GB1250891A - - Google Patents

Abstract

1,250,891. Radiation source containers. NATIONAL RESEARCH DEVELOPMENT CORP. 15 April, 1969 [15 Jan., 1968], No. 2052/68. Heading H5R. A radioactive source container includes a radiation shield formed of a fixed part and a movable part which abuts against the fixed part in the closed position and which is spaced from the fixed part in the open position; a fixed radiation source holder positioned to lie wholly within the movable part of the shield in the closed position; opening means for moving the movable part away from the fixed part against continuously acting closure means urging it towards the fixed part; and a latching mechanism for holding the movable part in the open position against the action of the closure means. In the arrangement of Fig. 3c the source-holder is mounted in a central axial bore of the shield which is formed by a fixed cylinder 1 and a cylinder 2 which is axially slidable against the action of springs 4 to expose the source which, as shown, lies in the middle of the gap in the exposed position, but is offset from the plane of abutment of the portions 1 and 2 when the latter are in the closed position. Cylinders 1 and 2 may be of uranium, tungsten, or lead, and cylinder 2 may be arranged such that either the whole cylinder can be withdrawn, as in Fig. 3c, or optionally a sector 14 only, as in Fig. 3b, to expose the source over only a limited circumferential angle. A modified arrangement for withdrawing cylinder 2 from the closed position of Fig. 4a includes a rod 3, with attached collars 27 and 29, slidable within a collar 28 attached to the cylinder 2. Movement of rod 3 to the right initiates the operation of a timer, and compresses springs 21 and 22 until the rod is retained in position by the movement of collar 27 beneath the latch 24, Fig. 4b. At a time determined by the timer the solenoid 25 is energized to raise the latch 23, whereupon cylinder 2 is urged to the right into the expose position (Fig. 4c, not shown) under the action of the spring 21, which initiates the operation of a second timer to cause the energization, after a predetermined interval, of the solenoid 26, to raise latch 24 and permit cylinder 2 to return to the closed position under the action of the spring 22. The use of hemispherical shielding bodies instead of cylinders 1 and 2 is referred to.