Loss of Elements in Ancient Red Chinese Ink on Japanese Paper through Proton-PIXE

For the purpose of studying loss of elements through PIXE analysis, a target of modern Japanese paper with ancient red Chinese ink on was prepared and analyzed. Red Chinese ink includes mercury sulfide which has low melting point of 583 °C at 1 atm. In this study, two classes of 2 MeV proton beams of about 5 nA/mm2 and 50 nA/mm2 were used. A simple data taking system of multi-spectra was establised and X-ray spectra by proton-PIXE were consecutively obtained every 10 seconds for about 2 hours. The obtained multi-spectra were used for the loss of each element in the target. The results show that S, Hg and Pb in the target gradually decrease with time under 50 nA/mm2 of a 2 MeV proton beam and the decreases start under about 25 nA/mm2. These elements, however, don’t decrease under 5 nA/mm2. Most of chlorine in modem Japanese paper was lost under 15 nA/mm2.