Lawrence lunching with future president Eisenhower and past president Hoover at Bohemian Grove, July 23, 1950.

Like the country as a whole, the Rad Lab demobilized rapidly and enthusiastically after 1945. Between 1946 and 1949 less than thirty percent of its contracted services related directly to military problems. The residual work centered in the Crocker Laboratory. There a group under Joseph Hamilton that had participated in the Bikini tests of 1946 advised the Navy on the decontamination of ships exposed to nuclear explosions. The tests also interested the Army Chemical Corps, which chose Hamilton as chairman of its Advisory Committee on Radioactive Warfare. The Crocker Laboratory studied the biological effects of radioactive aerosols and of fission products. The rest of the Laboratory's defense work in the early postwar years concerned the separation of fissionable elements. Thus was fulfilled its contractual obligation to assist the AEC on "problems for which the laboratory personnel or facilities are particularly well adapted."

Lawrence did not demobilize as fully as his laboratory. He continued to push the calutron process, the efficiency of which he promised to increase tenfold. He stayed more bullish than the AEC, which stopped calutron development in 1948. That was a mistake, Lawrence said, making an argument since become familiar: only ongoing improvement could guarantee "national leadership in this field." He also disagreed with the AEC's policy of exclusive custody of nuclear weapons, and with its General Advisory Committee's (GAC) depreciation of radiological warfare. Against the one he held that nuclear weapons should be domesticated by the military for strategic bombing; against the other, and with the Department of Defense, he proposed expansion of the sort of work that Hamilton was doing for the Navy. The old boosterism backed Hyman Rickover's plan for a nuclear power plant for submarines. "To be credible, the project would have to be big," he is reported to have told the Admiral, suggesting a three-year, hundred-million dollar, cash-and-crash program.

This zeal did not match the mood of the country or Truman's policy to seek international control of nuclear weapons through the Baruch plan. Lawrence declined to join Baruch's advisory panel. And the AEC turned down the proposal of its GAC that Lawrence direct a project on reactors that would speed up development of nuclear propulsion systems. The Commission decided that a crash program of the Lawrence type was not necessary and instead set up a Reactor Development Group under Walter Zinn at the Argonne National Laboratory.

Then came the first Soviet nuclear bomb, detonated on August 29, 1949, to the astonishment of Western politicians and the vindication of their scientific advisors. It strengthened Lawrence's conviction that Stalin sought world domination. What could the Laboratory do to help the nation meet the latest Soviet threat? Lawrence, Alvarez, and others decided to put the Laboratory behind Edward Teller's program for a thermonuclear weapon, or superbomb, which had withered in the shadow of fission development and international control. Consultation with Teller at Los Alamos convinced Lawrence that he could advance the program significantly by finding the neutrons to make the tritium necessary for the new weapon. He thought first to construct a heavy-water reactor like the Canadian plant at Chalk River and went to Washington to advocate his reactor and Teller's bomb. AEC commissioner Lewis Strauss liked the plan, as did members of the Armed Forces Special Weapons Project and the Joint Committee on Atomic Energy (JCAE). "A very great change has taken place in the climate of opinion," wrote GAC chairman Oppenheimer; "two experienced promoters have been at work, i.e., Ernest Lawrence and Edward Teller." GAC member I. I. Rabi of Columbia applauded the return of the champions. "It is certainly good to see the first team back in. You fellows have been playing with your cyclotrons and nuclei for four years and it is certainly time you got back to work!"

Confident that the project would be approved, Lawrence appointed Alvarez to direct it. While plans went forward to construct the reactor north of Berkeley at Benicia, Lawrence enlisted more congressional and AEC support and cleared the project with the University's regents. Late in October, however, Teller discovered that members of the GAC did not share his and Lawrence's sense of urgency. They even opposed a crash program for the superbomb. Lawrence sent Robert Serber, Oppenheimer's long-time friend and collaborator, to Princeton to persuade the GAC's chairman of the virtues of thermonuclear weapons. Alvarez planned to appear before the GAC itself to discuss the heavy-water reactor. To the great and pained surprise of Berkeley's lobbyists, the GAC voted to advise the AEC not to "pursue with high priority the development of a super bomb." Further, it extinguished Lawrence's reactor on the bay and recommended a more modest program under Zinn.

