The basic science of atomic weapons was known to both sides in 1942.
To be fair - and accurate....not quite
Heisenberg's conversation with Bohr indicated he had no idea how a "bomb" might be constructed or set off; as of 1942 he was still
running with the idea that a "bomb" was a reactor
allowed to run explosively critical.
To be fair and accurate, none of the 'public history' of the Bohr/Heisenberg conversation makes any sense.
Bohr ran off, having left Heisenberg in a pique, because of a drawing and a /suggestion/ that either German and World Scientists work together to avoid the development of atomic weapons (what would Bohr be able to do, from occupied Europe, his every letter under censorship by both sides, if it could even reach a post December-7 USA at all?) OR (what Bohr suggests) he tried to coopt The Great Dane into making Germany competitive with the 'far more advanced' Allied effort.
Indicating the Heisenberg knew he was in over his head, something repeatedly proven to him by a very bitter Paul Harteck who essentially made a fool of the 'Nobel Laureate' _repeatedly_ in the Epsilon tapes. Not least being an off the cuff neutron radius calculation which was more accurate than the one we were using and (and would continue to be so, until the 1960s and mainframe computers) and which made utter hash of Heisenberg's 'multiple ton' conditional material requirements via the simple fact that NOT EVERY ATOM NEEDS TO GO FISSILE TO GET RCR.
So why would Bohr run off like a little girl and leave Heisenberg sitting alone like a suitor with a ring on the veritable park bench? Could it be that this is NOT what happened? That the 'little box with lines radiating from it' was NOT what Bohr kept on him from that moment until he could self evacuate to Sweden and then onto America to show his fellow physicists?
Let's consider an alternative: Heisenberg is a traitor to the German cause. They are sitting on a park bench in a private, walled, garden because Bohr's home is likely bugged. The conversation has NOTHING to do with 'reactors and control rods' but is rather related to a GAS DIFFUSION PLANT which is the earliest form of radio isotope separation, pioneered by Jewish German Gustav Hertz.
On 27 April 1945, Thiessen arrived at von Ardenne's institute in an armored vehicle with a major of the Soviet Army, who was also a leading Soviet chemist. All four of the pact members were taken to the Soviet Union. Hertz was made head of Institute G, in Agudseri (Agudzery), about 10 km southeast of Sukhumi and a suburb of Gul’rips (Gulrip'shi). Topics assigned to Gustav Hertz's Institute G included: (1) Separation of isotopes by diffusion in a flow of inert gases, for which Gustav Hertz was the leader, (2) Development of a condensation pump, for which Justus Mühlenpfordt was the leader, (3) Design and build a mass spectrometer for determining the isotopic composition of uranium, for which Werner Schütze was the leader, (4) Development of frameless (ceramic) diffusion partitions for filters, for which Reinhold Reichmann was the leader, and (5) Development of a theory of stability and control of a diffusion cascade, for which Heinz Barwich was the leader;
Now, Hertz was descended from Jews. So he didn't get the kind of funding that the KWI and 'Uranium Club' did. But his IS the simplest method and yet it is also the SOLE method for which we don't see assigned university/professors. Bagge and Klusius did Thermal Diffusion. Harteck did Centrifuge. Weitzsacker (from memory) was on the Sluice. And Von Ardenne covered both electromagnetic separation (his system's capture tank was 20% more efficient than the Calutron) and probably the 'photo chemical method'. But no mention of a serious gas diffusion effort.
And you know, the funny thing about the SS is, they may have executed Jews by the trainful in The East but they were pragmatic about a lot of things related to 'Juden Physik' that would have been pshawed in the regular German university system as Reich's Research Council, headed by Heisenberg and his cronies.
So where is the Gas Diffusion Werke? The very fact that there isn't one, publically, is highly suggestive that there was.
And the easy contender is Buna 102 at Monawitz which never produced a pound of synthetic rubber and which was the focus of considerable interest at the Industrialist Trials in Nuremberg and was conveniently close to both Ohrdruf and the Joachimsthal mine complex.
