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Title: Range-energy relationships and energy straggling of energetic ions in various stopping media
Author: Al-Bedri, Mohammed Baker
ISNI:       0000 0001 3405 2253
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 1974
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A number of parameters of interest resulting from the penetration of charged particles through various stopping media have been investigated in the present work. They include energy loss, energy straggling, maximum range, mass stopping power and electronic stopping cross-section for protons, alpha particles and fission fragments in various gases and solids. The energy straggling of 241 Am alpha particles has been measured using a number of gaseous and solid absorbers, particular attention being paid to straggling near the end of the particle range where a sharp reduction in straggling with increasing absorber thickness is observed. This phenomenon is not predicted by theory. Experimental work was carried out in order to relate the straggling parameter to the atomic number and physical phase of the absorber. Comparisons were made with some theoretical predictions of energy straggling, suitably modified for reduced effective charge of the alpha particles near the end of the range. Thin film uniformity has been studied experimentally using energy straggling. The ranges of [241]Am alpha particles and [252]Cf fission fragments have been determined in various stopping media and compared with results from other workers and theoretical data. Mass stopping powers for alpha particles and electronic stopping cross-sections have been measured in some gases and solids, and comparisons made with experimental results and some theoretical predictions. The experimental determination of the range of alpha particles in tissue equivalent media has shown that underestimates may have taken place in earlier published work. Moreover, recent studies of epidermal skin thickness Whitton (1973) have shown that the assumption that alpha particles cannot penetrate to the sensitive basal layer of the skin is incorrect. Data have been presented in the present work estimating the dose equivalent rate (Al-Bedri and Harris, 1974a) to the basal layer from present permissible contamination levels and showing that these may result in exposures which exceed the maximum permissible for radiation workers.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available