Component Of Showers Research Articles

Study of muon bundles from extensive air showers with the ALICE detector at CERN LHC

ALICE is one of four large experiments at the CERN Large Hadron Collider, specially designed to study particle production in ultra-relativistic heavy-ion collisions. Located 52 meters underground with 28 meters of overburden rock, it has also been used to detect muons produced by cosmic-ray interactions in the upper atmosphere. The large size and excellent tracking capability of the ALICE Time Projection Chamber are exploited to study the muonic component of extensive air showers. We present the multiplicity distribution of these atmospheric muons and its comparison with Monte Carlo simulations. The latest version of the QGSJET hadronic interaction model was used to simulate the development of the resulting air showers. High multiplicity events containing more than 100 reconstructed muons were also studied. Similar events have been studied in previous underground experiments such as ALEPH and DELPHI at LEP without satisfactory explanations for the frequency of the highest multiplicity events. We demonstrate that the high muon-multiplicity events observed in ALICE stem from primary cosmic rays with energies above 1016 eV and that the frequency of these events can be successfully described by assuming a heavy mass composition of primary cosmic rays in this energy range.

Project of the URAN array for registration of atmospheric neutrons

The project of a new setup is directed at the registration of atmospheric neutrons (URAN) generated by hadronic component of extensive air showers (EAS). The setup includes 72 en-detector which simultaneously register two major EAS components: electromagnetic by the group passage of charged particles and hadron component by the thermal neutrons. The neutrons and charged particles are detected using a specialized scintillation composition made of granulated alloy of crystals based on the ZnS(Ag) powder with an admixture of B2O3.

CAMS newly detected meteor showers and the sporadic background

The Cameras for Allsky Meteor Surveillance (CAMS) video-based meteoroid orbit survey adds 60 newly identified showers to the IAU Working List of Meteor Showers (numbers 427, 445–446, 506–507, and part of 643–750). 28 of these are also detected in the independent SonotaCo survey. In total, 230 meteor showers and shower components are identified in CAMS data, 177 of which are detected in at least two independent surveys. From the power-law size frequency distribution of detected showers, we extrapolate that 36% of all CAMS-observed meteors originated from ∼700 showers above the N=1 per 110,000 shower limit. 71% of mass falling to Earth from streams arrives on Jupiter-family type orbits. The transient Geminids account for another 15%. All meteoroids not assigned to streams form a sporadic background with highest detected numbers from the apex source, but with 98% of mass falling in from the antihelion source. Even at large ∼7-mm sizes, a Poynting–Robertson drag evolved population is detected, which implies that the Grün et al. collisional lifetimes at these sizes are underestimated by about a factor of 10. While these large grains survive collisions, many fade on a 104-y timescale, possibly because they disintegrate into smaller particles by processes other than collisions, leaving a more resilient population to evolve.The meteors assigned to the various showers are identified in the CAMS Meteoroid Orbit Database 2.0 submitted to the IAU Meteor Data Center, and can be accessed also at http://cams.seti.org.

New electronics for the surface detectors of the Pierre Auger Observatory

The Pierre Auger Observatory is the largest installation worldwide for the investigation of ultra-high energy cosmic rays. Air showers are detected using a hybrid technique with 27 fluorescence telescopes and 1660 water-Cherenkov detectors (WCD) distributed over about 3000km2. The Auger Collaboration has decided to upgrade the electronics of the WCD and complement the surface detector with scintillators (SSD). The objective is to improve the separation between the muonic and the electron/photon shower component for better mass composition determination during an extended operation period of 8–10years. The surface detector electronics records data locally and generates time stamps based on the GPS timing. The performance of the detectors is significantly improved with a higher sampling rate, an increased dynamic range, new generation of GPS receivers, and FPGA integrated CPU power. The number of analog channels will be increased to integrate the new SSD, but the power consumption needs to stay below 10W to be able to use the existing photovoltaic system. In this paper, the concept of the additional SSD is presented with a focus on the design and performance of the new surface detector electronics.

