> On August 21, 1945, less than a week after Japan notified the US that it would accept the terms of the Potsdam Declaration, physicist Harry Daghlian was perfo

> On August 21, 1945, less than a week after Japan notified the US that it would accept the terms of the Potsdam Declaration, physicist Harry Daghlian was performing an experiment when he accidentally dropped a piece of “tamper” material, used to reflect neutrons back into the core, and triggered a critical mass. Daghlian used his bare hands to pull the mass apart to stop the chain reaction, and absorbed a fatal dose of radiation. He died three weeks later.