Donald A. Glaser
 

Glaser was born in Cleveland, Ohio, on September 21, 1926. After graduation from high school in Cleveland Heights, Glaser attended the Case Institute of Technology, where he earned a bachelor's degree in physics and mathematics in 1946. Three years later he was awarded a Ph.D. in the same subjects by the California Institute of Technology. His first teaching assignment was at the University of Michigan, where he later became professor of physics in 1957. In 1959 he assumed a similar position at the University of California at Berkeley. Glaser received the Nobel Prize in physics in 1960 for his invention of the bubble chamber. The idea for the invention occurred to him in 1949 while carrying out research on the new "strange particles" that had recently been discovered in cosmic ray interactions. The most common device then available for photographing these particles was the cloud chamber . A cloud chamber contains a vapor that has been cooled below its boiling point. When radiation passes through the chamber, it forms ions on which droplets of the vapor condense. The track formed by the droplets shows the path taken by the radiation. The problem for particle physicists was that the cloud chamber is not a very efficient detector for high energy particles like the "strange particles" Glaser was working on. He decided that a new type of detector was needed, one that contained a medium of higher density than the vapor in a cloud chamber. It occurred to Glaser that a superheated liquid might serve the purpose. A superheated liquid is one that has been heated to a temperature greater than its boiling point. The concept Glaser had in mind, therefore, was just the reverse of the cloud chamber: a device with a liquid ready to boil rather than a vapor ready to condense to a liquid. Glaser has described his experience studying bottles of beer, ginger ale, and soda water before settling on a model for the bubble chamber. His first device consisted of a glass container filled with diethyl ether heated to a temperature of 140 ° C (284° F) The normal boiling point of diethyl ether is 36 ° C (96.8° F). When high energy radiation passed through the container, it created ions in the ether. Each time an ion formed, the ether at that location immediately boiled. The overall result was a string of tiny bubbles that showed the path of the radiation through the chamber. Glaser next turned his attention to improvements in the bubble chamber. He varied the liquid used in the chamber and examined the effects of using containers of various shapes and sizes. Ultimately, the bubble chamber became one of the most powerful detection devices available to particle physicists.