Lateral Distribution Of Electrons Research Articles

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.

On the efficiency of the evaluation of the primary cosmic ray composition using lateral distributions of air shower electromagnetic component

New analysis of lateral distributions (LD) of electrons, muons and charged particles in extensive air showers generated by 1015 − 1019 eV cosmic rays has been made with respect to the scaling formalism for LD and air shower universality paradigm. It is found that lateral distributions of electrons and muons, when considered separately, are well described by one-parametric scaling functions, while for the charged particles mixture distributions the scaling description is not accurate in radial distance range where electrons and muons give a comparable contribution to the local particle densities. The use of scaling formalism enables enhancing the electron/muon separation capabilities and, when combined with theoretically motivated air shower universality concept, provides robust mass composition estimates. The proposed approach could be implemented for the present and future (multi-) hybrid air shower observations, especially in realizing the potential of Auger and Telescope Array observatories upgrades, as well as for re-analysis and cross-calibration of the data collected from different air shower arrays in a broad primary energy range.

Lateral distributions of electrons in air showers initiated by ultra-high energy gamma quanta taking into account LPM and geomagnetic field effects

Lateral distributions of electrons in air showers initiated by photons of ultra high energies (1018 − 1022 eV) obtained on the basis of numerical solution of adjoint cascade equations are presented. An extended analysis has been made considering separately the Landau-Pomeranchuk-Migdal (LPM) effect and the interaction of photons and electrons with the geomagnetic field (GMF) with respect to the scaling formalism for lateral distributions. It is shown that one-parametric scaling description of the lateral distribution of electrons remains valid up to the highest energies considering the LPM and GMF effects, that allows effective primary particle type discrimination using the surface detectors data of largest ground-based air shower arrays.

Improving the accuracy of cosmic ray mass composition estimation using the scale factor of the electron lateral distribution in air showers

The prospects for using the scale factor of the lateral distribution of electrons in air showers as an indicator of the type of cosmic ray primary particle is studied. The developed approach allows to improve the accuracy of reconstructing the mass composition of high-energy cosmic radiation on both an average and event-by-event basis, along with the reanalysis and verification of the congruence between data from different experiments and their cross-calibration and validation. The problem of estimating the scale factor of the electron lateral distribution using data from existing EAS arrays in light of their prospective upgrading is discussed.

Model-stable universality of the air shower electromagnetic component: An approach to solving the mass composition problem

On the basis of the scaling approach and CORSIKA simulations data the radial scale factor of lateral distribution of electrons in extensive air showers is confirmed as potentially effective primary mass estimator, and its sensitivity to hadronic interaction model is investigated. It is shown that improved composition results both on average and event-by-event basis can be achieved taking into account the universality property of air shower development expressed by the relation between radial scale factor and longitudinal age parameter. The enhancements of such a theoretically motivated tool for the unbiased cosmic ray composition deduction in a wide primary energy range from (multi-)hybrid air shower measurements of nearest future are discussed.

Model-stable universality of the air shower electromagnetic component: An approach to solving the mass composition problem

On the basis of the scaling approach and CORSIKA simulations data the radial scale factor of the lateral distribution of electrons in extensive air showers is confirmed as a potentially effective primary mass estimator, and its sensitivity to hadronic interaction model is investigated. It is shown that improved composition results both on average and event-by-event basis can be achieved taking into account the universality property of air shower development expressed by the relation between the radial scale factor and the longitudinal age parameter. The enhancements of such a theoretically motivated tool for an unbiased cosmic ray composition deduction in a wide primary energy range for current and future (multi-)hybrid air shower measurements are discussed.

Slope of the lateral density function of extensive air showers around the knee region as an indicator of shower age

Analyzing simulated extensive air shower (EAS) events generated with the Monte Carlo code CORSIKA, this paper critically studies the characteristics of lateral distribution of electrons in EAS around the knee energy region of the energy spectrum of primary cosmic rays. The study takes into account the issue of lateral shower age parameter as indicator of the stage of development of showers in the atmosphere. The correlation of lateral shower age parameter with other EAS observables is examined, using simulated data in the context of its possible use in a multi-parameter study of EAS, with a view to obtaining information about the nature of the shower initiating primaries at sea level EAS experiments. It is shown that the observed slope of the lateral density function in the 3-dimensional plot at least for the KASCADE data supports the idea of a transition from light to heavy mass composition around the knee.

