Fourth Spy Unearthed in U.S. Atomic Bomb Project, Part 4, Conclusion

From Part 3, we have a hint at an activity that might utilize Godsend’s skills. To explore further, we need to understand more than the famous milestones highlighted by histories. That focus will never get us the place of a figure as minor as Godsend. We have to look at the mistakes, dead ends, and activities that, while useful and supportive, did not leave much of a mark in time.

The number of dead ends explored by Manhattan was huge, a much larger story than the choices that worked. The entire uranium bomb effort, was, in retrospect, a wasteful duplication — if the far more complex plutonium “Fat Man” bomb could have been assumed to work. But it could not. Hence, 100% duplication, in the form of “Little Boy”, an inferior weapon of great expense.

Heavy water, which contains heavy hydrogen, a.k.a. deuterium, has been romanticized in movies and by historians. Lacking crucial purpose to the Manhattan project, it was almost a dead end. It was recognized early to be useful for the production of plutonium, but was never used by the U.S. for that purpose. (Neither is it of use to the Iranians for a uranium based program, one root of my suspicion that they have a second, completely hidden plutonium program, or an interest in the H-Bomb.)

Although it  became crucial to the H-bomb that came later, it never served a crucial role in the Manhattan project. Yet it kept Los Alamos busy between 1942-1944.

For the A-Bomb, heavy water is intriguing but unnecessary shortcut to obscure goals. It takes roughly a pound of natural uranium enriched with U-235,  dissolved in heavy water, to make a nuclear reactor.   In 1944, at Enrico Fermi’s instigation, a sphere of this liquid, which was named the “water boiler”, gave Los Alamos an experimental atom-splitting reactor to study. With enrichment with about 58 grams (about 2 ounces) of U-235, it went critical, meaning that the chain reaction could grow without bound. This was much less U-235 than required by solid-metal experiments. Unlike the massive reactors at Hanford used to make plutonium, the homely water boiler could be easily reconfigured by changing the uranium-water solution.

(A joke of record: the “water boiler” did not boil water, and it is  unrelated to boiling water reactors.)

The concentration, determined by experiment, is analogous to the critical mass of a bomb. The solution could be drained, dried, and analyzed for fission products. The result is an average of all the ways the cookie crumbles, the Fission Product Yield.

The water boiler reactor was tangential to the main effort. At best, it was a distant relative of the Bomb.  The ease of construction may have inspired continued interest in Oppenheimer’s  “hydride bomb”, which was actually tested years after the war, and fizzled twice. The chain reaction was produced by “thermal” neutrons, slowed down by the water. The Bomb, which has no moderator, uses fast neutrons.

But these were desperate times, and it gave the Los Alamos group something with which to test their pencils. What does this have to do with the fourth spy, Godsend, who ran Calutrons and mass spectrometers at Oak Ridge?

Godsend’s job at Los Alamos was similar to his job at Oak Ridge. The fission products produced by the water boiler could not be properly analyzed by wet chemistry, but would yield to the mass spectrometer, at which Godsend was expert at operation and maintenance.

At Trinity test,  Robert Oppenheimer’s memorable quote, from the Bhagavad Gita, was “Now I am become Death, the destroyer of worlds.” But there was also a minor act of creation, of isotopes and elements. What were they? The day after Trinity, Enrico Fermi and Julius Tabin drove to ground zero in a lead lined Sherman tank. Through a trap door in the bottom of the tank, they sampled  a new radioactive material, a green glass dubbed “trinitite.”

Fresh trinitite was dangerously radioactive.  But the risk, as then understood, was reduced acceptably by the minuscule quantities required by the mass spectrometer. Godsend was in business again, and busy for another half year at least, profiling the first instance of nuclear fallout.

The mass spectrometer also revealed how much of the bomb material was wasted, showing up as unreacted uranium or plutonium. This and the distribution of atomic splits facilitates calculation of total energy release.

All of this information was soon in the hands of Lavrentiy Beria, master of the security apparatus of the Soviet Union, a human monster and brilliant administrator who directly supervised both  the Soviet atomic effort and all related espionage.

As before, the above is not a documented history of Godsend’s role. It is an alternative approach, complimentary to the efforts of historians, providing insight that may not be available from archives.

This is a sad note for the end 2019.  It must not stand. There should be dancing in the streets!  I’ll do my best.

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