Component Of Cosmic Rays Research Articles

Simulation of displacement damage in Si & SiO2 caused by protons

Nowadays Si & SiO2 have been the most widely used materials in semiconductor devices as CPU and other various integrated circuit chips, utilized in aerospace electronic systems, and at the same time protons are important components of cosmic rays that can cause displacement damage in Si & SiO2. Therefore, it is essential to study the displacement damage of Si & SiO2 caused by protons. The software of Geant4 is adopted in this paper, to simulate transportation process of incident protons with different energy in Si & SiO2. The simulation results indicates that primary knock-on atom (PKA) generated by incident proton in Si & SiO2 is predominant in lower energy range, its spatial distribution increases gradually along the direction of incident proton, and the scattering angle of the PKA is about 90°, following a Gaussian distribution approximately. And in lower energy range, 28Si and 16O generated by elastic scattering are a primary source of radiation damage in Si & SiO2. But as the proton energy increases, the contribution of nuclear inelastic scattering becomes more and more important, but the overall level of induced damage diminishes gradually. Meanwhile, the simulation results indicate that with increasing depth of the material, the non-ionizing energy loss (NIEL) increases gradually, and NIEL caused by elastic scattering is higher near the surface layer of the materials, and as for NIEL caused by nuclear inelastic scattering is also higher near the surface layer of the materials. The simulation results in this paper can provide useful data and theoretical guidance for study on Si & SiO2 displacement damage caused by proton irradiation.

Constraints on cosmic-ray boosted dark matter with realistic cross section

Sub-MeV cold dark-matter particles are unable to produce electronic recoil in conventional dark-matter direct detection experiments such as XENONnT and LUX-ZEPLIN above the detector threshold. The mechanism of boosted dark matter comes into picture to constrain the parameter space of such low mass dark matter from direct detection experiments. We consider the effect of the leading components of cosmic rays to boost the cold dark matter, which results in significant improvements on the exclusion limits compared to the existing ones. To present concrete study results, we choose to work on models consisting of a dark-matter particle χ with an additional U(1)' gauge symmetry including the secluded dark photon, U(1)B-L, and U(1)L e-L μ . We find that the energy dependence of the scattering cross section plays a crucial role in improving the constraints. In addition, we systematically estimate the Earth shielding effect on boosted dark matter in losing energy while traveling to the underground detector through the Earth.

Dynamics of Changes in the Intensity of Hard and Soft Components of Cosmic Rays in the Atmosphere

The dynamics of changes in the homogeneous intensity of the hard and soft components of cosmic radiation and the intensity of each of them separately, depending on the length of the atmospheric air layer are studied in the work.

A Multiple Scattering-Based Technique for Isotopic Identification in Cosmic Rays

Analyzing the isotopic composition of cosmic rays (CRs) provides valuable insights into the galactic environment and helps refine existing propagation models. A particular interest is devoted to secondary-to-primary ratios of light isotopic components of CRs, the measurement of which can provide complementary information with respect to secondary-to-primary ratios like B/C. Given the complexity of the concurrent measurement of velocity and momentum required to differentiate isotopes of the same Z, a task typically accomplished using magnetic spectrometers, existing measurements of these ratios only effectively characterize the low-energy region (below 1 GeV/nucl). This study introduces a novel technique for isotopic distinction in CRs at high energies up to 100 GeV/nucl based on multiple scattering, which, combined with the proposed measurement of velocity, represent an interesting alternative to magnetic spectrometers. The performance of this technique was assessed through a dedicated simulation using the GEANT4 package, with specific emphasis on Z = 1 isotopes.

Cosmic-ray exposure assessment using particle and heavy ion transport code system: case study Douala-Cameroon.

