Abstract: This device comprises a single radioactive source (44), capable of creating an incident beam (120), and a target (48) placed opposite the source (44). The target (48) is capable of creating the second beam (130) by interacting with a first part of the incident beam (120), a second part of the incident beam (120) passing through the target (48) to form the first beam (124).

Abstract: This mandrel (10) comprises a body (16; 22) and a radially expandable annular sealing element (18) which comprises a centring arrangement (46) and a closure arrangement (44) which can be deployed radially between a contracted configuration and a dilated configuration. It further comprises an anchoring element (20) which is positioned at a longitudinal distance from the sealing element (18) and is radially expandable between a retracted state and a deployed state. The mandrel (10) comprises sequencing means (24) which are capable of radially deploying the closure arrangement (44) after the anchoring element (20) and the centring arrangement (46). In an at least partly deployed configuration, the centring arrangement (46) defines at least one axial passage (64) which extends through the annular sealing element (18). The closure arrangement (44) closes the or each axial passage (64) as it is deployed.

Abstract: The mandrel comprises a body having a longitudinal axis together with a radially-expandable annular assembly. The annular assembly presents a peripheral surface for pressing against a borehole and a peripheral surface for pressing against the body. Around the longitudinal axis, the annular assembly comprises a plurality of radial-expansion blocks. Each block has a first bearing surface, a second bearing surface, and two side surfaces disposed respectively facing a side surface of at least one adjacent block. The block are displaceable relative to one another between a radially-contracted configuration, and a radially-expanded, engagement configuration in which each side surface of a block is in contact with the side surface of the adjacent block.

Abstract: The mandrel comprises a body (16) presenting a longitudinal axis (X-X?) together with a radially-expandable annular assembly (18). The annular assembly (18) presents a peripheral surface (39) for pressing against a borehole and a peripheral surface (57) for pressing against the body (16). Around the longitudinal axis (X-X?), the annular assembly (18) comprises a plurality of radial-expansion blocks (40, 42). Each block (40, 42) presents a first bearing surface (44), a second bearing surface (46), and two side surfaces (48A, 48B) disposed respectively facing a side surface (48B, 48A) of at least one adjacent block (42, 40). The blocks (40, 42) are displaceable relative to one another between a radially-contracted configuration, and a radially-expanded, engagement configuration in which each side surface (48A, 48B) of a block (40, 42) is in contact with the side surface (48B, 48A) of the adjacent block (42, 40).