The First War of Physics (46 page)

‘We didn’t know beans about the military situation in Japan’, Oppenheimer later admitted. ‘We didn’t know whether they could be caused to surrender by other means or whether the invasion [of Japan] was really inevitable. But in the backs of our minds was the notion that the invasion was inevitable because we had been told that.’

With use of the bomb perceived as a
necessity
to end the war, the argument about saving American lives prevailed. The scientific panel issued a short report to the Interim Committee on the immediate use of nuclear weapons. The report acknowledged the lack of unanimity among Manhattan Project scientists, but concluded: ‘We can propose no technical demonstration likely to bring an end to the war; we see no acceptable alternative to direct military use.’ The report closed with some hand-washing worthy of Pilate:

With regard to these general aspects of the use of atomic energy, it is clear that we, as scientific men, have no proprietary rights. It is true that we are among the few citizens who have had occasion to give thoughtful consideration to these problems during the past few years. We have,
however, no claim to special competence in solving the political, social, and military problems which are presented by the advent of atomic power.

Harrison raised the Franck report at a further meeting of the Interim Committee, held on 21 June, to which the scientific panel was not invited. The report was discussed in the context of the scientific panel’s 16 June recommendations, and ‘The Committee reaffirmed the position taken at the 31 May and 1 June meetings that the weapon be used against Japan at the earliest opportunity, that it be used without warning, and that it be used on a dual target, namely, a military installation or war plant surrounded by or adjacent to homes or other buildings most susceptible to damage’. A request for Harold Urey to be made a member of the scientific panel to represent the views of the Met Lab scientists was refused.

Szilard was beaten, but he was not yet ready to quit. In early July he organised a petition to the President, urging that he exercise his power as Commander-in-Chief to rule that America should not resort to the use of atomic weapons. It was unlikely to change any decision that had by now been made, but that was not its primary purpose. Szilard wanted to ensure that those scientists who opposed the use of the bomb on moral grounds went ‘clearly and unmistakably’ on record. The petition gained 59 signatures from Met Lab scientists, and Szilard distributed copies to Oak Ridge and Los Alamos.

Teller took a copy to Oppenheimer and, over subsequent years, recorded various versions of Oppenheimer’s reaction. In an early version, Oppenheimer expressed the opinion that it was improper for a scientist to use his prestige as a platform for political pronouncements. Teller did not circulate the petition further. ‘I should like to have the advice of all of you whether you think it is a crime to continue to work’, he wrote to Szilard. ‘But I feel I should do the wrong thing if I tried to say how to tie the little toe of the ghost to the bottle from which we just helped it to escape.’ Teller’s mind was in any case preoccupied with springing a rather larger ghost from the bottle.

MLAD and CHARLES

Byrnes had bolted the front door, but the back door was open and leaking atomic secrets to the Soviet Union at a rapid rate.

Sax had decided to return to Harvard in early 1945, having failed his liberal arts courses the previous year. He had signed on for courses in physics, chemistry, astronomy and engineering. This left the NKGB without a courier for Hall. Gold was briefly discussed as a possible candidate, but he was already working with Fuchs (and, shortly, Greenglass), and it was considered inadvisable to give him this further responsibility. Kvasnikov had recently reactivated Lona Cohen, an attractive, Massachusetts-born 32-year-old Communist Party member who had been inducted into Soviet espionage by her husband, Morris. Yatskov now assigned her the role of courier for Hall.

Cohen made her way to New Mexico sometime in late April or early May 1945. She did not meet with Hall, but nevertheless returned with a package which she handed to Yatskov in a Manhattan coffee shop. Feklisov waited outside.
⁴
The contents of the package have not been identified, but there is circumstantial evidence to suggest that it contained a detailed description of the Fat Man bomb design.

Kvasnikov now faced something of a dilemma. If they were genuine, these espionage materials were of incredible importance. But he was not about to rush the information to Moscow until he could find a way of corroborating it. He sent a coded and enciphered cable to Moscow on 26 May but this did not contain much new information. He explained that: ‘The material has not been fully worked over. We shall let you know the contents of the rest later.’

