Observations Of Cosmic Rays Research Articles

Detection response of the active components of the SciBar Cosmic Ray Telescope at Sierra Negra

The Scibar Cosmic-Ray Telescope (SciCRT) is the most promising detector of the Sierra Negra Cosmic Rays Observatory (SN-CRO). At this location, being a target and a tracker of secondary cosmic rays, the SciCRT offers a high probability of observing solar energetic particles and lower energy galactic cosmic rays (LEGCR); also, it allows the identification of incoming particles by measuring their energy deposition. In this work we present a Geant4-based simulation of the energy deposited by neutrons, γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma $$\\end{document}-rays, protons, electrons and muons in the optimally running SciCRT components. We also calculated the detection efficiency of the SciCRT at its current state. Our simulation results provide new information about the SciCRT detection response that may be used as a basis to estimate and analyze the energy spectra of primary particles.

High resolution gamma/hadron and composition discriminant variable for water-Cherenkov detector cosmic-ray observatories

High resolution gamma/hadron and composition discriminant variable for water-Cherenkov detector cosmic-ray observatories

Мониторинг околоземного космического пространства, магнитосферы и атмосферы Земли в периоды Форбуш-эффектов в конце августа 2005 г.

We present the results of near-Earth interplanetary space, magnetosphere, and atmosphere monitoring during large-scale solar wind disturbances at the end of August 2005. The monitoring was carried out using ground-level cosmic ray (CR) observations made at the worldwide network of neutron monitors as well as muon telescopes in Yakutsk and Novosibirsk. As a result of the analysis performed by different methods, we have obtained variation properties of CRs of different rigidities in Earth’s orbit, their pitch angle anisotropy, orientation and configuration of the interplanetary magnetic field, changes in the planetary system of geomagnetic cutoff rigidities during geomagnetic disturbances, as well as mass average air temperature over CR stations equipped with muon telescopes. For the periods of geomagnetic disturbances, we have determined parameters of magnetospheric ring current and magnetopause currents.

Monitoring of near-Earth space, Earth’s magnetosphere and atmosphere during Forbush decreases in August 2005

We present the results of near-Earth interplanetary space, magnetosphere, and atmosphere monitoring during large-scale solar wind disturbances at the end of August 2005. The monitoring was carried out using ground-level cosmic ray (CR) observations made at the worldwide network of neutron monitors as well as muon telescopes in Yakutsk and Novosibirsk. As a result of the analysis performed by different methods, we have obtained variation properties of CRs of different rigidities in Earth’s orbit, their pitch angle anisotropy, orientation and configuration of the interplanetary magnetic field, changes in the planetary system of geomagnetic cutoff rigidities during geomagnetic disturbances, as well as mass average air temperature over CR stations equipped with muon telescopes. For the periods of geomagnetic disturbances, we have determined parameters of magnetospheric ring current and magnetopause currents.

Closer scrutiny of cosmic ray proton energy losses

The percent-level precision attained by modern cosmic ray (CR) observations motivates reaching a comparable or better control of theoretical uncertainties. Here we focus on energy-loss processes affecting low-energy CR protons (∼0.1–5 GeV), where the experimental errors are small and collisional effects play a comparatively larger role with respect to collisionless transport ones. We study three aspects of the problem: (i) We quantitatively assess the role of the nuclear elastic cross section, for the first time, providing analytical formulas for the stopping power and inelasticity; (ii) We discuss the error arising from treating both elastic and pion production inelastic interactions as continuous energy loss processes, as opposed to catastrophic ones. The former is the approximation used in virtually all modern numerical calculations; (iii) We consider subleading effects such as relativistic corrections, radiative and medium processes in ionization energy losses. Our analysis reveals that neglecting (i) leads to errors close to 1%, notably around and below 1 GeV, neglecting (ii) leads to errors reaching about 3% within the considered energy range, (iii) contributes to a minor effect, gauged at the level of 0.1%. Consequently, while (iii) can currently be neglected, (ii) warrants consideration, and we also recommend incorporating (i) into computations. We conclude with some perspectives on further steps to be taken towards a high-precision goal of theoretical CR predictions regarding the treatment of energy losses. Published by the American Physical Society 2024

The HERO Project (High Energy Cosmic Ray Observatory): Objectives and Design Layout

The HERO Project (High Energy Cosmic Ray Observatory): Objectives and Design Layout

Unveiling the mysteries of magnetic monopoles in the electroweak symmetry breaking era

