the manufacturing process of wire with UFG structure, a main restriction is the continuous drawing scheme in which this process occurs, thus it is important to consider the factors affecting the drawing efficiency. Despite the data on SPD steels such as strength, plasticity and conductivity, obtained by classical methodologies, further investigations are needed: a key information is the residual stresses (RS) status, and RS determination is an essential issue to improve knowledge of SPD effects. In this work, 15 wires samples made of low-alloyed quality structural steel Grade 08G2S GOST 1050 with accumulated shear deformation - as result of rolling with shear of the metal ingot and conventional wire drawing - have been investigated by neutron diffraction (ND). Results provide substantial data helping to evaluate the effect of shear deformation on RS of the considered steel, as well as additional support to complement the information already achieved by using the other characterization methodologies. Knowledge of the RS status can help developing a lowcarbon wire drawing technology with needed manufacturability and efficiency, playing a decisive role in the debugging of material selection and engineering design requirements.
Keywords:
Residual stresses; Neutron diffraction; Steel
Available at various institutes of the ASCR
Residual stress determination by neutron diffraction in low-carbon steel wires with accumulated shear deformation
Modern methods of severe plastic deformation (SPD) currently allow obtaining the ultrafine-grained (UFG) structure nearly in any material. In the manufacturing process of wire with UFG structure, a ...
Ion beam modification of materials for optics, electronic and spintronics -ion implantation using accelerators or laser induced plasma ion generation
Macková, Anna
2016 - Czech
Ion beam modification offers a broad field of the creating the new functional materials and nano-structures for optics, electronics, spintronics and other material branches. Using ions produced by ion accelerators or implanters\nmeans the usage of the monoenergetic beams for precise doped layer, nano-particles or cluster creation by varying the ion implantation specie versus matrix combination together with the implantation energy, ion flux etc. Recently\nappears the multienergetic ion implantation which is realized by using of the intense laser shot generating plasma from the specially designed targets, where the ions are accelerated and can be then implanted into the various\nmaterials. This contribution will present an overview and comparison of different ion beam modification techniques, plasma ion implantation will be also mentioned.
Keywords:
modification; materials; ion implantation
Available at various institutes of the ASCR
Ion beam modification of materials for optics, electronic and spintronics -ion implantation using accelerators or laser induced plasma ion generation
Ion beam modification offers a broad field of the creating the new functional materials and nano-structures for optics, electronics, spintronics and other material branches. Using ions produced by ion ...
Calibration and Exact Characterization of Aerosol Deposit colected by SDI Impactor
Havránek, Vladimír
2016 - English
Ion beam analytical methods as PIXE (Particle induced X-ray emission), PIGE (Particle induced gamma-ray emission) and RBS (Rutherford backscattering spectrometry) are frequently used for elemental analysis of different types of atmospheric aerosol samples in a form of aerosol deposits on thin plastic filters or foils (Alfassi and Peisach, 1991, Johansson and Campbell, 1988). An ideal sample for analysis is thin homogeneous aerosol deposit with known deposit area. However in practice such samples are rare. They are often thick (more than limit for thin target approximation i.e. larger then few hundred micrograms per square centimetres), of irregular shape and unknown deposit area. In such conditions all obtained elemental mass results should be corrected for apparent deposit thickness, deposit homogeneity and effective deposit area.
Keywords:
atmospheric aerosols; PIXE; RBS; calibration; elemental concentration
Available at various institutes of the ASCR
Calibration and Exact Characterization of Aerosol Deposit colected by SDI Impactor
Ion beam analytical methods as PIXE (Particle induced X-ray emission), PIGE (Particle induced gamma-ray emission) and RBS (Rutherford backscattering spectrometry) are frequently used for elemental ...
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