Hanle effect measurement of neon 2p5 3p level lifetimes

Abstract The lifetimes of eight of the neon 2p levels (Paschen notation) have been measured using the Hanle effect in a mild helium-neon discharge. Most of these levels show evidence of cascade of alignement from the 2s 4 , 3s 1 and 3d levels when, at low pressures, these levels are partially aligned, as are the 2p levels. Data obtained at higher pressures are found to be free of cascade effects and are used to establish upper limits for the lifetimes of the 2p levels, the results being subject to coherence narrowing. A correction for the coherence narrowing is estimated resulting in the following natural lifetimes in ns: 2p 2 17.6(6); 2p 4 19.2(1.0); 2p 5 18.6(1.3); 2p 6 18.2(7); 2p 7 19.4(9); 2p 8 19.6(1.0); 2p 9 18.7(7); 2p 10 24.6(5). These values are systematically less than those obtained by methods in which cascade effects have not been carefully eliminated. In common with other Hanle effect measurements for these levels, they are also marginally smaller than the lifetimes given by Bennett and Kindlmann.