Scopul nostru este sprijinirea şi promovarea cercetării ştiinţifice şi facilitarea comunicării între cercetătorii români din întreaga lume.
Autori: Leon Grigorescu, Anamaria Cristina Razdolescu, Maria Sahagia, Aurelian Luca, Constantin Ivan, Daniel Negut
Editorial: Agata Olariu, Kristina Stenström, Ragnar Hellborg, Editura Academiei Romane, Proceedings of the International Conference on Applications of High Precision Atomic and Nuclear Methods , Neptun, Romania, 2-6 September 2002, Ed. Academiei Romane, p.86 - 91, 2005.
48 V decays by positron emission and electron capture processes with a half life of 15.97 d. It was standardized by a special classic variant of the coincidence method. An usual 4π proportional counter- NaI(Tl) scintillator system was used. A complication arose due to a significant 46 Sc impurity. The low energy capture radiations were not registered and the 46 Sc radiations were included in a new simplified decay scheme. The gamma contribution in the 4π counter was determined by an extrapolation procedure. In the gamma channel, an energy window centered on the main 1312 keV γ ray was employed as to eliminate the disturbing effect of a non coincident photon. Even so, summation effects, different for two branches in the decay scheme had to be estimated. ‘Get-out’ summation effects were experimentally estimated and reduced with Pb absorbers. Their effect in the final calculus was of only 0.8%. A combined uncertainty of 1.4% was obtained, mainly from the impurity contribution. Two facts helped for a good standardization: use of a simplified decay scheme and equivalent photon energies for 48 V and 46 Sc.
Cuvinte cheie: 48V, standardization, coincidence method, simplified decay scheme