Response of microchannel plates to single particles and to electromagnetic showers

We report on the response of microchannel plates (MCPs) to single relativistic particles and to electromagnetic showers. Particle detection by means of secondary emission of electrons at the MCP surface has long been proposed and is used extensively in ion time-of-flight mass spectrometers. What has not been investigated in depth is their use to detect the ionizing component of showers. The time resolution of MCPs exceeds anything that has been previously used in calorimeters and, if exploited effectively, could aid in the event reconstruction at high luminosity colliders. Several prototypes of photodetectors with the amplification stage based on MCPs were exposed to cosmic rays and to 491MeV electrons at the INFN-LNF Beam-Test Facility. The time resolution and the efficiency of the MCPs are measured as a function of the particle multiplicity, and the results used to model the response to high-energy showers.

Novel method for detecting the hadronic component of extensive air showers

A novel method for studying the hadronic component of extensive air showers (EAS) is proposed. The method is based on recording thermal neutrons accompanying EAS with en-detectors that are sensitive to two EAS components: an electromagnetic (e) component and a hadron component in the form of neutrons (n). In contrast to hadron calorimeters used in some arrays, the proposed method makes it possible to record the hadronic component over the whole area of the array. The efficiency of a prototype array that consists of 32 en-detectors was tested for a long time, and some parameters of the neutron EAS component were determined.

Dependence of the muon pseudorapidity on the cosmic ray mass composition around the knee

In order to identify the mass composition of cosmic rays (CRs), we have investigated the mean muon pseudorapidity (〈η〉) values of muonic component in extensive air showers (EASs). For this purpose we have simulated EASs by CORSIKA 7.4 code for Hydrogen, Oxygen and Iron nucleus. The energy range was selected between 1014 eV and 1016 eV with zenith angle from 0°–18°. We have compared our calculations with KASCADE muon tracking detector (MTD) measurements to obtain results on the primary mass relationship with mean muon pseudorapidity values of EASs muonic component. It is shown that after the knee energies, experimental data tend to the heavy primaries and mass composition becomes heavier. Finally, linear equations between the mass of primary and mean η values for different energies are obtained.

Resistive Plate Chambers for the Pierre Auger array upgrade

In the framework of the Pierre Auger Observatory upgrade, Resistive Plate Chambers (RPCs) have been proposed as a dedicated detector to better estimate the muonic component of Extensive Air Showers (EAS), further constraining the nature of the cosmic rays and hadronic interactions that take place in Extensive Air Showers development. RPCs are a very interesting option to fulfill the requirements: to cover large areas at low cost; particle counting from one to thousands of particles; few ns time resolution and outdoor standalone operation with very low maintenance. The present work refers to the latest advances and outcomes in order to ensure the capability of RPCs to fulfill the totality of the Auger upgrade requirements.

Layered water Cherenkov detector for the study of ultra high energy cosmic rays

We present a new design for the water Cherenkov detectors that are in use in various cosmic ray observatories. This novel design can provide a significant improvement in the independent measurement of the muonic and electromagnetic component of extensive air showers. From such multi-component data an event by event classification of the primary cosmic ray mass becomes possible. According to popular hadronic interaction models, such as EPOS-LHC or QGSJetII-04, the discriminating power between iron and hydrogen primaries reaches Fisher values of ~2 or above for energies in excess of 1019eV with a detector array layout similar to that of the Pierre Auger Observatory.

Muons in air showers at the Pierre Auger Observatory: Measurement of atmospheric production depth

The surface detector array of the Pierre Auger Observatory provides information about the longitudinal development of the muonic component of extensive air showers. Using the timing information from the flash analog-to-digital converter traces of surface detectors far from the shower core, it is possible to reconstruct a muon production depth distribution. We characterize the goodness of this reconstruction for zenith angles around 60 deg. and different energies of the primary particle. From these distributions we define X(mu)max as the depth along the shower axis where the production of muons reaches maximum. We explore the potentiality of X(mu)max as a useful observable to infer the mass composition of ultrahigh-energy cosmic rays. Likewise, we assess its ability to constrain hadronic interaction models.

