Secondary Cosmic Ray Particles Research Articles

Explaining Muon Excess in Cosmic Rays Using the Gluon Condensation Model

Ultrahigh-energy cosmic rays are often characterized indirectly by analyzing the properties of secondary cosmic ray particles produced in the collisions with air nuclei. The particle number N μ of muon and the depth of shower maximum X max after air shower cascade are mostly studied to infer the energy and mass of the incident cosmic rays. Research has shown that there is a significant excess in the observed number of muons arriving at the ground from extensive air showers compared to the simulations using the existing cosmic ray hadronic interaction model. To explain this muon excess phenomenon, a new theoretical model, the gluon condensation model, is introduced in this paper and simulated by using the AIRES engine. We assume that the gluon condensation (GC) effect appears mainly in the first collision of the cascade, leading to a significant increase in the strangeness production, consequently, the production rate of kaons is increased, and n K /n π is greater than the value of the usual hadronic interaction process. In the calculation, the model assumes that only pions and kaons are produced in the GC state. The increase of strange particle yield would mean that the energy transferred from the hadronic cascade to the electromagnetic cascade through π 0 → 2γ decay is reduced. This would in turn increase the number of muons at the ground level due to meson decays. Our model provides a new theoretical possibility to explain the muon excess puzzle.

Shielding Cosmic Ray Muon using Copper and Aluminium Sheets Composited with Polyethylene Sheets for a Better Protection

Muons are usually among the most common secondary cosmic ray particles on Earth's surface. Muon research has confirmed their occurrence in a variety of locales. It has been claimed that cosmic radiation in general, and muons in particular, have disastrous consequences on biological things and electrical components on Earth and in space. According to medical sources, cosmic rays have been linked to many ailments affecting people and other creatures. Because of these issues, cosmic ray shielding has become a crucial component of this and comparative studies. Muons emitted by cosmic rays were detected using a muon telescope made of coaxial Geiger-Muller (GM) tubes. This experiment was carried out within the muon lab of Universiti Kebangsaan Malaysia (UKM) in Malaysia to examine how the cosmic ray muon count fluctuates with the shielding of metals (Copper (Cu) and Aluminium (Al)) and polyethylene. The measured muon count for each metal sample was statistically analysed. Using both metals as shielding in this experiment revealed that adding additional Cu and Al sheets reduced the muon count. Generally, the numbers drop as the thickness increases. The results suggest that Cu outperforms Al in shielding efficacy (19% vs 16%). Because Cu has a more significant density than Al, the correlation coefficient R2 for Cu = 0.9372 is greater than R2 for Al = 0.6593, indicating that the trend for Cu is better than the trend for Al in this experiment. To study the shielding capabilities of the two composites, Al/PE and Cu/PE, ten sheets of Polyethylene (PE) were gradually put individually between the Al and Cu sheets. The results showed that PE sheets slightly increased cosmic ray shielding.

Continental thunderstorm ground enhancement observed at an exceptionally low altitude

Abstract. Two long-lasting thunderstorm ground enhancement (TGE) events were registered at the Milešovka meteorological observatory in Czechia (50.55∘ N, 13.93∘ E; 837 m altitude) on 23 April 2018, during linearly organized thunderstorms. Two intervals of increased photon counts were detected by a plastic scintillator, respectively lasting 70 and 25 min and reaching 31 % and 48 % above the background radiation levels. Using numerical simulations, we verified that the observed increases in count rates are consistent with the energy spectrum of previously observed TGEs. We investigated the relevant data from a suite of meteorological instruments, a Ka-band cloud radar, an electric field mill, and a broadband electromagnetic receiver, all placed at the Milešovka observatory, in order to analyse the context in which these unique continental TGEs occurred at an exceptionally low altitude. The onset of the TGEs preceded the onset of precipitation by 10 and 3 min, respectively, for the two events. Both this delayed rain arrival and an energy threshold of 6.5 MeV for registered particles clearly exclude the detection the decay products of the radon progeny washout during the TGE intervals. At the same time, the European lightning detection network EUCLID detected numerous predominantly negative intracloud lightning discharges at distances closer than 5 km from the particle detector, while the occurrence of cloud-to-ground discharges was suppressed. The cloud radar recorded presence of graupel below the melting level, and the composition of hydrometeors suggested good conditions for cloud electrification. The observed variations in the near-surface electric field were unusual, with very brief negative-electric-field excursions reaching −20 kV in a quick succession. At the same time, sub-microsecond unipolar pulses emitted by close corona discharges saturated the broadband magnetic loop antenna. All these measurements indicate that a strong lower positive-charge region was present inside the thundercloud. The bottom thundercloud dipole was probably responsible for acceleration of the seed electrons in the air. These seed electrons might originate in the secondary cosmic ray particles but could also come from a high concentration of radon in the air collected during the propagation of the convective system above the uranium-rich soils before the thunderstorms overpassed the Milešovka observatory.