Although the GAC's technical and moral objections convinced three of the five members of the Commission, they did not move Strauss. He recommended to Truman that he order the AEC to place "the highest priority [on the development of the Super] subject to the judgment of the Department of Defense as to its value as a weapon." Gordon Dean, the fifth commissioner, Senator Brian McMahon of the JCAE, and representatives of the Department of Defense and the National Security Council campaigned for the big bomb. On January 31, 1950, three months after the GAC had rendered its decision and two weeks after Klaus Fuchs had revealed his treason, Truman followed the counsel of his secretaries of state and defense and announced that the program would proceed.

The vacuum vessel for Mark I went up before its enclosure, 1952.

While the debate flourished, Lawrence considered how to make grams of neutrons without a reactor. He believed that the nation would have to draw on a reservoir to synthesize tritium for the Super and substitutes for diminishing stocks of fissionable material. Lawrence's alternative neutron fountain was of course an accelerator, a huge linac that could make, say, plutonium by causing neutrons to irradiate tailings of depleted uranium-238 from Oak Ridge. To release the neutrons, an intense beam of deuterons with energy of several hundred MeV would be required. Lawrence proposed a prototype 25 MeV, high-intensity, linear accelerator to the AEC on New Year's day, 1950. Four days later he asked that, once the prototype worked, a machine delivering 350 MeV deuterons be built to make a gram of neutrons a day. It would have a beam intensity of about one ampere, a million times that of the synchrocyclotron. It would cost, he said, between $100 and $150 million.

The plan offered much. The Commission was worrying about procuring enough uranium to fuel its reactors and fill its bombs. A machine that could make plutonium from useless and practically inexhaustible uranium tailings without consuming fissionable material, and without presenting safety hazards that would require sequestering in a remote company town like Hanford, would be a most welcome way to crack what Lawrence called the "bottleneck of this raw material problem." To this weighty, practical rationale, he added a characteristic consideration: the new plant might prove even more important for uses unknown and necessarily unspecifiable than for the purposes for which it would be built. "Several men have stated it roughly as follows [Lawrence wrote the AEC]: 'I can't see how the AEC can afford to do without a high-performance accelerator. There are so many important things which can't be done with a pile, but need some sort of accelerator. One never knows when a new process of military importance will demand the existence of an accelerator. In fact, the mere existence of such a machine may easily influence the thinking of scientific and technical men along lines which they would otherwise dismiss at the outset as absurd.'"

Livermore Naval Air Station at about the time it became the site for Mark I.

The AEC approved construction of the prototype accelerator, Mark I, after Truman's decision to pursue the Super in January 1950, and design of the production machine, Mark II, after the Korean war started that summer. Mark I was designed to produce polonium for use in the weapons program and in radiological warfare. Mark II's target arrangement would permit manufacture of tritium and plutonium as well. Then there was Mark III, a high-intensity strong focusing cyclotron, which Lawrence began to urge in 1951. The vast undertaking received a new laboratory and a new administrative arrangement. The Livermore Auxiliary Naval Air Station about 45 miles from Berkeley became the site of Mark I, code named "Materials Testing Accelerator" or MTA. The California Research and Development Corporation (CR&D), a subsidiary of Standard Oil of California, assumed overall responsibility when the University declined to do so.

In contrast to the cyclotrons on which the Laboratory had chiefly built its reputation, the MTAs were intended to give extremely intense beams. New techniques for injection and focusing had to be devised, very high vacuum attained, spurious discharges suppressed, and a thousand other technical obstacles overcome. The staff was confident that it could solve them all. An engineering study completed in August 1950 concluded that the thing might work. Lawrence declared that "the Mark II program should go full speed ahead," somehow estimated its chances of success at ten to one, and urged that ten similar 1500 foot machines be built across the country. But the AEC, recalled to prudence by its GAC, postponed construction of Mark II until Mark I had proved itself.

