Cosmic Ray Extensive Air Showers Research Articles

Observing cosmic-ray extensive air showers with a silicon imaging detector

Extensive air showers induced from high-energy cosmic rays provide a window into understanding the most energetic phenomena in the universe. We present a new method for observing these showers using the silicon imaging detector Subaru Hyper Suprime-Cam (HSC). This method has the advantage of being able to measure individual secondary particles. When paired with a surface detector array, silicon imaging detectors like Subaru HSC will be useful for studying the properties of extensive air showers in detail. The following report outlines the first results of observing extensive air showers with Subaru HSC. The potential for reconstructing the incident direction of primary cosmic rays is demonstrated and possible interdisciplinary applications are discussed.

EUSO-SPB1 mission and science

The Extreme Universe Space Observatory on a Super Pressure Balloon 1 (EUSO-SPB1) was launched in 2017 April from Wanaka, New Zealand. The plan of this mission of opportunity on a NASA super pressure balloon test flight was to circle the southern hemisphere. The primary scientific goal was to make the first observations of ultra-high-energy cosmic-ray extensive air showers (EASs) by looking down on the atmosphere with an ultraviolet (UV) fluorescence telescope from suborbital altitude (33 km). After 12 days and 4 h aloft, the flight was terminated prematurely in the Pacific Ocean. Before the flight, the instrument was tested extensively in the West Desert of Utah, USA, with UV point sources and lasers. The test results indicated that the instrument had sensitivity to EASs of ⪆3 EeV. Simulations of the telescope system, telescope on time, and realized flight trajectory predicted an observation of about 1 event assuming clear sky conditions. The effects of high clouds were estimated to reduce this value by approximately a factor of 2. A manual search and a machine-learning-based search did not find any EAS signals in these data. Here we review the EUSO-SPB1 instrument and flight and the EAS search.

Modeling strangeness enhancements to resolve the muon excess in cosmic ray extensive air shower data

Experimental observations of extensive air showers have revealed an excess of the muon content with respect to their theoretical simulations, which we refer to as the muon puzzle. This muon puzzle hampers a precise determination of the ultra-high-energy cosmic ray mass composition. We investigate the potential of producing states of dense quark-gluon matter (which we call fireballs) to resolve the muon puzzle as quantified with data from the Pierre Auger Observatory on the depth of the shower maximum and the number of muons at ground. Adopting a phenomenological fireball model, we find that the inelasticity enhancement associated with the formation of a plasma state is in tension with data on the electromagnetic longitudinal shower development. Instead, we restrict the fireball model to only enhance the strangeness produced in Standard Model hadronic interactions, and dub this model the strangeball model. With an analytic approach based on the Heitler-Matthews model we then find explicit sets of strangeball parameters that resolve the muon puzzle. Constraints from data on shower-to-shower fluctuations of the muon number require strangeness enhancements already at energies accessible to current-generation collider experiments. At Tevatron and LHC energies we estimate 40% of the interactions to produce strangeballs, corresponding to a 5–9% increase of the average fraction of energy retained in the hadronic cascade compared to predictions from current hadronic interaction models. A comparison with relevant measurements of the LHCf and LHCb detectors does not directly exclude this scenario, though the obtained tension with LHCb suggests a stringent test at 14 TeV.

Locating sources of a high energy cosmic ray extensive air shower using HiSPARC data

In the physics community, there is continued interest in high energy cosmic rays and their co-location to stellar sources, including to supernovae. Observational history and corresponding theories link the high energies associated with these types of cosmic rays to those produced in various latter evolution stages of stellar bodies. We hypothesize that high-energy cosmic ray air showers have a source region associated with specific stellar bodies. Here, we present our analysis of the locations of possible high-energy cosmic ray sources by using data from University of Twente cosmic ray detectors that are part of the High School Project on Astrophysics Research with Cosmics (HiSPARC) network. As an example of the potential of the HiSPARC network to aid cosmic ray source location, we analyzed event count data from a high-energy air shower recorded during the first week of January 2014. The data was then processed such that the direction of the air shower could be ascertained to provide the likely area of air shower origin. Angle and time data were then inputted in to Stellarium™, a free open-source planetarium application from which sources could be located. Our results suggest two sources are candidates for the origins of the high-energy air shower: the Cepheid variable Polaris and the binary system, Iota Ursae Majoris A. In sum, we have shown the potential of the HiSPARC network to aid location of stellar sources that may be responsible for detected cosmic air showers.