That same day Yatskov met with Gold to brief him about his impending pre-arranged meeting with Fuchs in Santa Fe on 2 June. He also asked Gold to meet with Greenglass, whose wife Ruth had recently rented an apartment in Albuquerque, and gave him part of the cardboard top of a pack of processed dessert as a recognition signal. Gold baulked. This was not in the Soviet spy manual, and counter to his espionage training. But the mission was now of such importance that a deviation from strict protocol was deemed an acceptable risk. Yatskov lost his temper. ‘I have been guiding you idiots every step. You don’t realise how important this mission to Albuquerque is’, he exclaimed.

Fuchs, in the meantime, was also preparing for his rendezvous, sitting quietly in his room at Los Alamos, writing out detailed descriptions of both the uranium and plutonium bombs. The Little Boy design would have been quickly dealt with. The Fat Man design required a little more attention. Fuchs described the solid plutonium core, the polonium–beryllium initiator, the tamper, the bomb casing and the materials used to form the explosive lenses. He described calculations of the efficiency of the bomb, and wrote that it was expected to yield about 5,000 tons of TNT equivalent. He drew a schematic giving all the most important dimensions. He mentioned the intention to use the bomb against Japan.

Gold was at the agreed rendezvous point, the Castillo Street Bridge on Alameda Street, when Fuchs pulled up in his grey, second-hand Buick.
⁵
Fuchs drove them to a quiet cul-de-sac. They talked briefly. Fuchs had a few things to add to what was in the document he had written. Everyone at Los Alamos was working flat-out on preparations for the Trinity test, scheduled for 10 July. The efficiency of the bomb had been revised, to 10,000 tons of TNT.

Fuchs suggested another meeting in August, but Gold had already experienced difficulties getting time off work to make the current rendezvous, and thought an August meeting would be impossible. They fixed on 19 September, 6:00pm, at a different location. Fuchs passed over the envelope containing his handwritten report, Gold stepped out of the car and Fuchs drove away.

Gold spent the night in Albuquerque, and the next morning headed for the address that Yatskov had given him. At the door of an apartment at 209 North High Street, he told Greenglass: ‘Julius sent me’, and gave him the cardboard top. Greenglass fetched a matching part from the kitchen. The correct recognition signals had been given. They met again later that afternoon, and Greenglass gave Gold an envelope containing a list of potential espionage recruits at Los Alamos and a sketch of a high-explosive lens mould of the type used in the Fat Man design.

Gold passed the envelopes he had received from Fuchs and Greenglass to Yatskov in New York on 4 June. Kvasnikov had his corroboration. Fuchs’ report was even more detailed than the information he had received from Hall. He cabled a full report to Moscow on 13 June. Kurchatov was briefed on its contents a few weeks later, on 2 July.

Kvasnikov sent a further cable on 4 July, adding details that had been gleaned from a proper debriefing of Gold. The materials were now sufficiently important to warrant a summary for Beria himself. A letter to Beria, dated 10 July, cited two ‘reliable agent sources’, given the codenames MLAD and CHARLES, and summarised the information in Kvasnikov’s cables of 13 June and 4 July. ‘NKGB USSR received data that in the USA in July this year the first experimental explosion of the atomic bomb is scheduled. It is expected that the explosion will take place on the tenth of July.’ MLAD and CHARLES were the codenames for Hall and Fuchs.

Despite this evidence from spies at the heart of the Manhattan Project, there was no immediate effort to expand the scale of the Soviet bomb programme. Beria, it seems, remained highly sceptical of the intelligence materials, suspecting they were disinformation. Beria didn’t even trust his own scientists.

A small sun, shining in the desert

Bainbridge had constructed a small town out in the Alamogordo desert. His team had expanded from 25 to more than 250. At Point Zero a 110-foot tower had been constructed, at the top of which the bomb would be detonated. A concrete-reinforced command centre was situated 10,000 yards
south of Point Zero. A series of observation bunkers, a field laboratory and a Base Camp had also been constructed. An array of instruments had been assembled to measure the blast, ground shock, intensity of neutrons and gamma rays and the characteristics of the bomb radiation. Bainbridge had to beg Groves for $125,000 just to build roads. During construction they had to contend with scorpions, tarantulas and poisonous snakes, murderous heat and dust and occasional attacks by American aeroplanes which mistook Base Camp for one of their practice targets.

