scholarly journals PRIMARY ENERGY SPECTRUM AND MASS COMPOSITION DETERMINED WITH THE TUNKA EAS CHERENKOV ARRAY

2005 ◽  
Vol 20 (29) ◽  
pp. 6799-6801 ◽  
Author(s):  
D. V. CHERNOV ◽  
E. E. KOROSTELEVA ◽  
L. A. KUZMICHEV ◽  
V. V. PROSIN ◽  
I. V. YASHIN ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Distribution Function ◽  
Energy Spectrum ◽  
Monte Carlo Simulations ◽  
Light Pulse ◽  
Primary Energy ◽  
Cherenkov Light ◽  
Mass Composition ◽  
Knee Region ◽  
The Mean

New results of 300 hours of operation of the TUNKA array are presented. An improved parametrization of the Cherenkov light lateral distribution function (LDF), based on CORSIKA Monte Carlo simulations and the experiment QUEST, has been used for the reconstruction of EAS parameters. The corrected energy spectrum in the knee region is obtained. The mean depth of the EAS maximum has been derived both from the analysis of LDF steepness and the FWHM of Cherenkov light pulse. The mean mass composition around the knee is estimated.

scholarly journals Study of Cherenkov light lateral distribution function around the knee region in extensive air showers

2015 ◽  
pp. 79-85
Author(s):  
A. Al-Rubaiee ◽  
U. Hashim ◽  
M. Marwah ◽  
Y. Al-Douri
Keyword(s):  
Distribution Function ◽  
Cherenkov Radiation ◽  
Cosmic Ray ◽  
Primary Energy ◽  
Lateral Distribution ◽  
Cherenkov Light ◽  
Air Showers ◽  
Knee Region ◽  
Lateral Distribution Function ◽  
Primary Particles

The Cherenkov light lateral distribution function (LDF) was simulated with the CORSIKAcode in the energy range (1013 - 1016) eV. This simulation was performed for conditions and configurations of the Tunka EAS Cherenkov array for the two primary particles (p and Fe). Basing on the simulated results, many approximated functions are structured for two primary particles and different zenith angles. This allowed us to reconstruct the EAS events, which is, to determine the type and energy of the primary particles that produced showers from signal amplitudes of Cherenkov radiation measured by the Tunka Cherenkov array experiment. Comparison of the calculated LDF of Cherenkov radiation with that measured at the Tunka EAS array shows the ability to identify the primary particle that initiated the EAS cascades by determining its primary energy around the knee region of the cosmic ray spectrum.

A numerical study of the sedimentation of fibre suspensions

1998 ◽  
Vol 376 ◽  
pp. 149-182 ◽  
Author(s):  
MICHAEL B. MACKAPLOW ◽  
ERIC S. G. SHAQFEH
Keyword(s):  
Monte Carlo ◽  
Steady State ◽  
Monte Carlo Simulations ◽  
Numerical Study ◽  
Point Particle ◽  
Hydrodynamic Interactions ◽  
Dynamic Simulations ◽  
Slender Body Theory ◽  
Fibre Suspensions ◽  
The Mean

The sedimentation of fibre suspensions at low Reynolds number is studied using two different, but complementary, numerical simulation methods: (1) Monte Carlo simulations, which consider interparticle hydrodynamic interactions at all orders within the slender-body theory approximation (Mackaplow & Shaqfeh 1996), and (ii) dynamic simulations, which consider point–particle interactions and are accurate for suspension concentrations of nl3=1, where n and l are the number density and characteristic half-length of the fibres, respectively. For homogeneous, isotropic suspensions, the Monte Carlo simulations show that the hindrance of the mean sedimentation speed is linear in particle concentration up to at least nl3=7. The speed is well predicted by a new dilute theory that includes the effect of two-body interactions. Our dynamic simulations of dilute suspensions, however, show that interfibre hydrodynamic interactions cause the spatial and orientational distributions to become inhomogeneous and anisotropic. Most of the fibres migrate into narrow streamers aligned in the direction of gravity. This drives a downward convective flow within the streamers which serves to increase the mean fibre sedimentation speed. A steady-state orientation distribution develops which strongly favours fibre alignment with gravity. Although the distribution reaches a steady state, individual fibres continue to rotate in a manner that can be qualitatively described as a flipping between the two orientations aligned with gravity. The simulation results are in good agreement with published experimental data.