According to UNSCEAR, cosmic radiation contributes to ~16% (0.39mSv/y) of the total dose received by the public at sea level. The exposure to cosmic rays at a specific location is therefore a non-negligible parameter that contributes to the assessment of the overall public exposure to radiation. In this study, simulations were conducted with the Particle and Heavy Ion Transport code System, a Monte Carlo code, to determine the fluxes and effective dose due to cosmic rays received by the population of Douala. In minimum solar activity, the total effective dose considering the contribution of neutron, muon+, muon-, electron, positron and photon, was found to be 0.31±0.02mSv/y at the ground level. For maximum solar activity, it was found to be 0.27±0.02mSv/y at ground level. During maximum solar activity, galactic cosmic rays are reduced by solar flares and winds, resulting in an increase in the solar cosmic-ray component and a decrease in the galactic cosmic-ray component on Earth. This ultimately leads to a decrease in the total cosmic radiation on Earth. These results were found to be smaller than the UNSCEAR values, thus suggesting a good estimation for the population of Douala city located near the equatorial line. In fact, the cosmic radiation is more deflected at the equator than near the pole. Muons+ were found to be the main contributors to human exposure to cosmic radiation at ground level, with ~38% of the total effective dose due to cosmic exposure. However, electrons and positrons were found to be the less contributors to cosmic radiation exposure. As regards the obtained results, the population of Douala is not significantly exposed to cosmic radiation.

Intensity of the neutron component of cosmic rays and air humidity

Neutron monitor data is currently corrected only for the barometric effect. We cannot, however, exclude that changes in air humidity affect the intensity of the cosmic-ray neutron component recorded by neutron monitors. In this regard, we have carried out continuous measurements of air humidity and temperature when observing variations in the cosmic ray intensity with a neutron monitor in Novosibirsk. Analysis of the results of observations of meteorological parameters and cosmic ray intensity in Novosibirsk, as well as data from the global network of neutron monitors, made it possible to identify neutron component intensity variations caused by changes in air humidity. The estimated humidity effect indicates the need to regularly take it into account in the neutron monitor data. To do this, along with atmospheric pressure, regular measurements of humidity and air temperature should be performed.

Investigate cosmic rays: Analysis of the air showers

In this lab report, the concept of cosmic rays and their components that can be detected on the earth’s surface is introduced. In this experiment, four CosmicWatch muon detectors were used to detect the components of cosmic rays. This report describes the setup of the experiment as well as the method and algorithms used to filter the true signals of cosmic rays out of the background radioactive noises. Some process of the algorithm is visualized using histograms. The rate of air showers was found to be 0.151 mHz ± 0.022 mHz for a separation of 6.73 cm ± 0.08 cm, and 0.096 mHz ± 0.015 mHz for a separation of 13.5 cm ± 0.1 cm. Other sources of uncertainties are also analyzed in this report.

Galactic Diffuse Emission from Radio to Ultra-high-energy γ-Rays in Light of Up-to-date Cosmic-Ray Measurements

Cosmic rays (CRs) travel throughout the Galaxy, leaving traces from radio to ultra-high-energy γ-rays due to interactions with the interstellar gas, radiation field, and magnetic field. Therefore, it is necessary to utilize multiwavelength investigations on the Galactic diffuse emission to shed light on the physics of CR production and propagation. In this work, we present a spatially dependent propagation scenario, taking account of a local source contribution, while making allowances for an additional CR component freshly accelerated near their sources. In this picture, after reproducing the particle measurements at the solar system, we calculated the intensity and compared the spectral energy distribution to observations from Fermi-LAT and LHAASO-KM2A in the γ-ray band, and from WMAP and Planck among other radio surveys at lower energies. Multiband data considered in conjunction, the former comparison exhibits sufficiently good consistency in favor of our model, while the latter calls for improvement in data subtraction and processing. From this standpoint, there remains potential for advanced observations at energies from milli-eVs to MeVs toward the Galactic plane, in order to evaluate our model further and more comprehensively in the future.