The theoretical existence of magnetic monopoles within the framework of electroweak unification and quantum field theories presents one of the most intriguing puzzles in modern physics. This article explores the formation, theoretical implications, and potential experimental signatures of magnetic monopoles emerging from electroweak symmetry breaking. Through a detailed analysis of their theoretical foundation, including Dirac's quantization, monopole solutions in non-Abelian gauge theories, and their role in Grand Unified Theories (GUTs), we delve into the profound implications these entities have for the Standard Model and beyond. We further examine the challenges and prospects of detecting magnetic monopoles through particle accelerator experiments, cosmic ray observations, and their significance in the quest for a unified theory of quantum gravity. Our investigation not only highlights the current state of theoretical and experimental efforts but also underscores the pivotal role magnetic monopoles play in bridging the gap between quantum mechanics and cosmological phenomena, offering insights into the early universe's symmetry-breaking events and the fundamental forces that shape our universe.

Optical Properties and Possible Origins of Atmospheric Aerosols over LHAASO in the Eastern Margin of the Tibetan Plateau

The accuracy of cosmic ray observations by the Large High Altitude Air Shower Observatory Wide Field-of-View Cherenkov/Fluorescence Telescope Array (LHAASO-WFCTA) is influenced by variations in aerosols in the atmosphere. The solar photometer (CE318-T) is extensively utilized within the Aerosol Robotic Network as a highly precise and reliable instrument for aerosol measurements. With this CE318-T 23, 254 sets of valid data samples over 394 days from October 2020 to October 2022 at the LHAASO site were obtained. Data analysis revealed that the baseline Aerosol Optical Depth (AOD) and Ångström Exponent (AE) at 440–870 nm (AE440–870nm) of the aerosols were calculated to be 0.03 and 1.07, respectively, suggesting that the LHAASO site is among the most pristine regions on Earth. The seasonality of the mean AOD is in the order of spring > summer > autumn = winter. The monthly average maximum of AOD440nm occurred in April (0.11 ± 0.05) and the minimum was in December (0.03 ± 0.01). The monthly average of AE440–870nm exhibited slight variations. The seasonal characterization of aerosol types indicated that background aerosol predominated in autumn and winter, which is the optimal period for the absolute calibration of the WFCTA. Additionally, the diurnal daytime variations of AOD and AE across the four seasons are presented. Our analysis also indicates that the potential origins of aerosol over the LHAASO in four seasons were different and the atmospheric aerosols with higher AOD probably originate mainly from Northern Myanmar and Northeast India regions. These results are presented for the first time, providing a detailed analysis of aerosol seasonality and origins, which have not been thoroughly documented before in this region, also enriching the valuable materials on aerosol observation in the Hengduan Mountains and Tibetan Plateau.

One large area trigger detector for cosmic ray telescope system

The large area trigger detector is a key instrument in cosmic ray telescope system. One large area detector, sensitive size 1.3 * 2 m2, is proposed in this paper based on plastic scintillator tiles and wavelength shift optical fibers. Thanks to the wavelength shift fibers coupling to the scintillator tiles, only one photomultiplier tube is used to output the signals for whole large area detector. So this detector is simple and economy. The signal uniformity of this detector is better than 96% over the whole surface including the edges or corners. The detection efficiency of the muon is higher than 95%, and the time resolution is better than 10 ns over the entire detector. These performances are sufficient for the trigger detector in most cosmic ray telescope system.

Ecological transition for the gas mixtures of the MRPC cosmic ray telescopes of the EEE Project

The Extreme Energy Events (EEE) Collaboration is fully involved in an ecological transition. The use of the standard gas mixture, C2H2F4 + SF6, has stopped in favor of an alternative green mixture based on C3H2F4 with the addition of He or CO2.The choise of these new mixtures is motivated by the significant lower Global Warming Potential (GWP) to reduce the emission of gases potentially contributing to the greenhouse effect.The EEE experiment consists of 61 muon telescopes based on Multigap Resistive Plate Chambers (MRPCs), each telescope composed of 3 chambers filled with gas.Several EEE detectors are today completely fluxed with the new ecological mixture. This contribution will report recent results about the telescope performance obtained from studies with the eco-friendly alternative mixture carried out in the last years.