Preface

AtmoHEAD (ATmospheric Monitoring for High Energy Astroparticle Detectors) is a periodic 3-days international workshop on the influence of the atmosphere on high-energy cosmic-ray and gamma-ray astroparticle detectors. The 2022 edition is focused on atmospheric monitoring and on the detection and study of events related to atmospheric electricity. The event follows the tradition of previous AtmoHEAD conferences - AtmoHEAD 2013 in Saclay, 2014 in Padova, 2016 in Olomouc and 2018 in Anacapri.The atmosphere is an integral component of many high-energy astroparticle detectors. These include Imaging Atmospheric Cherenkov Telescopes (IACTs) and ground or space based cosmic-ray extensive air shower detectors. All these observatories use the atmosphere as a giant calorimeter where cosmic rays and gamma rays deposit their energy and initiate extensive air showers; it is also the medium through which the resulting Cherenkov and Fluorescence light propagates, and through which it is attenuated and scattered before reaching the detectors. Clearly, a precise and quantitative monitoring of the atmospheric aerosol and molecular conditions are mandatory for an accurate reconstruction of the detected events. Moreover, in the last years there is a growing interest in the detection of electrical phenomena (ELVES, TGFs, ...) developed in atmosphere with high-energy astroparticle detectors, which represent a unique opportunity to study the characteristics of these events with large statistics and precision.New and common monitoring and calibration instruments including lidars, distant laser facilities, cloud monitors, all sky cameras, sun/moon photometers, satellite observations, lightning sensors, as well as simulations, are among the most important tools of these observatories.These online workshop proceedings are grouped in two main sections, Atmospheric Characterization and Atmospheric Electricity and focus on the state-of-the-art and future perspectives of techniques and instruments.Some more detail on the topics treated in the workshop :• the influence of the atmosphere on the measurements of present and future UHECR and gamma-ray experiments• terrestrial gamma-ray flashes, transient luminous events and general topics in atmospheric electricity• analysis techniques and instruments• public global data sets, models and simulationsWe take advantage of this preface to thank all the participants for the very fruitful discussions that came up during the workshop in a friendly and collaborative atmosphere, among participants of different but complementary fields. This was the main goal of AtmoHEAD 2022.AtmoHEAD 2022 was organized by the Department of Physics “E. Pancini ” of the University of Napoli Federico II and by the Napoli Division of the National Institute of Nuclear Physics (INFN).

Reconstructing the cosmic ray energy spectrum with HiSPARC

The high school project on astrophysics research with cosmics (HiSPARC) employs a large number of small detection stations that sample the footprint of extensive cosmic ray air showers. The cosmic ray energy spectrum between 1016–1019eV is reconstructed by combining data from multiple four-detector stations located at the Amsterdam Science Park. The obtained cosmic ray flux values agree well with data from other experiments. Also the value of the slope (−3.08±0.02) matches the literature value. Additionally, a new method is presented in which a single two-detector station is used to probe the cosmic ray energy spectrum at a complementary energy regime between 1012–1016eV. The flux values and its slope value (−2.71±0.07) are in good agreement with literature data. However, numerous simplifying assumptions bring about large systematic uncertainties which are not well quantified. The possibility to reconstruct the cosmic ray energy spectrum augments HiSPARC’s primary goal, which is to engage high school students with modern physics and let them contribute to real scientific research.

