Ernest Courant

Ernest Courant (March 26, 1920 – April 21, 2020) was a German-born American physicist. He was important for the creation of modern large-scale particle accelerator concepts. 
His most notable discovery was his 1952 work with Milton S. Livingston and Hartland Snyder on the Strong focusing principle, a critical step in the development of modern particle accelerators like the synchrotron. 
Courant was a member of the National Academy of Sciences. He worked at Brookhaven National Laboratory. 
He turned 100 in March 2020 and died the following month.