scholarly journals Universal dependence of the total number albedo of photons on the mean number of photon scatterings

2011 ◽  
Vol 26 (3) ◽  
pp. 249-253 ◽  
Author(s):  
Vladan Ljubenov ◽  
Rodoljub Simovic
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Analytic Functions ◽  
Least Squares Method ◽  
Mcnp Code ◽  
Initial Photon ◽  
Aluminum Iron ◽  
Universal Dependence ◽  
The Mean ◽  
Good Agreement

This paper presents the results of research on photon reflection from plane targets based on Monte Carlo simulations performed by the MCNP code. Five materials (water, concrete, aluminum, iron, and copper) are examined in the area of initial photon energies of up to 200 keV. The values of the total number albedo for photons dependent on the initial photon energy or the mean number of photon scatterings are calculated and graphically presented. We have shown that the values of the total number albedo for different target materials, expressed as a function of the mean number of photon scatterings, are in good agreement with each other and can be approximated by simple, universal analytic functions obtained by the least squares method. The accuracy of these analytic appoximations is confirmed by their comparison with the results of PENELOPE and FOTELP Monte Carlo codes.

scholarly journals The highest-energy cosmic-rays – the past, the present and the future

2019 ◽  
Vol 210 ◽  
pp. 00001
Author(s):  
Alan Watson
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Mass Distribution ◽  
Mass Composition ◽  
Future Prospects ◽  
Telescope Array ◽  
Hadronic Interactions ◽  
The Past ◽  
Shower Maximum ◽  
The Mean

The greater part of this paper is concerned with a historical discussion of the development of the search for the origins of the highest-energy cosmic-rays together with a few remarks about future prospects.Additionally, in section 6, the situation with regard to the mass composition and energy spectrum at the highest energies is discussed. It is shown that the change of the depth of shower maximum with energy above 1 EeV, measured using the Telescope Array, is in striking agreement with similar results from the Auger Observatory. This implies that either the mean mass of cosmic rays is becoming heavier above ~4 EeV or that there is a change in details of the hadronic interactions in a manner such that protons masquerade as heavier nuclei. A long-standing controversy is thus resolved: the belief that pure protons dominate the mass distribution at the highest energies is no longer tenable.

Energy spectrum from single TGFs detected by ASIM

2020 ◽  
Author(s):  
Anders Lindanger ◽  
Martino Marisaldi ◽  
Nikolai Østgaard ◽  
Andrey Mezentsev ◽  
Torstein Neubert ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Spectral Analysis ◽  
Energy Spectrum ◽  
Monte Carlo Simulations ◽  
Energy Range ◽  
Gamma Ray ◽  
High Energy ◽  
Energy Calibration ◽  
Energy Detector ◽  
Instrumental Effects

<p>Terrestrial Gamma-ray Flashes (TGFs) are sub milliseconds bursts of high energy photons associated with lightning flashes in thunderstorms. The Atmosphere-Space Interactions Monitor (ASIM), launched in April 2018, is the first space mission specifically designed to detect TGFs. We will mainly focus on data from the High Energy Detector (HED) which is sensitive to photons with energies from 300 keV to > 30 MeV, and include data from the Low Energy Detector (LED) sensitive in 50 keV to 370 keV energy range. Both HED and LED are part of the Modular X- and Gamma-ray Sensor (MXGS) of ASIM.<br><br>The energy spectrum of TGFs, together with Monte Carlo simulations, can provide information on the production altitude and beaming geometry of TGFs. Constraints have already been set on the production altitude and beaming geometry using other spacecraft and radio measurements. Some of these studies are based on cumulative spectra of a large number of TGFs (e.g. [1]), which smooth out individual variability. The spectral analysis of individual TGFs has been carried out up to now for Fermi TGFs only, showing spectral diversity [2]. Crucial key factors for individual TGF spectral analysis are a large number of counts, an energy range extended to several tens of MeV, a good energy calibration as well as knowledge and control of any instrumental effects affecting the measurements.</p><p>We strive to put stricter constraints on the production altitude and beaming geometry, by comparing Monte Carlo simulations to energy spectra from single ASIM TGFs. We will present the dataset and method, including the correction for instrumental effects, and preliminary results on individual TGFs.</p><p>Thanks to ASIM’s large effective area and low orbital altitude, single TGFs detected by ASIM have much more count statistics than observations from other spacecrafts capable of detecting TGFs. ASIM has detected over 550 TGFs up to date (January 2020), and ~115 have more than 100 counts. This allows for a large sample for individual spectral analysis.</p><p>References:</p><ol><li>Dwyer, J. R., and D. M. Smith (2005), A comparison between Monte Carlo simulations of runaway breakdown and terrestrial gamma-ray flash observations, Geophys. Res. Lett., 32, L22804, doi:10.1029/2005GL023848.</li> <li>Mailyan et al. (2016), The spectroscopy of individual terrestrial gamma-ray flashes: Constraining the source properties, J. Geophys. Res. Space Physics, 121, 11,346–11,363, doi:10.1002/2016JA022702.</li> </ol>

