 George Volkoff , a friend of Christy who was a year ahead of him at UBC , was accepted as a graduate student at the University of California , Berkeley , by Robert Oppenheimer , who led the most active school of theoretical physics in the United States at that time . This inspired Christy to apply to the University of California as well . He was accepted , and was awarded a fellowship for his first year . At Berkeley he shared an apartment with Volkoff , Robert Cornog , Ken McKenzie and McKenzie 's wife Lynn McKenzie . For his thesis , Oppenheimer had him look at mesotrons , subatomic particles called muons today that then recently been found in cosmic rays . They were so @-@ called because they were larger than electrons but smaller than protons . With the help of Shuichi Kusaka he performed detailed calculations of the particle 's spin . He published two papers on mesotrons with Kusaka in the Physical Review , which formed the basis of his 1941 Doctor of Philosophy ( PhD ) thesis 
