INVESTIGATION OF THE DISTRIBUTION OF RADIOACTIVE FISSION PRODUCT NUCLEI IN IRRADIATED FUEL SPECIMENS BY PRECISION GAMMA-RAY SCANNING

摘要

A technique is described which enables the distribution of gamma emitting radio¬active fission product nuclides in irradiated fuel specimens to be obtained. The gamma rays from a selected area of the prepared specimen, obtained by suitable collimation, are detected and resolved by means of their energies. The specimen is then scanned by move-ment along two axes at right angles to each other and at right angles to the collimator by two electrically pulsed stepping motors. The recording system is driven synchronously by means of two similar motors.nA system has been devised to represent the variations in the distribution of the intensity of an individual fission product nuclide in the specimen by means of a colour mosaic. This picture is obtained by means of a special colour camera which is described. Examples of specimens scanned in this way are shown together with the effects of some of the variable parameters in the system.