Lateral Distribution Function Research Articles

THE SIMULATION AND PARAMETRIZATION OF THE LATERAL DISTRIBUTION FUNCTION IN EAS AT ULTRA HIGH ENERGIES

To characterize the features of EASs, this study used the AIRES simulation tool (Version 19.04.0) to estimate the lateral distribution function (LDF) at very high energies of different types of cosmic ray particles. An array of zenith angles spanning from 1018 to 1020 eV was used for the proton and iron primary simulations. The EASs's LDF curves are fitted with new coefficients for various primary particles and zenith angles using a polynomial fit, and these coefficients are applicable to the energy range described before. The findings of the simulation were compared with actual data from the Yakutsk EAS array, which showed decent agreement for proton and iron at 1019 eV for angled showers at θ=10ˢ.

The shape of the electron and muon lateral distribution functions of extensive air showers

The shape of the electron and muon lateral distribution functions of extensive air showers

Muons in EASs with E0 = 1019 eV According to Data of the Yakutsk Array

Lateral distribution functions of particles in extensive air showers with the energy {{E}_{0}} approx {{10}^{{19}}}{kern 1pt} eV recorded by ground-based and underground scintillation detectors with a threshold of {{E}_{mu }} approx {kern 1pt} 1.0 times {text{sec}}{kern 1pt} theta GeV at the Yakutsk array during the continuous observations from 1986 to 2016 have been analyzed using events with zenith angles θ ≤ 60°. Experimental functions have been compared to the predictions obtained with the QGSJet-01-d hadron interaction model by applying the CORSIKA code. The entire dataset indicates that cosmic rays consist predominantly of protons.

Simulation of Lateral Distribution Function of Cherenkov Light in Extensive Air Showers for Yakutsk Array

The simulation of Cherenkov light Lateral distribution function (LDF) for primary particles like primary protons, Iron nuclei, Oxygen, Nitrogen, Calcium, Neutron and Argon have been performed with CORSIKA code for conditions and configuration of Yakutsk array in the energy range 1014-1016 eV for four zenith angles 0o, 5o, 10o and 15o. The results of this simulation are compared with the measurements of Yakutsk array for the same particles and energyrange

Signal model and event reconstruction for the radio detection of inclined air showers

The detection of inclined air showers (zenith angles θ ≳ 65°) with kilometer-spaced radio-antenna arrays allows measuring cosmic rays at ultra-high energies (E ≲ 1020 eV). Radio and particle detector arrays provide independent measurements of the electromagnetic and muonic shower components of inclined air showers, respectively. Combined, these measurements have a large sensitivity to discriminate between air showers initiated by lighter and heavier cosmic rays. We have developed a precise model of the two-dimensional, highly complex and asymmetric lateral radio-signal distributions of inclined air shower at ground — the “radio-emission footprints”. Our model explicitly describes the dominant geomagnetic emission with a rotationally symmetric lateral distribution function, on top of which additional effects disturb the symmetry. The asymmetries are associated with the interference between the geomagnetic and sub-dominant charge-excess emission as well as with geometrical projection effects, so-called “early-late” effects. Our fully analytic model describes the entire footprint with only two observables: the geometrical distance between the shower impact point at the ground and the shower maximum d max, and the geomagnetic radiation energy E geo. We demonstrate that with this model, the electromagnetic shower energy can be reconstructed by kilometer-spaced antenna arrays with an intrinsic resolution of 5% and a negligible bias.

Dependence of normalized phase angle of cosmic ray radio signals on core location of an extensive air shower

High energy cosmic rays hitting the earth atmosphere induce extensive air showers propagating downward with a high gamma factor. Determining the core location of such air shower is a necessary step to measure other important characteristics of a cosmic ray such as the lateral distribution function. In this study and based on computer simulations and radio signal analyses we investigate the relation between normalized radio signal phase angle emitted from particles in an air shower to the position of a shower core. We perform a series of simulations based on CORSIKA and COREAS code for cosmic rays with different types of primary particles with an energy range from 0.1 to 1 EeV. The results show a direct relationship between the average slope of normalized radio signal phase angle as a function of frequency to the absolute distance from extensive air shower core location. We have calculated the normalized radio signal phase angle to have the absolute minimum value at close distances to a shower core location. We discuss a possible approach to estimate core location with different types of virtual radio arrays.