Electron and thermal neutron lateral distribution functions in EAS at high altitude

EAS array of novel type have been constructed on the base of ARGO-YBJ experiment (Tibet, China). It consists of the four specially designed scintillator en-detectors capable to measure two main EAS components: hadrons through thermal neutrons (n) and electrons (e). The results of simulation for these arrays using CORSIKA and GEANT4 codes are presented. Simulated thermal neutron and electron lateral distributions are compared with experimental data. Obtained distributions are compared with those obtained by other arrays.

Correlation of angular and lateral distributions of electrons in extensive air showers

The aim of this paper is to explain the weak correlation of the angular and lateral deflections of electrons in extensive air showers in the primary energy range 1016–1019 eV, when compared with that in some models of electron propagation. We derive analytical formulae for the correlation coefficient in the multiple scattering model with energy losses and show a strong role of the ionisation in diminishing the correlation. By considering a Heitler-like model of an electromagnetic cascade we show also that the presence of photons, parent to electrons, causes a decrease of the correlation, roughly explaining quantitatively the small correlation in air showers.

An extended universality of electron distributions in cosmic ray showers of high energies and its application

It is shown that the shape of any electron distribution in a high energy air shower is the same in all such showers, if taken at the same age, independently of the primary energy, mass and thus, of the interaction model. A universal behaviour has been also found within a single shower, such that the lateral distributions of electrons with fixed energies, at various shower ages, can be described by a single function of only one variable. The angular distributions of electrons with a fixed energy can be represented, at a given lateral distance, by a function of the product θ·Eα only, which is explained by a model of small angle electron scattering with simplified energy losses. These results have been obtained by Monte Carlo simulations of the extensive air showers. The electron universality can be used as a method for determining the longitudinal profile of any single shower from its optical images measured by the fluorescence light technique, which is particularly useful with showers observed with large fraction of the Cherenkov light.

Air shower universality in the energy range of 1014 to 1022 eV

Universality in the development of air showers initiated by photons and the nuclei of cosmic rays is studied over a wide range of energies (1014–1022 eV). The scaling invariance of the lateral distribution of electrons and the universal relationship between a cascade’s age and radial scaling parameter (the root-meansquare radius of the electron component) are found to remain valid up to ultimate high energies with allowance for the Landau-Pomeranchuk-Migdal effect and interaction with the geomagnetic field. Possible applications of universality for matching, reanalyzing, and verifying the validity of data from different experiments, and for reducing the effect of the nuclear interaction model’s uncertainty on estimates of the mass composition of primary cosmic rays, are discussed.

Numerical Study of the Electron Lateral Distribution in Atmospheric Showers of High Energy Cosmic Rays

The study of the lateral distribution of electrons in an atmospheric cascade can lead to useful conclusions on the mass and energy of the primary cosmic particle. In this work we compare the results we get from simulations by the CORSIKA program, with the theoretical NKG function expressing the lateral distribution of electrons. We then modify the original NKG function to fit better the data of the simulation. Finally, we propose this procedure as a method to approach the mass of the primary particle which started the atmospheric cascade.

Scaling behaviour of lateral distribution of electrons in EAS

From a Monte Carlo simulation study of cosmic ray air showers around the knee of the primary energy spectrum it is shown that, despite a strong radial dependence of the lateral shower age parameter, the lateral density distribution of electrons in cosmic ray EAS displays universality when expressed in terms of local age parameters. The nature of the radial variation of local age is found to depend on the choice of the effective Moliere radius, particularly for radial distances below about 400 m. The possible use of shower age parameters in a multi-parameter study of EAS for extracting information about the nature of the shower initiating particles, has been re-examined.

Model-independent approach to deducing the mass composition of primary cosmic rays on the basis of the scale invariance in the radial distribution of electrons in extensive air showers

A new approach to deducing the mass composition of primary cosmic rays is proposed using the air showers universality and the scaling property of the electron lateral distribution function. Experimental data from the KASCADE, MSU, and KASCADE-Grande arrays have been analyzed, allowing conclusions as to the variations of mass composition above the knee to be drawn independently of the hadron-nucleus interaction model.

