0000000000103346
AUTHOR
Iiro Riihimäki
Mobility determination of lead isotopes in glass for retrospective radon measurements rad
In retrospective radon measurements, the 22-y half life of 210Pb is used as an advantage. 210Pb is often considered to be relatively immobile in glass after alpha recoil implanted by 222Rn progenies. The diffusion of 210Pb could, however, lead to uncertain wrong retrospective radon exposure estimations if 210Pb is mobile and can escape from glass, or lost as a result of cleaning-induced surface modification. This diffusion was studied by a radiotracer technique, where 209Pb was used as a tracer in a glass matrix for which the elemental composition is known. Using the ion guide isotope separator on-line technique, the 209Pb atoms were implanted into the glass with an energy of 39 keV. The di…
Point-defect mediated diffusion in intrinsic SiGe-alloys
The aim of this thesis was to obtain fundamental diffusion data and to improve the understanding of point-defect mediated dopant diffusion in Si1- xGex alloys. The thesis consists of experimental studies published in international journals and a summary section. The experimental part consists of the following four articles: In article I, diffusion coefficients and Arrhenius parameters have been determined in relaxed intrinsic Si1-xGex in the whole concentration range (0<x<1). In article II, diffusion coefficients and Arrhenius parameters have been determined for Ga and Sn diffusion in relaxed intrinsic and relaxed heavily p-doped germanium. In article III, diffusivity values have been deter…