$^{\alpha}$-Zählung von Plutonium-Isotopen mit Flüssig-Szintillatoren : Vermeidung von Fehlern, die von einer Wandadsorption des Plutoniums herrühren

Tri-n-octylphosphineoxide (TOPO) has been found to be a suitabl non-quenching complexing agent for application to internal liquid scintillation of Pu eliminating the errors due to chemical wall-adsorption of hydrolized species of Pu-ions. The excellent light yield and transmission properties of the (Dioxan + PPO + POPOP + Naphtalene + TOPO) liquid scintillator allow the use of conventional counting equipment as normally used with ZnS and NaJ scintillation crystals. With such equipment counting plateaus with a slope of less than 0.1 % per 100 V over the best range are readily obtained. With low noise equipment excellent precision for absolute alpha-counting can be achieved. The scintillator mixes with samples of aqueous Pu-solutions containing considerable quantities of salts and with samples of organic Pu-solutions containing organic complexing agents of low volatility. Both these types of samples cause difficulti for counting plate techniques due to self-absorption. The liqui scintillation method described is therefore especially favourable in the analytical evaluation of solvent extraction experiments