divest its wartime military obligations. Lawrence and Groves managed to persuade Sproul to accept a contract extension. In 1946, the Manhattan Project spent $7 on physics at the University of California for every dollar spent by the university. The 184-inch cyclotron was completed with wartime dollars from the Manhattan Project. It incorporated new ideas by Ed McMillan, and was completed as a synchrocyclotron. It commenced operation on November 13, 1946. For the first time since 1935, Lawrence actively participated in the experiments, working with Eugene Gardner in an unsuccessful attempt to create recently discovered pi mesons with the synchrotron. César Lattes then used the apparatus they had created to find negative pi mesons in 1948. Responsibility for the national laboratories passed to the newly created Atomic Energy Commission (AEC) on January 1, 1947. That year, Lawrence asked for $15 million for his projects, which included a new linear accelerator and a new gigaelectronvolt synchrotron which became known as the bevatron. The University of California's contract to run the Los Alamos laboratory was due to expire on July 1, 1948, and some board members wished to divest the university of the responsibility for running a site outside California. After some negotiation, the university agreed to extend the contract for what was now the Los Alamos National Laboratory for four more years and to appoint Norris Bradbury, who had replaced Oppenheimer as its director in October 1945, as a professor. Soon after, Lawrence received all the funds he had requested. Notwithstanding the fact that he voted for Franklin Roosevelt, Lawrence was a Republican, who had strongly disapproved of Oppenheimer's efforts before the war to unionize the Radiation Laboratory workers, which Lawrence considered "leftwandering activities". Lawrence considered political activity to be a waste of time better spent in scientific research, and preferred that it be kept out of the Radiation Laboratory. In the chilly Cold War climate of the post-war University of California, Lawrence accepted the House Un-American Activities Committee's actions as legitimate, and did not see them as indicative of a systemic problem involving academic freedom or human rights. He was protective of individuals in his laboratory, but even more protective of the reputation of the laboratory. He was forced to defend Radiation Laboratory staff members like Robert Serber who were investigated by the university's Personnel Security Board. In several cases, he issued character references in support of staff. However, Lawrence barred