A NOVEL METHOD FOR SOLVING LITHIUM-CARBONATE PELLET BY BINARY-ACID FOR TRITIUM PRODUCTION-RATE MEASUREMENT BY LIQUID SCINTILLATION-COUNTINGTECHNIQUE

Lithium carbonate pellets are frequently used for estimation of tritiu m production rate in irradiated samples in fusion blanket neutronics e xperiment and the activity is measured by liquid scintillation countin g technique. In this measurement, it is essential to solve the lithium carbonate pellet as much as possible and to mix the pellet solution i nto scintillation cocktail homogeneously at stable condition. For this purpose, a novel binary-acid method has been developed to solve lithi um carbonate and to mix the pellet solution into scintillation cocktai l. High solubility is attained by adopting two acids, HNO3 and CH3COOH , and a good compatibility of the pellet solution with scintillator is obtained by emulsion cocktail resulting in high counting efficiency. Defining a product of dissolved mass and counting efficiency as a Figu re of Merit (FOM), the present method has higher FOM value than the co nventional method and is extremely simple in a sample preparation proc edure. In the present work, solubility, compatibility and counting eff iciency were systematically examined for different mixing ratios of tw o acids, and the condition for a maximum FOM was determined. The FOM v alue of a factor of two higher than the conventional method was fully attained.