Muon and neutrino collimation in extensive air shower cores

Detailed simulations of extensive air showers have been carried out with the CORSIKA program in order to evaluate the energy brought by the different shower components at ground level and transmitted underground. A special attention is given to the angular distributions and to the collimation of beams penetrating deep underground or underwater. The natural collimation of high energy particles in extensive air shower cores results mainly from the ratio between the transverse and the longitudinal momenta of secondary particles generated in the earliest interactions. This collimation is partly conserved by the high energy muons and neutrinos. It is comparable to the magnetic focusing of charged pions and kaons decaying in tunnels of suitable length after production in accelerators. Such is the case for neutrino beams of KEK J-PARC/T2K (300km to Kamiokande), OPERA (730km to Gran Sasso) and MINOS (735km to Irvine Mine).

Study of the hadronic component of extensive air showers at the Carpet-2 EAS array

A method for the detection of hadrons with a muon detector at the Carpet-2 EAS array (Baksan Neutrino Observatory, Institute for Nuclear Research, Russian Academy of Sciences) has been described. Events induced by cosmic-ray hadrons have a signature that makes it possible to reliably distinguish them from muons. The characteristics of the hadronic component of extensive air showers with Ne ≥ 105 have been presented.

The influence of low energy hadron interaction models in CORSIKA code on atmospheric ionization due to heavy nuclei

The largest uncertainties in a numerical simulation of cosmic ray induced atmospheric cascade are due to hadron interaction models. The influence of low energy hadron interaction models in CORSIKA code on longitudinal cascade development is important. It results longitudinal cascade development, respectively energy deposit and atmospheric ionization by secondary particles. In this work are presented simulations with CORSIKA 6.990 code using GHEISHA 2000, FLUKA 2011 and QGSJET II hadron generators. The energy deposit in the atmosphere by various nuclei, namely Helium, Oxygen and Iron is calculated. The ion pair production in the atmosphere and the impact of the different shower components, precisely the electromagnetic, muon and hadron is estimated according the used hadron generators. The yield function Y for total ionization is compared for various cases. The observed differences and applications are discussed.

Supervision of double extensive air showers

Double extensive air showers were investigated at Tien-Shan high mountain scientific station of P.N. Lebedev Institute by means of two various installations. One installation registered electron-photon air shower component, another – Vavilov-Cherenkov radiation. On both installations the double showers divided by a time interval of ~100 nanoseconds have been registered. In the present work frequency of occurrence of such showers in each of installations is analysed, and is shown that at supervision of vertical showers (zenith angle θ <60°) these frequencies coincide.

Air shower simulation for background estimation in muon tomography of volcanoes

Abstract. One of the main sources of background for the radiography of volcanoes using atmospheric muons comes from the accidental coincidences produced in the muon telescopes by charged particles belonging to the air shower generated by the primary cosmic ray. In order to quantify this background effect, Monte Carlo simulations of the showers and of the detector are developed by the TOMUVOL collaboration. As a first step, the atmospheric showers were simulated and investigated using two Monte Carlo packages, CORSIKA and GEANT4. We compared the results provided by the two programs for the muonic component of vertical proton-induced showers at three energies: 1, 10 and 100 TeV. We found that the spatial distribution and energy spectrum of the muons were in good agreement for the two codes.

