Development Of Extensive Air Showers Research Articles

LOW ENERGY γ-RAY DETECTION (E ≤ 30 GEV): EFFECT OF EARTH'S MAGNETIC FIELD AND A NOVEL TRIGGER TECHNIQUE

Here we discuss two related aspects of the detection of low energy gammas by IACT's (Imaging Atmospheric Cherenkov Telescope): the effect of the Earth's magnetic field and a possible novel trigger technique. The Earth's magnetic field affects the development of extensive air showers (EAS), spreading the collected photons and, therefore, decreasing the sensitivity of the Cherenkov telescope. The new effects that appear in low energy showers can be partially offset modifying the trigger criteria. The result is a large collection area (> 1000 m2) below 10 GeV for a typical 17 m class telescope, increasing its sensitivity at these energies.

Longitudinal development of extensive air showers: Hybrid code SENECA and full Monte Carlo

New experiments, exploring the ultra-high energy tail of the cosmic ray spectrum with unprecedented detail, are exerting a severe pressure on extensive air shower modelling. Detailed fast codes are in need in order to extract and understand the richness of information now available. Some hybrid simulation codes have been proposed recently to this effect (e.g., the combination of the traditional Monte Carlo scheme and system of cascade equations or pre-simulated air showers). In this context, we explore the potential of SENECA, an efficient hybrid tri-dimensional simulation code, as a valid practical alternative to full Monte Carlo simulations of extensive air showers generated by ultra-high energy cosmic rays. We extensively compare hybrid method with the traditional, but time consuming, full Monte Carlo code CORSIKA which is the de facto standard in the field. The hybrid scheme of the SENECA code is based on the simulation of each particle with the traditional Monte Carlo method at two steps of the shower development: the first step predicts the large fluctuations in the very first particle interactions at high energies while the second step provides a well detailed lateral distribution simulation of the final stages of the air shower. Both Monte Carlo simulation steps are connected by a cascade equation system which reproduces correctly the hadronic and electromagnetic longitudinal profile. We study the influence of this approach on the main longitudinal characteristics of proton, iron nucleus and gamma induced air showers and compare the predictions of the well known CORSIKA code using the QGSJET hadronic interaction model.

Depth development of extensive air showers from muon time distributions

We develop an algorithm that has the potential to relate the depth development of ultra high energy extensive air showers and the time delay for individual muons. The time distributions sampled at different positions at ground level by a large air shower array are converted into distributions of production distances using an approximate relation between production distance, transverse distance and time delay. The method is naturally restricted to inclined showers where muons dominate the signal at ground level but could be extended to vertical showers provided that the detectors used can separate the muon signal from electrons and photons. We explore the accuracy and practical uncertainties involved in the proposed method. For practical purposes only the muons that fall outside the central region of the shower can be used, and we establish cuts in transverse distance. The method is tested using simulated showers by comparing the production distance distributions obtained using the method with the actual distances in the simulated showers. It could be applied in the search for neutrinos to increase the acceptance to highly penetrating particles, as well as for unraveling the relative compositions of protons and heavy nuclei. We also illustrate that the obtained depth distributions have minimum width when both the arrival direction and the core position are well reconstructed.

Investigation of the structure of a muon disk for E 0 ≥ 5 × 1016 eV according to data of the Yakutsk array for studying extensive air showers

The results are presented that were obtained at the Yakutsk array by investigating the time structure of a muon disk in extensive air showers of primary energy in the region E0 ≥ 5 × 1016 eV at distances of 250 to 1500 m from the shower core. The measurements were performed with a large muon detector that has an area of 184 m2 and a detection threshold of Eµ≈0.5secθ GeV and which began operating in November 1995. Two components having different muon-disk thicknesses were discovered, and this requires strong modifications in the currently prevalent idea of the development of extensive air showers. The problem of the existence of E0 ≥ 1020 eV events is considered.

Spatio-temporal structure of the muon disk at E 0 ≥ 5 × 1016 eV from Yakutsk EAS array data

We present the results of our study of the temporal structure of the muon disk at the Yakutsk array in extensive air showers with primary energies E0 ≥ 5 × 1016 eV at distances of 250–1500 m from the shower axis obtained using a large muon detector with an area of 184 m2 and a detection threshold of Eμ ≈ 0.5 sec θ GeV. We have found two components with different muon disk thicknesses that require significant revisions of our view of the development of extensive air showers.

Radio detection of cosmic ray air showers by the CODALEMA experiment

The possibilities of measuring Extremely High Energy Cosmic Rays by radio detection of electromagnetic pulses radiated during the development of extensive air showers in the atmosphere are investigated. We present the demonstrative CODALEMA experiment, set up at Nançay Radio-Observatory (France). The radio-decametric array has been adapted to measure radio transients in time coincidence between antennas.