A minimal model for understanding secondary cosmic rays

We take a phenomenological approach in a minimal model to understand the spectral intensity of secondary cosmic-ray particles like positrons, antiprotons, Lithium, Beryllium and Boron. Our analysis shows that cosmic rays at ∼ GeV energies pass through a significant amount of matter in regions surrounding the sources. This grammage decreases with increasing cosmic-ray energy and becomes negligible beyond ∼100 GeV. During the subsequent propagation in the interstellar medium cosmic rays of all energies up to ∼105 GeV/n pass through about 1–2 g cm−2 of matter before leaking into the intergalactic medium. It is in the interstellar medium that the bulk of the positrons and antiprotons are generated. Also cosmic-ray nuclei like C, N, and O at all energies generate additional amounts of Li, Be and B nuclei with a spectrum similar to those of C, O etc. The implications of these findings of the minimal model to the observations of gamma rays and also the importance of spatial and temporal discreteness of cosmic-ray sources for modeling cosmic-ray propagation are briefly pointed out.

Testing the superposition model in small CORSIKA shower simulations

The idea of superposition in the high-energy interactions of cosmic ray nuclei and the development of extensive air showers initiated by them has been known for more than half a century. It has been thoroughly and successfully tested in a number of simulations for primary energies around 1015 and above. In this work, we will investigate its applicability to lower energies. At the lowest energies, when the shower contains on average about one charged particle (or even less), deviations from the superposition model can be seen in the simulation results. Fluctuations of higher moments of the main shower parameters are systematically broader than expected. Further studies to confirm superposition in particular in the shower longitudinal profile are in progress. A correct description of the longitudinal development of the small shower, a precise description of its fluctuations on the observational level with a correct implementation of the superposition principle will enable to construct a simple and fast phenomenological algorithm generating small showers indispensable for the interpretation of measurements made using a small local shower array and determination of the flux of single, incoherent, secondary cosmic ray particles.

Simulation of cosmic rays in the Earth’s atmosphere and interpretation of observed counts in an X-ray detector at balloon altitude near tropical region

The study of secondary particles produced by the cosmic-ray interaction in the Earth’s atmosphere is very crucial as these particles mainly constitute the background counts produced in the high-energy detectors at balloon and satellite altitudes. In the present work, we calculate the abundance of cosmic-ray generated secondary particles at various heights of the atmosphere by means of a Monte Carlo simulation and use this result to understand the background counts in our X-ray observations using balloon-borne instruments operating near the tropical latitude (geomagnetic latitude: ~14.50°N). For this purpose, we consider a 3D description of the atmospheric and geomagnetic field configurations surrounding the Earth, as well as the electromagnetic and nuclear interaction processes using Geant4 simulation toolkit. Subsequently, we use a realistic mass model description of the detector under consideration, to simulate the counts produced in the detector due to secondary cosmic-ray particles.

Effects of re-acceleration and source grammage on secondary cosmic rays spectra

ABSTRACT The ratio between secondary and primary cosmic ray (CR) particles is the main source of information about CR propagation in the Galaxy. Primary CRs are thought to be accelerated mainly in supernova remnant shocks and then released in the interstellar medium. Here, they produce secondary particles by occasional collisions with interstellar matter. As a result, the ratio between the fluxes of secondary and primary particles carries information about the amount of matter CRs have encountered during their journey from their sources to the Earth. Recent measurements by AMS-02 revealed an unexpected behaviour of two main secondary-to-primary ratios, the Boron-to-Carbon ratio and the antiproton-to-proton ratio. In this work, we discuss how such anomalies may reflect the action of two phenomena that are usually overlooked, namely the fact that some fraction of secondary particles can be produced within the acceleration region, and the non-negligible probability that secondary particles encounter an accelerator (and are re-accelerated) during propagation. Both effects must be taken into account in order to correctly extract information about CR transport from secondary-to-primary ratios.

