Separation du cesium et du baryum des terres rares dans la source d’ions d’un separateur electromagnetique d’isotopes

Abstract

In a previous work we studied the separation of cesium from a lanthanum target bombarded by protons in the thermoionic ion source of an electromagnetic isotope separator. After irradiation the principal elements found in the targets were Cs, Ba, Ce and La. We have extended this method to the separation of cesium and barium from metallic lanthanum targets and from lanthanum oxides. It is based on the thermoionization efficiency and on the behaviour of the element studied in the heated cavity, which depends on its volatility if it is under metallic form, and on its reduction and on the volatility of resulting compounds if it is under compound form. In the metallic system we obtained on the collector successively cesium and barium with respective overall yields of about 5% and 0.2%. In the oxide system, we obtained cesium as Cs⁺ ions and simultaneously barium as BaO⁺ ions which are separated from Ba⁺ by 16 masses avoiding the interference with cesium isotopes. The overall yield of the barium separation is about 0.2%. A discussion on the value of barium ionization potential is given.