 In 1934 , Cockcroft arranged for Oliphant become a fellow of St John 's College , Cambridge , which paid about £ 600 . When Chadwick left the Cavendish Laboratory for the University of Liverpool in 1935 , Oliphant and Ellis both replaced him as Rutherford 's Assistant Director for Research . The job came with a salary of £ 600 ( equivalent to AUD $ 49 @,@ 900 in 2010 ) . With the money from St John 's , this gave him a comfortable income . Oliphant soon fitted out a new accelerator laboratory with a 1 @.@ 23 MeV generator at a cost of £ 6 @,@ 000 ( equivalent to AUD $ 499 @,@ 000 in 2010 ) while he designed an even larger 2 MeV generator . He was the first to conceive of the proton synchrotron , a new type of cyclic particle accelerator . In 1937 , he was elected to the Royal Society . When he died he was its longest @-@ serving fellow . 