Heisenberg's 'box with arrows' was NOT a reactor and the reason that Bohr got himself out of country and over to the Allies RIGHT NOW after his little conversation with his student was that Heisenberg, 'The White Jew', had somehow learned of this off the books SS effort and shown him a gas diffusion process rendering, with input:output efficiency levels, similar to 'The Monster' which South Africa built for Qaddafi.
Now the arrows can have a number representing a given percentage Hex going in one side and a given concentration of U235 coming out the other. Rinse Repeat, X-many months to critical mass quantities of weaponized material.
Though it is a prime producer at industrial scales, Gas Diffusion is one continuous plumbing disaster waiting to happen with the caustic, radioactive, explosive UF6 running through it. We had ENORMOUS problems getting the molecular filter sieves correct at Oak Ridge so that they would capture but not clog and hold together long enough to make a few runs to get enough enriched gas to really begin to cluster up atoms. But the Germans were master molecular chemists. IG Farben was the pillaged essence of all the big American bigchem/bigpharma companies today. And with alloys like Bondur, they could have gotten ahead.
If that piece of paper says: "They are getting 10% per run and can make a bomb in a year." Bohr is going to pat his student on the head and call MI6 to come make a pickup because that piece of paper is going to tell the U.S. Manhattan District that they need to seriously get into the game. Look at the funding dates for the big expansions at Oak Ridge vs. Buna 102 and ask yourself: is the big brouhaha between Bohr and Heisenberg really what it seems?
How far ahead were they? We still can't account for over half the 3,000 tons of Uranium taken from Belgium. And the Germans had a process, which Harteck saw, that produced a ton of metallic uranium PER DAY. Thus the fantasy that there was a 'Uranium Shortage' in German during the wartime years is an _utter farce_.
Just last year, we finally found and presumably raised (Glomar) the last two U-Boat war graves which 'private interests' (CIA) had sponsored the search for, for over 70 years. Those U-Boats were among 19 which were making routine runs between Jakarta and Germany, of which 11 were sunk, in 1944 alone. U-864 is going to be entombed in concrete, despite the certainty that it will crush the hull and release any mercury in it's glass philes which was the justification for it's encapsulation to begin with. Why? Because they are terrified that the world will someday discover that the Germans and Japanese were world nuclear leaders, passing around highly refined, weapons grade, U233 or even transmutated (Bell = Tokomak) Pu240. And Lucy will have a lot of splainin' to do. U-534, which was raised, was left to sit in the open for five years, rusting away, before being gutted and turned into a museum piece. Why? Cooling off period for a nuclear cargo removed from it's belly?
Oppenheimer: "The bombs were of German provenance."
Teller: "The Germans did much of the ground work for the fusion weapons. The best physicists stayed in Germany."
Radecs: "The bombs exploded over Japan were not of U.S. origin. The first U.S. designed bombs were not detonated until 1947 over Enivetok."
The Germans had the bomb. The Germans didn't use the bomb, even to defend their own territory, because Hitler didn't want a weapon which would end life for centuries across the planet. The U.S. faced the utter exposure of the massive fraud of a 3 billion dollar weapons program whose Jewish Genius had produced Zip Squat Denadda with a U.S. Senator threatening to expose the truth via independent review. And so, to cover their own behinds, the U.S. military dropped weapons of mass destruction, in direct violation of the Hague Convention and indeed ANY moral code, on a helpless nation's civilian targets. For no better reason than to cover up their own ineptitude with the displayed result of a mazcat of over 200,000 dead.
The were not U.S. Bombs. Little Boy in particular doesn't even look American. And the 60kg/132lbs of fuel in it was more than we should have had in the ENTIRE U.S. stockpile, even if they had not been using U235 to hot-cycle the breeder at Hanford.
We have been lied to for _decades_.