Hiroshima bomb: Women helped to make it without knowing it – 09/08/2023 – Science

It was 1943, the height of World War II, and Ruth Huddleston had just finished high school in her small town in Tennessee, in the United States.

She had gotten a job at a local hosiery factory, but noticed that most of her co-workers were applying to work at a large facility that was being built in a nearby town called Oak Ridge.

Several of her friends encouraged her to apply as well.

As she had no way to get there, she asked her father if he could take her. He himself decided that he would also take the opportunity to see if he could land one of the coveted jobs offered by this new major project of the US Department of State.

“We both got jobs,” Ruth would recall many decades later, now 93, during an interview in a special series called “Voices from the Manhattan Project” conducted by the Atomic Heritage Foundation.

Unbeknownst to Ruth and her father, they were working for Oak Ridge National Laboratory, a key part of the secret US plan to build an atomic bomb in the famous Manhattan Project, subject of the film Oppenheimer.

As a teenager, Ruth began working at one of the Oak Bridge factories called Y-12 as a “cubicle operator”.

“We used to call it that, but nowadays they call us the calutron girls”, said the veteran in the 2018 interview, the year in which the Oak Ridge National Laboratory turned 75.

What did the ‘calutron girls’ do?

Ruth was part of a group of about 10,000 young people who, without knowing it, were involved in a task that would be fundamental to the development of Little Boy — the atomic bomb that would be dropped two years later on the Japanese city of Hiroshima.

These women operated the control panels for the calutrons, machines used to separate uranium isotopes so that it could be enriched and used as nuclear fuel.

And, although they didn’t know it, the Y-12 was actually a plant created to separate electromagnetic isotopes on an industrial scale, separating the lighter uranium 235 from the heavier and more common uranium 238, to enrich it.

Although the more than 1,500 calutrons — mass spectrometers adapted by American nuclear chemist Ernest Lawrence to enrich uranium as part of the Manhattan Project — performed an extremely sophisticated task, operating them was not very complex: you had to monitor the gauges and know when to adjust. the buttons.

Given the shortage of skilled labor due to the war, the project promoters decided to recruit young women from the surrounding area.

Through a series of tests, they found that these girls did an even better job than many scientists handling the calutrons, as the experts tended to get distracted by the machines or try to experiment with them.

Ruth remembers the first time she came across these strange giant devices.

“After they gave us the go-ahead to start work, they took us into a room full of what we called cubicles, which were big metal devices with all kinds of gauges, which they taught us how to operate,” recalled Ruth.

“They explained to us that if the caliber was too far to the right, we had to adjust it with the dial to re-center it, and if it was too far to the left, same thing. the supervisor.”

The workers’ central task was to keep the temperature in the tank stable. If it got too hot, they cooled it down (with liquid nitrogen).

“We spent the day sitting on stools in front of the cubicles, barely getting up to go to the bathroom,” recalls Ruth of this task.

“You were afraid to go out because the machine might ‘break’, as we said,” she says.

State secret

What Ruth remembered most about that time was the secrecy surrounding all operations.

“Before starting work, they trained us for several weeks and the first thing they told us was that we couldn’t talk about anything that was going on or what we were doing there,” she said.

“They took it very seriously. We were told there would be consequences, including fines, if we were caught doing something, and we would automatically be fired,” she recalled.

Ruth said that, strictly speaking, if someone asked her what she did, she “wouldn’t say what she did because the truth is, I really didn’t know.”

Like Ruth, most women engaged in uranium enrichment never knew what they were doing.

“I wondered why we never asked each other what we were doing,” she admitted in her old age. “Why didn’t we talk about it? But the truth is, I don’t remember thinking about it at the time.”

According to the Manhattan Project National Park, some of the “calutron gals” were more curious.

“Several of these women recall instances of co-workers disappearing from their posts unexpectedly, often because they were too curious about their work,” the agency noted.

Ruth only remembers that “the only thing they told us was that we were helping to win the war, but we had no idea how we were helping”.

Hiroshima

On August 6, 1945, when the US dropped an atomic bomb on Japan, they were told what they had been working on for two years. Ruth remembered what she felt that day.

“I was at work when it was announced. At first, we were happy to think the war was over. The first thing I thought was, ‘My boyfriend will be able to come home,'” she said of her partner, who, like so many others, young Americans, was sent to war.

“But then they started talking about all those people who died there. And I started thinking about something else, that I had a part in this,” she said.

“I didn’t like the idea of ​​being a part of it,” he acknowledged.

“But you know, war is war and there’s nothing you can do about it but try to stop it,” he concluded of the conflict, which continued despite the fact that the Nazis had already surrendered in May of that year.

“I still don’t like the idea. But you have to do it. [o trabalho]. Someone has to do it,” she said.

It is believed that between 50,000 and 100,000 people died the day Little Boy exploded, carrying a 64-kilogram cargo of uranium-235 produced at the Y-12 plant.

The explosion generated a heat wave of more than 4,000ºC in a radius of approximately 4.5 km.

About 50% of those who survived the explosion died from radiation.

Despite working near highly radioactive material, the “calutron girls” suffered no consequences (their radiation levels were measured every day).

Three days after Little Boy was dropped, the US government dropped a second atomic bomb, Fat Man, which—unlike the first—was made of plutonium.

Japan finally surrendered, and on September 2, 1945, World War II came to an end.