Uranium glass in museum collections

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Conservação e Restauro Área de especialização – Vidro

The presence of uranium glass objects in museum and private collections has raised radiation protection concerns resulting from possible exposure to ionizing radiation emitted by this type of object. Fourteen glass objects with different uranium contents were studied. Dose rates (β + γ radiation) were measured with a beta/gamma probe at several distances from the glass objects. In general the determined dose rates did not raise any concern as long as some precautions were taken. Radon (222Rn), usually the most important contributor for the overall natural dose exposure resulting from radium (226Ra) decay in the uranium natural series, was also evaluated and it was found to be within the background values. Non-invasive analyses of the uranium content in fourteen glass objects were made using micro energy dispersive X-ray fluorescence spectrometry, measuring the radiation emitted by the objects and using fluorescence spectroscopy. Alpha spectrometry was tested in four glasses to determine the uranium isotope composition in order to distinguish which objects used depleted and non-depleted uranium. This information is useful to dating the objects.