Explaining the characteristics of lateral shower age of cosmic ray extensive air showers

A simple analytical argument is proposed for a possible explanation of the characteristics of the lateral shower age (s) of proton (p)/nuclei-initiated showers. The argument states that the lateral density distribution (LDD) of electrons of a p-initiated shower is due to the superposition of several electromagnetic (EM) sub-showers developed at a very early stage in the atmosphere from the decay of neutral pions ( $$\pi ^{0}$$ s). Thanks to the superposition property of the electron LDD in a p shower, a plausible analytical parametrisation has been worked out by giving a well represented lateral density function for the electron LDDs of p- and $$\pi ^{0}$$ -initiated showers. Based on cosmic ray extensive air shower simulations, we have validated how the various characteristics of s can be understood in the context of the proposed argument. The s parameter of a p shower and its correlations with the shower ages of electron- and $$\pi ^{0}$$ -initiated showers support the idea that the result of superposition of several EM sub-showers initiated by $$\pi ^{0}$$ s with varied energies at a very early stage might produce the LDD of electrons of a p shower. It is also noticed with the simulated data that the present conjecture works well relating to the notion of the local shower age parameter.

Behaviour of the lateral shower age of cosmic ray extensive air showers

Some simple arguments are introduced for a possible explanation of the behavior of the lateral shower age of proton-initiated showers. The corresponding analytical treatment based on the proposed argument is then illustrated. Using the Monte Carlo simulation (MC) code CORSIKA, we have validated how the different characteristics associated with the lateral shower age predicted in the present analytical parametrization, can be understood. The lateral shower age of a proton-initiated shower and its correlations with the lateral shower ages of electron- and neutral pion-initiated showers supports the idea that the result of superposition of several electromagnetic sub-showers initiated by neutral pions might produce the lateral density distribution of electrons of a proton initiated shower. It is also noticed with the simulated data that the stated feature still persists even in the local shower age representation.

Modeling the optical Cherenkov signals by cosmic ray extensive air showers directly observed from suborbital and orbital altitudes

Future experiments based on the observation of Earth's atmosphere from sub-orbital and orbital altitudes plan to include optical Cherenkov cameras to observe extensive air showers produced by high-energy cosmic radiation via its interaction with both the Earth and its atmosphere. As discussed elsewhere, particularly relevant is the case of upward-moving showers initiated by astrophysical neutrinos skimming and interacting in the Earth. The Cherenkov cameras, by looking above Earth's limb, can also detect cosmic rays with energies starting from less than a PeV up to the highest energies (tens of EeV). Using a customized computation scheme to determine the expected optical Cherenkov signal from these high-energy cosmic rays, we estimate the sensitivity and event rate for balloon-borne and satellite-based instruments, focusing our analysis on the Extreme Universe Space Observatory aboard a Super Pressure Balloon 2 (EUSO-SPB2) and the Probe of Extreme Multi-Messenger Astrophysics (POEMMA) experiments. We find the expected event rates to be larger than hundreds of events per hour of experimental live time, enabling a promising overall test of the Cherenkov detection technique from sub-orbital and orbital altitudes as well as a guaranteed signal that can be used for understanding the response of the instrument.

“HADRON-55” complex setup for study of hadron interactions within the central part of cosmic ray extensive air showers (EAS) cores

“HADRON-55” with scintillation detectors and ionization calorimeters is used for studies in high-energy gamma-astronomy and cosmic ray physics. The “HADRON-55” consists of two parts - the upper gamma block and the lower hadron block. The gamma block absorbs and detects the electron-photon components of cosmic rays, while hadrons are not absorbed when they pass through the gamma block and begins to form particles in the hadron block. Project's main idea is to select events where there is the interaction in gamma block and no interaction in hadron block. Analysis of experiments results on “HADRON-55” accounts for ∼ 6% of such events. The peripheral part of “HADRON-55” consists of 8 scintillation detectors placed in 2 circles with radii of 40 and 100 m. Over 4 years, more than 120,000 events with high energy of 1015 eV were detected.