On total inelastic cross sections and the average depth of the maximum of extensive air showers

The model dependence of the development of extensive air showers generated by high-energy cosmic-ray particles in the atmosphere is studied. The increase of proton–proton and proton–air inelastic cross sections and values for the elasticity are varied in the hadronic interaction model QGSJET. Using the CORSIKA simulation program, the impact of these changes is investigated on air shower observables such as the average depth of the shower maximum Xmax and the number of muons and electrons at ground level. Calculating the mean logarithmic mass from experimental Xmax values, it is found that a moderate logarithmic increase of the proton–proton inelastic cross section from σinelpp = 51 mb at E0 = 106 GeV to σinelpp = 64 mb at E0 = 108 GeV, and an elasticity, additionally increased by 10%–15%, describe the data best. Using these parameters, the mean logarithmic mass ⟨ln A⟩ derived from Xmax measurements is compatible with the extrapolations of the results of direct measurements to high energies using the poly-gonato model.

On the semihard hadronic interactions in extensive air shower

A consistent scheme to incorporate the semihard processes into Gribov-Regge models of hadronic interactions is proposed. Particle production during the soft preevolution, before the hard parton—parton scattering, is explicitely taken into account. Perturbative parton cascade is described on the basis of the unified evolution equation. The effect of the unitarization of the hard partonic scattering amplitude is discussed. Some consequences for Extensive Air Shower development and for EAS data analysis are considered.

Validity of the superposition model for extensive air showers

The VENUS model of relativistic nucleus-nucleus collisions is used to study interactions of various nuclei with 14N in view of their influence on the development of extensive air showers initiated by cosmic ray nuclei in the atmosphere. As is well known, only some of the projectile nucleons take part in the interaction (participants) whereas the others (spectators) do not lose an appreciable amount of energy. Our main result is that the nucleus-nucleus collision, at the high energies of interest, can be described to a good approximation by the superposition of Np nucleon-nucleus collisions where Np is the number of participant projectile nucleons. Therefore the superposition model frequently employed in the calculation of air shower development in the atmosphere should represent a rather good approximation. This is in disagreement with some statements in the literature but is corroborated by simulation calculations of extensive air showers employing the VENUS program. Possible reasons for this discrepancy are discussed.

Reexamining the jet contribution to the photoproduction cross section.

We reexamine the contribution of minijet production to the total photoproduction cross section. We show that previous calculations showing a dramatic increase of the cross section with energy have overestimated the minijet contribution at very high energies (${\mathit{E}}_{\ensuremath{\gamma}}$>${10}^{6}$ GeV). We present revised quantitative predictions. Understanding the high energy behavior of the photoproduction cross section should be a high priority as it is dictated by the gluon structure of high energy photons which will be studied in detail at the DESY ep collider HERA. It is also essential for understanding the development of extensive air showers.

Study of the longitudinal development of individual EAS inferred from the Cherenkov light pulse shape: method and results

The method of Cherenkov pulse shape for the study of longitudinal development of extensive air showers (EAS) is considered. Some results obtained with this method are described: the dependence of the depth of the EAS maxima on the primary energy, evaluation of the inelastic p- 14N cross section, and individual EAS cascade curves.

Calculations of characteristics of gamma ray and hadron families

The Monte-Carlo method is used to calculate the three-dimensional development of extensive air showers in the range of primary energy 3*1014-1016 eV for different observation levels: 60, 200 and 590 g cm-2. The data obtained are analysed from the viewpoint of the construction of gamma ray and hadron families. It is concluded that the fraction of families initiated in one collision alone (pure families) is rather low and that they are hardly separable from the others.

Theoretical Studies of the Longitudinal Development of Extensive Air Showers. II: Average Behaviour of the Electron Component

The longitudinal development of the electron component of the air shower is investigated in connection with high energy nuclear interaction. The method of calculations and analyses developed for the study of the nuclear active component in a previous paper are used again. The transition curves of the electrons are considered. First, the transition curves are represented by four numerical constants. Next, model dependent features of the transition curves are discussed by investigating systematically the relationship between the four constants and parameters in the model of high energy nuclear interaction. From the results of the present work, a model of the longitudinal development of the electron component is presented, and is compared with other models ancl other simulations of air showers. § ] . lntrod ueLion The purpose of the present work is to provide a systematic view of the relationship between the basic properties of high energy nuclear interaction and the characteristic features of the longitudinal development of the air shower. In this paper, following the investigation of the nuclear active component of the air shower grven m a previous paper (hereafter referred to as PJ), we deal with the electron ,·ornponent in a similar way. The transition curves of the electnms, under consideration in the present paper, would be of great use in understanding the experimental data such as the size spectra at various altitudes, the angular distribution of the air showers 21 and the direct measurement of the transition curves by air scintillation light. 31 In the present and the previous paper, however, our investigations are restricted to the average transition curves of the fixed primary energy. For precise comparison of the theoretical results with experimental data, the fluctuations of the transition curves haYe to be taken into account. Stochastic properties of the transition curves due to fluctuations in the nuclear collisions vvill be discussed in detail in a following paper. In the coun>e of the present work, \Ve have found that the transition curves

