Rossi could have stumbled on a simple way like "cryogenic distillation" - who knows?
More likely, he gets it from ENEA Frascati - using Focardi's connections. From: James Bowery Isotopes of Carbon, Oxygen, and Nitrogen can be purified by chilling these gases or compounds nearly to their liquification temperature in very tall columns (200 to 700 feet tall-70 to 200 meters). The heavier isotopes sink and the lighter isotopes rise, where they are easily collected. The process was developed in the late 1960s by scientists at Los Alamos National Laboratory. <http://en.wikipedia.org/wiki/Isotope_separation#cite_note-8> [8] This process is also called "cryogenic distillation". <http://en.wikipedia.org/wiki/Isotope_separation#cite_note-9> [9] http://en.wikipedia.org/wiki/Isotope_separation#Gravity
