Study of K-capture probability in the decay of²⁰⁹Po

Abstract

The alpha and weak EC decay of 209Po have been studied. The K-capture probability and (L+M+. . .)/K capture ratio for the second forbidden unique EC transition of 209Po to the 896.6 keV level of 209Bi have been measured from the K X-ray and 896.6 keV gamma -ray intensities. The value thus obtained is compared with the theoretical estimates using the theory of Behrens and Buhring (1971). The result indicates a significant contribution of capture for higher shells.

Preparation and Calibration of Carrier-Free Po-209 Solution Standards

“…As indicated, the relative α branching to the two lowest energy levels in 205 Pb is largely unknown. Neither of the two most complete studies of 209 Po α decay [ 12 , 13 ] could resolve differences in an a transition to the 205 Pb ground state ( J π = 5/2 − ) or to the 2.3 keV ( J π = 1/2 − ) first excited state. The energy of the principal a branch ( E α = 4.883 MeV) measured in these studies is assumed to correspond to the branch to the 2.3 keV level.…”

“…The relative intensity of K x rays is I Kx / I EC = P κωκ . The capture ratio P L+M+N+ … /P K was experimentally determined by Mandel et al [ 13 ] to be 0.42 ± 0.07, and which may be compared to a value of 0.39 from theoretical estimates of Behrens and Buhring [ 31 ]. If one adopts a value of 0.4 ± 0.1 (and given that P K +P L +P M +… = 1 ), then P K = 0.70±0.015.…”