further to betray secrets of the greatest possible value and importance to this land,” the Lord Chief Justice sentenced Klaus Fuchs to the maximum term of fourteen years.
Even before the first presidential announcement of the thermonuclear program, Stanislaw Ulam had lost patience with Teller's assaults on Los Alamos's dedication to Super work. “Teller… kept insisting on certain special approaches of his own,” Ulam writes. “I must admit that I became irritated by his insistence; in collaboration with my friend [Cornelius] Everett one day [in December 1949] I decided to try a schematic pilot calculation which could give an order of magnitude, at least, a ‘ballpark’ estimate of the promise of [Teller's Super] scheme.” Ulam and Everett had prepared calculations for the MANIAC earlier in 1949, but that machine was far from completion, as was John von Neumann's Princeton original. Now they undertook to calculate a simplified version of the problem by hand. At the same time, Los Alamos began preparing a simplified machine version that von Neumann could farm out to the ENIAC.
The problem — whether a D + T burn would ignite a large mass of deuterium — required tracking the progress of thermonuclear reactions using Monte Carlo methods. “Each morning,” Ulam recalls, “I would attempt to supply several guesses as to the value of certain coefficients referring to purely geometrical properties of the moving assembly involving the fate of the neutrons and other particles going through it and causing, in turn, more reactions.” Ulam supplied his guesses in the form of random numbers which he generated by tossing one die of a pair of dice. Teller certainly understood the mathematical authority of Ulam's random-number generator, but he must have quailed to see his grand design held hostage to a crap shoot.
The calculations were lengthy and tedious, Ulam writes:
We started work each day for four to six hours with slide rule, pencil and paper, making frequent quantitative guesses… These estimates were interspersed with stepwise calculations of the behavior of the actual motions [of particles]… The real times for the individual computational steps were short… and the spatial subdivisions of the material assembly very small… The number of individual computational steps was therefore very large. We filled page upon page with calculations, much of it done by Everett. In the process he almost wore out his own slide rule… I do not know how many man hours were spent on this problem.
At first, writes Franchise Ulam, her husband “worked just with Everett, then with an added bevy of young women who had been hastily recruited to grind manually on electric calculators.” Francoise helped out with the effort. It did not favor Teller's design, she notes. “I was well placed to watch how personally Teller took the fact that Stan and Everett were the first to blow the whistle with their crude calculations. Every day Stan would come into the office, look at our computations, and come back with new ‘guesti-mates,’ while Teller objected loudly and cajoled every one around into disbelieving the results. What should have been the common examination of difficult problems became an unpleasant confrontation.”
Ulam and Everett issued an interim fifty-page report on March 9, 1950, concluding, Carson Mark writes, that the amount of tritium chosen for the calculation “was not nearly enough; so the first calculation was discontinued… and a second calculation, with a larger amount of tritium, was started immediately. “(Ulam put the conclusion of the first calculation more bluntly; it revealed, he reported, “that the model considered is a fizzle.”) As the second calculation proceeded, says Ulam, “it naturally attracted quite a lot of attention among the physicists Teller was trying to interest in the ‘super’ project… ” The results continued to point “to the mediocre progress of the reaction.” Teller for his part blamed not his Super design but his opponents for discouraging recruiting. “I feel that the attitude of the members of the GAC has been a serious difficulty in our recruiting efforts, and I continue to wish for a clear- cut change of heart, publicized at least in their closest circle,” he wrote William Borden, who was becoming a confidant. “A man like Conant or Oppenheimer can do a great deal in an informal manner which will hurt or further our efforts.”
