Oppenheimer worked closely with Nobel Prize -winning experimental physicist Ernest O. Lawrence and his cyclotron pioneers, helping them understand the data that their machines were producing at Berkeley's Radiation Laboratory, which eventually developed into today's Lawrence Berkeley National Laboratory. In 1936, Berkeley promoted him to full professor at an annual salary of $3,300 (equivalent to $72,000 in 2023). In return, he was asked to curtail his teaching at Caltech, so a compromise was reached whereby Berkeley released him for six weeks each year, enough to teach one term at Caltech.