Applying stable cosmogenic 21Ne to understand surface processes in deep geological time (107–108 yr)

This work sets out to test the applicability of stable cosmogenic 21Ne for quantifying the rates of surface processes over time scales of 107–108 yr and the potential limitations and pitfalls associated with such time spans. First, we examine several processes in addition to in-situ production during exposure that affect the final measured concentration of 21Ne. We calculate the magnitude of 21Ne produced by interaction with secondary cosmic ray particles after burial (muogenic Ne) and by non-cosmogenic sources (nucleogenic Ne). We also evaluate the fraction of 21Ne lost through diffusion out of the quartz crystal as a function of time and temperature (depth). We then apply our calculations to 21Ne concentrations measured in sediments that were deposited along the northern passive margin of Gondwana during the late Precambrian, Cambrian, and Lower Cretaceous. In light of the measured concentrations in the sediment samples, we discuss the limitations imposed by our calculations and show that 21Ne concentrations measured in Lower Cretaceous samples can be interpreted in terms of surface exposure times or average erosion rates during the time of erosion and transport. In contrast, concentrations measured in Cambrian and Precambrian samples are limited in their use as surface process indicators although they still yield valuable geological information. We conclude that this novel application of in situ stable cosmogenic nuclides holds the potential as a tool for quantifying surface processes and understanding landscape evolution during the deep geological past and provides insight into macro-scale processes that have shaped Earth over the past hundreds of millions of years.

Observation of galactic cosmic ray spallation events from the SoHO mission 20-yr operation of LASCO

A shower of secondary Cosmic Ray (CR) particles is produced at high altitudes in the Earth's atmosphere, so the primordial Galactic Cosmic Rays (GCRs) are never directly measured outside the Earth magnetosphere and atmosphere. They approach the Earth and other planets in the complex pattern of rigidity's dependence, generally excluded by the magnetosphere. GCRs revealed by images of single nuclear reactions also called spallation events are described here. Such an event was seen on Nov. 29, 2015 using a unique LASCO C3 space coronagraph routine image taken during the Solar and Heliospheric Observatory (SoHO) mission observing uninterruptedly at the Lagrangian L1 point. The spallation signature of a GCR identified well outside the Earth's magnetosphere is obtained for the 1st time. The resulting image includes different diverging linear "tracks" of varying intensity, leading to a single pixel, this frame identifies the site on the silicon CCD chip of the coronagraph camera. There was no solar flare reported at that time, nor Coronal Mass Ejection (CME) and no evidence of optical debris around the spacecraft. More examples of smaller CR events have been discovered through the 20 years of continuous observations from SoHO. This is the first spallation event from a CR, recorded outside the Earth's magnetosphere. We evaluate the probable energy of these events suggesting a plausible galactic source. Key words: Sun: Galactic Cosmic Rays, Solar Energetic Particles, Heliosphere.

Thunderstorm effects according to data from a comprehensive study of variations in secondary cosmic ray particles

Thunderstorms have been studied at the Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences) since the summer of 2013 using a measuring instrumentation complex. During the period of observation, three events of continuous night-sky airglow correlating with the disturbances in the flux of energetic particles have been recorded during thunderstorms. It is established that there is interaction between a thunderstorm’s front and the precipitation of protons from the Earth’s radiation belt into the atmosphere due to seismic activity.

Relation of muon flux local anisotropy with primary spectrum index

Muon hodoscope URAGAN allows to obtain the angular distribution of the muon flux. This distribution may be characterized by a vector of local anisotropy (the sum of the vectors of the particle arrival directions, normalized to the total number of muons). It was shown that annual variations in the vertical projection of the anisotropy vector AZ are not related with changes in atmospheric conditions. The dependence of AZ on the index of the primary particles spectrum γ was calculated for several zenith angle intervals with the help of simulation of generation and propagation of secondary cosmic ray particles through the atmosphere using the CORSIKA package. Experimental temporal series of the vertical projection of the local anisotropy AZ for several intervals of zenith angles were obtained for 2007-2015. According to the obtained AZ time series, annual and diurnal changes of Δγ were estimated.

