Mankind entered the atomic age just before 5.30 a.m. on July 16, 1945 as dawn was breaking over the New Mexico desert. There, about 200 km south of Albuquerque, the first experimental atomic bomb was detonated by the United States Army. It produced a fireball brighter, it was said, than a thousand suns.

Robert Oppenheimer, Director of the Los Alamos laboratory where the bomb had been made, said, at the time: “There floated through my mind a line from the Bhagavad-gita: ‘I am become death, the shatterer of worlds.’”

This dramatic event took only a few seconds but it brought to a climax the intensive work of tens of thousands of scientists and engineers and other specialists who had been engaged in the Manhattan Project, the multidimensional research effort of the United States government to produce an atomic bomb.
 

Louis Slotin in New Mexico, in 1945, "armouring" the first atomic bomb, a procedure nicknamed "tickling the dragon's tail." Sloting at the time was on the edge of death's abyss. [Photo, courtesy Lost Alamos Laboratories, New Mexico]

One of the most critical, and arguably the most dangerous, aspects of this research project had been assigned to a young Canadian scientist, Louis Slotin. He had been responsible for the final assembly of the finished plutonium core of that first experimental bomb. This assembly procedure was so perilous that it was nicknamed “tickling the dragon’s tail.” Slotin and those working with him had been on the edge of death’s abyss. One slight slip and Slotin and his group would have suffered a slow and painful death from ionizing radiation. The core itself would have become unusable. Obviously, the slightest slip had been avoided.

This historic event in the desert occurred because Louis Slotin had completed, in his quiet unassuming way, a dangerous assignment with great care and precision despite disturbing interruptions.

Born on December 1, 1910, to Yiddish-speaking parents who had escaped the pogroms of Czarist Russia, Louis Slotin received his Bachelor of Science degree from the University of Manitoba in 1932, winning the gold medal in chemistry and physics. Following his Master of Science degree, also from Manitoba, the next year he pursued advanced research at King’s College, London, England, winning a prize in biophysics and receiving, in 1936, his Ph.D. in physical chemistry from the University of London.

Returning home to see his parents in Winnipeg, Slotin stopped in Chicago where he met Professor William D. Harkins, noted professor of nuclear chemistry at the University of Chicago. In 1942, Slotin was involved in the work of the Manhattan Project there. Later, after assisting in another aspect of the atomic bomb project at Oak Ridge, Tennessee, he went to New Mexico where Oppenheimer had set up a secret laboratory.

Above is a view of the laboratory room in New Mexico following the tragic accident of May 21, 1946 which took the life of Dr. Louis Slotin nine days later. With his left thumb wedged into the cavity of the top half of a beryllium-coated sphere of plutonium (seen in this photo on the floor of the lab), Slotin was experimentally moving this sphere closer to the stationary lower portion (viewed on platform table), one micro-inch at a time. The purpose of this procedure was to convert the encased plutonium to a critical state. In Slotin’s right hand had been a screwdriver to keep the two spheres from touching. When the screwdriver slipped, the two spheres touched and the plutonium went critical. Physically separating the two spheres, Slotin absorbed the lethal doses of gamma and neutron radiation by thrusting himself over the deadly exposure. At the time, it was as if he had confronted an exploding atomic bomb at a distance of 4800 feet. By this determined act, Slotin, who earlier had been the first to put together the core of “Trinity,” the first atomic bomb detonated by the U.S. Army on the New Mexico desert, July 16, 1945, heroically saved the lives of seven men working with him at the time of the accident in addition to those of the many other scientists in the immediate vicinity. [Photo, courtesy, Los Alamos National Laboratory/Neg. 3769]

There, at Los Alamos, Slotin became a member of the critical assemblies group who conducted experiments to establish the best methods for assembling the central core of atomic bombs and to ensure that their detonation mechanisms would function effectively. Since experiments could not involve actual detonations, it was essential that the team determine the precise detonation point without actually reaching it.

By the end of 1944, dozens of critical assembly experiments had been completed successfully. Slotin’s expertise in these experiments proved that he had the ability, the patience, and the courage to accept the responsibility of completing the critical assembly for the first experimental atomic bomb.

Slotin had hoped that he might be permitted to go with the first bombs to the island of Trinian from which the flights for the atomic bombing were to take off. But he was refused permission because he was not an American citizen. Instead, he took a short holiday during which a tragedy of ironic proportions occurred. Slotin’s close colleague, Harry Daghlian, had gone to the laboratory on August 21, 1945, planning to carry out alone the assembly he had watched Slotin complete so often, even though it was against regulations for Daghlian to do this. When something went wrong, Daghlian received a lethal dose of ionizing radiation. Upon receiving word of the accident, Slotin hurried back and was constantly at Daghlian’s side during the month in which radiation slowly killed him.

Although Slotin was looking forward to a peacetime position in the Institute of Biophysics and Radiobiology at the University of Chicago, he felt obliged to continue at Los Alamos until another scientist was trained to take his place.

While he was demonstrating the perilous techniques of the assembly to his successor, an accident occurred. Instantly a blue glow, stronger than the spring sunshine, filled the laboratory. There was a wave of unbearable heat. Some present experienced a dry, prickly sensation on their tongues – a sign of excessive radiation. Immediately Slotin threw himself forward, separating the two hemispheres with his bare hands. The chain reaction ended; the blue glow was gone; the unbearable heat subsided. It was 3:23 p.m. on Tuesday afternoon, May 21, 1946. And Louis Slotin had begun to die traumatically.

After some initial nausea it seemed as if he might survive. His left hand was terribly affected: it became swollen and red and began to blister. Gradually his other arm and the lower part of his body became red and tender.

Slotin’s parents were flown from Winnipeg to be with him. Though profoundly saddened, his mother and father had pleasant conversations with him. Soon, however, it became obvious that the periodic division of cells within Slotin’s body – a process going on all the time in healthy bodies — had ceased to occur. On the morning of the ninth day after the accident, Louis Slotin died quietly. His parents took his body back to Winnipeg and, while thousands shared their grief, buried their son, a Canadian hero. After he died, his colleagues wrote of Slotin’s selflessness, his modesty, and his sure and quiet competence: “He was undeterred by big undertakings and great responsibilities.... His death, like his life, was quiet.

D. McCormack Smyth