Theoretical Studies of the Longitudinal Development of Extensive Air Showers. I: Average Behaviour of Nuclear Active Component

Theoretical Studies of the Longitudinal Development of Extensive Air Showers. I: Average Behaviour of Nuclear Active Component

Properties of hadronic interactions at≈106GeV: Clues from cosmic-ray air showers

We calculate the effect of intranuclear cascades and rising cross sections on the development of extensive air showers at energies up to 1${0}^{7}$ GeV. We find that these effects do not completely eliminate previously reported discrepancies between calculated and observed shower properties. We conclude that these discrepancies can only be removed by new features of high-energy interactions, predominantly heavy primaries at these energies, or both.

Eigenschaften der starken Wechselwirkung in der Theorie großer Luftschauer

Results of threedimensional Monte Carlo Simulations of extensive air shower development are presented and compared with empirical data. The possibility to conclude on various strong interaction parameters is discussed.

Der Einfluß der Primärmasse auf die Struktur großer Luftschauer

Abstract Results of Monte Carlo Simulations of Extensive Air Shower Development are discussed with respect to the influence of primary mass on shower characteristics (energy spectrum and lateral distribution of hadrons, frequency of nuclear active "multicores", mean total energy of hadrons, fluctuation of total hadron energy, mean total number of myons, fluctuation of total myon number, mean central electron density, frequency of electromagnetic "multicores"). Critical comments are presented concerning some empirical data.

Longitudinal Distribution of Čerenkov Light from Extensive Air Showers

The longitudinal development of extensive air showers of \ensuremath{\sim}${10}^{13}$ eV is studied both experimentally and theoretically. The risetime and duration of \ifmmode \check{C}\else \v{C}\fi{}erenkov pulses in uv light at 3500 m above sea level are studied experimentally with high-speed techniques. The results are in quite good agreement with an accurate Monte Carlo estimate in the $B"$ approximation of electromagnetic shower theory.

Lateral Density Distribution of Charged Particles in the Central Region of Extensive Air Shower

The lateral density distribution of the ionizing particles around the core of the extensive air shower has been observed with ten plastic scintillation counters at mountain altitude (2775 meters above sea level). The lateral density distribution, which has seemed so far to be expressed by the unique function of the distance from the central axis of extensive air showers, has been clearized as that it could be expressed by 1/ r n approximately is a range of 20 meters from the axis and n varies from 0.8 to 2.0 by the character of each shower. The result seems to have a relation to the fluctuation which has been presented in the previous paper or to the fluctuation of nuclear cascade in the development of extensive air showers. The density spectrum at single counter has been also analysed and the result supports above conclusion.

On the Structure of Extensive Air Showers. II

Assuming a simple model of extremely high energy collisions we investigate the relation between the one-dimensional development of extensive air showers (EAS) and the mechanism of multiple mes.on production. The gross structure of EAS based on the model is given graphically or numerical!y, in a form useful, as a first step, for further investigations. In particular, varying the value of in­ elasticity of high energy collisions we discuss its effect on various quantities. As a preliminary con­ clusion it is shown that it seems difficult to explain the experimental result of the constancy of the attenuation length of the electron component over a ·wide range of primary energies, 10l4~10l7eV, without introducing any energy dependence of the inelasticity or a stronger energy dependence of multiplicity with increasing energy, though. it is desirable that further experiments furnish us with more abundant and reliable data. Attention will also be paid to the problem of what quantities must be measured to determine more directly and less ambiguously the angular and energy distribu­ tions of secondary particles produced by high energy collisions. § I. Introduction The purpose of this paper is to analyse the structure of extensive air showers (EAS). with a vtew of investigating the mechanism of multiple meson production in extremely high· energy collisions. The skeleton of EAS is the nucleonic cascade process in the atomosphere developed due to high energy collisions, through which particles of other components, namely electrons, photons; muons, etc., are produced secondarily. There are not very many analyses of EAS which treat this process directly, because the mathematical treatments are very difficult and the process of high energy collisions involves many un. known factors. The works which have been published may be roughly classified into two types : (a) Existing theories of multiple meson production are applied to. analyse EAS and they are examined accordin5 to whether or not they can explain experimental results well. (b) A phenomenological model is assumed and parameters introduced in it are fitted by comparison with experimental data. The works of Amaldi et aVl and Oda2l belong to the former and those of the Soviet group,3 ·4 ·5J Messel et al.6 •7l and Budini