Abstract: A load transfer apparatus for transferring a structural load includes: (a) a load-bearing frame including a first plate, a second plate spaced vertically apart from the first plate and having an opening coaxial with the vertical axis, and a vertical support between and coupling the first and second plates; (b) an intermediate plate slidably mounted to the frame vertically intermediate the first and second plates for engagement with the structural load through the opening in the second plate; and (c) an integrated actuator assembly including: (i) a plurality of tension rods extending vertically between and coupling the intermediate plate and the second plate, and (ii) a plurality of mechanical tensioning actuators integrated with respective tension rods. Each tensioning actuator is operable to exert a tensioning force across a respective tension rod to pull the intermediate plate towards the second plate for transfer of the structural load through the apparatus.

Abstract: A compact circular magnetic induction accelerator (betatron) for use as a borehole gamma ray source includes a field magnet and generally circular pole pieces composed of a class of ferrite having the general formula M.sup.2+ Fe.sub.2.sup.3+ O.sub.4, where M represents two or more divalent metal ions from the group consisting of Mn, Zn and Ni. The core magnet is in the form of two symmetrical closed loops, with one leg of each loop passing axially through the circular pole pieces. The field coil and the core coil may be arranged in series or in parallel, and switching circuits are provided for effecting electron beam capture and ejection. In an illustrative borehole application, the betatron is used as a gamma ray source in a bulk density logging tool.