Persons at STU
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Basic information about a final thesisAdditional informationAdditional information about the final thesis follows. Click on the language link to display the information in the desired language.
|Language of final thesis:||Slovak|
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|Title of the thesis:||GaAs fast neutron detectors|
|Summary:||The theme of this work was to modify the semiconductor detectors based on SI (semiinsulating) GaAs to register fast neutrons. The work is divided into four chapters. The first chapter describes the sources of radiation and what types there are and how they originate. The second chapter describes the semiconductor detectors, their electrical properties, their use in the detection and optimization of radiation. The third chapter describes gallium arsenide (GaAs) material for detecting radiation, the benefits to other semiconductor materials and general characteristics. The fourth chapter describes the experiment and evaluate the results, which were made at the Institute of Experimental and Applied Physics ČVUT in Prague. For neutron conversion, we used the conversion layer of HDPE (High Density Polyethylene) film, which is fixed on the surface of GaAs detector. This material is rich in hydrogen and the neutrons interact with hydrogen nuclei by means of elastic scattering, where those incurred monoenergetic neutron irradiated our detector. Neutrons created of nuclear fusion of deuterium and tritium at the Van de Graaff where those incurred monoenergetic neutron irradiated our detector. This resulted in the monoenergetic neutrons with kinetic energy of 16,755 MeV alfa particle. We studied the detection efficiency of the detector and the thickness of the HDPE layer effect to it. We have changed the layer thickness and seek the optimal thickness. With increasing thickness increases the likelihood of interaction of neutrons with hydrogen nuclei. Range of protons in the conversion layer (up to 3 mm) is limited to registration in the detector. We layer thickness varied from 800 microns to 3200 microns. Detection rate increased with thickening to a thickness of 2400 microns. I compared the results of the experiment with theoretical assumptions that I simulated in MCNPX (Monte Carlo N-Particle Transport) code. Experimental results were in quite good agreement with the results of the simulation. The detection efficiency for simulation was the same and that the maximum thickness of 2400 microns. We also watched as the increases cut-off voltage detection efficiency for detector which has resulted increasing the active area of the detector.|
|Key words:||semiconductor, matter, neutron|
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