Alborz observatory is an EAS array in the heights of Alborez mountain chain near Tehran. For the development of the array, more number of detectors is inevitable. The managing the financial resources and achieving the highest efficiency of the array is important for the project. Therefore, Water Cherenkov Detectors has been used for 9 months in the same way as the previous experiment with Scintillation Detectors in a 4-fold square arrangement. After a hardware calibration procedure, the experimental data set was simulated by CORSIKA code and the experimental restrictions were applied over the data set. In this work, the simulation is calibrated with the real experimental results, and it presents a comparable parameter between the experiment and the simulation. The obtained results show that the simulation is in agreement with the experimental results.

Monte Carlo simulation with CORSIKA code using QGSJET hadronic interaction model is applied on more than 5000 cosmic ray primaries to investigate dependence of maximum air shower development (Hmax) on mass and energy of, primaries.

Different high energy interaction models are the applied in CORSIKA code to simulate Extensive air showers (EAS) generated by Cosmic Rays (CR). In this work the effects of QGSJET01, QGSJETII, DPMJET, SIBYLL models on Xmax and multiplicity of secondary electrons and muons at observation level are studied.

In this paper some characteristics of age parameter (s) are studied on the basis of showers from Yakutsk array data having energy ranging from 1018 eV to 1019 eV.

One of the common methods in the study of cosmic rays induced Extensive air shower on the Earth's surface is using an array of scintillation detectors. Dimensions and distances between detectors are among the most important parameters that determine the energy range detectable by the array. Furthermore, the geometry of the array has an important role in determining of optimum distance Ropt, which is defined as the distance from the shower core, where uncertainty in lateral density of secondary particles is minimized. In the present work, dependence of Ropt on array geometry and characteristics of cosmic rays has been studied for the Alborz-1 array. It is shown that the value of ropt is independent on shower characteristics like energy, incident angle and primary mass. On the other hand, according to our results, the ropt value has explicit dependence on array geometry specially distances between detectors. Our investigation shows that the cluster layout is the best layout for the detectable energy range of ALBORZ-1 array (1015 eV). We have found Ropt= 9 ± 1m for the ALBORZ-1 array.

Optimum distance is defined as a distance from the air-shower core in which the density of a number of particles calculated by the lateral distribution function at that distance has the least uncertainty. Furthermore, with a good approximation, this distance is independent of the characteristics of primitive ray and it only depends on the geometric shape of array. In this paper, by simulating 1000 vertical EAS of protons with the energy 300 TeV, using the CORSIKA Monte Carlo code and trigger condition, the calculated distance for the array triggering ALBORZ-1 was found to be equal to 9± 1 m. Also, it was found that this distance as well as the density of the number of calculated particles was independent of the lateral distribution function used in the calculations.

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.

Colliding high energy cosmic rays to the earth atmosphere produces secondary particles which generate Extensive air shower (EAS) that develops in lateral and longitudinal directions. It was found that electron density in two directions is related to the age parameter. Dai et. al. [1] clarified the difference between the lateral and longitudinal age parameters in 1990. However, some scientists believe that the lateral age parameter from NKG model is not sufficient to describe the electro lateral dispersion. In the current study, given the experimental and simulation data and also given the results of Dai et. al. work, the dependence of the lateral and longitudinal age parameter to core distance is investigated. Finally, contrary to NKG theory, at Linsley theory, the age parameter is not a constant parameter, so it increases with an increase in core distance.

A shower cooling tower (SCT) operates without fill because of salt decomposition on the fill that leads to deterioration of conventional cooling tower performance. This study presents a two-dimensional mathematical model for energy and exergy analysis of multi-diameter droplets and air interaction along with the height of the forced draft SCT, to predict the exit condition of water droplet for industrial application. Different inlet air dry bulb temperatures (DBT) were used for the study and the model was validated with experimental results. At the inlet of the tower, ten different diameters of water droplets simultaneously were used at a given time for analysis and the droplet diameter model based on Rosin Rammler distribution. The result showed that thermal efficiency and second law efficiency relatively increased along the height of SCT with increase of the inlet air temperature. It was confirmed that maximum reduction in water droplet temperature along the height of SCT was achieved by minimum inlet air DBT. It was also noticed that exergy supplied by water was more than exergy absorbed by air and maximum destruction of total exergy took place at the beginning of air-water interaction.

In this research, using CORSIKA simulation code with QGSJETII04 and GHEISHA2002d as high and low energy interaction models respectively, proton and iron cosmic ray primaries with 10 17 eV energy and 20-60 o zenith angle are simulated at Tehran observation level (1200m above sea level). By using azimuth angle, arrival time and local coordinates of the muon and electron secondaries as well as rise times of received pulses are calculated. By investigating the rise time as a function of the distance to the shower Core for different azimuth angle, it is shown that there is an azimuthal asymmetry in the rise time distribution which can be used for mass discrimination of primary cosmic rays.