The high-performance DIRC for the ePIC detector at the EIC

The next-generation nuclear physics facility in the United States will be the Electron-Ion Collider (EIC), scheduled to be built at Brookhaven National Laboratory (BNL). Excellent particle identification (PID) is one of the key requirements for the EIC central detector called ePIC. Identification of the hadrons in the final state is critical to study how different quark flavors contribute to nucleon properties. A detector using the Detection of Internally Reflected Cherenkov light (DIRC) principle, with a radial size of only 7-8 cm, was chosen as the PID system for the ePIC barrel region. Within the framework of the EIC R&D programs, the development of a high-performance DIRC (hpDIRC) detector was undertaken with the aim of significantly advancing state-of-the-art performance. Key components of the hpDIRC detector are a 3-layer compound lens and small pixel-size photo sensors. Currently, the hpDIRC R&D program is focused on developing and validating the radiation hard 3-layer lens, quality assurance of the BaBar DIRC radiation bars, and the early stage of the hpDIRC prototype program with Cosmic Ray Telescope at Stony Brook University, in preparation for beam tests at Fermilab in 2024.

A Comprehensive Comparison of Various Galactic Cosmic-Ray Models to the State-of-the-art Particle and Radiation Measurements

Galactic cosmic rays (GCRs) are the slowly varying background energetic particles that originate outside the solar system, are modulated by the heliospheric magnetic field, and pose ongoing radiation hazards to deep space exploration missions. To assess the potential radiation risk, various models have been developed to predict the GCR flux near Earth based on propagation theories and/or empirical functions. It is essential to benchmark these models by validating against the state-of-the-art measurements. In this work, a comprehensive model–observation comparison of the energy-dependent particle flux has been performed, by combining five typical GCR models and observational data from the Cosmic Ray Isotope Spectrometer on board the Advanced Composition Explorer spacecraft at relatively lower energies and data from the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics and Alpha Magnetic Spectrometer at higher energies. The analysis shows that, out of the five models investigated in this study, the optimal model, characterized by minimal relative difference or reduced chi-square divergence from measurements, depends on the particle type, energy range, and epoch of interest. Furthermore, a silicon slab is applied to compute the absorbed dose rate using conversion factors applied to GCR model outputs, and the results are compared to measurements from the Cosmic Ray Telescope for the Effects of Radiation. The comparisons in this paper have implications for the strengths and limitations of individual GCR models, advance our comprehension of the underlying GCR transport mechanisms, and also have strong application aspects for mitigating space radiation risks.

Evolution of the cosmic ray spectrum during a Forbush decrease

The Antarctic Cosmic Ray Observatory (ORCA) has been in continuous operation since January 2020 and in nominal phase since March 2021 at the Spanish Antarctic Base Juan Carlos I (Livingston Island, Antarctica 62°39′46′′S,60°23′20′′W at 12 m above sea level) at an effective vertical cutoff rigidity of R=2.37 GV. ORCA consists of two neutron monitors, ORC-A with three BF3 counter tubes following the NM64 standard, and ORC-B, with three bare BF3 counter tubes; and a muon telescope, ORC-M consisting of two 1 m2 scintillators with the neutron monitors between them. ORCA provides neutron count rates at two different energy thresholds (provided by ORC-A and ORC-B) and muon count rates and muon incidence directions throughout the ORCA volume. The neutron-producing cosmic rays observed in ORC-A have a lower rigidity threshold than the muon-producing ones observed in ORC-M. The relationship between them gives an idea about the change in the slope of the cosmic ray spectrum at the corresponding thresholds, 2.37 GV for ORC-A and ≈12 GV for ORC-M. This relation allows to investigate the change in the cosmic ray spectrum along the different regions in an Interplanetary Coronal Mass Ejection, i.e. the shock, the sheath and the magnetic cloud. ORCA first observations are presented, focusing on the analysis of the Forbush Decrease (FD) that happened at the beginning of November 2021. We present these observations and show the promising capabilities of the Antarctic Cosmic Ray Observatory, which represents a new concept of cosmic ray and solar energetic particle detector. The cosmic ray spectrum changes during the Forbush decrease detected in early November 2021 as seen in the change in the ratio of ORC-A to ORC-M count rates. This change is clear after the arrival of the shock and during the magnetic cloud being smoother or even flat in the sheath. In addition, the secondary muons show changes in their arrival directions along the ICME, being clear the different behavior in shock, sheath and magnetic cloud.

Spectra and anisotropy of cosmic rays during gle64

Ground-based observations of cosmic rays by the spectrographic global survey method were used to study the ground-level enhancement in cosmic ray intensity on August 24, 2002. Spectra of variations of primary cosmic rays and their anisotropy were obtained. Based on measurements from the GOES spacecraft and global network of cosmic ray stations, the differential rigidity spectra of accelerated particles in the vicinity of the Sun were calculated. The maximum rigidity to which solar particles were accelerated was estimated.

