FIGURE 2 PHYSICS AND CHEMISTRY OF HARD CONDENSED MATTER, EARTH SCIENCES SYNCHROTRON SOLEIL HIGHLIGHTS 2020 PUMA BEAMLINE Associated publication Short and long term effects of X-ray synchrotron radiation on cotton paper. A. Gimat, S. Schöder, M. Thoury, M. Missori, S. Paris-Lacombe, A.- L. Dupont. Biomacromolecules, 21, 2795(2020). References To monitor irradiation changes over longer time scales, the samples [1] L. Bertrand et al. , Physics Reports 519, 51 (2012). were stored under controlled thermohygrometric conditions and the [2] E. Pouyet et al., Analytica Chimica physio-chemical changes were studied over a period of two years. We Acta 982, 20 (2017). could show that the UV-luminescence signal and the yellowing of the paper (Figure 3), as well as the depolymerization and the auto-oxidation Corresponding author of cellulose continued increasing over time, indicating that the chemical degradation reactions were still taking place several months after the Alice Gimat irradiation. This finding is important for conservators, as it shows that Centre de recherche sur la conservation des collections a simple check for macroscopic changes after the irradiation does not CRCC preclude potential future harm to the material. USR3224 CRC Our results quantify the impact of X-rays radiation to paper samples Muséum national d’histoire naturelle at both the molecular and macroscopic scale for the first time. Further 36 rue Geoffroy-Saint-Hilaire - CP 21 work is in progress to better understand the effect of natural aging and 75005 Paris the impact of additives (sizing, inks, fillers) that are part of real artefacts. alice.gimat@mnhn.fr FIGURE 3 Captions FIGURE 1: Experiments on PUMA beamline: a) paper inside a plastic bag with silica gel to maintain a stable relative humidity during irradiation with the macro beam and b) paper irradiation with the micro beam. FIGURE 2: Glycosidic scissions concentration (S) as a function of SR-X dose. The irradiation took place at different relative humidity levels (0%, 50% and 80%) at room temperature. FIGURE 3: UV luminescence image of Whatman no. 1 paper samples irradiated on PUMA beamline at 3.8 kGy at various relative humidity levels (0%, 50% and 80%) at room temperature. Luminescence appears in the irradiated area (1x2 cm²) gradually and differently depending on the relative humidity. 75