Lifetimes of the 3 1,3P and 3 1,3D states of helium

Abstract

Measurements have been made of the helium n = 3 singlet and triplet P and D state lifetimes using the electron photon coincidence technique. For each state visible n = 3 to n = 2 photons were detected in coincidence with the inelastically scattered electron. The 3 1P lifetime as a function of atomic beam density shows the influence of resonance radiation imprisonment as applicable to He(n 1P) coincidence studies. Self absorption of the emitted radiation from the other n = 3 levels due to increased source density has also been investigated.