17 resultados para heavy ion reactions


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Ionoluminescence (IL) of the two SiO2 phases, amorphous silica and crystalline quartz, has been comparatively investigated in this work, in order to learn about the structural defects generated by means of ion irradiation and the role of crystalline order on the damage processes. Irradiations have been performed with Cl at 10 MeV and Br at 15 MeV, corresponding to the electronic stopping regime (i.e., where the electronic stopping power Se is dominant) and well above the amorphization threshold. The light-emission kinetics for the two main emission bands, located at 1.9 eV (652 nm) and 2.7 eV (459 nm), has been measured under the same ion irradiation conditions as a function of fluence for both, silica and quartz. The role of electronic stopping power has been also investigated and discussed within current views for electronic damage. Our experiments provide a rich phenomenological background that should help to elucidate the mechanisms responsible for light emission and defect creation.

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Introduction - SiO 2 •Simple composition and structure; Crystalline and amorphous phases •Adequate for atomistic simulations •Abundant in nature. Relevant for many technologies -Irradiation with swift heavy ions: •They provide EXTREME physical conditions •Very high excitation densities similar to high power lasers •Very high local temperatures •By playing with high energy and heavy mass (SHI) : •One can go from low electronic excitations (collisions regime) to high electronic excitations (electronic regime