Investigating the heliosphere, magnetosphere, atmosphere, and properties of cosmic rays during the 2018 Aug 25–26 strong geomagnetic storm

We investigated the conditions of the heliosphere, magnetosphere, and atmosphere from cosmic ray (CR) observations during the 2018 Aug 25–26 strong geomagnetic storm. The analysis involved the global survey (GS) and the spectrographic global survey (SGS) methods created and developed at the Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy of the Siberian Branch of the Russian Academy of Sciences (ShICRA SB RAS) and at the Institute of Solar-Terrestrial Physics of the Siberian Branch of the Russian Academy of Sciences (ISTP SB RAS). Also, in our analysis, we used the data on direct measurements of the interplanetary medium parameters from the known OMNI database, CR measurements at the GOES geostationary satellites, from the global network of neutron monitors and muon detectors, from the Sayan spectrograph, and from the A.I. Kuzmin Yakutsk spectrograph of CR. When analyzing this event, the SGS enabled to obtain the data on the orientation of the mean interplanetary magnetic field, on the geomagnetic cutoff rigidity and its variations during the geomagnetic storm. Also, this method allowed us to estimate the bulk temperature over the point of recording CR, the ring current and the magnetopause current, as well as their contributions to the Dst-index, and also to establish differential rigidity spectra of CR at different stages of the magnetic storm evolution. Through the GS method, we determined the value and the directions for the first two spherical harmonics of CR distribution, and the direction to their anisotropy source. The results obtained through two different global survey methods are shown to be agree and mutually supplement each other. Using the Yakutsk spectrograph records enabled to determine the index for the power energy spectrum of variations in CR intensity during the investigated event.

Study of Atmospheric Depth Profiles at LHAASO Using the MSISE-90 Model

High Altitude Cosmic Ray Observatory (LHAASO) is located at Haizi Mountain in Daocheng County, Sichuan Province. Its Wide Field of view Cherenkov Telescope Array (WFCTA) primarily studies cosmic rays by observing the Cherenkov light signals produced during extensive air showers. Calibration, simulation, and reconstruction of WFCTA are all related to atmospheric depth. The currently used atmospheric depth model is the US Standard Atmosphere Depth Profile Model. In this study, the US Standard Atmosphere Depth Profile Model is compared with the atmospheric depth profile recorded by the infrared radiometer SABER carried by the satellite TIMED at LHAASO from 14 km to 50 km, as well as with the atmospheric depth recorded by the ground meteorological station at LHAASO. The atmospheric depth obtained from the US Standard Atmosphere Model is consistently smaller. The MSISE-90 atmospheric model describes the neutral temperature and density from the Earth's surface to the thermosphere. Further research shows good consistency between the MSISE-90 atmospheric model and the atmospheric depth recorded by TIMED/SABER and the ground standard meteorological station at LHAASO. According to the MSISE-90 atmospheric model, the mean atmospheric depth profile at LHAASO is lowest in January, followed by February, March, April, November, and December, which are also the optimal observation months for WFCTA operation. The atmospheric boundary layer is highest in April, and there is about 2% diurnal variation in atmospheric depth. Using the functional form of the US Standard Atmosphere Model, the atmospheric depth profiles from 4.4 to 100 kilometers were fitted for each month, obtaining monthly atmospheric depth profile models at the LHAASO site. And compared the lateral distribution of the Cherenkov photons produced by 100 TeV cosmic-ray protons incident at a zenith angle of 30° in the MSISE-90 atmospheric model and the US Standard Atmosphere Model,with the maximum difference reaching approximately 20%.

EUSO-Offline: A comprehensive simulation and analysis framework

The complexity of modern cosmic ray observatories and the rich data sets they capture often require a sophisticated software framework to support the simulation of physical processes, detector response, as well as reconstruction and analysis of real and simulated data. Here we present the EUSO-Offline framework. The code base was originally developed by the Pierre Auger Collaboration, and portions of it have been adopted by other collaborations to suit their needs. We have extended this software to fulfill the requirements of Ultra-High Energy Cosmic Ray detectors and very high energy neutrino detectors developed for the Joint Exploratory Missions for an Extreme Universe Observatory (JEM-EUSO). These path-finder instruments constitute a program to chart the path to a future space-based mission like POEMMA. For completeness, we describe the overall structure of the framework developed by the Auger collaboration and continue with a description of the JEM-EUSO simulation and reconstruction capabilities. The framework is written predominantly in modern C++ (compliled against C++17) and incorporates third-party libraries chosen based on functionality and our best judgment regarding support and longevity. Modularity is a central notion in the framework design, a requirement for large collaborations in which many individuals contribute to a common code base and often want to compare different approaches to a given problem. For the same reason, the framework is designed to be highly configurable, which allows us to contend with a variety of JEM-EUSO missions and observation scenarios. We also discuss how we incorporate broad, industry-standard testing coverage which is necessary to ensure quality and maintainability of a relatively large code base, and the tools we employ to support a multitude of computing platforms and enable fast, reliable installation of external packages. Finally, we provide a few examples of simulation and reconstruction applications using EUSO-Offline.