Performance of the thermal neutron detector array in Yangbajing, Tibet for cosmic ray EAS detection

The measurement of thermal neutrons generated by cosmic ray extensive air showers (EAS) on the Earth’s surface provides a new method for studying the composition and energy of cosmic rays with energy in the so-called “knee” region. Given the success of the PRISMA-YBJ array, a new type of thermal neutron detector array was installed at the high-altitude cosmic ray observatory in Yangbajing, Tibet. The array consists of 16 EN-detectors and utilizes a new type scintillator based on a compound alloy of ZnS(Ag) and B2O3 with natural boron. This report describes the deployment of the detector array and its operational results.

Local shower age and segmented slope parameters of lateral density distributions of cosmic ray shower particles

The paper describes lateral density distributions of electrons and muons of cosmic ray extensive air showers (EAS) in the energy regime of the KASCADE experiment. Potential EAS observables are extracted while some suitable lateral distribution functions are introduced to describe these lateral density distributions of simulated/observed cosmic ray showers. Mass-sensitivity of these parameters are demonstrated particularly for the KASCADE electron and muon distributions data. Our studies indicate that the KASCADE data favours an idea of gradual change of cosmic ray mass composition from lighter concentration to heavier concentration in terms of these parameters.

A novel approach for deducing the mass composition of cosmic rays from lateral densities of EAS particles

A Monte Carlo (MC) simulation study of cosmic-ray (CR) extensive air showers (EAS) has been carried out in the energy regime of the KASCADE experiment. From the characteristics of lateral distributions of electrons and muons of simulated EAS, some important EAS observables are extracted by a novel approach, and their CR mass sensitivity is demonstrated. The study takes into account the issue of the experimental lateral density profiles of EAS electrons and muons after introducing the notion of the local age and segmented slope parameters, aimed to extract information on CR mass composition from observed data. The estimated lateral shower age and slope from the analysis of the KASCADE data (KCDC) agrees with the idea of a gradual change of CR mass composition from light to heavy around the knee.

The use of aerosol data in Auger Fluorescence Detector analysis

The Pierre Auger Observatory’s Fluorescence Detector (FD) consists of 27 telescopes arranged in four sites around the perimeter of the 3000 square kilometre Surface Detector (SD). Cosmic ray extensive air showers are viewed via the nitrogen fluorescence light they induce in the atmosphere. Careful treatment of light attenuation processes must be made, especially given that some showers are viewed at distances in excess of 30 km. Of particular importance is the attenuation due to scattering by aerosol particles, a challenging topic given that aerosol concentrations can vary on time-scales of hours. At the Auger Observatory, the vertical distribution of aerosols is measured hourly with a series of bi-static lidar systems (consisting of central laser facilities and each of the FD sites), and three times per night with a Raman lidar system. In this contribution we describe the use of aerosol profiles in the analysis of air shower data, in particular in the estimation of the cosmic ray primary energy, and the depth of shower maximum, Xmax. We also demonstrate how statistical and systematic uncertainties in the aerosol concentrations propagate through to a contribution to energy and Xmax uncertainties.

Observation of ultra-high energy cosmic rays with the Telescope Array experiment

The origin of ultra-high energy cosmic rays (UHECRs) has been a longstanding mystery. The Telescope Array (TA) is the largest experiment in the northern hemisphere observing UHECR in Utah, USA. It aims to reveal the origin of UHECR by studying the energy spectrum, mass composition and anisotropy of cosmic rays. TA is a hybrid detector comprised of three air fluorescence stations which measure the fluorescence light induced from cosmic ray extensive air showers, and 507 surface scintillator counters which sample charged particles from air showers on the ground. We present the cosmic ray spectrum observed with the TA experiment. We also discuss our results from measurement of the mass composition. In addition, we present the results from the analysis of anisotropy, including the excess of observed events in a region of the northern sky at the highest energy. Finally, we introduce the TAx4 experiment which quadruples TA, and the TA low energy extension (TALE) experiment.

