UBC Theses and Dissertations
A search for the photodisintegration of neon with the University of British Columbia Van de Graaff generator Woods, Stuart Brownlee
The construction of a radio-frequency electrodeless discharge type of positive ion source and its installation, in the Van de Graaff generator is described. An ion current of 15 microamperes, approximately one third protons, has been obtained with 1.5 MeV of energy. This performance is sufficient for the production of gamma rays by the proton-bombardment of light elements such as fluorine or lithium. A search for the photodisintegration of Ne²⁰ by the 6 and 7 MeV fluorine gamma rays and the 17 MeV lithium gamma rays has been carried out using a gridded ionization chamber. The equipment was calibrated by measuring the photodisintegration of deuterium for which the cross-section is known at these gamma ray energies. It is concluded that, unless unsuspected ayatematic errora exist, the probability is 97 percent that the photodisintegration cross-section for Ne²⁰ by the fluorine gamma rays is less than 4 x 10⁻³⁰ cms². Similarly the probability is 65 percent that the cross-section for Ne²⁰ by the 17 MeV lithium gamma rays is less than [symbol omitted] x 10⁻³⁰ cms².
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