The Allied victory over the Axis powers during the Second World War did not just dent Hitler’s hope of world domination. It also dented his hopes of developing nuclear technology and using it to power weapons. This hypothesis can be confirmed, if researchers at the Pacific Northwest National Laboratory (PNNL) are able to confirm that the uranium cubes in their possession, indeed, belong to the Nazi era. Their research will be presented at the meeting of the American Chemical Society, this fall.
During the 1940s, scientists in Germany were looking at nuclear fission reactions to produce plutonium to be used during the War. Among these were two prominent teams led by Werner Heisenberg and Kurt Diebner, each working out at separate locations in the country. Both the teams were supplied with two-inch (5 cm) uranium cubes for their experiments. By placing these cubes in “heavy” water (made up of deuterium, an isotope of hydrogen), the scientists hoped that the uranium would decay in a chain-like reaction.
Thankfully the approach did not work. When the Allied troops seized Heisenberg’s lab in 1945, they shipped over 600 such cubes to the US. However, there are few records to track them inside the US and the researchers believe only 12 of these cubes remain in the public domain. Even the one at PNNL lacks provenance and therefore, the researchers want to determine their origins.
Brittany Robertson, a doctoral student at the lab, is using radiochronometry – an age determining method for radioactive elements to first determine if the block is indeed from the Nazi era. Even in their natural state, radioactive elements decay and convert into elements with a lower atomic number. Robertson plans to use this to determine the age of the blocks. When made, the blocks were made up of pure uranium. But over the years, the uranium has decayed into thorium and protactinium. By measuring the exact amounts of the latter elements, Robertson can determine the age of the blocks. Additionally, Robertson is also on the lookout for some rare earth elements that might throw up some clues about where the uranium was mined.
Interestingly, the team across another such block at the University of Maryland and found it was coated with styrene. PNNL’s block uses a coating that is cyanide-based. The coatings are used to limit the oxidation of uranium. It is also known that Heisenberg’s lab used blocks that used the cyanide-based coating, while Dibenar’s lab used the styrene-coated uranium blocks. Since Diebner’s laboratory was never raided by the Allied Forces and the whereabouts of the blocks they used remain unknown, it is likely that Diebner’s lab shipped some uranium to Heisenberg’s lab during the experiments.
By testing their science against some of the preliminary materials of the nuclear era, the researchers want to make sure that their science is sound, before implementing it in today’s world.