Efficiency of neutron tomography in visualizing the internal structure of metal artefacts from Mapungubwe museum collection with the aim of conservation

Abstract

To aid conservation management of metal artefacts improved knowledge of the internal structure and degree of corrosion therein is highly desired. In this study, neutron- and X-ray tomography were chosen as two complementary noninvasive visualization techniques to study internal structure and corrosion of five representative examples of archaeological metal artefacts from the Mapungubwe museum collection. Tomography was performed at the Neutron Radiography (SANRAD) facility of the South African Nuclear Energy Corporation where thermal neutrons as well as complementary X-rays are conveniently available under one roof. Comparative studies revealed neutron tomography to be generally superior to X-ray tomography due to the enhanced penetration properties of neutrons through the metal objects. In this paper the rich capability of neutron tomography as a nondestructive visualization aid for scientific conservation purposes is introduced and supported by results achieved for the five selected real artefacts.