Muon lateral distribution function of extensive air showers: Results of the Sydney University Giant Air-shower Recorder versus modern Monte Carlo simulations

The Sydney University Giant Air-shower Recorder (SUGAR) measured the muon component of extensive air showers with a unique array of muon detectors. The SUGAR data allow us to reconstruct the empirical dependence of muon density on the distance from the axis of the shower, the lateral distribution function (LDF). We compare the shape of this function with the predictions of hadronic-interaction models, QGSJET-II-04 and EPOS-LHC, in the energy range 10^17.6 - 10^18.6 eV. We find a difference between the observed data and the simulation: the observed muon density falls faster with the increased core distance than it is predicted in simulations. This observation may be important for interpretation of the energy-dependent discrepancies in the simulated and observed numbers of muons in air showers, known as the "muon excess".

Reconstruction of Air-Shower Parameters through Lateral Distribution Function of Ultra-High Energy Particles

In this study, the necessity of the simulation study for exploring the interactions of ultra-high energy particles cosmic rays was examined. Different hadronic interaction models such as (SIBYLL, QGSJET, and EPOS) were simulated by using air showers simulation AIRES system (version 19.04.00). Also, the charged particle density of Extensive Air Showers (EAS) was calculated by estimating the lateral distribution function (LDF). Moreover, the LDF simulation of the two primary particles (proton and iron nuclei) was performed, taking into account their primary energies effect and the zenith angle of charged particles that produced in the EAS, within the energy range (10^17-10^19) eV. At extremely high energies (10^17, 10^18, and 10^19) eV, new parameters as a function of the primary energy were obtained by fitting the lateral distribution curves of EAS using Sigmoidal function (Logistic model). Comparison of the results showed a good agreement between the values obtained from the parameterized LDF using Sigmoidal function with experimental results by AGASA EAS observatory for the primaries proton as well iron nuclei, with the production of (electron positron) pair and the charged muons secondary particles at high energy about 10^19 eV and (theta = 0 degree).

Estimating the Lateral Distribution of High Energy Cosmic Ray Particles by Depending on Nishimura-Kamata-Greisen Function

The calculation of charged particles density in Extensive Air Showers (EAS) that reach the earth’s surface is described through estimating the lateral distribution function (LDF) at very high energies of different primary particles. The simulation of LDF is performed through the simulator of air shower which is called AIR-shower Extended Simulations (AIRES) system (2.8.4a version). The LDF simulation is performed for different charged particles like the muons, electron-positron pair production and all charged particles as well as gamma rays at very high energies (1016, 1018 and 1019) eV. The influence of the primary energies, primary particles (such as the proton and the iron nuclei) and the zenith angle (θ) on the charged particles LDF that generated in the EAS has been taken into the account. The calculation of charged particles LDF is fulfilled using “Nishimura-Kamata-Greisen” (NKG) function. The LDF using NKG function is compared with that simulated using AIRES system and gave a good agreement at high energies for (electron and positron) secondary particles, which were initiated by the primary proton.

Thinning energy effect on the fluctuations of charged particles lateral distribution produced in extensive air showers

In this work, the effects of the extensive air showers (EAS) were described by estimating the lateral distribution function (LDF) at very high energies of various cosmic ray particles. LDF was simulate for charged particles such as the electron and positron pair production, gamma, muons and all charged particles at very high energies1016, 1018 and 1019eV.The simulation was performed using AIRES air shower simulator system version 2.6.0. The effect of primary particles, energies, thinning energy and zenith angle (θ) on the charged LDF particles produced in the EAS was taken into account. The comparison of the estimated LDF of the charged particles such as the electron and positron pair production and muons with the simulated results by Sciutto and experimental results by Yakutsk EAS observatory gives good acceptance at 1019eV for zenith angles 0̊ and 10̊.

