Date of Award

1-1-2001

Thesis Type

Masters

Document Type

Thesis

Divisions

Faculty of Science

Department

Department of Physics

Institution

Universiti Malaya

Abstract

Dosimetry of terrestrial ultraviolet (UV) using thermoluminescence (TL) material is an attractive method for a number of reasons. Such as the low cost per phosphor, the possibility to produce them in laboratory with simple facilities, the absence of any associated electronics at the site of measurement and the small size of solid phosphors which can also be used in personal dosimetry. In this research, we are searching for a suitable lanthanide oxide powder and commercial TLD material that can detect solar UV radiation using intrinsic method. The investigated lanthanide oxide powders include Gd₂O₃, La₂O₃ and Y₂O₃ doped with different rare earth elements. They were sintered in air at temperature of ~ 1200°C. The studied commercial TLD include TLD-100H, TLD-700H, TLD-200, TLD-500 and TLD-900. These materials were exposed to UV lamp and sunlight to check their response to UV radiation. Some of them such as Gd₂O₃:Pr³⁺ , Y₂O₃:Pr³⁺ and TLD-400 showed no response to this radiation. TLD-500 and TLD-900 showed high sensitivity to UV radiation. TLD-900 has a linear response to UV lamp and sunlight being similar to UV photometer in its response. In general, the glow peak at low temperature is not stable in the dark at room temperature. Only the glow peak at high temperature is stable and can be used in UV dosimetry. It has been found that, ordinary light is also play the main role in the TL fading of this material. It can remove ~100% of TL intensity caused by UV radiation.

Initial

snms

Additional Information

Dissertation (M.A) -- Faculty of Science, Universiti Malaya, 2000.

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