The First War of Physics by Jim Baggott Page B

hydrogen nucleus consists of a single proton. The heavier deuterium nucleus consists of one proton and one neutron.
    3 A beta particle is a fast-moving electron ejected directly from a neutron inside the nucleus during beta radioactive decay. During this process the neutron is transformed into a proton.

Chapter 2

    ELEMENT 94
    September 1939–September 1940
    M uch to Leo Szilard’s frustration, Einstein’s letter to Roosevelt was slow to have any kind of impact. The letter had been drafted in early August 1939 but as the days and weeks passed he heard nothing from Sachs. In the meantime, war in Europe had begun.
    When Szilard and Wigner visited Sachs towards the end of September, they discovered to their dismay that Sachs still had the letter in his possession. He had tried repeatedly to gain an audience with Roosevelt to discuss the matter, but had not so far managed to get past Roosevelt’s secretary.
    Sachs finally gained access to Roosevelt in the Oval Office on 11 October. He prepared the ground with a parable about Napoleon, and this prompted Roosevelt to ask for a carafe of Napoleon brandy and a couple of glasses. As Sachs sipped brandy with Roosevelt he tried to present a verbal summary of the content of Einstein’s letter. But Roosevelt appeared distracted and inattentive, and asked if Sachs could return the next day. Fearing he had blown his chance, he returned next morning with some trepidation. But this time Roosevelt was ready and willing to listen.
    Using his own 800-word précis of Einstein’s letter, Sachs chose to emphasise the peaceful uses of nuclear power, mentioning last of all the threat of ‘bombs of hitherto unenvisaged potency and scope’. He concludedwith the observation that we ‘can only hope that [man] will not use [subatomic energy] exclusively in blowing up his next door neighbour’.
    Roosevelt got the message. ‘Alex,’ he said, ‘what you are after is to see that the Nazis don’t blow us up.’ He called for immediate action, and responded to Einstein’s letter a week later.
    It was quickly agreed that the administration would establish an Advisory Committee on Uranium to be headed by Lyman J. Briggs, director of the US National Bureau of Standards. The committee consisted of nuclear physicists and ordnance experts from the US Army and Navy. To Szilard and his fellow Hungarian conspirators, it looked as though something was finally going to happen.
    The first meeting of the Advisory Committee took place on 21 October in Washington. Szilard and Wigner held a pre-meeting with Sachs at the Carlton Hotel to discuss tactics, before joining Teller and other members of the Advisory Committee at the Bureau of Standards offices in the Department of Commerce. Einstein had been invited to attend, but declined.
    Szilard explained the scientific background and the importance of putting the theory of nuclear chain reactions to the test in large-scale reactor experiments, which he proposed should be constructed from uranium oxide and graphite. These were experiments he had been trying, but failing, to set up with Fermi at Columbia University since July. The ordnance experts were openly sceptical of the physicists’ claims. The destructive potential of an atomic bomb was simply way beyond their reckoning. It takes two wars, Lieutenant Colonel Keith Adamson declared, before one can know if a new weapon is any good or not.
    The physicists themselves were relatively ill-prepared. When asked directly how much was needed from Treasury funds to start work on Szilard’s proposed experiments, they were at a loss for a reasoned answer. Teller leapt forward with a request. He asked for just $6,000. ‘My friends blamed me,’ he later said, ‘because the great enterprise of nuclear energy was to start with such a pittance: they haven’t forgiven me yet.’
    After the meeting, Szilard – who would shortly estimate that they needed at least $33,000 for the graphite alone – nearly murdered Teller for