Search for Ultra-High-Energy Neutrinos with the Telescope Array Surface Detector

We present an upper limit on the flux of ultra-high-energy down-going neutrinos for $E > 10^{18}\ \mbox{eV}$ derived with the nine years of data collected by the Telescope Array surface detector (05-11-2008 -- 05-10-2017). The method is based on the multivariate analysis technique, so-called Boosted Decision Trees (BDT). Proton-neutrino classifier is built upon 16 observables related to both the properties of the shower front and the lateral distribution function.

Atomistic Molecular Dynamics Simulations of Propofol and Fentanyl in Phosphatidylcholine Lipid Bilayers.

Atomistic molecular dynamics (MD) and steered MD simulations in combination with umbrella sampling methodology were utilized to study the general anesthetic propofol and the opioid analgesic fentanyl and their interaction with lipid bilayers, which is not yet fully understood. These molecules were inserted into two different fully hydrated phospholipid bilayers, namely, dioleoylphosphatidylcholine (DOPC) and dipalmitoylphosphatidylcholine (DPPC), to investigate the effects that these drugs have on the bilayer. We determined the role of the lipid chain length and saturation on the behavior of the two drugs. Pure, fully hydrated DOPC and DPPC bilayers were also simulated, and the results were in excellent agreement with the experimental values. Various structural and mechanical properties of each system, such as the area per lipid, area compressibility modulus, order parameter, lateral lipid diffusion, hydrogen bonds, and radial distribution functions, have been calculated to assess how the drug molecules affect the different bilayers. From the calculated results, we show that fentanyl and propofol generally follow similar trends in each bilayer but adopt different favorable positions close to the headgroup/chain interface at the carbonyl groups. Propofol was shown to selectively form hydrogen bonds at the carbonyl carbon in each bilayer, whereas fentanyl interacts with water molecules at the headgroup interface. From the calculated free-energy profiles, we determined that both molecules show a preference for the low-density, low-order acyl chain region of the bilayers and both significantly preferred the DOPC bilayer with propofol and fentanyl having energy minima at −6.66 and −43.07 kcal mol–1, respectively. This study suggests that different chain lengths and levels of saturation directly affect the properties of these two important molecules, which are seen to work together to control anesthesia in surgical applications.

Parametric analysis of the Lateral Distribution Function of Cherenkov light for Yakutsk EAS Array in the Energy Range 1–20 PeV

In this research, the simulation of lateral distribution function (LDF) of Cherenkov radiation was performed using CORSIKA software for two hadronic models QGSJET and GHEISHA. This simulation was performed for several elementary particles such as protons, iron nuclei, electrons and gamma quanta, in the range of energies 1-20 PeV for three zenith angles 0°, 20° and 30°. A parameterization of Cherenkov light LDF was performed for that simulated curves using Lorentzian function. The comparison between the obtained results for LDF of Cherenkov light with that measured with Yakutsk EAS array gave a good agreement within the distances of 100-1000 m from the shower axis.

On the Problem of Ultrahigh Energy Cosmic Ray Mass Composition Evaluation from Lateral Distributions of EAS Charged Particles Measured at Different Ranges of Radial Distances

The results of the analysis of simulations of extensive air showers (EAS) generated by ultrahigh energy cosmic rays are presented. The analysis was performed within the framework of the scaling approach developed by the authors to describe the lateral distribution functions of electrons and muons of EAS. We discuss a method to evaluate the mass composition of cosmic rays from the experimental data of existing ground-based hybrid experiments with consideration of the potential of their forthcoming extensions as well as the next generation experiments. The discussed method allows minimizing the influence of the uncertainty of nuclear interaction model, instrumental and methodical biases on physical conclusions with respect to the type of primary particle.
 It is shown that the use of the scale parameters of the lateral distributions as an indicator of primary particle, as well as the universal relationship between the scale parameters of the lateral distribution and the (longitudinal) age of the cascade, provides improving mass composition estimations on both the average and event-by-event basis by a single method in a wide primary energy range.

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.

Lateral Distribution Functions of Signals in Surface Scintillation Detectors of the Yakutsk Array, New Energy Estimates of Extensive Air Showers and the Energy Spectrum of the Primary Cosmic Radiation at Energies ∼1017–1019 eV

Fluctuations of lateral distributions of signals in the surface scintillation detectors of the Yakutsk array are found to be large. New estimates of the inclined shower energy had been suggested. In view of these estimates the Yakutsk energy spectrum becomes quite comparable with the spectra observed at the Pierre Auger Observatory and the Telescope Array. The shower energy calculated using the data of only one detector may be overestimated if fluctuations are neglected.

