Investigation of electrostatic discharges during irradiation of elements of thermal control coatings of spacecraft radiators
Investigation of electrostatic discharges during irradiation of elements of thermal control coatings of spacecraft radiators
V. A. BASOV
This study analyzes the characteristics of electrostatic discharges occurring on the surface of K-208 glasses irradiated in a vacuum of $10^{-4}$~Pa by electrons with an energy of 40 keV at a particle flux density of $3\cdot 10^{10}$~cm$^{-2}$~s$^{-1}$ and varying the fluences from $10^{14}$ to $10^{16}$~cm$^{-2}$. Discharges of type 1 and type 2 with plasma ejection into the surrounding space were observed when the glasses were irradiated. The frequency of discharges increased and the amplitude of discharge currents decreased when the fluences were varied from $10^{14}$ to $10^{16}$~cm$^{-2}$. This is explained by the increase of glass electric conductivity caused by the change of stoichiometry and structure of the material during discharges. Along with electrostatic discharges, there are also breakdowns on the irradiated surface of the sample to the metal subsurface material of glass K-208. Under certain conditions, these processes may stimulate each other, that is, an electrostatic discharge may provoke a breakdown and vice versa.
Show AbstractDegradation of ECOM-1 material under electron irradiation
Degradation of ECOM-1 material under electron irradiation
A. M. Shamaev
The impact of ionizing radiation from outer space on the materials of the outer surfaces of spacecraft (SC) leads to the degradation of their functional properties. In particular, polymer composite materials used as a thermoregulatory coating for spacecraft are subjected to high dose loads. The article investigates the changes in the spectral reflectance of samples of the ECOM-1 material as a result of a series of four stages of irradiation in vacuum with electrons with energies of 40 keV and exposure of the samples between the next radiation exposure in room conditions. EKOM-1 is a composite material based on an acrylic copolymer filled with ZnO particles, and therefore one of the channels for its degradation, especially when irradiated with medium-energy particles, is the radiation-stimulated decomposition of the ZnO molecule. To interpret the experimental results, an elementary model of accumulation and annealing of radiation defects is presented. In the elementary model proposed below, it is postulated that the rate of change in the defect concentration $n(х,t)$ is proportional to the normalized energy release function $S_{normal}(x)$ in the ECOM-1 sample under electron irradiation. The calculation results, which demonstrate the nature of the change in the concentration of color centers during irradiation, showed that the concentration of defects with the time of irradiation reaches a certain level of saturation, which depends on the intensity of irradiation. This is due to the fact that during irradiation, along with the formation of defects, their annihilation occurs, for example, due to interaction with electrons thermalized in the material. The presented model requires its development, and at present can only serve to illustrate the process of accumulation of defects in the irradiated material.
Show AbstractSemi-empirical relations for the half-lives of superheavy elements
Semi-empirical relations for the half-lives of superheavy elements
D. F. Bayramov, T. Yu. Tretyakova
We considered phenomenological equations for the half-lives of superheavy elements through alpha decay and spontaneous fission channels predictions. Based on modern experimental data, new values of the fitting parameters were obtained and predictions of the full half-life and half-life periods were made by using spontaneous fission and alpha decay channels for Fm ($Z = 100$) and No ($Z=102$) isotopes.
Show AbstractElliptical and triangular flows of charged particles in relativistic collisions of Xe and Pb nucleus in the HYDJET++ model and experiment CMS (LHC)
Elliptical and triangular flows of charged particles in relativistic collisions of Xe and Pb nucleus in the HYDJET++ model and experiment CMS (LHC)
D. A. Miagkov$^1$, S. -. Petrushanko$^2$
This paper describes the simulation of particle production in Pb--Pb and Xe--Xe collisions at the energies of the Large Hadron Collider (LHC) using the HYDJET++ Monte Carlo generator. The distributions of elliptical $v_{2}$ and triangular $v_{3}$ flows of charged particles in two types of collisions are studied. The results of the HYDJET++ generator simulation are qualitatively compared with the experimental data of the Compact Muon Solenoid (CMS) detector.
Show AbstractImprovement of TalysLib library
Improvement of TalysLib library
G. V. Pampushik$^1$, N. A. Fedorov$^2$
This work describes the main features of TalysLib library. The addition of a functionality to TalysLib for automatically obtaining experimental information from EXFOR is discussed. Several approaches to automating the acquisition of experimental data have been tested.
