Microwave Hardening of Free-Falling Radioactive Droplets

We describe the design and generation of a microwave system in which liquid droplets of radioactive solutions are solidified during free fall. Upon passage through a vertically positioned H10p resonant cavity, the droplets are heated within 0.25 sec to 100°C by 80 W of microwave power at 14 GHz. Major advantages of the microwave process over previous methods are (i) contact-free heating of the radioactive substance and (ii) no need for precipitation baths and/or washing solutions, which would became radioactively contaminated.