Deuteration of molecular clumps induced by cosmic rays

The D/H ratio in astrophysical environments has instigated the scientists for at least 50 years. The wide range of values in the interstellar medium (ISM) from 10e to 7 to 10e-1 have usually been claimed to be due to small zero-point energy differences between reactants and products involving D and H (mainly at low temperatures). Here, we present a new source of deuteration processes in the ISM clouds as a result of cosmic ray irradiation. As a study object, we consider a typical molecular clump under the presence of incoming cosmic rays simulated computationally. The calculations were performed employing the Monte Carlo toolkit GEANT4 code (considering hadronic physics) and considering mainly the proton and alpha component of the incoming cosmic rays from the ISM (the dominant ones for the production of secondary protons and deuterons). The results suggest an increasing D/H ratio as function of time in the central part of molecular clumps (<200 AU) with the largest deuteration in the central region of the cloud, and a bump in the D/H ratio around 2–10 AU (which becomes more pronounced for clouds with larger timescales; > 10 Myrs). The results also show that for timescales between 10 and 100 Myrs the central part of the cloud has D/H around 6-16e-3, a value compatible with the observed D/H in some interstellar clouds. This work adds a new piece to the D/H puzzle of the ISM and might also help to explain the D/H ratio measured in different objects inside the Solar system.

The composition of cosmic rays according to the data on EAS cores

The main purpose of this work is to find the causes of the break of the cosmic ray spectrum at an energy of 3 PeV, which is called the knee. The solution of the problem is associated with the determination of the nuclear composition of cosmic rays in the knee area. The conclusions of this work are based on the analysis of the characteristics of the EAS cores obtained using X-ray emulsion chambers. According to these data, a number of anomalous effects are observed in the knee region, such as scaling violation in the spectra of secondary hadrons, an excess of muons in EAS with gamma families and others. At the same energies equivalent to 1-100 PeV the laboratory system colliders show scaling behavior. So analysis of the data on the EAS cores suggests that the knee in their spectrum is formed by a component of cosmic rays of a non-nuclear nature, possibly consisting of stable (quasi-stable) particles of hypothetical strange quark matter, which named strangelets. This is the only model of the knee compatible with the magnetic rigidity of the nuclear spectra break R=100 TV. In fact, stranglets are stable heavy quasi-nuclei with a positive electric charge of Z=30-1000, so the mechanism of their acceleration coincides with the nuclear one. The break of the cosmic ray spectrum can be associated with a significantly larger mass of strangelets compared to nuclei.

On irregularities in the cosmic ray spectrum of \(10^{16}-10^{18}\) eV range

Existing small, medium and large arrays for the study of cosmic rays of ultra-high energies are aimed for obtaining information about our galaxy and extragalactic space, namely to search and study astronomical objects that produce the flux of relativistic particles. The drift and interaction of such particles with magnetic fields and shock waves taking place in interstellar space causes the same interest. The shape of the energy spectrum of cosmic rays in the energy range 10^{15}-10^{18}1015−1018 eV, where the "knee" and the "second knee’’ are observed, can be formed as a superposition of the partial spectra of various chemical elements. Verification of galactic models, using recent experimental spectral data, makes it possible to study the nature of the galactic and extragalactic components of cosmic rays. The paper presents the result of the energy spectrum of cosmic rays in the range 10^{16}-10^{18}1016−1018 eV of measurements obtained with the Small Cherenkov array - a part of the Yakutsk array.

Implications of a Possible Spectral Structure of Cosmic-Ray Protons Unveiled by the DAMPE

The recent observations revealed that the cosmic-ray (CR) proton spectrum showed a complex structure: the hardening at ∼200 GeV and softening at ∼10 TeV. However, so far, the physical origins of this spectral feature remain strongly debated. In this work, we simulate the acceleration of CR protons in a nearby supernova remnant (SNR) by solving numerically the hydrodynamic equations and the equation for the quasi-isotropic CR momentum distribution in the spherically symmetrical case to derive the spectrum of protons injected into the interstellar medium, and then simulate the propagation process of those accelerated CR particles to calculate the proton fluxes reaching the Earth. Besides, we use the DRAGON numerical code to calculate the large-scale CR proton spectrum. Our simulated results are in good agreement with the observed data (including the observed data of proton fluxes and dipole anisotropy). We conclude that the spectral feature of CR protons in this energy band may originate from the superposition of the distribution from the nearby SNR and background diffusive CR component. We find that the release of particles from this nearby SNR has a time delay. Besides, it can be found that the nonlinear response of energetic particles, the release time of CR protons, and age of the local SNR can leave strong signatures in the spectrum of the resulting CR proton fluxes.