Contribution of cosmic ray particles to radiation environment at high mountain altitude: Comparison of Monte Carlo simulations with experimental data

A numerical model for assessment of the effective dose due to secondary cosmic ray particles of galactic origin at high mountain altitude of about 3000 m above the sea level is presented. The model is based on a newly numerically computed effective dose yield function considering realistic propagation of cosmic rays in the Earth magnetosphere and atmosphere. The yield function is computed using a full Monte Carlo simulation of the atmospheric cascade induced by primary protons and α− particles and subsequent conversion of secondary particle fluence (neutrons, protons, gammas, electrons, positrons, muons and charged pions) to effective dose. A lookup table of the newly computed effective dose yield function is provided. The model is compared with several measurements. The comparison of model simulations with measured spectral energy distributions of secondary cosmic ray neutrons at high mountain altitude shows good consistency. Results from measurements of radiation environment at high mountain station - Basic Environmental Observatory Moussala (42.11 N, 23.35 E, 2925m a.s.l.) are also shown, specifically the contribution of secondary cosmic ray neutrons. A good agreement with the model is demonstrated.

Numerical model for computation of effective and ambient dose equivalent at flight altitudes

A numerical model for assessment of the effective dose and ambient dose equivalent produced by secondary cosmic ray particles of galactic and solar origin at commercial aircraft altitudes is presented. The model represents a full chain analysis based on ground-based measurements of cosmic rays, from particle spectral and angular characteristics to dose estimation. The model is based on newly numerically computed yield functions and realistic propagation of cosmic ray in the Earth magnetosphere. The yield functions are computed using a straightforward full Monte Carlo simulation of the atmospheric cascade induced by primary protons and α -particles and subsequent conversion of secondary particle fluence (neutrons, protons, gammas, electrons, positrons, muons and charged pions) to effective dose or the ambient dose equivalent. The ambient dose equivalent is compared with reference data at various conditions such as rigidity cut-off and level of solar activity. The method is applied for computation of the effective dose rate at flight altitude during the ground level enhancement of 13 December 2006. The solar proton spectra are derived using neutron monitor data. The computation of the effective dose rate during the event explicitly considers the derived anisotropy i.e. the pitch angle distribution as well as the propagation of the solar protons in the magnetosphere of the Earth.

SCALER MODE OF THE AUGER OBSERVATORY AND SUNSPOTS

Recent data from the Auger Observatory on low energy secondary cosmic ray particles are analyzed to study temporal correlations together with data on the daily sunspot numbers and neutron monitor data. Standard spectral analysis demonstrates that the available data shows 1/f^{\beta} fluctuations with {\beta} approximately 1 in the low frequency range. All data behave like Brownian fluctuations in the high frequency range. The existence of long-range correlations in the data was confirmed by detrended fluctuation analysis. The real data confirmed the correlation between the scaling exponent of the detrended analysis and the exponent of the spectral analysis.

The Pierre Auger Observatory scaler mode for the study of solar activitymodulation of galactic cosmic rays

Since data-taking began in January 2004, the Pierre Auger Observatory has been recording the count rates of low energy secondary cosmic ray particles for the self-calibration of the ground detectors of its surface detector array. After correcting for atmospheric effects, modulations of galactic cosmic rays due to solar activity and transient events are observed. Temporal variations related with the activity of the heliosphere can be determined with high accuracy due to the high total count rates. In this study, the available data are presented together with an analysis focused on the observation of Forbush decreases, where a strong correlation with neutron monitor data is found.

