NEW FRONTIERS IN THE ATOM — LAWRENCE 173 



Another interesting product of these atomic bombardments was the neutron, 

 a particle often found in the atomic nucleus. It adds to the weight of the 

 nucleus but has no electrical charge, hence its name. When atoms were smashed 

 by the bullets from the cyclotron, they flew into two parts. One might be an 

 atom of a new radioactive element, and another an atom of a light element such 

 as hydrogen or helium. But more often than either of these two, a neutron 

 would appear. When the cyclotron was going full blast, 10 billion of these 

 particles could be liberated every second. 



It was found that radioactive elements, such as sodium and phosphorus, had 

 certain advantages over radium which might make them extremely valuable 

 for treatment of human disease. Preliminary experiments indicated that 

 radioactive phosphorus might solve the problem of leukemia, the wasting blood 

 disease for which no cure has yet been found. Radioactive sodium, iodine, 

 phosphorus, and many other of the newly created elements proved to be price- 

 less instruments in the hands of scientists interested in finding out more about 

 our fundamental body processes. Finally, streams of released neutrons gave 

 every indication of being a more powerful weapon against cancer than the 

 X-ray. These discoveries marked the end of the first cycle of the cyclotron's 

 career. So promising were the medical applications of its products that plans 

 were laid to build a new 225-ton cyclotron. This machine was finished and 

 housed in the William H. Crocker Radiation Laboratory on the University 

 campus during the spring of 1939. 



In its first performance the new atom smasher produced deuteron beams with 

 a strength of 17 million volts, and "alpha rays," or beams of helium atoms, 

 with an intensity of 34 million volts. These voltages were greater than any 

 obtained with the original machine even though the electric current used to 

 energize the particles within the cyclotron chamber was only 60 kilowatts. 

 Such results were entirely unexpected, far exceeding anything Dr. Lawrence 

 had hoped for on the first trial run. 



On April 8, 1940, The Kockefeller Foundation of New York City 

 announced its willingness, under certain conditions, to contribute 

 $1,500,000 toward construction of a 4,900-ton cyclotron at the Uni- 

 versity. It would be 56 feet long, 15 feet wide, and have an over-all 

 height of approximately 30 feet. About 12 feet of the vertical struc- 

 ture would be underground. It is estimated that 3,700 tons of steel 

 and 300 tons of copper windings would be used in the construction. 

 It is believed that such a machine could produce a deuteron beam 140 

 feet in length as compared with the 5 -foot beam produced by the 

 present 225-ton machine. This next cyclotron is now under con- 

 struction at the University of California (see pis. 8 and 9) and when 

 it is completed the problem of subatomic energy may be solved and a 

 new power may be released to run the wheels of industry. 



