In this paper, using simulation code CRPropa3. 0, the propagation of 104 primary cosmic rays of proton and iron with energy range of 1018 to 1021 eV was simulated. The spectra of the secondary photons and electron-positrons generated in the interactions of Ultra-high energy cosmic rays (UHECRs) with cosmic background photons were investigated. The photon and electron spectra considered here are generated in photopion production, beta decay, and pair production. The minimum energy of primaries and the spectral index of source injection is changed separately and the effect of these changes on the spectra is investigated. Also, the total primary energy percent which transfers to secondaries, is calculated. It is found that for both primaries, lowering the minimum energy of the primaries leads to the decrease of the flux of secondaries. This also results in the decrease of the total energy percent carried by beta and photopion products and the increase of the energy percent of pair production. Finally, in is shown that by increasing the spectral index, the flux and the energy percent of all secondaries decreases for proton and iron primaries.

Muon-electron ratio and median zenith angle of Extensive Air Shower (EAS) is calculated for the energy range of 1019 to bigger than 1020 eV. The results are compared with the simulation work of Capdevielle et al. The results show a good correspondence with proton primary composition up to energy level of 7×1019 eV. In higher energies above GZK cut off, a considerable increase is calculated in cosmic primary photons. In addition, event frequency distribution above energy 7×1019 eV shows increasing concentration towards super galactic plane.

The first phase of the Alborz Observatory Array (Alborz-1) consists of 20 plastic scintillation detectors each one with surface area of 0. 25 spread over an area of realized to the study of Extensive Air Showers around the knee at the Sharif University of Technology campus. The first stage of the project including construction and operation of a prototype system has now been completed and the electronics that will be used in the array instrument has been tested under field conditions. In order to achieve a realistic estimate of the array performance, a large number of simulated CORSIKA showers have been used. In the present work, theoretical results obtained in the study of different array layouts and trigger conditions are described. Using Monte Carlo simulations of showers the rate of detected events per day and the trigger probability functions, i. e., the probability for an extensive air shower to trigger a ground based array as a function of the shower core distance to the center of array are presented for energies above 1 TeV and zenith angles up to. Moreover, the angular resolution of the Alborz-1 array is obtained. For experimental study of the array, Alborz-1 sub-array consists of 5 detectors on a pentagon configuration similar to the central cluster of the Alborz-1 array have been collecting data since 2014 February for 14 month in 4th floor of physics department at Sharif University of Technology. Alborz-I, made of 20 scintillation detectors is set up in a cluster layout to study the cosmic ray spectrum in the energy range of 1012 to 1016 eV. . This paper reveals the zenith angle distribution function of detected air showers by this sub-array.

The amount of cosmic rays varies widely with the altitude, latitude and longitude in each region. In this study, the radiation doses due to the cosmic rays were estimated in two steps: in the first step, the neutron and gamma components of the radiation dose were measured for a roundtrip flight on 3 flight routes (Shiraz-Asaluye, Asaluye-Rasht and Shiraz-Mashhad) using a gamma-tracer photon detector and a Thyac 190N, neutron detector. The minimum values of the measured gamma and neutron doses of 0.15 and 0.04 mSv were measured on the Asaluyeh-Shiraz route at the lowest altitude of 19000 ft, while for Rasht-Asaluyeh route at an altitude of 35000ft those values were found to be 2.52 and 1.09mSv, respectively. In the second step, a number of aircrew members were equipped with thermoluminescence dosimeters (TLD cards) for evaluating the gamma dose and polycarbonate dosimeters (SSNTD) for assessing the neutron dose for one year. The measured value of the annual effective dose received by the crew ranged between 0.5 mSv/y and 1.16 mSv/y, with an average of 0.9 mSv/y for the gamma component and between 0.37 mSv/y and 0.77 mSv/y with an average of 0.61 mSv/y for the neutron component. The results of this investigation are comparable with the investigations that have been conducted in other countries. For instance in UK, the reported annual effective dose of aircrew is about 2mSv, and in Canada, it is estimated to be between 1 to 5mSv, depending on the flight situations (such as the latitude and longitude of the cities, the flight altitude, etc).

Considering the spectral energy of the observed cosmic rays in the earth and using a propagational model of these rays, the minimum required energy for production of these rays in the center of galaxy studied. Assuming an equation for the time scope from the galaxy and a relation for their diffusion, calculations show that the central part of the galaxy, the most energetic part of the galaxy, does not have the necessary conditions to produce all these rays. But the centre of the galaxy has the possibility to produce energy range between 3*1015to4*1018eV.The spectral energy of this energy is suggested to be BE-2.9cm-2s-1sr-1eV-1.

It has previously been reported that differences in life expectancy can be linked to income. In Norway, a registry-based study that included all Norwegian residents aged ≥,40 years (2005-2015) was performed. This study showed substantial and increasing gaps in life expectancy by income level during the interval between 2005-2015. Compared to the United States, the largest life expectancy differences were for individuals in the lower to middle part of the income distribution, although differences were observed at all income levels. Despite its undeniable strengths and although this paper can be considered as a significant contribution to this field, it has some shortcomings. The first shortcoming of this study is due to ignoring the effects of population exposures to natural and man-made ionizing and non-ionizing radiation on life expectancy. Another shortcoming arises from ignoring the strong impact of education on lifestyle. In summary, what is observed in this study might be at least to some extent, due to education-related changes in lifestyle and not necessarily income (despite the mutual links between education and income).

In this work the design of a target converting high energy electrons to bremsstrahlung x-ray is described. The system has been optimized for different energy of the accelerated electron beam, using the EGS4 Monte-Carlo computer code. For this purpose the thickness of the layers in the target, including the main converter, cooling and lower layer (for the energy spectrum tuning), suitable to the desired and practical conditions have been obtained. In order to evaluate the calculated results, measurements have been carried out for the same geometry using the x-ray converter target, for 2MeV, 5MeV and 10 MeV electron beam. It is shown that the calculated data are in good agreement with the experimental results.

Secondary electrons at ground level of simulated extensive air showers have been analyzed using a wavelet transform based technique, in order to investigate the variation of fractal dimensions of the lateral distribution of the electrons with shower energy and primary particle mass number. The fractal dimension is shown to increase with shower energy and seems to saturate to constant values near the core of the shower at higher energies. Using the fractal dimension properties at different core distances, a multi-parameter separation technique is then applied to the data. It has been shown that the technique has good accuracy at high energy, provided the energy of the shower is obtained independently.

Deviation angles of secondary electrons and muons in simulated extensive air showers were studied. The angles have wide distribution, whose width depends on energy cuts imposed on shower particles. In this work, variation of deviation angles with the energy of secondary particles, shower energy, primary direction, and core distance was investigated. The results put limitations on application of hodoscopic devices in cosmic ray and gamma ray observations.

In this paper, we present a Mont Carlo simulation by using the inhomogeneous diffusion equation suggested by Lagutin et al. in a fractal interstellar medium for a supernova, as being the main source of Galactic cosmic rays in an energy range up to 1016ev. When the numerical results of this simulation are compared with the predicted energy density of cosmic rays from the supernova model of Erlikyn and Wolfendale (EW), they show a strong consistency with the observed experimental parameters of cosmic rays, i.e. Galactic radial gradient, percentage of total supernova energy transfer to cosmic particles etc., which is also confirmation of a supernova being of cosmic ray origin.