TABLE 2

α-Particle Emitters: Physical Properties

Radionuclide	E_av* (MeV)	R_av^† (μm)	Half-life
²¹¹At	6.79	60	7.2 h
²¹²Bi	7.80	75	61 min
²¹³Bi	8.32	84	46 min
²²⁵Ac	6.83	61	10 d

↵* Mean energy of α-particles emitted per disintegration (12).
↵^† Mean range of α-particles calculated using second order polynomial regression fit (data from [13]): R = 3.87E + 0.75E² − 0.45; where R is the range (in micrometers) in unit density matter and E is the α-particle energy (MeV).