A sprawling group of buildings on an impressive campus site in the Berkeley hills provides the home of the Radiation Laboratory of the University of California. A succession of large accelerators has been built there, the latest of which is the Bevatron. It is the largest and highest-energy accelerator in operation at the present time. It was built and is operated under contract with the United States Atomic Energy Commission. It is of the type known as a proton synchrotron, of which there are two others in operation, one at the University of Birmingham, England, whose energy is 1 Bev (billion electron volts), and another at the Brookhaven National Laboratory, known as the Cosmotron, which operates at 3 Bev. The Bevatron accelerates protons (stripped nuclei of hydrogen atoms) to an energy of 6.2 Bev. The design was started in 1947 under the direction of Professor E. O. Lawrence, and although it was the product of collaboration of a large group of physicists and engineers, the original conception was due to William Brobeck who also contributed more than any other individual. A working quarter-scale model was built and operated in 1948 and 1949 to verify the correctness of the design concept. …

On April 1, a new energy peak of 6.1 Bev was attained with the Bevatron. Scattered particles monitored with a counter telescope in triple coincidence gave approximately 100 counts per beam pulse. April 2s the machine was down to air to allow work on beam monitoring equipment. Test operations resumed April 5. Though the total number of accelerated particles is still small, due to low energy beam losses, some cloud chamber tracks have been observed. Several plates have been exposed for Goldhaber. Stars with up to 29 prongs have been observed. The following consists of a discussion of the administration, operation and some of the experimental techniques evolved in the use of the Cosmotron.

Six subjects received a few millicuries Of tritium by inhalation of isotopically labeled hydrogen gas. The concentration of H{sup 3} in the urine of these individuals has been followed for a period of some 15 days. The rate of excretion of the tritium was found to be constant for a given subject but to vary considerably, among individuals. Data on five individuals arbitrarily normalized to coincide at zero time showed a range in biological half-life from about 9 days to nearly 13 days. These values are to be compared with the value calculated for the Chalk River ``Standard Man`` of 13.5 days, assuming the tritim to be confined to the body water.