[en] Silicon On Insulator (SOI-SIMOX) buried oxides and Suprasil silica glasses have been irradiated so as to compare charge trapping and paramagnetic defect center generation phenomena. Parameters used in the study were: X or γ-ray irradiation, and electric field bias applied during irradiation. Positive or negative charge trapping is depending upon the sign of the bias field in the SIMOX (Separation by Implantation of Oxygen) buried MOS structure, and is correlated with E' paramagnetic center generation. In the two cases, the charge trapping mechanism or E' center generation are very sensitive to the electric field magnitude. In the SIMOX oxide, synthesized by oxygen implant, the EPR spectrum is confirmed to exhibit a characteristic 2-peak structure