Improved two-dimensional electron gas transport characteristics in AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor with atomic layer-deposited Al2O3 as gate insulator

The effects of Al2O3 gate insulator grown by atomic layer deposition (ALD) system on the two-dimensional electron gas (2DEG) transport characteristics in AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor (MISHEMT) were investigated. The shape of the electron lateral distribution in the quantum well at AlGaN/GaN interface was found to be slightly influenced by the Al2O3 thin layer. The drift mobility (μd) of the electrons in ALD-Al2O3/AlGaN/GaN MISHEMT is increased due to the surface passivation effects of the included dielectric layer. The higher dynamic channel current of the MISHEMT indicates that the electron saturation velocity (vsat) is also increased. These results show the improvement of the transport characteristics of 2DEG in Al2O3/AlGaN/GaN MISHEMT by the excellent properties of the Al2O3 grown by ALD.

Cosmic ray primary mass composition above the knee: deduction from lateral distribution of electrons

Influence of shower fluctuations on the shape of lateral distribution of electrons in EAS of fixed size measured by scintillation counters is analyzed in framework of scaling formalism. Correction factors for the mean square radius of electrons are calculated for the experimental conditions of KASCADE array. Possible improvement of the primary mass discrimination by analysis of lateral distribution of EAS electrons is discussed in detail.

Lateral Distribution of Electrons Trapped in Nitride Layers

ABSTRACTThe recent advent of nitride-based localized charge-trapping storage has raised much interest in the lateral characterization of the trapped charge distribution, which is fundamental in defining scalability and retention properties. A direct characterization technique based on amplitude-sweep charge-pumping measurements is exploited here to investigate the lateral distribution of trapped electrons along the channel length. Further, the technique is applied to monitor the charge redistribution in time at high temperature.

PCR nuclear composition at 1–30 PeV according to lateral distributions of electrons in EAS accompanied by high energy particles in emulsion chambers

New data on the primary cosmic ray nuclear composition were derived from the electron lateral distributions of EAS at Tien-Shan. The dependence on EAS electron size is presented from N e = 5·10 5 to 3·10 7. Data were obtained for all EAS as well as for EAS accompanied by high energy gamma-rays and hadrons in X-ray emulsion chambers. According to model simulations the latter events are generated predominantly by primary protons. Results showed that the fraction of protons and light nuclei does not decrease above the “knee” from N e = 10 6 up to 10 7 (∼10 – 20 PeV primary energy).

EAS lateral distribution functions in the framework of the universal hadronic interaction model neX us

An Extensive Air Shower (EAS) calculation scheme based on the solution of cascade equations is applied to obtain lateral distributions of shower particles. The universal hadronic interaction model neX us is used to prepare necessary input data, i.e. inclusive energy spectra of secondary hadrons and their transverse momentum distributions. The calculated lateral distributions of electrons and muons are compared to the experimental data of the KASCADE array. It is shown that a good agreement with the measurements may be achieved if one takes into account the increasing abundance of heavy nuclei in the primary Cosmic Ray (CR) composition above the knee of the CR spectrum. Some methodical problems concerning electron lateral distribution calculations at large distances are discussed.

Comparative study of depth and lateral distributions of electron excitation between scanning ion and scanning electron microscopes

In order to study the contrast difference between scanning ion microscopes (SIM) and scanning electron microscopes (SEM), the depth and lateral distributions of secondary electrons escaped from surfaces of 17 metals with atomic numbers, Z2, of 4-79 were calculated for bombardment with 30 keV Ga ions and for 10 keV electrons. For both projectiles, the excitation depth generally decreased with increasing Z2, while showing the same periodic change as the secondary-electron yield. However, an opposite trend in Z2 dependence between the Ga ion and electron bombardments was calculated with the lateral distribution of secondary electrons escaped from the surface. Except for low Z2 metals, the lateral distribution, which is much narrower for 30 keV Ga ions than for 10 keV electrons, indicates that the spatial resolution of the secondary-electron images is better for SIM than for SEM, if zero-sized probe beams are assumed. Furthermore, the present calculation reveals important effects of electron excitation by recoiled material atoms and reflected electrons on the lateral distribution, as well as the secondary-electron yield, for the Ga ion and electron bombardments, respectively.