Cascade Particles in Extensive Air Showers with Energy Above 1017 eV According to Longstanding Measurements at the Yakutsk Array

Lateral distribution of cascade particles was studied in extensive air showers initiated by cosmic rays with energy above 1017 eV. The study is based on the data collected with ground-based scintillation detectors of the Yakutsk array during the continuous observational period from 1977 to 2017. Particle density measured in experiment is compared to the results of simulations performed for primary protons and iron nuclei within the framework of four ultra-high energy hadronic interaction models. Particle density obtained in the simulation was converted to signal of the scintillation detectors of the array. From the parameters of the resulted lateral distribution function, features of extensive air showers longitudinal development were derived.

Muon Content of Extensive Air Showers: Comparison of the Energy Spectra Obtained by the Sydney University Giant Air-Shower Recorder and by the Pierre Auger Observatory

The Sydney University Giant Air-shower Recorder(SUGAR) measured the energy spectrum of ultra-high-energy cosmic rays reconstructed from muon detector reading. Comparison of their spectra SUGAR and Pierre Auger Observatory allows us to reconstruct the empirical dependence of the number of muons in a vertical shower on the primary energy for energies between 1017 and 1018 eV. We compared this dependence with the predictions of hadronic interaction models QGSJET-II-04, EPOS-LHC and SIBYLL-2.3c. In addition, we analyzed the response of the array of muon detectors in order to determine the slope of the muon lateral distribution function. It is important to understand how much the number of muons differs from the predictions of modeling at different distances from the shower axis.

Study of lateral density distributions of Cherenkov photons in extensive air showers at primary energy 50 GeV and above

An EAS (extensive air shower) refers to the cascade of secondary particles created from the interactions of high energy primary cosmic ray particles with the air nuclei and subsequent decay of the particles produced. Ultra-relativistic secondary charged particles in the atmosphere produce Cherenkov radiation, which may be detected by ground based detector array. Such an array, HAGAR (High Altitude GAmma Ray) experiment is operating at Hanle, Ladakh, at an energy threshold of about 100 GeV, which will be lowered to 50 GeV using MACE telescope. We have studied the simulations of the distribution patterns of lateral density of Cherenkov photons generated in EAS for different primary particles (γ, p) incident with the fixed primary energy 50 GeV and these are compared with those of 100 GeV showers using the standard CORSIKA code. From our study it has been found that, for all primary particles, the variation of lateral density distribution of Cherenkov photons almost obey the functional relation, ρch (r) = ρ0 e(−βr). The steepness of the lateral distribution function is found to depend on the primary mass composition. Further a prominent hump is observed in the lateral distribution for gamma shower only.

Measurement of the Crab Nebula Spectrum Past 100 TeV with HAWC

Abstract We present TeV gamma-ray observations of the Crab Nebula, the standard reference source in ground-based gamma-ray astronomy, using data from the High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory. In this analysis we use two independent energy estimation methods that utilize extensive air shower variables such as the core position, shower angle, and shower lateral energy distribution. In contrast, the previously published HAWC energy spectrum roughly estimated the shower energy with only the number of photomultipliers triggered. This new methodology yields a much-improved energy resolution over the previous analysis and extends HAWC’s ability to accurately measure gamma-ray energies well beyond 100 TeV. The energy spectrum of the Crab Nebula is well fit to a log-parabola shape with emission up to at least 100 TeV. For the first estimator, a ground parameter that utilizes fits to the lateral distribution function to measure the charge density 40 m from the shower axis, the best-fit values are (TeV cm2 s)−1, , and . For the second estimator, a neural network that uses the charge distribution in annuli around the core and other variables, these values are (TeV cm2 s)−1, , and β = 0.06 ± 0.01 ± 0.02. The first set of uncertainties is statistical; the second set is systematic. Both methods yield compatible results. These measurements are the highest-energy observation of a gamma-ray source to date.