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The characterization of the collimated beams of fast neutrons with the CLID detecion system
Ansorge, Martin; Novák, Jan; Majerle, Mitja; Kozic, Ján
2022 - anglický
A new detection device for the measurements of light ions (p, d, t, α) emitted as the products of the nuclear reactions induced by fast neutrons (5-33 MeV) was recently developed at the Nuclear Physics Institute of the Czech Academy of Sciences. The main objective of the Chamber-for-Light-Ion-Detection (CLID) is to produce new differential nuclear data of high interest for the material applications related to fusion and aerospace technologies and to potentially test and validate models of nuclear reactions. Hereby the experimental set-up for the measurements with the CLID is described in detail. The experimental characterization of the collimated fast neutron beams produced by the cyclotron-driven converter (p(35 MeV)+Be(2.5 mm)) is presented. In particular, the implementation of the Proton-Recoil-Telescope technique used for neutron energy spectra determination with the CLID is described.
Klíčová slova:
CLID; collimated fast neutron beams; cyclotron U-120M; NPI; Proton-Recoil-Telescope
Plné texty jsou dostupné v digitálním repozitáři Akademie Věd.
The characterization of the collimated beams of fast neutrons with the CLID detecion system
A new detection device for the measurements of light ions (p, d, t, α) emitted as the products of the nuclear reactions induced by fast neutrons (5-33 MeV) was recently developed at the Nuclear ...
Spectrometry of neutron field based on p(20)+Be source reaction
Kozic, Ján; Štefánik, Milan
2022 - anglický
The research deals with a spectrometry of neutron field based on the p(20)+Be source reaction. The p(20)+Be interaction stands for a nuclear reaction where protons accelerated to energy of 20 MeV bombard Be target. Produced neutron field has broad energy distribution up to 18 MeV. The research was carried out at the Nuclear Physics Institute of the Czech Academy of Sciences and was motivated by extension of experimental possibilities of the NG-2 target station. To determine the neutron spectrum, the activation foil technique was used. During the experiment, ten activation foils were irradiated. Activated foils were measured using the HPGe detector to determine the reaction rates of observed reactions. The neutron field was simulated in the MCNPX code, and the simulation served as a priori information for the unfolding of the neutron spectrum in the SAND-II code. A determined neutron spectrum is essential for various experiments, e.g., material research, measurements of nuclear data, etc.
Klíčová slova:
Accelerator-driven neutron source; activation foil technique; beryllium target station NG-2; neutron energy spectrum; SAND-II
Plné texty jsou dostupné v digitálním repozitáři Akademie Věd.
Spectrometry of neutron field based on p(20)+Be source reaction
The research deals with a spectrometry of neutron field based on the p(20)+Be source reaction. The p(20)+Be interaction stands for a nuclear reaction where protons accelerated to energy of 20 MeV ...
Strain Measurements on Samples of an 3D-printing Maraging Steel by a High-resolution Neutron Diffraction
Mikula, Pavol; Ryukhtin, Vasyl; Michalcová, A.
2022 - anglický
In our contribution we present strain measurements on several samples related to the 3D printing material with an unconventional high-resolution neutron diffraction. This method is based on the three-axis diffractometer setting when a conventional two axis neutron diffraction scanner does not provide a relevant resolution.
Klíčová slova:
3D printing material; high resolution; neutron diffraction
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Strain Measurements on Samples of an 3D-printing Maraging Steel by a High-resolution Neutron Diffraction
In our contribution we present strain measurements on several samples related to the 3D printing material with an unconventional high-resolution neutron diffraction. This method is based on the ...
The effect of the heat treatment at 450°C on distribution of residual stresses of modified Cr-Mo steel welds
Mráz, L.; Hervoches, Charles; Mikula, Pavol; Kotora, J.
2020 - anglický
The effect of low-temperature long-term heat treatment on distribution of residual stresses on the modified chromium-molybdenum steel of the type 7 CrMoVTiB10-10 and known as the T24 steel which was studied by using neutron diffraction method, is presented.
Klíčová slova:
neutron diffraction; stress analysis
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
The effect of the heat treatment at 450°C on distribution of residual stresses of modified Cr-Mo steel welds
The effect of low-temperature long-term heat treatment on distribution of residual stresses on the modified chromium-molybdenum steel of the type 7 CrMoVTiB10-10 and known as the T24 steel which was ...
On a possible High-Resolution Residual Strain/Stress Measurements by Three Axis Neutron Diffractometer
Mikula, Pavol; Šaroun, Jan; Rogante, M.
2020 - anglický
The new unconventional high-resolution neutron diffraction three axis set-up for strain/stress measurements of rather large bulk polycrystalline samples is presented.
Klíčová slova:
neutron diffraction; 3 axis neutron diffractometer
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
On a possible High-Resolution Residual Strain/Stress Measurements by Three Axis Neutron Diffractometer
The new unconventional high-resolution neutron diffraction three axis set-up for strain/stress measurements of rather large bulk polycrystalline samples is presented.
Laser-generated nanoparticles to change physical properties of solids, liquids and gases
Torrisi, Alfio; Cutroneo, Mariapompea; Ceccio, Giovanni; Cannavó, Antonino; Horák, Pavel; Torrisi, L.; Vacík, Jiří
2019 - anglický
Synthesis of nanoparticles was possible employing a Nd: YAG pulsed laser at fundamental harmonic. The production of nanoparticles in water depends mainly on the laser parameters (pulse duration, energy, wavelength), the irradiation conditions (focal spot, repetition rate, irradiation time) and the medium where the ablation occurs (solid target, water, solution concentration). The nanoparticles can be introduced in solids, liquids or gases to change many physical characteristics. The optical properties of polymers and solutions, the wetting ability of liquids, the electron density of laser-generated plasma, represent some examples that can be controlled by the concentration of metallic nanoparticles (Au, Ag, Ti, Cu). Some bio-medical applications will be presented and discussed.
