Date of Award

2003

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Dr. Salah A. Makhlouf

Second Advisor

Dr. Bashar Afif lisa

Third Advisor

Dr. Mahmoud Said Rasheedy

Abstract

Many materials that are usually found in the earth's crust contain small but measurable amount of naturally occurring radioactivity.

In the present study, the natural radioactivity due to the presence of 238U, 232Th and 40K in beach sand along the UAE costal line has been measured. The measurements were performed using gamma-ray spectrometry with a high-purity Germanium (HPGe) detector connected to a multi-channel analyzer.

Chapter 1 includes an introduction about natural radioactivity, gamma ray spectrometry, types of detectors employed and analysis of gamma ray spectra. A literature review of the related work is also included at the end of this chapter.

Chapter 2 explains the details of the experimental work. Collection procedure and treatments of the samples; and description of the measuring system are explained. Energy as well as efficiency calibration and background measurement methods are also described in this chapter.

The results and discussion are presented in chapter 3. Factors affecting the measured gamma spectra such as volume of the sample container, detector resolution and the measuring time are firstly addressed. Determination of the specific activity of 238U, 232Th and 40K in all samples are presented and discussed. Activity levels of 238U, 232Th and 40K are found to be lower than the world average. The data, however, indicate higher natural radioactivity levels in region I (Abu Dhabi emirate) compared with that in region II (Northern emirates) and region III (Eastern Emirate). The total absorbed gamma dose rate in air in the beach area are found to be 23.08, 12.90 and 4.08 nGy/h in regions I, II and III respectively which is lower than the world average dose rate.

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