Application of the electrostatic separation of recoil atoms to the²²⁵Ac-²²¹Fr-²¹⁷At-²¹³Bi decay series

The focus of this research was to develop a novel approach for the separation of ²²¹Fr and ²¹³Bi from ²²⁵Ac. First a method was developed to electrodeposit the actinium onto a cathode from a pH = 2 nitric acid solution. Yields for the electrodeposition approached 99% for a one hour deposition. The Joliot Equation was used to quantitate the process. A linear velocity constant of 0.23 cm/min was measured for the electrodeposition of ²²⁵Ac on a Pt electrode. To separate the ²²¹Fr and ²¹³Bi, the atoms were caught in an electrostatic field as they recoiled from the cathode. The collection yield was found to be dependent on the electrostatic field strength with a critical voltage of about 2000 volts, above which the yield leveled off. The maximum yields for ²²¹Fr were found to occur after 40 minutes of collection. The yield for ²²¹Fr approached 50% while that for ²¹³Bi approached 99%. It was found that the activity of ²²¹Fr on the collector plate could be calculated by multiplying the chain decay equation by a geometry correction factor of the form: f= 0.5(1 - cosΘ) where Θ = tan^-1(R/d) and R = the radius of the collector and d is the distance between the plates. If secular equilibrium is assumed, then the equation reduces to simply: A_FR = A_Ac*f- The collection of the recoil atoms of ²²¹Fr and ²¹³Bi in an electrostatic field has been shown an effective and efficient means of their separation from ²²⁵Ac.