It might have been a while ago- here [0] is a link to a press release from 2005 saying that the isotopic enrichment of silicon-28 for the Avogadro Project (to r

It might have been a while ago- here [0] is a link to a press release from 2005 saying that the isotopic enrichment of silicon-28 for the Avogadro Project (to redefine the kilogram using a perfect sphere of isotopically pure single-crystal silicon-28) was done at two Russian institutions. Here [1] is a 2004 press release from the International Science and Technology Center, whose first objective is to "Provide weapons scientists in the CIS the opportunity to redirect their talents to peaceful activities." Page 9 describes their involvement in the Avogadro Project. Here [2] is the project description on the ISTC website. [0]https://www.ptb.de/cms/en/presseaktuelles/journals-magazines/ptb-news/ptb-news-ausgaben/archivederptb-news/news05-3/avogadro-project-first-isotope-pure-silicon-single-crystal.html https://www.ptb.de/cms/en/presseaktuelles/journals-magazines... [1]https://www.istc.int/upload/files/6yoyjz8txt44oc0g8cs8.pdf https://www.istc.int/upload/files/6yoyjz8txt44oc0g8cs8.pdf [2]https://istc.ru/istc/sc.nsf/html/projects.htm?open&id=2630 https://istc.ru/istc/sc.nsf/html/projects.htm?open&id=2630