Radon decay curves

Figure 3. Growth and decay curves for radon and its short-lived decay products.

The calculated size distribution of newly attached decay products is shown as curve C in Fig. 1.9. The activity median diameter is 0.16 /zm. With passage of time, the distribution would be shifted to larger particle sizes, as coagulation proceeds. George (1972) used diffusion batteries to measure the size distribution of nuclei carrying radon decay products and found activity median diameters (AMD) averaging 0.18,0.11, and 0.30 /um in a city basement, fifth floor room, and rural outside air, respectively. 

Fig. 2.4 Radioactive decay follows first order kinetics and a plot of the number of nuclides against time is an exponential decay curve. The graph shows a decay curve for radon-222, which has a half-life of 3.82 days.

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