“Teller was not easily reconciled to our results,” Ulam observes. “I learned that the bad news drove him once to tears of frustration, and he suffered great disappointment. I never saw him personally in that condition, but he certainly appeared glum in those days, and so were other enthusiasts of the H-bomb project.” Ulam visited von Neumann in Princeton that spring and they discussed their ongoing calculation with Fermi and Oppenheimer; Ulam thought Oppenheimer “seemed rather glad to learn of the difficulties.” By then Teller suspected that Ulam was deliberately biasing the calculation against the Super; the Polish mathematician told von Neumann on one occasion that Teller “was pale with fury yesterday literally — but I think is calmed down today.” Teller wrote von Neumann of his discouragement early in May; von Neumann, preparing to run the ENIAC calculation, responded on May 18 with a letter meant to cheer him up:
I am sorry to see from your letter that the strain which your work puts on you is exceedingly great. I want to assure you that I certainly don't want to make it any greater, and I regret in particular that I am unable to find a modus procedendi which will reassure you completely regarding the course which our calculations are taking now… This calculation is not and never was intended to be the only one that we shall make… Politically, I would chiefly like to have a tolerable chance of producing a positive result, although I don't see why a negative result should be too much feared, if it produces enough subsidiary information from which to derive better guesses about the plausible limits of a successful arrangement.
But the same day von Neumann heard from Ulam that “the thing gives me the impression of being miles away from going.” The Super design that Ulam and Everett were calculating was not only miles away from going. Their calculations also indicated that the one hundred grams of tritium that Teller had told Washington each Super would require — the basis for the Special Committee's March 9 recommendation of ten thermonuclear weapons per year using a total of one kilogram of tritium — would be (the GAC reported a few months later) “quite inadequate” and pointed to “a lower limit for this model in the range of 3 to 5 kilograms.” If the AEC succeeded in producing one kilogram of tritium per year, one Super would need at least three to five years’ production and would consume neutrons sufficient to make plutonium for about one hundred atomic bombs. No wonder Teller was pale with fury.
Searching for the Unknown Subject — Unsub, “Raymond,” Klaus Fuchs's American cut-out — FBI agents interviewed Kristel and Robert Heineman in Cambridge, Massachusetts, in mid-February 1950. Kristel did not remember the name of the man who had visited her home in 1944 and 1945, but she supplied a general description and two significant clues: that he had identified himself as a chemist and had mentioned having a wife and twin children about the age of her own. She or her husband supplied several other details of great significance: that the man had spoken of a partner or colleague whose partners had cheated him in business; that the colleague's firm was known as the Chemurgy Design Corporation; that the colleague had been working on developing an aerosol container and a process for making the pesticide DDT; that Unsub was interested in starting a laboratory of his own. Fuchs had supplied another important point of identification in his confessions: that Raymond was interested in and had done some work on thermal diffusion.
Robert Lamphere and his partner Ernest Van Loon combed the FBI's files for chemists and engineers and came up with several hundred names. They showed photographs of these suspects to both Kristel and Robert Heineman and had them shown to Fuchs in London on March 13. Fuchs paused at a photograph of a heavyset Brooklyn-born civil engineer and said he “might be the man.” The Heinemans did not corroborate Fuchs's identification, but Lamphere and Van Loon thoroughly investigated the hapless engineer anyway.
At some point after the Heineman interviews, Van Loon identified the principal of the Chemurgy Design Corporation: Abe Brothman, whom Elizabeth Bentley had named as a source of espionage information in her 1945 confession to the FBI and 1947 grand jury testimony. “Brothman and Gold had been among the first people we'd looked at when I first uncovered Fuchs’ probable espionage,” Lamphere reveals, “back in September 1949.” Fuchs had not identified their photos, but Hoover now was raging for Un-sub's capture. The agents went fishing. Hoover evidently authorized a bag job on Abe Brothman's offices sometime in February or early March. The burglary netted what looked like a prize: a “typewritten document,” as an FBI summary describes it, “the title of which was obliterated, but the contents of which referred to the industrial application of a process of thermal diffusion. This document was considered of extreme significance… [It] did not bear the name of its author… ” Whoever wrote the thermal diffusion document was very likely Fuchs's cut-out.
