TABLE 1

α- and β-Radiation Emitted in Decay Chain of ²²³Ra

Parameter	²²³Ra	²¹⁹Rn	²¹⁵Po	²¹¹Pb	²¹¹Bi	²⁰⁷Tl
Half-life	11.43 d	3.96 s	1.78 ms	36.1 min	2.17 min	4.77 min
α-Energy (mean) (MeV)	5.64	6.75	7.39		6.55
β-Energy (maximum) (MeV)				1.37		1.42
Energy fraction*	0.207	0.248	0.271	∼0.017	0.24	∼0.017

↵* Relative to total emitted energy for complete decay chain. Energy from emitted radiation associated with decay of ²²³Ra and daughters is ∼27.5 MeV. Fraction of energy borne by particulate radiation emitted as α-particles is ∼97%. Fraction of energy emitted as β-particles is ∼3%.