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Studies Related to Establishment of an Array Including 20 Scintillation Detectors

Pezeshkian, Yousef | 2015

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 47101 (04)
  4. University: Sharif University of Technology
  5. Department: Physics
  6. Advisor(s): Bahmanabadi, Mahmoud; Pourmohammd, Davoud
  7. Abstract:
  8. Alborz-I array with 20 detectors will be established at Sharif University of Technology, to study Extensive Air Showers with energies around the knee of cosmic ray spectrum. In this thesis studies related to construction of this array is performed in two parts. First part is dedicated to evaluate detectors of Alborz-I array. Each detector consists of a plane plastic scintillator, 50×50×2 cm3 each, which is enclosed in a pyramidal light enclosure with a 5 cm photomultiplier tube at the vertex of the light enclosure. In order to optimize the height of the light enclosure, two parameters are considered: efficiency and uniformity of different parts of the detector. By building and comparing four light enclosures with heights of 10, 20, 30 and 40 cm, the light enclosure with 20 cm height is approved to be more effective in the Alborz-I array. Simulation of detector performance confirms the results of the experiments. We have shown that average time resolution of detectors with 20 cm light enclosure is 1.31 ns. Simulation results show that among 41000 photons created inside the scintillator when a charged particle passes through it, only 1% of them reach the PMT and among photons reaching the PMT, about 15% encounter no collisions with the walls of light enclosure, i.e. reach directly to PMT. This little amount of photons is enough to detect a particle and measure the detection time. In the second part, the performance of the array is studied. Simulations indicate that this array is capable of detecting extensive air showers corresponding to cosmic rays with energies around 4×1013 eV up to energies higher than 1016 eV. We have also found that the maximum number of detected showers will have energies between 2×1014 eV and 4×1014 eV (about 6 to 7 thousands of daily records). By simulating angular resolution of the array and number of daily detectable showers, array size and configuration beside the trigger condition are discussed. We concluded that for clustered pentagon configuration, the angular resolution is better. In this configuration, azimuthal angle resolution will be about 2 to 4 degrees
  9. Keywords:
  10. Cosmic Rays ; Extensive Air Showers ; Scintillation Detector ; Ground Based Detectors Array

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