Abstract: In per se known manner, this apparatus comprises a radioactive source locked within a cylindrical source holder, which is itself fitted in an appropriate cylindrical recess. The cylindrical recess is higher than a larger diameter cylindrical recess, in whose walls are partly fitted at least one locking ring and at least one lug. The source holder has in its lower part a flange, whose upper portion is chamfered, as well as an annular groove and at least one slot, inclined with respect to the axis of revolution of the source holder and whose width is at least equal to the diameter of the said lug. This slot, which issues onto the upper face of the flange, is such that the position of the lug in the bottom of the slot corresponds to that of the locking ring in the annular groove. The apparatus has particular application to cobalt therapy equipment, particularly to the ALCYON head.

Abstract: Apparatus for the transfer and positioning of targets in an irradiation installation equipped with an access lock of axis Z.sub.3 Z.sub.4 and within which there is a high vacuum, the installation being located in a protective enclosure defined by a shielded wall, including a telescopic assembly of axis X.sub.1 X.sub.2 located within the protective enclosure, the telescopic assembly having a free end able to carry the target to be positioned and being located on a support, and the support can be given a movement enabling it to move between a first target handling position in which the satisfactory operation of its components can be checked and a second position in which the X.sub.1 X.sub.2 axis of the telescopic assembly coincides with the Z.sub.3 Z.sub.4 axis of the access lock and the free end introduced into the lock.