CONICET | Buscador de Institutos y Recursos Humanos

Electron paramagnetic resonance (EPR) is a widely employed technique for non-destructive measurements of defect centers in organic materials caused by irradiation. Applications include general radiation dosimetry, analysis of out-coming products after radiation chemistry and supervision of food irradiation processes. In particular, L-Alanine (L-Ala) and Hydroxyapatite (HAp) are good based materials to employ in gamma-irradiation dosimetry. After ionising radiation both systems exhibit defects that are stable in time and can be measured by EPR. The possibility of combining these materials with other phases that allow manipulation of dierent physical properties opens new elds for the design of specic sensors. For example, a bifunctional material can combine a magnetic phase, which allows the manipulation of the system through an external applied eld, and a radiation sensitive phase that gives information of the received dose.With this objective we fabricated Fe3O4 and ZnxFe3-xO4 nanoparticles with diameters of 10-20 nm by the high-temperature decomposition method. Subsequently we combined the nanoparticles with the L-Ala or HAp phases through a simple wet chemical route. TEM micrographs conrmed the presence of magnetic nanoparticles embedded in the organic materials. The systems were gamma-irradiated at the RA-6 Nuclear Research Reactor located at the Centro Atomico Bariloche. Prior to irradiation, no L-Ala or HAp signals were detected by EPR. After irradiation, all systems exhibited the superimposed signals of both counterparts. The nanoparticles broad line remains unaltered after irradiation, while the defects generated on the corresponding organic phase arise with intensities depending on the received dose. Here we present the preliminary results on these new bifunctional systems and discuss the possible application as specic sensors.

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