Decay of (86)Rn-210(124) to Levels in (85)at-210(125)

Artikel i vetenskaplig tidskrift, 1973

The decay of 210Rn to 210At has been investigated. Gamma rays were recorded in singles and coincidence using Ge(Li) detectors. Conversion electrons were studied with a Si(Li) detector and a double focusing magnetic spectrometer. Internal conversion coefficients have been deduced and several transition multipolarities have been determined. A decay scheme is presented and spin assignments are made. The electron capture decay from 210Rn has been found to proceed mainly to three levels in 210At: 2 280.8 keV (0-, (1-)), 1 525.5 keV (1+) and 1 488.6 keV (1+), with log ft values <5.5 (L-capture), 7.0, and 7.1, respectively. The nature of these states is discussed. The feeding to the 2 281 keV level is interpreted as a first forbidden beta decay due to either a πh9/2 → νg9/2 or a πs1/2 → νp1/2 transition leading to a [π(h9/23)ν(g9/2p 1/2-2)]0- or a [π(h9/24s1/2-1) ν(p1/2-1)]0 state, respectively. The 1 526 and 1 489 keV states may arise from the π(h9/22|≠0h9/2) ν(f5/2-1) and possibly the π(h9/22f7/2) ν(f5/2-1) configurations. The π(h9/23)ν(p1/2-1) doublet is found at 0 and 72.7 keV. Two levels assigned as members of the π(h9/22|0 h9/2)ν(f5/2-1) configuration are found at 530.9 keV (3+) and 496.1 keV (4+).