Circular polarization of radio emission from air showers in thunderstorm conditions

We present measured radio emission from cosmic-ray-induced air showers under thunderstorm conditions. We observe for these events large differences in intensity, linear polarization and circular polarization from the events measured under fair-weather conditions. This can be explained by the effects of atmospheric electric fields in thunderclouds. Therefore, measuring the intensity and polarization of radio emission from cosmic ray extensive air showers during thunderstorm conditions provides a new tool to probe the atmospheric electric fields present in thunderclouds.

The knee in the cosmic ray energy spectrum from the simultaneous EAS charged particles and muon density spectra

In this work we examine with the help of Monte Carlo simulation whether a consistent primary energy spectrum of cosmic rays emerges from both the experimentally observed total charged particles and muon size spectra of cosmic ray extensive air showers considering primary composition may or may not change beyond the knee of the energy spectrum. It is found that EAS-TOP observations consistently infer a knee in the primary energy spectrum provided the primary is pure unchanging iron whereas no consistent primary spectrum emerges from simultaneous use of the KASCADE observed total charged particle and muon spectra. However, it is also found that when primary composition changes across the knee the estimation of spectral index of total charged particle spectrum is quite tricky, depends on the choice of selection of points near the knee in the size spectrum.

JUPITER AS A GIANT COSMIC RAY DETECTOR

We explore the feasibility of using the atmosphere of Jupiter to detect Ultra-High-Energy Cosmic Rays (UHECR's). The large surface area of Jupiter allows us to probe cosmic rays of higher energies than previously accessible. Cosmic ray extensive air showers in Jupiter's atmosphere could in principle be detected by the Large Area Telescope (LAT) on the Fermi observatory. In order to be observed, these air showers would need to be oriented toward the Earth, and would need to occur sufficiently high in the atmosphere that the gamma rays can penetrate. We demonstrate that, under these assumptions, Jupiter provides an effective cosmic ray "detector" area of $3.3 \times 10^7$ km$^2$. We predict that Fermi-LAT should be able to detect events of energy $>10^{21}$ eV with fluence $10^{-7}$ erg cm$^{-2}$ at a rate of about one per month. The observed number of air showers may provide an indirect measure of the flux of cosmic rays $\gtrsim 10^{20}$ eV. Extensive air showers also produce a synchrotron signature that may be measurable by ALMA. Simultaneous observations of Jupiter with ALMA and Fermi-LAT could be used to provide broad constraints on the energies of the initiating cosmic rays.

Selecting gamma-ray showers from hadronic background using lateral shower age of EAS

A Monte Carlo (MC) simulation study has been carried out, aimed at identifying and rejecting the background component, constituted by hadronic cosmic rays, from γ-ray primaries in the multi-TeV region. In this work, our main focus is to discuss the possible role of the local age parameter (LAP) of cosmic ray extensive air shower (EAS) for separating γ-ray initiated showers from hadron initiated showers. Assigning a mean LAP to each EAS event, we found that the parameter might be useful for selecting γ-ray showers from hadron initiated showers in ground-based EAS experiments without muon measurement facilities.

Estimating Air Shower Fluctuations from the Monte Carlo Simulation Code CORSIKA

The study of cosmic ray extensive air showers (EAS) offers a unique way to estimate hadronic interaction cross-section at energies beyond the reach of accelerator experiments. Usually the hadron-air cross-section is estimated either by evaluating the absorption of the hadron initiated EAS flux penetrating the atmosphere or from the distribution of shower maximum. Employing a detailed Monte Carlo (MC) simulation code, the present work critically examined the analysis method usually adopted in obtaining cross- section through attenuation of EAS and estimated the degree of air shower fluctuations affecting the measurements of hadron-air cross sections.