Convolution of TLD and SSNTD measurements during the BRADOS-1 experiment onboard ISS (2001)

The Russian BRADOS experiment onboard the International Space Station (ISS) was aimed at developing methods in radiation dosimetry and radiobiology to improve the reliability of risk estimates for the radiation environment in low-Earth orbit. Experimental data from thermoluminescence detectors (TLDs) and solid state nuclear track detectors (SSNTDs) gathered during the BRADOS-1 (24 February–31 October 2001) mission are reviewed and convolved to obtain absorbed dose and dose equivalent from primary and secondary cosmic-ray particles. Absorbed dose rates in the ISS Russian Segment (Zvezda) ranged from 208 ± 14 to 275 ± 14 μ Gy d - 1 . Dose equivalent rates were determined to range from 438 ± 29 to 536 ± 32 μ Sv d - 1 , indicating a quality factor between 1.95 ± 0.15 and 2.11 ± 0.20 . The contribution of densely ionizing particles ( LET ⩾ 10 keV μ m - 1 ) to dose equivalent made up between 54% and 64%.

Detection of primary and secondary cosmic ray particles aboard the ISS using SSNTD stacks

To study the radiation environment inside the International Space Station, solid state nuclear track detector stacks were used. Within the BRADOS experiments, Phase 1, seven stacks were exposed at different locations of the Russian segment 'Zvezda' for 248 days in 2001. It was supposed that the radiation field inside the ISS was composed from primary cosmic ray particles penetrating the wall of the ISS and secondaries, mainly neutrons induced by primaries in the wall and other structural materials surrounding the detectors. Based on the calibration made by utilising the high energy neutron reference field CERF at CERN (Geneva, Switzerland), the tracks induced by neutrons were separated from those induced by primary particles. Thus, the stacks, on one hand, provided the secondary neutron ambient dose equivalent. On the other hand, from the analysis of the rest of the tracks, the linear energy transfer spectra were computed and the flux and the dose of the primary particles were determined as shown in this paper.

THE GIANT FORBUSH DECREASE IN OCTOBER/NOVEMBER 2003: DATA ANALYSIS FOR THE SOLAR NEUTRON DETECTOR AT GORNERGRAT

In connection with the X17.2 flare on October 28, 2003, a coronal mass ejection was emitted at a high speed directly towards the Earth and caused a dramatic Forbush decrease (Fd) in the count rates of the worldwide network of ground-based cosmic ray detectors. During the initial phase of this Fd the ratios of the two Gornergrat solar neutron telescope particle channels (charged + neutral) and neutral show a step-like increase lasting about three days. This phenomenon is investigated based on Monte Carlo simulations of the cosmic ray cascades in the Earth's atmosphere and of the interactions of the secondary cosmic ray particles with the detector.

AMS measurements of 26Al in quartz to assess the cosmic ray background for the geochemical solar neutrino experiment LOREX

LORandite EXperiment (LOREX) plans to measure the time integrated solar neutrino flux of the last few million years via the product of the reaction 205Tl(υe,e−)205Pb in lorandite of the Allchar mine in Macedonia. Utilizing this reaction is only possible if the background of 205Pb produced by the interaction of secondary cosmic ray particles and particles originating from the natural radioactivity within the rock mineral itself is substantially lower than the expected signal from neutrino interactions. Low abundance of cosmic ray induced 205Pb implies good shielding of the mine by the overlying rock. For the assessment of this background fraction it is necessary to acquire information about the past erosion activity at this site.In the present study the erosion rates have been estimated via cosmogenic 26Al produced in situ in quartz of surface rock materials of the Allchar site. Details of the first determinations of in situ produced 26Al with the AMS method at VERA are described, and a rough estimate of the erosion rates at the Allchar site is given.

AMS measurements of 26Al in quartz to assess the cosmic ray background for the geochemical solar neutrino experiment LOREX

LORandite EXperiment (LOREX) plans to measure the time integrated solar neutrino flux of the last few million years via the product of the reaction 205Tl(υe,e−)205Pb in lorandite of the Allchar mine in Macedonia. Utilizing this reaction is only possible if the background of 205Pb produced by the interaction of secondary cosmic ray particles and particles originating from the natural radioactivity within the rock mineral itself is substantially lower than the expected signal from neutrino interactions. Low abundance of cosmic ray induced 205Pb implies good shielding of the mine by the overlying rock. For the assessment of this background fraction it is necessary to acquire information about the past erosion activity at this site. In the present study the erosion rates have been estimated via cosmogenic 26Al produced in situ in quartz of surface rock materials of the Allchar site. Details of the first determinations of in situ produced 26Al with the AMS method at VERA are described, and a rough estimate of the erosion rates at the Allchar site is given.