1992 Volume 41 Issue 12 Pages 618-626
Autoradiographic observations using a photographic film on a granite rock slice have been established for two-dimensional distribution of elements, Al, Mn, and Na, which produce relatively short-lived radionuclides after pure thermal neutron irradiation. In the case of aluminium detection, it was suggested from semi-empirical estimation that an obstacle reaction of 28Si (n, p) 28Al with fast neutrons significantly overcomes the objective 28Al-activity from the neutron capture reaction of aluminium, in addition to the contribution of after-glow phenomena with reactor exposure to sensitize the photographic film. As a result, the fine textures of aluminium pattern among mineral constituents could be conveniently recognized as well as in the case of manganese distribution.
Subsequently, the imaging plate based on photo-stimulated luminescence phenomena has proven to be preferentially employed for the quantitative treatments of imaging patterns due to neutron-induced radionuclides. The advantageous points of the imaging plate, involving ultra-high sensitivity and acquisition of quantitative information, are discussed in comparison with the traditional photographic technique.
