uranium-235 content to between 13% and 15%, and shipped the first few hundred grams of this to Los Alamos laboratory in March 1944. Only 1 part in 5,825 of the uranium feed emerged as final product. The rest was splattered over equipment in the process. Strenuous recovery efforts helped raise production to 10% of the uranium-235 feed by January 1945. In February the Alpha racetracks began receiving slightly enriched (1.4%) feed from the new S-50 thermal diffusion plant. The next month it received enhanced (5%) feed from the K-25 gaseous diffusion plant. By April 1945 K-25 was producing uranium sufficiently enriched to feed directly into the Beta tracks. On July 16, 1945, Lawrence observed the Trinity nuclear test of the first atomic bomb with Chadwick and Charles A. Thomas. Few were more excited at its success than Lawrence. The question of how to use the now functional weapon on Japan became an issue for the scientists. While Oppenheimer favored no demonstration of the power of the new weapon to Japanese leaders, Lawrence felt strongly that a demonstration would be wise. When a uranium bomb was used without warning in the atomic bombing of Hiroshima, Lawrence felt great pride in his accomplishment. Lawrence hoped that the Manhattan Project would develop improved calutrons and construct Alpha III racetracks, but they were judged to be uneconomical. The Alpha tracks were closed down in September 1945. Although performing better than ever, they could not compete with K-25 and the new K-27, which commenced operation in January 1946. In December, the Y-12 plant was closed, thereby cutting the Tennessee Eastman payroll from 8,600 to 1,500 and saving $2 million a month. Staff numbers at the Radiation laboratory fell from 1,086 in May 1945 to 424 by the end of the year. Post-war career Big Science After the war, Lawrence campaigned extensively for government sponsorship of large scientific programs. He was a forceful advocate of Big Science with its requirements for big machines and big money, and in 1946 he asked the Manhattan Project for over $2 million for research at the Radiation Laboratory. Groves approved the money, but cut a number of programs, including Seaborg's proposal for a "hot" radiation laboratory in densely populated Berkeley, and John Lawrence's for production of medical isotopes, because this need could now be better met from nuclear reactors. One obstacle was the University of California, which was eager to