The completed oscillator for Mark I.

While the AEC debated Mark II, the Laboratory was finishing a preliminary study for Mark III, a 350 MeV, high-intensity cyclotron. In November Lawrence asked that it be constructed immediately. His former colleague Pitzer, director of the AEC's Division of Research, warned that although the Commission attached "the greatest importance to the prompt development of an efficient neutron production accelerator," it had no interest in "small production. . . by 'quick and dirty' or inefficient methods." Among causes for doubt was the problem of extracting a beam from a cyclotron, which had not yet been solved satisfactorily for conventional machines. Mark III called for the simultaneous emergence of three beams directed at three different targets.

In March 1951 the AEC deemed Mark I sufficiently promising to justify siting studies for Mark II. And that was enough to return Lawrence to lobbying for Mark III. In testimony before the JCAE early in April, he pointed out the comforts of a family of high-intensity accelerators. "If these processes work... they can be used in peacetime for the production of fissionable material, but when war comes, they could overnight be producing radioactive materials. . . on a scale so that we could do all our fighting with radioactive materials and not use atomic bombs. That would be a great thing." The JCAE admired the argument. It put pressure on the AEC, which authorized another feasibility study, which found favorably for Mark III. The Laboratory proposed a 300 MeV model, to be called the J-16.

Even Lawrence's associates at California Research and Development doubted the wisdom of proceeding simultaneously with three untried machines. Research on targets for Mark II had fallen three months behind schedule, and CR&D feared more delays should the J-16 be authorized. In any case neither design had matured to the point that the Laboratory was willing to set the principal engineering parameters. During the war the MED had ordered a freeze on calutron designs. No one in the AEC wished to do as much for Mark II. Instead, the agency deferred its construction pending a thorough review of its economic potential.

One of the chief justifications of MTA was need for fissionable material should foreign sources of uranium fail. By the summer of 1952 the argument no longer weighed. The AEC had found another and cheaper way. By offering bonuses for new domestic sources of uranium and by increasing the price of ore, the Commission stimulated prospecting that uncovered rich deposits on the Colorado plateau. It appeared that the country did not require an emergency operation to make plutonium from scrap uranium. Attempts to convince the AEC to favor accelerator production of uranium-233, whose relatively small critical mass fit it for use in gun-type bombs and tactical warheads, did not avail. Nor did calculations to demonstrate that the fissionable materials yielded by MTA would release more energy than consumed in producing them. On August 7 the AEC terminated Mark II and reduced Mark I to a small program in its Division of Research.

Meanwhile two major changes had come over the Livermore site. First, Mark I showed that it could hold a high vacuum and a large potential gradient and enabled its builders to judge it a success. Second, in June 1952 the AEC had established at Livermore the locus for what Teller called "healthy competition" for Los Alamos. The Livermore Weapons Laboratory became a branch of the University of California Radiation Laboratory under the direction of Herbert York. The administrative arrangement lasted until 1971. Until then Livermore took most of the Laboratory's work in applied science, including weapons development and projects Pluto (nuclear rockets), Plowshare (peaceful applications of nuclear explosives), and Sherwood (controlled thermonuclear reactions). The division of labor not only encouraged the Berkeley branch to reconcentrate on basic nuclear science, it also reduced and eventually eliminated classified research there. The Livermore branch was a consequential legacy of MTA. Or, as Lawrence put it from the reverse perspective, "the MTA project made it possible for us to save at least a year or perhaps two years on the development of the Livermore Weapons Laboratory.

The parent Laboratory gained $375,000 severance pay to increase the magnetic field of the 184-inch cyclotron to 23,000 gauss, which made possible acceleration of protons to 750 MeV. The rationale was that the AEC desired to know the neutron yield at such an energy. Perhaps most important, experience gained in MTA and a few pieces of its furniture assisted the completion of the long-awaited Bevatron at an energy almost double that planned before the Mark brothers came on the scene.