Soft X-ray Radiation and Monte Carlo Simulations: Good Tools to Describe the Radiation Chemistry of Sub-keV Electrons

Lucie Huart (1, 2, 3) , Christophe Nicolas (2) , Josiane Kaddissy (3) , Jean-Michel Guigner (1) , Alain Touati (1) , Marie-Françoise Politis (4) , Pascal Mercère (2) , Benoît Gervais (5) , Jean-Philippe Renault (3) , Marie-Anne Hervé Du Penhoat (1)

1 IMPMC - Institut de minéralogie, de physique des matériaux et de cosmochimie
2 SSOLEIL - Synchrotron SOLEIL
3 LIONS - Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire
4 LAMBE - UMR 8587 - Laboratoire Analyse, Modélisation et Matériaux pour la Biologie et l'Environnement
5 CIMAP - UMR 6252 - Centre de recherche sur les Ions, les MAtériaux et la Photonique

The description of the biological effects of ionizing radiation requires a good knowledge of the dose deposition processes at both the cellular and molecular scales. However, experimental studies on the energy deposition specificity of sub-keV electrons, produced by most radiations, including high-energy photons and heavy ions, are scarce. Soft X-rays (0.2–2 keV) are here used to probe the physical and physico-chemical events occurring upon exposure of liquid water to sub-keV electrons. Liquid water samples were irradiated with a monochromatic photon beam at the SOLEIL synchrotron. Hydroxyl radical quantification was conducted through HO• scavenging using benzoate to form fluorescent hydroxybenzoate. The yields of HO• radicals exhibit a minimum around 1.5 keV, in good agreement with indirect observation. Moreover, they are relatively independent of the benzoate concentration in the range investigated, which corresponds to scavenging times of 170 ns to 170 ps. These results provide evidence that sub-keV electrons behave as high linear energy transfer particles, since they are able to deposit tens to hundreds of electronvolts in nanometric volumes.

Domains: Chemical Sciences; Material chemistry; Chemical Sciences; Theoretical and/or physical chemistry

Lucie Huart, Christophe Nicolas, Josiane Kaddissy, Jean-Michel Guigner, Alain Touati, et al.. Soft X-ray Radiation and Monte Carlo Simulations: Good Tools to Describe the Radiation Chemistry of Sub-keV Electrons. Journal of Physical Chemistry A, In press, 124 (10), pp.1896-1902. ⟨10.1021/acs.jpca.9b10539⟩. ⟨cea-02496226⟩