Multi-technique study of He+ micro-irradiation effects on natural quartz crystals contained in archaeological pottery

The effect of α irradiation on natural quartz is commonly known in geology, resulting in the formation of luminescent halos around radioactive inclusions. In archaeological ceramics quartz grains are present and can be surrounded by radioisotopes contained in the clay. The aim of this study is a first attempt to detect similar halos on the outer rims of quartz grains isolated from archaeological pottery. Such identification could be of interest in luminescence dating and as an alternative method for ceramic artworks authentication. Isolated grains were characterized with cathodoluminescence imaging, SEM-EDX and Raman spectroscopy. Some of the crystals were irradiated for reference with a microbeam of He+ accelerated ions and investigated by means of real-time ionoluminescence. Obtained results seem to confirm that the natural effect on archaeological quartz might be too weak to be detected with these techniques and underline the importance of the multi-technique approach to avoid misinterpretations.