الفهرس 
Chapter One : General IntroductionOnly 14 pages are availabe for public view
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Abstract
The study of the effects of radiation on polymer materials is an area of rapidly increasing interest. The radiation regimes of primary utility are either high energy, ionizing radiation such as from gamma or neutron sources, or ultraviolet radiation from arc lamps or synchrotron sources.
The present work aimed to study the effect of ultraviolet and gamma rays on the bulk etching rate and optical properties of CR-39 detector, because the bulk-etching rate is a very important parameter in the field of solid-state nuclear track detectors. There are many factors affecting the performance of solid state nuclear track detectors, mainly the chemical etching and its conditions so that we will discuss the effect of ultraviolet and gamma rays on the bulk etch rate of CR-39 detector.
CR-39 detectors are used in very broad field of technical applications for detection of charged particles from protons to heavy ions. Besides the simple registration of particle flux density or fluencies in the environmental dosimetry.
The samples were irradiated for different times (1, 2, 4, 8 &16 hrs), and also CR-39 detectors were exposed to different gamma doses (1, 2, 4, 8 & 10 M.rad). The detectors were treated in etching solution of NaOH 6.25 M at 70 Cο for different times (1, 2,...7 hrs). The bulk etching rate was determine using mass change method in two cases.
The optical properties of the detectors were studied using furrier transformation infrared (FTIR) and atomic force microscope (AFM). In many cases, cells are sensitive to surface topography and a wide variety of cell properties can be affected. Surface topography is an important factor in controlling the shape and orientation. FTIR spectroscopic measurements shows maintenance of the main vibrational band with minor changes results from changing irradiation times. UV/vis optical absorption spectrum reveals an obvious change in the optical energy gap with irradiation times. The effect of ultraviolet (UV) irradiation on the bulk etching rate was studied. The bulk etching rate of CR-39 detector was measured experimentally before and after irradiation using UV radiation. from the results we found that the values of the bulk etching before irradiation are 1.18 µm and after irradiation has ranged from 1.20 to 1.70 µm depending on the time of irradiation. In the case of gamma radiation we find that the values of bulk etching rate increasing with increasing gamma doses and it ranged from 5.28 to 6.11µm.h-1. The change in bulk etching rate of the detectors which were exposed to different gamma doses are higher than the bulk etching rate in the case of ultraviolet radiation; also gamma rays causes destroy in the structure of the detectors and make change in their colors to the yellow one. from the results we can conclude that, UV irradiation can be used to shorten track formation time on these thin PADC films. This means that if we use UV radiation the time of the bulk etching will be decreased and thus the time will be saved or one can make bulk etching for many detectors in short time.