Show AbstractMass relations for unknown atomic nuclei mass predictions
Mass relations for unknown atomic nuclei mass predictions
T. Yu. Tretyakova$^{1,2}$, A. P. Ivleva$^2$
On the basis of the AME2020 data we consider the mass relations such as $\Delta_{np}$, $\delta V_{np}$ and Harvey-Kelson relations that are associated with neutron-proton correlations and can be used to predict masses of unknown atomic nuclei. The behavior of these characteristics is analyzed within the framework of the liquid drop model and in the Hartree-Fock microscopic approach in comparison with modern experimental data. New approximations of $\Delta_{np}$ and $\delta V_{np}$ as functions of the mass number $A$ are obtained.
Show AbstractDirected propagation of the scalar potential of Pocchammer-Chree waves in auxetics: projection operators method
Directed propagation of the scalar potential of Pocchammer-Chree waves in auxetics: projection operators method
D. V. Ampilogov, M. A. Dmitrieva
We investigate the problem of propagation of scalar potential of Pocchammer-Chree waves in cylindrical auxetic. The approximated equation of evolution of are built by means of projection operators method. The general solution for left and right waves is obtained.
Show AbstractAerogel radiator for the Super Charm-Tau Factory
Aerogel radiator for the Super Charm-Tau Factory
A. A. Katcin$^{1,2}$, A. Yu. Barnyakov$^{1,3}$, M. Yu. Barnyakov$^{1,3}$, V. S. Bobrovnikov$^{1,2}$, A. R. Buzykaev$^1$, A. F. Danilyuk$^4$, S. A. Kononov$^{1,2}$, E. A. Kravchenko$^{1,2}$, I. A. Kuyanov$^1$, I. V. Ovtin$^{1,2}$, N. A. Podgornov$^{1,2}$, A. S. Shalygin$^4$
Particle identification system based on Focusing Aerogel RICH (FARICH) detector is considered as an option for the future experiments at the Super Charm-Tau Factory (Russia). New samples of focusing 4-layer aerogels with maximal refractive index 1.065 were produced in 2020–2021. First beam test results with relativistic electrons demonstrate single photon resolution (SPR) of 9-10 mrad. According to simulation results, the aerogels with such SPR are able to provide mu\pi-separation at the level of more than 3 standard deviations for tracks with momentum 1.5 GeV/c.
Show AbstractRare Semileptonic $B^+ \to \pi^+ \tau^+ \tau^-$ Decay within Perturbative QCD
Rare Semileptonic $B^+ \to \pi^+ \tau^+ \tau^-$ Decay within Perturbative QCD
I. M. Parnova, A. Y. Parkhomenko
Rare $B$-meson decays originated by flavor changing neutral currents (FCNCs), $b\to s$ and $b\to d$ quark transitions, are especially sensitive to New physics effects due to the smallness of their decay width. $B$-meson decays due to the $b\to s$ transition have been studied experimentally and theoretically, in a difference to $b\to d$ transitions, in particulear, the $B^+ \to \pi^+ \mu^+ \mu^-$ decay was observed by the LHCb collaboration in 2012 only. This decay is well studied theoretically and predictions are in agreement with experimental data obtained by same collaboration in 2015. It is also of interest to consider a similar decay, where a pair of tauons is chosen as the final pair of leptons. Theoretical predictions for the $B^+ \to \pi^+ \tau^+ \tau^-$ branching fraction are presented based on the effective electroweak Hamiltonian approach, depending on the choice of the parametrization of the formfactors entering the $B \to \pi$ matrix elements. A possibility of the $B \to \pi \tau^+ \tau^-$ observation at the LHC and SuperKEKB is discussed.
Show AbstractThe spatial resolution measurements of the Super charm-tau factory drift chamber small prototype
The spatial resolution measurements of the Super charm-tau factory drift chamber small prototype
I. Yu. Basok$^1$, A. V. Bykov$^1$, B. D. Kutsenko$^{1,2}$, D. A. Kyshtymov$^{1,2}$, V. G. Prisekin$^1$, K. Yu. Todyshev$^{1,2}$
The Budker Institute of Nuclear Physics is actively developing the Super charm-tau factory (SCTF) project, which is a mega-science class installation, that will be used to study rare c-quark and tau-lepton decays. The main part of a SCTF detector is a drift chamber, based on which the track reconstruction of charged particles is carried out. Accuracy of the trajectory reconstruction, i.e. a spatial resolution, is one of the main characteristics of the detector. This work is devoted to the experimental measurement of the spatial resolution on a drift chamber small prototype. The wire structure of the prototype consists of seven hexagonal cells that reproduce the cell of the first detector layer. The setup was calibrated during cosmic particles track reconstructions. In the work, the resolution of (97 ± 6) µm was obtained, and this demonstrates the possibility of obtaining the design parameters of the drift chamber based on the proposed wire structure. The results of this study were presented at the «Super c-tau factory» summer scientific school in Sarov in 2022.
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