Richard Feynman called it “tickling the dragon’s tail.”
Enrico Fermi warned he’d be “dead within a year” if he didn’t stop doing it.
And yet, Winnipeg-born physicist Dr. Louis Slotin continued the dangerous experiments at Los Alamos that, in May 1946, would cost him his life.
Slotin was one of a handful of Canadian scientists recruited by the Manhattan Project — the secret U.S. effort to develop the atomic bomb — and one of only five Canucks to work in the rustic, heavily secure labs in the wilds of New Mexico.
Journalist and biographer Martin Zeilig, who helped produce a documentary on Slotin’s life, described the humble Winnipegger as an often-overlooked but nonetheless vital player in the project, helping to create our modern age.
“He was such a focused, dedicated scientist — if you’d put a task before him, he’d do his utmost to get it done,” Zeilig said. “Like a lot of guys, he was driven.”
Slotin was born in 1910 to refugees of the Russian pogroms, fleeing to Canada and making themselves a home at 125 Scotia St. in north Winnipeg.
Slotin was an exceptional student, enrolling at the University of Manitoba at 16, graduating with his Master of Science. He went on to get a PhD in physical chemistry from King’s College London in 1936.
Turned down for a National Research Council job in Ottawa, Slotin went south — earning a research position at the University of Chicago where he was introduced to the emerging field of nuclear physics.
It wouldn’t be long before he’d attract the attention of the Manhattan Project.
Nuclear weapons are complicated in detail but in broad terms quite simple devices.
Shortly after the atom was split in 1938, physicists quickly realized the potential of nuclear fission as a weapon.
Atoms of uranium will split when struck by neutrons — which in turn release more neutrons and energy.
Lots of energy.
If enough of these newly emerged neutrons strike other uranium atoms, a domino-like “chain reaction” will occur.
Controlled, this energy could be used to heat water to generate clean, inexpensive electricity.
Uncontrolled, this nuclear chain reaction could — in the blink of an eye — release enough energy to level a city.
That’s what the scientists in the Manhattan Project were trying to do, and before Nazi Germany did it first.
While initial research centred around uranium, there was interest in the weaponization of plutonium — an element two spaces to the right on the periodic table and discovered in 1934 by Enrico Fermi — who had moved his research to the University of Chicago while Slotin was employed there.
Slotin even assisted in Fermi’s development of Chicago Pile-1 — the world’s first man-made nuclear reactor — under the bleachers of a university sports field, Zeilig said.
That earned Slotin a position at the Manhattan Project.
Slotin’s first job was at the project’s labs in Oak Ridge, Tenn., where work was underway to enrich natural uranium — much coming from Canadian mines — in weapons-grade material suitable for use in atomic detonation.
“From Oak Ridge, he was recruited to Los Alamos, which he described as a ‘disorganized mess’ when he first got there,” Zeilig said.
The super-secret “atomic city” in the rugged, isolated hills of New Mexico was home to thousands of people during the Second World War, including some of the greatest scientific minds in the western world — six of whom were Nobel Prize winners.
Slotin’s work in 1944 centred around the dangerous task of determining “criticality” — the stage at which nuclear reactions begin in spheres of uranium and plutonium.
When that chain reaction starts to “run away,” that critical mass has turned “supercritical” — a bomb is born.
An atomic bomb is merely a mechanism to maintain a supercritical mass until it blows itself to pieces.
Los Alamos came up with two ways to do this: slam two subcritical masses into each other (the 15-kiloton “Little Boy” detonated over Hiroshima in August 1945) or crushing a subcritical sphere into a supercritical mass.
Developed by fellow Canadian Los Alamos scientist Robert Christy, it’s deceivingly simple: a grapefruit-sized “pit” of uranium or plutonium is “imploded” by a surrounding layer of high explosive.
“Implosion” would be successfully demonstrated in the July 1945 ‘Trinity’ test, and a month later over Nagasaki (the 21-kiloton “Fat Man”) — and form the basis of every nuclear weapon produced ever since.
Canada’s contribution to the atomic age is often overlooked, Zeilig said.
“The Manhattan Project changed the world forever, and Canadians were a part of it — for better or for worse,” he remarked.
Much more than nuclear weapons came out of the Manhattan Project. Radiation therapy has saved the lives of countless cancer patients, harnessing the X-ray has led to brand-new insights into the human body, and nuclear power plants — aside from some conspicuous stumbles — continue to provide cheap and emissions-free electricity.
It was Slotin’s job to assemble the bombs’ “physics package” — expertise that kept him around Los Alamos after the end of the Second World War, while many of his contemporaries returned to academia.
“Louis developed an unrivalled reputation at assembling the critical firing mechanism for the atomic bomb,” Zelig said.
This expertise forced him to stay put — “I am one of the few people left here who are experienced bomb putter-togetherers,” Slotin once said.
But it wouldn’t be long before Slotin’s reputation for lab risk-taking would take his life.
“Fermi actually warned him during the Manhattan Project if he kept doing things the way he did, he would succumb,” Zelig said.
While performing one such experiment on May 21, 1946, the screwdriver he used to separate two hemispheres of neutron-reflecting beryllium surrounding a plutonium bomb core slipped.
Slotin and his assistants felt nothing as the core went supercritical, except for flashes of Cherenkov radiation from radioactive particles striking the water inside their eyeballs.
Slotin reflexively threw the beryllium to the floor to stop the reaction but, by then, he’d already absorbed a lethal dose of neutrons.
The plutonium sphere that took Slotin’s life, which came to be known as the “demon core,” had killed once before.
In September 1945, fellow Los Alamos physicist Harry Daghlian died when a similar experiment on the same core went wrong, sentencing him to an agonizing, 25-day death.
Slotin’s death likewise didn’t come quickly.
Flown to Los Alamos from Winnipeg, Slotin’s parents witnessed their son’s agonizing, 10-day death from injuries described as a “three-dimensional sunburn.”
As his internal organs fell apart, Slotin slipped into a coma and died on May 30.
His body was flown home and buried in Winnipeg’s Shaarey Zedek Cemetery.
A small park dedicated to his memory was established close to his family home, at the foot of Luxton Ave. on the banks of the Red River in north Winnipeg.