Oppenheimer had recruited his brother Frank to provide administrative support to Bainbridge and to help troubleshoot the test. Frank Oppenheimer had been working with Lawrence at the Rad Lab. He now left his wife and children in Berkeley and made his way to New Mexico. He arrived at the Trinity test site in late May, and observed the feverish activity taking place in the desert. One of his administrative tasks was to work out escape routes in case disaster struck, ‘making little maps so everybody could be evacuated’.

The plutonium for the test bomb had arrived at Los Alamos, also at the end of May. The efficacy of the solid core design was confirmed by Frisch’s group on 24 June. The core was somewhat less than a critical mass but would be squeezed to a density equivalent to twice the critical mass by the implosion. Just five kilos was needed, less in physical size than a small orange. It was warm to the touch.

The Trinity test had originally been scheduled for 4 July, but at the end of June the Cowpuncher committee felt it had no choice but to push the timing back to 4:00am on 16 July, at the earliest. Truman, hoping to have news of a successful test in his back pocket at the next meeting of Allied heads of state in Potsdam, had negotiated a delay to the start of the conference, to 15 July. To ensure that Truman had what he needed, Groves insisted that the scientists adhere to the target date of 16 July.

The problem lay in the high-explosive lenses. The moulds for the lenses that had been delivered to Kistiakowsky’s laboratory were found to be cracked and pitted. X-ray inspection of the explosives cast from the moulds revealed air cavities that would impair the lens performance and risk an unsymmetrical implosion. There were more faulty castings produced
than acceptable ones, and by 9 July it looked as though there wouldn’t be enough lenses. To make matters worse, Oppenheimer had insisted on a ‘dry run’ implosion test, which required a duplicate Fat Man structure without the plutonium core. Struggling to produce enough lenses even for one test, Kistiakowsky was now obliged to find enough for two.

Kistiakowsky laboured heroically through the night to fix some of the faulty castings using a dental drill and molten explosive. ‘You don’t worry about it’, he said. ‘I mean, if fifty pounds of explosives goes in your lap, you won’t know it.’

The dry run was carried out five days later, on 14 July, at an isolated canyon near Los Alamos. It was a failure. Oppenheimer called an emergency meeting. The last few weeks had visibly taken their toll on the Los Alamos scientific director; his nerves were frayed and he was close to despair. He now ripped into Kistiakowsky. The failure of the dry run surely meant the impending failure of the Trinity test and, Oppenheimer now argued, with emotions running high, Kistiakowsky was therefore personally responsible for the failure of the entire project. When Groves and Conant arrived in Albuquerque shortly afterwards, Kistiakowsky was carpeted for what seemed like an age.

The former Cossack couldn’t understand it. He questioned the results of the magnetic measurements used to assess the symmetry of the implosion, and was further accused of questioning the validity of Maxwell’s equations, the basis of the theory of electromagnetism which had been established since 1860. But he stood firm: he bet Oppenheimer a month’s salary to ten dollars that his part of the bomb would work. Oppenheimer accepted the bet. The mood over dinner that evening was gloomy, with Oppenheimer again seeking solace in snatches of the Bhagavad-Gita: ‘in the depths of shame, The good deeds a man has done before defend him.’

There was some relief the next morning. Bethe had worked through the night analysing the theory behind the dry run experiment. There was no doubting the validity of Maxwell’s equations but, he now reported, the results of the dry run magnetic measurements were meaningless. If the implosion had been perfectly symmetrical it would not have produced results different to those that had been observed. While he could not say
categorically that the dry run implosion had worked, he could at least say that it had not failed.

The gloom lifted, but there was still much to worry about. Analysis of a test explosion of 100 tons of TNT and spent reactor slugs from Hanford, a ‘calibration and rehearsal’ shot on 7 May, suggested that high winds in the wrong direction might carry radioactive fallout from the Trinity test over populated areas of New Mexico. It was hoped that by detonating Fat Man 110 feet above the ground this risk would be reduced. Teller had worried about rattlesnakes, and asked Serber what he was going to do. He would take a bottle of whisky, he said. Teller was also worrying once more about the risk of setting fire to the atmosphere: what did Serber think of that? ‘I’ll take another bottle of whisky’, Serber said. When Fermi offered to take bets on whether or not the atmosphere would be ignited, Groves was not impressed.