Heinigerd Rebel

Simulation of atmospheric muon and neutrino fluxes with CORSIKA

The three dimensional Monte Carlo simulation code CORSIKA is used to calculate the fluxes of atmospheric neutrinos with the hadronic interaction models DPMJET, VENUS, and UrQMD. For this purpose the original CORSIKA is extended by a parametrization of the solar modulation and a microscopic calculation of the directional dependence of the geomagnetic cut-off functions. A precise description for the geography of the Earth has been included by a digital elevation model, tables for the local magnetic field in the atmosphere, and various atmospheric models for different geographic latitudes and annual seasons. The neutrino fluxes obtained are compared with other calculations.

First results on characterization of Cherenkov images through combined use of Hillas, fractal and wavelet parameters

Based on Monte Carlo simulations using the CORSIKA code, it is shown that Cerenkov images produced by ultrahigh energy

Image and non-image parameters of atmospheric Cherenkov events: a comparative study of their γ-ray/hadron classification potential in ultrahigh energy regime

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New cosmic rays experiments in the underground laboratory of IFIN-HH from Slanic Prahova, Romania

-rays and cosmic ray nuclei (proton, Neon and Iron) are fractal in nature. The resulting multifractal and wavelet moments when employed in association with the conventional Hillas parameters as inputs to a properly-trained artificial neural network are found to provide more efficient primary characterization scheme than the one based on the use of Hillas or fractal parameters alone.Abstract Based on Monte Carlo simulations using the CORSIKA code, it is shown that Cherenkov images produced by ultrahigh energy γ-rays and cosmic ray nuclei (proton, Neon and Iron) are fractal in nature. The resulting multifractal and wavelet moments when employed in association with the conventional Hillas parameters as inputs to a properly-trained artificial neural network are found to provide a more efficient primary characterization scheme than the one based on the use of Hillas or fractal parameters alone.

Cosmic rays and the environment

In this exploratory simulation study, we compare the event-progenitor classification potential of a variety of measurable parameters of atmospheric Cherenkov pulses which are produced by ultra-high energy (UHE) gamma-ray and hadron progenitors and are likely to be recorded by the TACTIC array of atmospheric Cherenkov telescopes. The parameters derived from Cherenkov images include Hillas, fractal and wavelet moments, while those obtained from non-image Cherenkov data consist of pulse profile rise-time and base width and the relative ultraviolet to visible light content of the Cherenkov event. It is shown by a neural-net approach that these parameters, when used in suitable combinations, can bring about a proper segregation of the two event types, even with modest sized data samples of progenitor particles.Abstract In this exploratory simulation study, we compare the event-progenitor classification potential of a variety of measurable parameters of atmospheric Cherenkov pulses which are produced by ultrahigh energy γ-ray and hadron progenitors and are likely to be recorded by the TACTIC (TeV atmospheric Cherenkov telescope with imaging camera) array of atmospheric Cherenkov telescopes. The parameters derived from Cherenkov images include Hillas, fractal and wavelet moments, while those obtained from non-image Cherenkov data consist of pulse profile rise time and base width and the relative ultraviolet to visible light content of the Cherenkov event. It is shown by a neural-net approach that these parameters, when used in suitable combinations, can bring about a proper segregation of the two event types, even with modest sized data samples of progenitor particles.

The Muon Charge Ratio In Cosmic Ray Air Showers

Since 2006 a modern laboratory has been developed by IFIN-HH in the underground of Slanic Prahova salt ore. This work presents a short review of previous scientific activities performed in the underground laboratory, in parallel with some plans for the future. A mobile detector for cosmic muon flux measurements has been set up at IFIN-HH, Romania. The device is used to measure the muon flux on different locations at the surface and underground and it consists of two detection layers, each one including four large scintillator plates. A new rotatable detector for measurements of the directional variation of the muon flux has been designed and it is presently under preliminary tests. Built from four layers of sensitive material and using for collecting the signals and directing them to the micro PMTs a new technique, through optical fibers instead wave length shifters, it allows an easy discrimination of the moun flux on the arrival directions of muons. Combining the possibility to rotate and the directionality properties, the underground muon detector is acting like a muon tomography device, being able to scan, using cosmic muons, the rock material above the detector. In parallel new detection system based on SiPM will be also installed in the following weeks. It should be composed by four layers, each layer consisting in 4 scintillator plates what we consider in the following as a module of detection. For this purpose, first two scintillator layers, with the optical fibers positioned on perpendicular directions are put in coincidence with other two layers, 1 m distance from the first two, with similar optical fiber arrangement, thus allowing reconstructing muon trajectory. It is intended also to design and construct an experimental device for the investigation of such radio antennas and the behavior of the signal in rock salt at the Slanic salt mine in Romania. Another method to detect high energy neutrinos is based on the detection of secondary particles resulting from the interaction with the salt massive. We intent to design and construct a 3D array in the underground of Slanic Prahova salt ore.

Monte Carlo Simulations and Semianalytical Parameteri-Sations of the Atmospheric Muon Flux

There are multiple links between cosmic rays and the environment. Cosmic rays are the source of a significant component of our radiation environment. In typical cases the exposure to the radiation field associated with cosmic rays is responsible for about 1/6 of the natural radiation dose, but in specific cases its contribution can be much enhanced. Cosmogenic nuclides produced by cosmic rays interactions in the atmosphere or lithosphere participate in atmospheric transport or geological processes. They can be used as tracers of various processes or for dating specific events, giving thus information on the relevant processes. The knowledge gained in the study of cosmic rays, frequently related also to a detailed understanding of various environmental factors, can be successfully transferred to other fields of study. The techniques and the infrastructure developed for cosmic rays studies can be applied for specific environmental studies.

Energy spectrum and mass composition of high-energy cosmic rays

The muon charge ratio of the lateral muon density distributions in single Extended Air Showers (EAS) is studied on basis of Monte Carlo simulations, in view of proposals to measure this observable in coincidence with EAS observations. Differences of the azimuthal variation of the muon densities of opposite charges and the azimuthal variation of the muon charge ratio appear to be very much pronounced, dependent on the direction of the EAS incidence and the position of the observer in respect to the Earths magnetic vector. The influence of the geomagnetic field, which induces comparable effects in radio emission from EAS, is obviously of great interest for understanding the shower development.

A mobile detector for measurements of the atmospheric muon flux in underground sites

The atmospheric muon flux have been simulated using the CORSIKA code for two different geographical positions (Bucharest: 44°N, 26°E and Hiroshima: 34°N, 132°E). The simulations have been done for different angles of incidence between 0° and 70°. The comparison between the simulations and the experiment have been done using the measurements of the muon charge ratio with the WILLI detector in Bucharest. The results of the Monte Carlo simulations of the muon flux for the geographical positions of Hiroshima and Bucharest are compared with the semi-analytical formulae of Judge and Nash, and of Gaisser for different angles of incidence between 0° and 70° and with experimental results of the Bess experiment (vertical incidence). Various sensitivities of the approach of Judge and Nash, in particular to variations of the pion and kaon production spectra have been studied.