Is Thermalization Due to Electronic Self-Trapplng?

1995 ◽  
Vol 377 ◽  
Author(s):  
Mathieu Kemp
Keyword(s):  
Monte Carlo ◽  
Energy Spectrum ◽  
Monte Carlo Simulations ◽  
Photoluminescence Spectrum ◽  
Lifetime Distribution ◽  
Red Shift ◽  
Self Trapping ◽  
Photoluminescence Lifetime

ABSTRACTThe interpretation that the red shift of the a-Si:H photoluminescence spectrum is due to carrier hopping is incompatible with Monte-Carlo simulations. We suggest that thermalization is instead the result of slow, gradual, electronic self-trapping. We show how this model reconciles the narrowness of the photoluminescence lifetime distribution with the observed red-shift of the energy spectrum.

Estimating of Cherenkov Radiation in Extensive Air Showers Using CORSIKA Code for Tunka133 EAS Cherenkov Array

2015 ◽  
Vol 754-755 ◽  
pp. 807-811
Author(s):  
A.A. Al-Rubaiee ◽  
Uda Hashim ◽  
Mohd Khairuddin Md Arshad ◽  
A. Rahim Ruslinda ◽  
R.M. Ayub ◽  
...  
Keyword(s):  
Energy Spectrum ◽  
Energy Range ◽  
Cosmic Ray ◽  
High Energy ◽  
Extensive Air Showers ◽  
Cherenkov Light ◽  
Mass Composition ◽  
Air Showers ◽  
Good Ability ◽  
The Given

The simulation of Cherenkov light Lateral distribution function (LDF) in Extensive Air Showers (EAS) initiated primary particles such as primary calcium, argon, proton iron nuclei, neutron and nitrogen have been performed using CORSIKA program for conditions and configurations of Tunka133 EAS Cherenkov array. The simulation was fulfilled at the high energy range 1014-1016eV for four different zenith angles 0o, 10o, 15oand 30o. The results of the simulated Cherenkov light LDF are compared with the measurements of Tunka133 EAS array for the same particles and energy range mentioned above. This comparison may give the good ability to reconstruct the energy spectrum and mass composition of the primary cosmic ray particles in EAS. The main feature of the given approach consists of the possibility to make a library of Cherenkov light LDF samples which could be utilized for analysis of real events which can be detected with different EAS arrays and reconstruction of the primary cosmic rays energy spectrum and mass composition of EAS particles.

scholarly journals Parameterization of Cherenkov Light Lateral Distribution Function as a Function of the Zenith Angle around the Knee Region

2016 ◽  
Vol 66 ◽  
pp. 71-78
Author(s):  
Marwah M. Abdulsttar ◽  
A.A. Al-Rubaiee ◽  
Abdul Halim K. Ali
Keyword(s):  
Distribution Function ◽  
Zenith Angle ◽  
Lateral Distribution ◽  
Extensive Air Showers ◽  
Cherenkov Light ◽  
Primary Proton ◽  
Air Showers ◽  
Knee Region ◽  
Lateral Distribution Function ◽  
Shower Core

Cherenkov light lateral distribution function (CLLDF) simulation was fullfiled using CORSIKA code for configurations of Tunka EAS array for different zenith angles. The parameterization of the CLLDF was carried out as a function of the destance from tehe shower core in extensive air showers (EAS) and zenith angle on the basis of the CORSIKA simulation for primary proton around the knee region with the energy 3.1015 eV at different zenith angles. The parametrized CLLDF is verified in comparison with the simulation that performed using CORSIKA code for two zenith angles.

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