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Construction of the first stage of the Pierre Auger Observatory has begun. The aim of the Observatory is to collect unprecedented information about cosmic rays above 10 18 eV: The first phase of the project, the construction and operation of a prototype system, known as the engineering array, has now been completed. It has allowed all of the subsystems that(More)
We have studied the procedure commonly recommended by dosimetry protocols for the determination of the absorbed dose in water for low-energy x-rays beams, generated with potentials up to 150 kVp. X-ray beams with different spectra obtained with the XCOMP5R code were transported using the Monte Carlo code PENELOPE in order to calculate backscatter factors(More)
In this paper, the specific absorption rate (SAR) in scaled human head models is analysed to study possible differences between SAR in the heads of adults and children and for assessment of compliance with the international safety guidelines, while using a mobile phone. The finite-difference time-domain method (FDTD) has been used for calculating SAR values(More)
In this work, the procedures for safety assessment in the close proximity of cellular communications base-station antennas at three different frequencies (900, 1800 and 2170 MHz) are analysed. For each operating frequency, we have obtained and compared the distances to the antenna from the exposure places where electromagnetic fields are below reference(More)
The Monte Carlo code penelope is benchmarked for X-ray beams with energies between 30 and 300 keV. The results of different simulations performed with penelope are compared with those obtained with a semi-empirical computational model and with experimental measurements. Half-value layer indexes obtained from the attenuation curves for Al and Cu and depth(More)
A simple analytical expression aiming to calculate the backscatter factor used in dosimetry protocols to determine the absorbed dose in water for low energy X-rays beams is presented. This expression is based on the linear dependence of the backscatter factor with the generating potential, for fixed values of the half-value layer. The results of a recent(More)
PURPOSE To study the use of quality indexes based on ratios of absorbed doses in water at two different depths to characterize x-ray beams of low and medium energies. METHODS A total of 55 x-ray beam spectra were generated with the codes XCOMP5R and SPEKCALC and used as input of a series of Monte Carlo simulations performed with PENELOPE, in which the(More)
PURPOSE In this work, recent results from experiments and simulations (with EGSnrc) performed by Ross et al. [Med. Phys. 35, 4121-4131 (2008)] on electron scattering by foils of different materials and thicknesses are compared to those obtained using several Monte Carlo codes. METHODS Three codes have been used: GEANT (version 3.21), Geant4 (version 9.1,(More)