A METHODOLOGICAL TEST OF EXTERNAL BEAM PIXE ANALYSIS ON INKS OF ANCIENT MANUSCRIPTS

Extensive scientific investigations on the materials used for preparin g inks in medieval and Renaissance manuscripts (before invention of pr inting) are still missing. With our external PIXE setup, we are beginn ing such an investigation. The present paper deals with a preliminary methodological research aimed at the identification of the critical co mpositional parameters and at the definition of operating procedures w hich permit reliable information to be obtained and in particular the homogeneity of the home-made inks to be checked. We chose three 11th c entury manuscripts of well known origin. and performed composition mea surements on five ink areas on each of six pages per manuscript. On on e of the five areas a scan in steps of 200 mum was also performed with the purpose of checking ink composition homogeneity even at this smal l scale. Five measurements on each of the six pages' parchments allowe d us to evaluate the contribution to the collected ''ink'' spectra ari sing from the underlying parchment. Critical parameters for ink charac terization have been found to be e.g. the K contents, the Fe-Cu-Zn Pb compositional pattern, and the sulphur to metals ratio. In addition, w e have detected ink-parchment physico-chemical interactions altering t he apparent Cl and Ca contents.