Precipitation-related increase events of the electromagnetic component of secondary cosmic rays: Spectral analysis

We report the measurement results of differential spectra of electromagnetic radiation in the range 0.1–4 MeV, which occurs in the atmosphere as a component of secondary cosmic rays. Spectral monitoring was performed using a spectrometer based on the Nai (TL) crystal in 2022–2023. The main purpose of the measurements was to determine spectral characteristics of the electromagnetic radiation during increase events, when the electromagnetic radiation flux from the atmosphere rises by tens of percent with respect to the background level. From a thorough analysis of the spectra of many dozens of events, we have drawn a conclusion that although the lines of natural radionuclides are present on the spectra and contribute their share, their total contribution to the increase events is ~0.1 of the total energy supplied during an increase. We unambiguously conclude that the effect of increasing electromagnetic radiation during precipitation is not due to the presence of radionuclides in precipitation.

Связанные с осадками события возрастания электромагнитной компоненты вторичных космических лучей: спектральные измерения и анализ

We report the measurement results of differential spectra of electromagnetic radiation in the range 0.1–4 MeV, which occurs in the atmosphere as a component of secondary cosmic rays. Spectral monitoring was performed using a spectrometer based on the Nai (TL) crystal in 2022–2023. The main purpose of the measurements was to determine spectral characteristics of the electromagnetic radiation during increase events, when the electromagnetic radiation flux from the atmosphere rises by tens of percent with respect to the background level. From a thorough analysis of the spectra of many dozens of events, we have drawn a conclusion that although the lines of natural radionuclides are present on the spectra and contribute their share, their total contribution to the increase events is ~0.1 of the total energy supplied during an increase. We unambiguously conclude that the effect of increasing electromagnetic radiation during precipitation is not due to the presence of radionuclides in precipitation.

Simulation of cosmic rays inside an aircraft: spectral perturbation and dose reduction due to aircraft structures and contents.

In this study, an intricate combinatorial geometry model of a Boeing 777-300ER aircraft was constructed for Monte Carlo transport simulations. The aircraft-induced perturbations of the energy spectra and effective doses of secondary cosmic rays at a typical civil aviation altitude (10km) were investigated on a component-by-component basis, which included neutrons, protons, photons, electrons, positrons, muons and charged pions. Two geomagnetic cutoff rigidities (1.35 and 15.53 GV) and two solar modulation parameters (430 and 1360 MV) were considered in the aforementioned simulations. The characteristics of various cosmic-ray components at six locations along the fuselage were assessed and compared with those of an unperturbed radiation field in the atmosphere. Aircraft structures and contents reduced the effective doses of personnel inside the aircraft to varying degrees, up to an ~32% reduction in the middle section of the passenger cabin. On average, the dose reduction was ~12-16% depending on geomagnetic and solar conditions. Quantifying the aircraft's self-shielding effects can further improve the estimation accuracy of aircrew and passengers' exposure to cosmic radiation. Information regarding the perturbed energy spectra of cosmic rays may be useful for designing onboard experiments or analyzing onboard measurement data.

The Formalism of Milky-Way Antimatter-Domains Evolution

If baryosynthesis is strongly nonhomogeneous, macroscopic regions with antibaryon excess can be created in the same process from which the baryonic matter is originated. This exotic possibility can become real, if the hints to the existence of antihelium component in cosmic rays are confirmed in the AMS02 experiment, indicating the existence of primordial antimatter objects in our Galaxy. Possible forms of such objects depend on the parameters of models of baryosynthesis and evolution of antimatter domains. We elaborate the formalism of analysis of evolution of antibaryon domain with the account for baryon-antibaryon annihilation at the domain borders and possible “Swiss cheese” structure of the domain structure. We pay special attention to evolution of various forms of high, very high and ultrahigh density antibaryon domains and deduce equations of their evolution in the expanding Universe. The proposed formalism will provide the creation of evolutionary scenarios, linking the possible forms and properties of antimatter bodies in our Galaxy to the mechanisms of nonhomogeneous baryosynthesis.

