DOES THE "KNEE" IN PRIMARY COSMIC RAY SPECTRUM EXIST?

2003 ◽  
Vol 18 (18) ◽  
pp. 1225-1234 ◽  
Author(s):  
YURI V. STENKIN
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Power Law ◽  
Cosmic Ray ◽  
New Physics ◽  
Point Of View ◽  
Experimental Point ◽  
Primary Spectrum ◽  
Hadronic Structure ◽  
Knee Problem

The problem of the knee in primary cosmic ray at energy about 3–5 PeV is the most exciting problem in cosmic ray physics. Since 1958, physicists have been trying to solve this problem. In our opinion, the problem could be solved from the experimental point of view, whereas the primary spectrum would follow a pure power law. A key to the "knee" problem lies in the hadronic structure of EAS and its propagation in the Earth's atmosphere. Neither exotic processes nor new physics are used. An explanation of the approach and some results of Monte Carlo simulations are given below.

Channeling in 4H-SiC from an Application Point of View

2019 ◽  
Vol 963 ◽  
pp. 386-389 ◽  
Author(s):  
Peter Pichler ◽  
Tomasz Sledziewski ◽  
Volker Häublein ◽  
Anton Bauer ◽  
Tobias Erlbacher
Keyword(s):  
Monte Carlo ◽  
Ion Implantation ◽  
Monte Carlo Simulations ◽  
Electronic Devices ◽  
Point Of View ◽  
Power Electronic ◽  
Application Point ◽  
Doping Profiles

During ion implantation into monocrystalline semiconductors, some of the implanted atoms will be deflected to crystal directions along which they may penetrate deeply into the crystal. We investigate such channeling effects for Al and N implantation into 4H-SiC by Monte Carlo simulations. The focus of the work is on the effects of channeling on doping profiles, the relevance for the net doping of typical power electronic devices, and the influence of scattering oxides.

scholarly journals Soil Moisture and Air Humidity Dependence of the Above-Ground Cosmic-Ray Neutron Intensity

2021 ◽  
Vol 2 ◽  
Author(s):  
Markus Köhli ◽  
Jannis Weimar ◽  
Martin Schrön ◽  
Roland Baatz ◽  
Ulrich Schmidt
Keyword(s):  
Monte Carlo ◽  
Soil Moisture ◽  
Monte Carlo Simulations ◽  
Count Rate ◽  
Neutron Transport ◽  
Cosmic Ray ◽  
Mathematical Treatment ◽  
Specific Response ◽  
Air Humidity ◽  
Parameter Equation

Investigations of neutron transport through air and soil by Monte Carlo simulations led to major advancements toward a precise interpretation of measurements; they particularly improved the understanding of the cosmic-ray neutron footprint. Up to now, the conversion of soil moisture to a detectable neutron count rate has relied mainly on the equation presented by Desilets and Zreda in 2010. While in general a hyperbolic expression can be derived from theoretical considerations, their empiric parameterization needs to be revised for two reasons. Firstly, a rigorous mathematical treatment reveals that the values of the four parameters are ambiguous because their values are not independent. We found a three-parameter equation with unambiguous values of the parameters that is equivalent in any other respect to the four-parameter equation. Secondly, high-resolution Monte-Carlo simulations revealed a systematic deviation of the count rate to soil moisture relation especially for extremely dry conditions as well as very humid conditions. That is a hint that a smaller contribution to the intensity was forgotten or not adequately treated by the conventional approach. Investigating the above-ground neutron flux through a broadly based Monte-Carlo simulation campaign revealed a more detailed understanding of different contributions to this signal, especially targeting air humidity corrections. The packages MCNP and URANOS were used to derive a function able to describe the respective dependencies, including the effect of different hydrogen pools and the detector-specific response function. The new relationship has been tested at two exemplary measurement sites, and its remarkable performance allows for a promising prospect of more comprehensive data quality in the future.

scholarly journals Muon Measurements with IceTop

2019 ◽  
Vol 208 ◽  
pp. 03003 ◽  
Author(s):  
Javier G. Gonzalez
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Cosmic Ray ◽  
Shower Axis ◽  
South Pole ◽  
Air Showers ◽  
Hadronic Interaction ◽  
Interaction Models ◽  
Lateral Distance ◽  
Cosmic Ray Flux

We present the measurement of the density of GeV muons in near-vertical air showers by the IceTop array at the South Pole. The muon density is measured at 600 m and 800 m lateral distance from the shower axis in air showers between 1 PeV and 100 PeV. This result can be used to constrain hadronic interaction models by comparing it with the outcome of Monte Carlo simulations. We show that some models do not produce muon densities in agreement with this result unless an unphysical composition of the primary cosmic ray flux is assumed.

ENERGY SPECTRA AND MASS COMPOSITION OF COSMIC RAYS IN THE FRACTAL-LIKE GALACTIC MEDIUM

2005 ◽  
Vol 20 (29) ◽  
pp. 6834-6836 ◽  
Author(s):  
A. A. LAGUTIN ◽  
A. G. TYUMENTSEV ◽  
A. V. YUSHKOV
Keyword(s):  
Cosmic Rays ◽  
Cosmic Ray ◽  
Energy Spectra ◽  
Mass Composition ◽  
Primary Spectrum ◽  
Composition Variation ◽  
Region 10 ◽  
Basic Features ◽  
Galactic Sources ◽  
Knee Problem

We consider the problem of the cosmic ray spectrum formation assuming that cosmic rays are produced by galactic sources. The fractional diffusion equation proposed in our recent papers is used to describe the cosmic rays propagation in interstellar medium. We show that in the framework of this approach it is possible to explain the locally observed basic features of the cosmic rays in the energy region 1010 ÷ 1020 eV : difference between spectral exponents of protons and other nuclei, mass composition variation, "knee" problem, flattening of the primary spectrum for E ≥ 1018 ÷ 1019 eV .

Monte Carlo Simulations for Changes in the Cosmic-ray Flux on the Earth's Surface Due to Heavy-Metal Pollution in the Atmosphere

2011 ◽  
Vol 61 (8) ◽  
pp. 727-733
Author(s):  
Jaw Won SHIN ◽  
Tae-Sun PARK ◽  
Seung-Woo HONG* ◽  
Oubong GWUN ◽  
Chong Yeal KIM
Keyword(s):  
Heavy Metal ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Metal Pollution ◽  
Heavy Metal Pollution ◽  
Cosmic Ray ◽  
Cosmic Ray Flux

scholarly journals Determination of cosmic-ray primary mass on an event-by-event basis using radio detection

2019 ◽  
Vol 216 ◽  
pp. 02005
Author(s):  
Washington Carvalho ◽  
Jaime Alvarez-Muñiz
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Cosmic Ray ◽  
Primary Mass ◽  
Radio Detection ◽  
Shower Development ◽  
Radio Signals ◽  
Event Basis

Traditionally, the depth of maximum shower development Xmax has been used as a surrogate observable for composition. Here we present the possibility of a new methodology to discriminate between light and heavy cosmic-ray primaries on an event-by-event basis. This method is based on comparisons between detected radio signals and Monte Carlo simulations, but instead of first reconstructing Xmax, we try to infer the cosmic-ray composition directly. We show that a large discrimination efficiency could in principle be reached for zenith angles above θ≃65°, even when some of the typical uncertainties in radio detection are taken into account.

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