Iskanje po repozitoriju

A+ | A- | | SLO | ENG

Opis: The Pierre Auger Observatory, located near Malargüe, Argentina, is the world’s largest cosmic-ray detector. It comprises a 3000 km^2 surface detector and 27 fluorescence telescopes, which measure the lateral and longitudinal distributions of the many millions of air-shower particles produced in the interactions initiated by a cosmic ray in the Earth’s atmosphere. The determination of the nature of cosmic rays and studies of the detector performances rely on extensive Monte Carlo simulations describing the physics processes occurring in extensive air showers and the detector responses. The aim of the Monte Carlo simulations task is to produce and provide the Auger Collaboration with reference libraries used in a wide variety of analyses. All multipurpose detector simulations are currently produced in local clusters using Slurm and HTCondor. The bulk of the shower simulations are produced on the grid, via the Virtual Organization auger, using the DIRAC middleware. The job submission is made via python scripts using the DIRAC-API. The Auger site is undergoing a major upgrade, which includes the installation of new types of detectors, demanding increased simulation resources. The novel detection of the radio component of extensive air showers is the most challenging endeavor, requiring dedicated shower simulations with very long computation times, not optimized for the grid production. For data redundancy, the simulations are stored on the Lyon server and the grid Disk Pool Manager and are accessible to the Auger members via iRODS and DIRAC, respectively. The CERN VMFile System is used for software distribution where, soon, the Auger Offline software will also be made available.
Ključne besede: Pierre Auger Observatory, indirect detection, fluorescence detection, surface detection, radio detection, ultra-high energy, cosmic rays, Monte Carlo simulation, computing resources, compute clusters, high capacity storage
Objavljeno v RUNG: 04.10.2023; Ogledov: 2354; Prenosov: 8
Celotno besedilo (1,54 MB)
Gradivo ima več datotek! Več...

Opis: The Pierre Auger Observatory investigates the properties of the highest-energy cosmic rays with unprecedented precision. The aim of the AugerPrime upgrade is to improve the sensitivity to the primary particle type. The improved mass sensitivity is the key to exploring the origin of the highest-energy particles in the Universe. The purpose of the Radio Detector (as part of AugerPrime) is to extend the sensitivity of the mass measurements to zenith angles in the range from 65° to 85°. A radio antenna, sensitive in two polarization directions and covering a bandwidth from 30 to 80 MHz, will be added to each of the 1661 surface detector stations over the full 3000 km^2 area, forming the world’s largest radio array for the detection of cosmic particles. Since November 2019, an engineering array comprised of ten stations has been installed in the field. The radio antennas are calibrated using the Galactic (diffuse) emission. The sidereal modulation of this signal is monitored continuously and is used to obtain an end-to-end calibration from the receiving antenna to the ADC in the read-out electronics. The calibration method and first results will be presented. The engineering array is also fully integrated in the data acquisition of the Observatory and records air showers regularly. The first air showers detected simultaneously with the water-Cherenkov detectors and the Radio Detectors will be presented. Simulations of the detected showers, based on the reconstructed quantities, have been conducted with CORSIKA/CoREAS. A comparison of the measured radio signals with those predicted by simulations exhibits satisfying agreement.
Ključne besede: Pierre Auger Observatory, AugerPrime, indirect detection, radio detection, radio antenna array, surface detection, ground array, ultra-high energy, cosmic rays, galactic radio emission
Objavljeno v RUNG: 04.10.2023; Ogledov: 2027; Prenosov: 8
Celotno besedilo (1,62 MB)
Gradivo ima več datotek! Več...

Opis: This study investigates low luminosity Fanaroff-Riley Type 0 (FR0) radio galaxies as a potentially significant source of ultra-high energy cosmic rays (UHECRs). Due to their much higher prevalence in the local universe compared to more powerful radio galaxies (about five times more than FR-1s), FR0s may provide a substantial fraction of the total UHECR energy density. To determine the nucleon composition and energy spectrum of UHECRs emitted by FR0 sources, simulation results from CRPropa3 are fit to Pierre Auger Observatory data. The resulting emission spectral indices, rigidity cutoffs, and nucleon fractions are compared to recent Auger results. The FR0 simulations include the approximately isotropic distribution of FR0 galaxies and various intergalactic magnetic field configurations (including random and structured fields) and predict the fluxes of secondary photons and neutrinos produced during UHECR propagation through cosmic photon backgrounds. This comprehensive simulation allows for investigating the properties of the FR0 sources using observational multi-messenger data.
Ključne besede: ultra-high energy cosmic rays, UHECR propagation, CRPropa, active galactic nuclei, jetted AGN, FR0 radio galaxies, Pierre Auger Observatory, UHECR energy spectrum
Objavljeno v RUNG: 24.08.2023; Ogledov: 2308; Prenosov: 5
Celotno besedilo (1,12 MB)
Gradivo ima več datotek! Več...

Opis: The growth of wireless applications and spectral limitations are grave anxiety for the military service and for civilian communities. A particular spectrum task force set up by Federal Communications Commission discloses that in many bands spectrum access is a more important problem than physical scarcity of the spectrum. This is in part because present systems use a procedure draw up in the1920s where different frequency bands are allocated to users or service providers, and licenses are needed to operate with those bands. To avail unused spectrum more efficiently in dynamic environments, we desire a communication system that adapts to rapidly changing environmental conditions while ensuring that minimal or at least manageable interference is introduced to existing users. Such a technology is known as cognitive radio (CR) technology. Transform domain communication system (TDCS) and wavelet domain communication system (WDCS) have been reported to have interference avoiding capability under hostile environmental conditions. Conventionally, the Pseudo Random phase vectors in TDCS and WDCS were generated by a maximum length binary Pseudo Random sequence, which allows only a relatively small amount of users in the systems. This paper reports a method of Digital modulations schemes (FSK, PSK, CSK) and communications systems (TDCS,WDCS) for efficient utilization of the spectrum in Cognitive radio.
Ključne besede: cognitive radio, TDCS, WDCS, spectrum sensing
Objavljeno v RUNG: 02.04.2021; Ogledov: 2775; Prenosov: 14
Povezava na celotno besedilo
Gradivo ima več datotek! Več...

Ključne besede: Pierre Auger Observatory, Auger Engineering Radio Array, inclined air showers
Objavljeno v RUNG: 16.06.2020; Ogledov: 3702; Prenosov: 79
Celotno besedilo (1000,76 KB)