Mathematical modeling methods are used to estimate the heating of solid targets irradiated by a kilovolt electron beam. When carrying out the calculations, a mathematical model was used that takes into account the separate contribution to the energy loss of electrons absorbed in the target and backscattered. The calculation results showed that for heavy targets the dependence of target overheating on the beam electron energy is non-monotonic: in the region of about 3-4 keV a local minimum appeared, due to the significant contribution of backscattered electrons to the energy loss. A qualitative assessment of heat transfer by radiation showed that for a low-energy electron probe, when setting boundary value problems, it is justified to consider the body flux through the outer surface of the target to be zero.
Show AbstractThe work studies the structure of a coating based on Mo/silicon substrate radiation using a combination of ion-assisted and magnetron deposition in various modes. It is shown that the surface of the coating has a structural composition and demonstrates radiation-stimulated diffusion of molybdenum into the depth of the substrate with a concentration of up to 1 at%, to a depth of up to 500 nm. The resulting coatings have stable resistive and thermoelectric properties and a wind roughness of no more than 2.5. nm in conditions of 10x10 nm and provide strength properties and density. The hardness of the coatings, obtained by interpreting the indentation results, is up to 70 GPa and controlled wettability, obtained by interpreting the indentation results, which makes it possible to subsequently form protective or electronic layers from them, makes it possible to form thin-film IR emitters based on MoSi2 from them, which is extremely important. when creating optical gas analyzers. built on the principle of dispersive-free IR spectroscopy.
Show AbstractThe results of experiments at the Large Hadron Collider gave clear confirmation of the modern Standard Model (SM) of fundamental interactions, but at the same time they raised the challenge of expanding this model to solve its existing problems. One of the demonstrations of the SM expansion models is new massive carriers of interactions, which can be detected in the form of resonances. Particular attention is paid to the search for resonances that are born accompanied by heavy quarks and decay into heavy quarks. To analyze such processes, we consider systems consisting of two t and two b quarks, formed in pp collisions at an energy of 13 TeV, where a maximum cumulative luminosity of 140 fb-1 has been accumulated. The work presents models of interactions that include the birth and decay of such resonances. Methods for their identification and categories of events in which pairs of heavy quarks are present, effective event analysis variables, and the relationship of these variables with resonance parameters are considered. The role of Monte Carlo modeling of SM processes and the birth of new resonances for describing the characteristics of measured interactions is shown. The results of a joint description of the characteristics of such interactions and preliminary estimates of the probability of the presence of new massive resonances in systems of several heavy SM quarks are presented.
Show AbstractThis paper elaborates and expands on earlier presented likelihood-based asymptotic methods of statistical analysis in high-energy physics. An explicit derivation of earlier presented asymptotic formulae for estimating the statistical significance of the discovery of new phenomena and setting upper limits on parameters of «new physics» models is given using the results of Wilks and Wald. The formulae obtained in combination with the use of the so-called «Asimov dataset» are of great interest due to their simplicity and the possibility of accounting for systematic uncertainties. The methodology of using these formulae is also shown in this paper and their accuracy is being verified by Monte Carlo modeling.
Show AbstractThis study describes the angular distributions of nuclear fission fragments, based on the following main approaches: the fissile nucleus remains cold until it scission into fission fragments, the formation of spin and orbital moments of fission fragments occurs due to transverse bending and wriggling vibrations. Using the wave functions of zero transverse bending and wriggling vibrations, an analytical formula was constructed to estimate the average value of the orbital momentum and the angular distribution of fission fragments. These results are important for understanding nuclear fission processes and can be used to model them more accurately.
Show AbstractAddition of a Λ-hyperon to non-strange nuclei can result in an increase of binding energy and formation of bound hypernuclei with unbound nucleon cores, effectively shifting the nucleon drip lines on the hypernuclear chart. The structure of light neutron-rich hypernuclei is treated within the Hartree-Fock approach with potentials in the Skyrme form. We show that nuclei 10Li is likely bound by a Λ-hyperon, while adding the hyperon to 9He and 10He does not bind them.
Show AbstractThis work examines existing approaches to simulation of polymer materials destruction processes under the action of superthermal oxygen atoms with respect to the conditions of the near-Earth space. The parameters of the reactions between hyperthermal oxygen atoms and a polyimide monomer, leading to the formation of volatile products such as CO2, CO and OH have been calculated using the density functional based tight-binding (DFTB) method and molecular dynamics method. The parameters obtained with two methods were compared.
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