Device for non-destructive testing using ionizing radiation, comprising: - a source of ionizing radiation, emitting ionizing radiation into a box with walls (3a-3f) that are able to at least partially confine said ionizing radiation, - a cover extending along a longitudinal axis (I-I), having a substantially circular cross section that is centred on the longitudinal axis (I-I), and comprising a lateral wall, an upper wall and/or a lower wall that are able to at least partially confine said ionizing radiation, - a plate in the form of a disc, which is able to rotate about the longitudinal axis (I-I) in the cover, an inner cavity being defined between the plate, the lateral wall and the upper wall and lower wall of the cover, characterized in that it has: - a lateral access opening, provided in the lateral wall of the cover and affording access to the inner cavity in a first radial direction (II-II), - a communication opening between the box containing the source of ionizing radiation and the inner cavity, disposed substantially diametrically opposite the lateral access opening with respect to the longitudinal axis (I-I), - at least four radial walls (12a-12d), as one with the plate and extending respectively from the plate along the longitudinal axis (I-I) and in respective radial directions (III-III, IV-IV, V-V, VI-VI), defining between one another at least four angular sectors (13a-13d) of the plate, said radial walls (12a-12d) having a material that is able to at least partially absorb the ionizing radiation, wherein the radial walls (12a-12d), the lateral access opening and the communication opening are arranged such that the passage between the lateral access opening and the communication opening is obstructed by said radial walls (12a-12d) regardless of the angular position of the plate about the longitudinal axis (I-I). - a source of ionizing radiation, emitting ionizing radiation into a box with walls (3a-3f) that are able to at least partially confine said ionizing radiation, - a cover extending along a longitudinal axis (I-I), having a substantially circular cross section that is centred on the longitudinal axis (I-I), and comprising a lateral wall, an upper wall and/or a lower wall that are able to at least partially confine said ionizing radiation, - a plate in the form of a disc, which is able to rotate about the longitudinal axis (I-I) in the cover, an inner cavity being defined between the plate, the lateral wall and the upper wall and lower wall of the cover, - a lateral access opening, provided in the lateral wall of the cover and affording access to the inner cavity in a first radial direction (II-II), - a communication opening between the box containing the source of ionizing radiation and the inner cavity, disposed substantially diametrically opposite the lateral access opening with respect to the longitudinal axis (I-I), - at least four radial walls (12a-12d), as one with the plate and extending respectively from the plate along the longitudinal axis (I-I) and in respective radial directions (III-III, IV-IV, V-V, VI-VI), defining between one another at least four angular sectors (13a-13d) of the plate, said radial walls (12a-12d) having a material that is able to at least partially absorb the ionizing radiation,