In 1944 he became a part of the British Mission to the Manhattan Project in Los Alamos , New Mexico led by James Chadwick , where he made the first measurements on the energy released in fusion processes . During his time in Los Alamos , he took many Kodachrome slides which appear to constitute a unique coloured record of that research site . His pictures , which are now held by the Churchill Archives Centre , include photographs of Enrico Fermi , Edward Teller and the Trinity site in New Mexico after the first atomic bomb was detonated , showing the surface light brown sand turned to a green-blue glass
Trinity
Trinity (nuclear test)
Egon Bretscher