Measurements of the muonic component of air showers at the Pierre Auger Observatory

Several methods have been developed by the Pierre Auger Collaboration to estimate the muon content of air showers from ultra-high energy cosmic rays. The data of the Pierre Auger Observatory will be compared with predictions based upon EPOS 1.99 and QGSJET-II-3 hadronic interaction models. In addition to the direct measures of the muonic content, the combination of a fluorescence detector and a muon sensitive surface array allows for a direct test of air shower simulations which is sensitive to both the shower core and large distances from the core. These methods reveal a deficit of muons in air shower simulations with proton primaries and that the energy assignment basedupon simulations of the surface array signal is systematically higher than that derived from the florescence detector. Summary: I will discuss the deficit in the number of muons currently predicted by simulations when compared to the data of the Pierre Auger Observatory. I will describe the methods used to measure the muon content, including sources of systematic uncertainty, and give their current results. Finally, I will present the Collaborations current understanding of the nature of the discrepancy, which could arise from an energy scale problem, composition, or deficiencies in the hadronic interaction models.

Measurements of the muonic component of air showers at the Pierre Auger Observatory

Several methods have been developed by the Pierre Auger Collaboration to estimate the muon content of air showers from ultra-high energy cosmic rays. The data of the Pierre Auger Observatory will be compared with predictions based upon EPOS 1.99 and QGSJET-II-3 hadronic interaction models. In addition to the direct measures of the muonic content, the combination of a fluorescence detector and a muon sensitive surface array allows for a direct test of air shower simulations which is sensitive to both the shower core and large distances from the core. These methods reveal a deficit of muons in air shower simulations with proton primaries and that the energy assignment basedupon simulations of the surface array signal is systematically higher than that derived from the florescence detector. Summary: I will discuss the deficit in the number of muons currently predicted by simulations when compared to the data of the Pierre Auger Observatory. I will describe the methods used to measure the muon content, including sources of systematic uncertainty, and give their current results. Finally, I will present the Collaborations current understanding of the nature of the discrepancy, which could arise from an energy scale problem, composition, or deficiencies in the hadronic interaction models.See references [1, 2].

Measurement of atmospheric production depths of muons with the pierre auger observatory

The time structure of muons at ground retains valuable information about the longitudinal development of the hadronic component in extensive air showers. Using the signals collected by the surface detector array of the Pierre Auger Observatory it is possible to reconstruct the Muon Production Depth (MPD) distribution. In this work we explore the main features of these reconstructions for zenith angles around 60 ◦ and different energies of the primary particle. From the MPDs we define a new observable, X max , as the depth, along the shower axis, where the maximum number of muons is produced. The potentiality of X max to infer the mass composition of cosmic rays is studied.

Observation of double extensive air showers

Double extensive air showers were studied at the Tien Shan high-mountain scientific station of the Lebedev Physical Institute using two different installations. One measured the electron-photon shower component, the other measured Cherenkov radiation. Double showers separated by a time interval of ∼100 ns were detected by both setups. The frequency of the occurrence of such showers in each setup is analyzed. It is shown that these frequencies are identical when observing vertical showers (the zenith angle ϑ < 60°).

Measurement of Cosmic Ray Spectrum and Anisotropy with ARGO-YBJ

The combined measurement of the cosmic ray (CR) energy spectrum and anisotropy in their arrival direction distribution needs the knowledge of the elemental composition of the radiation to discriminate between different origin and propagation models. Important information on the CR mass composition can be obtained studying the EAS muon content through the measurement of the CR rate at different zenith angles. In this paper we report on the observation of the anisotropy of galactic CRs at different angular scales with the ARGO-YBJ experiment. We report also on the study of the primary CR rate for different zenith angles. The light component (p+He) has been selected and its energy spectrum measured in the energy range (5 - 200) TeV for quasi-vertical events. With this analysis for the first time a ground-based measurement of the CR spectrum overlaps data obtained with direct methods for more than one energy decade, thus providing a solid anchorage to the CR spectrum measurements carried out by EAS arrays in the knee region. Finally, a preliminary study of the non-attenuated shower component at a zenith angle $\theta >$ 70$^{\circ}$ (through the observation of the so-called horizantal air showers) is presented.