Klíčová slova:
bio-medical applications; laser; nanoparticles
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Laser-generated nanoparticles to change physical properties of solids, liquids and gases
Synthesis of nanoparticles was possible employing a Nd: YAG pulsed laser at fundamental harmonic. The production of nanoparticles in water depends mainly on the laser parameters (pulse duration, ...
Residual stresses of laser-welded pressure vessel steel determined by X-ray and neutron diffraction
Trojan, K.; Vlk, A.; Čapek, J.; Hervoches, Charles; Ganev, N.
2019 - anglický
To gain insight into the quality of the laser weld, information about the residual stress state across the weld is very useful. In this contribution, the residual stress profiles for lowalloy carbon steel plates of P355NL1 grade, which were laser welded from both sides, are presented. To separate the effects of the production of plates from the welding process, the samples were annealed for stress relieving. Using X-ray and neutron diffraction, the surface and bulk RS profiles were obtained. From the obtained data, first, the difference in the character of the longitudinal (parallel to the weld axis) and the transversal component of the RS tensor can be seen. The longitudinal component has a tensile character with a maximum value approximately 500 MPa. Values and character of the transversal component vary strongly with depth and distance from the weld axis.
Klíčová slova:
nondestructive examination; ferromagnetic materials; residual stresses
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Residual stresses of laser-welded pressure vessel steel determined by X-ray and neutron diffraction
To gain insight into the quality of the laser weld, information about the residual stress state across the weld is very useful. In this contribution, the residual stress profiles for lowalloy carbon ...
On a possible use of neutron three axis diffractometer for studies of elastic and plastic deformation of polycrystalline materials
Mikula, Pavol; Ryukhtin, Vasyl; Rogante, M.
2019 - anglický
Feasibility of using a high-resolution three axis neutron diffractometer performance for elastic and plastic deformation studies of metallic polycrystalline samples is presented. The method consists of unconventional set up employing bent perfect crystal (BPC) monochromator and analyzer with a polycrystalline sample in between. After the realization of focusing conditions in real and momentum space at the neutron wavelength of 0.162 nm, a high angular resolution up to FWHM(d/d)=2x10-3 was achieved on the standard Fe(110) sample (2 mm diameter) which then opened the possibility for the measurements of small lattice parameter changes of samples. The feasibility of the instrument for macro-and microstrain as well as grain size studies is demonstrated on the polycrystalline samples of low carbon shear deformed steel wires and the NiTi plates subjected to heat treatment.
Klíčová slova:
instrumentation; neutron diffraction; strain measurements
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
On a possible use of neutron three axis diffractometer for studies of elastic and plastic deformation of polycrystalline materials
Feasibility of using a high-resolution three axis neutron diffractometer performance for elastic and plastic deformation studies of metallic polycrystalline samples is presented. The method consists ...
Study of lithium encapsulation in porous membrane using ion and neutron beams
Ceccio, Giovanni; Cannavó, Antonino; Horák, Pavel; Torrisi, Alfio; Tomandl, Ivo; Hnatowicz, Vladimír; Vacík, Jiří
2019 - anglický
Ion track-etched membranes are porous systems obtained by etching of the latent ion tracks using a suitable etchant solution. In this work, control of the pores' spatial profiles and dimensions in PET polymers was achieved by varying etching temperature and etching time. For determination of the pores' shape, Ion Transmission Spectroscopy technique was employed. In this method, alterations of the energy loss spectra of the transmitted ions reflect alterations in the material density of the porous foils, as well as alterations of their thickness. Simulation code, developed by the team, allowed the tomographic study of the ion track 3D geometry and its evolution during chemical etching. From the doping of porous membranes with lithium-based solution and its analysis by Thermal Neutron Depth Profiling method, the ability of porous PET membranes to encapsulate nano-sized material was also inspected. The study is important for various applications, e.g., for catalysis, active agents, biosensors, etc.
Klíčová slova:
doping; etching; ion transmission spectroscopy; thermal neutron depth profiling
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Study of lithium encapsulation in porous membrane using ion and neutron beams
Ion track-etched membranes are porous systems obtained by etching of the latent ion tracks using a suitable etchant solution. In this work, control of the pores' spatial profiles and dimensions in PET ...
Mechanical properties of WN43 magnesium alloy prepared by spark plasma sintering
Knapek, Michal; Minárik, P.; Greš, A.; Zemková, M.; Cinert, Jakub; Král, R.
2019 - anglický
The spark plasma sintering (SPS) method was used to prepare bulk materials form WN43 magnesium alloy atomized powder. Compression tests were carried out in order to investigate the effect of different sintering regimes (10 min at 400, 450, or 500 degrees C) on the mechanical properties of the material. Furthermore, complementary in-situ acoustic emission (AE) recording was employed to reveal the dynamics of deformation processes during compression. It was shown that by increasing the sintering temperature, the ultimate compressive strength and ductility were significantly improved. The AE data and microstructure observations suggest that pronounced twin nucleation takes place around the yield point whereas twin growth and dislocation activity are the dominant deformation mechanisms in the later stages of deformation.
Klíčová slova:
spark plasma sintering; magnesium; deformation; twinning; acoustic emission
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Mechanical properties of WN43 magnesium alloy prepared by spark plasma sintering
The spark plasma sintering (SPS) method was used to prepare bulk materials form WN43 magnesium alloy atomized powder. Compression tests were carried out in order to investigate the effect of different ...
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