Cosmic ray mass independent energy reconstruction method using Cherenkov light and muon content in LHAASO

The wide field-of-view Cherenkov telescope array of the Large High Altitude Air Shower Observatory (LHAASO) measures the longitudinal development of Cherenkov light in the air shower of cosmic rays, while the kilometer-square array of LHAASO measures the number of muons in the air shower. The unique detector arrangement of LHAASO can facilitate the precise reconstruction of the cosmic ray energy in the knee region. Thus, this study proposed a new energy reconstruction method by simultaneously using the Cherenkov light size and the number of muons, which is insensitive to the primary particle type. Using this method, the energy bias and resolution of the light component (proton and helium) were less than 1% and 10% at approximately 1 PeV, respectively. Moreover, the difference in energy bias between helium and proton was less than 1% at approximately 1 PeV. In addition, the dependence of this energy reconstruction method on hadronic interaction models and cosmic ray components was also discussed.

Cosmic-Ray Acceleration in Supernova Remnants

Supernova Remnants (SNRs) are generally believed to produce the cosmic rays in our Galaxy due to the powerful supernova blast waves generated by expanding SNRs. In contrast to the leptonic cosmic-ray component that is clearly seen by the SNR emission in a wide wavelength range, from radio to high-energy γ-ray, the hadronic cosmic-ray component can be detected only by very high energy γ-ray emission. Galactic SNRs of various ages have been intensively studied at very high energies. Among them are the shell-type SNRs: Tycho’s SNR, Cas A, IC 443, γCygni SNR, G166.0+4.3. The results of investigations of listed SNRs obtained in observations at 800 GeV–100 TeV energies by SHALON telescope are presented with spectral energy distribution and emission maps compared with experimental data from the wide energy range, from radio to high-energy gamma-rays. The TeV emission maps of supernova remnants obtained by SHALON are overlaid with ones viewed in radio- frequencies and X-rays to reveal SNR’s essential features which can lead to the effective generation of cosmic rays. The presented experimental data from high and very high energies are considered together with theoretical predictions to test the cosmic ray origin in these objects.

Correction of the Temperature Effect of Muon Counts Observed at the Guangzhou Station

Muons are the main component of secondary cosmic rays, and the variation in muon intensity indicates the variation in primary cosmic ray intensity. However, before using muons to study the variation in the intensity of cosmic rays, it is necessary to eliminate the atmospheric effects, such as pressure and temperature effects. In this work, the temperature effect of the muons is corrected in terms of empirical method by using ground temperature. The temperature correction is applied to the muon data observed at the Guangzhou station during the period 2010–2021 after a barometric correction. It is found that the effect of seasonal variations in temperature on muon counts is greatly eliminated in the corrected data. Furthermore, the muon data are well correlated with the neutron data in comparison, which verifies the reliability of the corrected muon data. Our results show that the correction of muon data by using ground temperature is an effective method.

Approaches to composition independent energy reconstruction of cosmic rays based on the LHAASO-KM2A detector

The kilometer-square array (KM2A) of the Large High Altitude Air Shower Observatory (LHAASO, located at 4410 m above sea level with an atmospheric depth of $600\text{ }\text{ }\mathrm{g}/{\mathrm{cm}}^{2}$) can simultaneously measure air shower sizes of both electromagnetic particles and muon contents with high precision for cosmic rays with energies in the knee region. An advantage of the LHAASO experiment is that it can be performed at the maximum depth of air showers of cosmic rays in the knee region. In this study, different methods to reconstruct the cosmic ray energy are investigated, including those based on traditional and combined parameters. The traditional methods based on ${N}_{\mathrm{size}}$ or ${\ensuremath{\rho}}_{50}$ to reconstruct the primary energy are dependent on the cosmic ray components. Based on Heitler's electromagnetic and Matthews' hadronic shower models, two combined parameters of ${N}_{e*\ensuremath{\mu}}$ and ${N}_{e\ensuremath{\mu}}$ are proposed. The examination of cosmic ray energy reconstruction methods based on the LHAASO-KM2A detector by combining the parameters of muons and electromagnetic particles, and the simulation results, confirmed the reduction in component dependence and bias of individual components. The dependence of energy reconstruction on hadronic interaction models is also discussed.