Messung der Lebensdauer von Elektronen im 3P- und 4D-Zustand des Natrium

Lifetimes of electrons in the 3P- and 4D-levels of sodium are measured. The sodium-atoms are excited by short pulses of electrons with energies between 2 and 8 eV. The time dependence of the emitted light is determined by direct oscillographing via photomultiplier as well as by counting single quantas. The counting technique corresponds to the delayed coincidence method and employs a sampling oscilloscope. Lifetimes of the 3P- and 4D-levels were found to be 14.0 and 52.1 nsec respectively. From these values the absorption oscillator strengths 1.11 and 0.095 were calculated for the 3S-3P- and 3P-4D-transitions.