Louis P. Slotin at Work

Louis P. Slotin

Louis P. Slotin received a lethal dose of radiation during an experiment to determine critical mass.  This experiment was commonly referred to as "Tickling the Tail of the Dragon"

The accident occurred on Tuesday, May 21, 1946.  He died 9 days later, on May 30, 1946.

On May 21, 1946, group leader Louis Slotin was demonstrating the criticality experiment to other senior scientists, including Raemer Schreiber and Ted Perlman, when a screwdriver being used to separate two beryllium hemispheres that surrounded a plutonium core slipped.  Immediately a blue flash surrounded the beryllium tamper.  At the same instant, Slotin flipped the outer top tamper shell off using the fingernails of his left hand.  This stopped the reaction.

Thomas Brock quotes from a June 1946 letter from Emily Morrison, Philip Morrison's wife, to a friend.  It reveals the "series of strange coincidences" involved in both mishaps: "Both Louis Slotin's and Harry Daghlian's accidents occurred on Tuesday the 21st; both used the same piece of plutonium material; and both died in the same room at the Los Alamos hospital."

After the 24-year-old Harry Daghlian's death, Nobel Laureate Enrico Fermi warned Slotin that he wouldn't last a year - "if you keep doing that experiment."

" Dr. Slotin's quick reaction at the immediate risk of his own life prevented a more serious development of the experiment which would certainly have resulted in the death of the seven men working with him, as well as serious injury to others in the general vicinity."

The above diagram was drawn by Los Alamos scientists Louis Slotin and Alvin Graves soon after the accident to determine levels of radiation exposure.