AN ALTERNATIVE MODEL FOR NEUTRALIZATION OF RADON DECAY PRODUCTS

The widely held view that the majority of radon decay products carry a positive charge at birth, independent of the electric field at the si te of production, is challenged. Following Wellisch [Philos. Mag. Supp l. 26, 623 (1913)] we propose that the fraction born charged is in fac t a strong function of the electric field, and that neutralization of the decay products must be treated in two distinct parts corresponding to recombination in the initial ionization column and neutralization in the volume of the gas. We illustrate our argument with measurements relating to the birth (by momentum recoil at a surface) of Tl-208 ion s, and their subsequent transport through argon and air. (C) 1998 Amer ican Institute of Physics.