Design of an on-line selective ion source for fission products

This project is part of a more vast project for producing radioactive ions starting from the reaction 238U(γ,f). A drawback of this type of production by fission is the difficulty of separating efficiently the simultaneously produced isobars, except for a few particular elements (rare gases, alkali metals, halogens). For alkali metals and halogens one makes use of the high sensitivity of their surface ionization. The rare gases can be easily separated from other elements due to their high volatility related to the lack of reactivity. The new design goes still farther in this direction extending the method to elements of medium or low volatility. The apparatus is inserted between the target-containing crucible where the nuclides under study are generated and the ionization chamber in which the beam is generated. The difference in volatility of the elements will be used by the ionization chamber in selecting the isobaric elements. The paper presents the principle and basic hypotheses on which a calculation was done to compare the evaporation of tin and antimony. The results are discussed. A practical solution of the project was found by using a model and Compromising between the numerous thermal, geometrical and temporal parameters and by making use of a computerized model, a practical solution of the project was found