The contamination with radioactive material of the notebook written by Marie Curie, collected in the library of Melsel University, Tokyo, was studied by use of Imaging Plate to obtain the distribution images of the contamination on the front and back covers, Si detector to obtain the energy spectrum of α-particles from the cover, and HPGe detector to obtain γ-ray spectrum. The distribution images showed that the contamination appeared mainly at the area held with hands, and even the end of the notebook was contaminated. Many dots of the contamination might imply that there were powdery contaminations around her circumstances. Energy spectra of α-particles and γ-rays showed that most of the nuclei were 226Ra and the daughters. The radioactivity level at the intensely contaminated part was just below the permissible level, 4 Bq/cm2, of surface contamination for α-nuclides of Japan. Number of pages written in every month over 15 years was examined for the purpose to imagine the circumstances at that time, and some remarks were given by referring her biographies which include a matter on a Japanese researcher.
Japan Radioisotope Association