Long‐Term Variation of the Galactic Cosmic Ray Radiation Dose Rates

AbstractIn this work, a model for calculating the galactic cosmic rays (GCRs) radiation dose rate is developed. The model is based on a GCR modulation model, which is established by Shen and Qin, and the fluence‐dose conversion coefficients (FDCCs) published by the International Commission on Radiological Protection (ICRP). With the model, the radiation absorbed dose rate of GCRs near the lunar surface over long time periods is calculated and compared with the observation data from the Cosmic Ray Telescope for the Effects of Radiation and the Lunar Lander Neutron and Dosimetry. First, the energy spectrum of GCRs at 1 AU in the ecliptic, where the lunar orbit is located, is computed using the GCR modulation model. Then, using the FDCCs of ICRP 123, the absorbed dose rates of 15 human organs/tissues at the lunar orbit position are calculated to represent the general absorbed dose rate of the body (in water). Furthermore, considering the albedo radiation (excluding neutrons) and using the water‐silicon conversion coefficients, the total absorbed dose rates of GCRs near the lunar surface (in silicon) are calculated, it is shown that our modeling results generally agree with the observations from spacecraft. This work is useful for future manned space exploration to the Moon or other celestial bodies in the solar system.

Small-scale Cosmic-Ray Anisotropy Observed by the GRAPES-3 Experiment at TeV Energies

GRAPES-3 is a mid-altitude (2200 m) and near-equatorial (11.°4N) air shower array, overlapping in its field of view for cosmic-ray observations with experiments that are located in the Northern and Southern Hemispheres. We analyze a sample of 3.7 × 109 cosmic-ray events collected by the GRAPES-3 experiment between 2013 January 1 and 2016 December 31 with a median energy of ∼16 TeV for study of small-scale (<60°) angular-scale anisotropies. We observed two structures, labeled A and B, that deviate from the expected isotropic distribution of cosmic rays in a statistically significant manner. Structure A spans 50°–80° in R.A. and from −15° to 30° in decl. The relative excess observed in structure A is at the level of (6.5 ± 1.3) × 10−4 with a statistical significance of 6.8 standard deviations. Structure B is observed in the R.A. range 110°–140° and at decl. from −10° to 30°. The relative excess observed in this region is at the level of (4.9 ± 1.4) × 10−4 with a statistical significance of 4.7 standard deviations. These structures are consistent with those reported by Milagro, ARGO-YBJ, and HAWC. These observations could provide a better understanding of the sources of cosmic rays, their propagation, and the magnetic structures in our Galaxy.

Reconstruction of air shower muon lateral distribution functions using integrator and binary modes of underground muon detectors

The investigation of cosmic rays holds significant importance in the realm of particle physics, enabling us to expand our understanding beyond atomic confines. However, the origin and characteristics of ultra-high-energy cosmic rays remain elusive, making them a crucial topic of exploration in the field of astroparticle physics. Currently, our examination of these cosmic rays relies on studying the extensive air showers (EAS) generated as they interact with atmospheric nuclei during their passage through Earth’s atmosphere. Accurate comprehension of cosmic ray composition is vital in determining their source. Notably, the muon content of EAS and the atmospheric depth of the shower maximum serve as the most significant indicators of primary mass composition. In this study, we present two novel methods for reconstructing particle densities based on muon counts obtained from underground muon detectors (UMDs) at varying distances to the shower axis. Our methods were analyzed using Monte Carlo air shower simulations. To demonstrate these techniques, we utilized the muon content measurements from the UMD of the Pierre Auger cosmic ray Observatory, an array of detectors dedicated to measuring extensive air showers. Our newly developed reconstruction methods, employed with two distinct UMD data acquisition modes, showcased minimal bias and standard deviation. Furthermore, we conducted a comparative analysis of our approaches against previously established methodologies documented in existing literature.