The Los Alamos Primer

The Laboratory’s first official technical report captures what was known about atomic weaponry in 1943.

By Whitney Spivey | July 19, 2023

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Robert Serber and J. Robert Oppenheimer Niels Bohr Library & Archives

“Are we saying there’s a chance that when we push that button, we destroy the world?”

In the movie Oppenheimer, that’s the question General Leslie Groves (played by Matt Damon) asks physicist J. Robert Oppenheimer (played by Cillian Murphy) in reference to the imminent test of the Gadget—the world’s first atomic device—in July 1945.

When Oppenheimer responds that “chances are near zero,” Groves snidely replies, “Zero would be nice.”

Moviegoers might be interested to know that a version of this conversation did, in fact, happen in real life. “Physicist Edward Teller said the atmosphere might catch on fire,” paraphrases John Lestone, a scientist at Los Alamos National Laboratory. “And physicist Hans Bethe went away and came back an hour later and said ‘rubbish.’ He knew there was no way the atmosphere would catch on fire.”

This anecdote and many others are captured in the The Los Alamos Primer: The First Lectures on How to Build an Atomic Bomb

The book documents a lecture series given by physicist Robert Serber in April 1943 to his fellow Manhattan Project scientists at the secret wartime laboratory in Los Alamos, New Mexico. Physicist Edward Condon transcribed the lectures and compiled the notes into the first official Los Alamos technical report, or LA-1, which was then distributed to incoming scientists. LA-1 was declassified in 1965. In 1992, the report was published as a book in which Serber (then 83 years old) annotated his lecture notes.

The purpose of Serber’s lecture series was to outline the goal of the project and the current understanding of nuclear physics. Serber didn’t waste any time getting to the point. Right off the bat, he told his audience of approximately 50 people that “the object of the project is to produce a practical military weapon in the form of a bomb in which the energy is released by a fast neutron chain reaction in one or more of the materials known to show nuclear fission.”

“Oppenheimer’s whole thing was free exchange of information,” explains Lestone, referencing the Laboratory’s first director who authorized the lecture series. “People are more inspired when they know what they’re working on.”

The Primer goes on to discuss fission, fast neutron chain reactions, neutron capture, and more than a dozen other topics.

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“When The Primer was published, I just began digging into it,” recalls Cameron Reed, author of A Physicist's Guide to the Los Alamos Primer.  “What struck me was the breadth of issues in its 24 pages—Serber touches on everything.”

Lestone agrees. “What did they miss? What’s the chapter they should have added? I can’t think of one. They knew it all in 1943.”

And not only did they know it all, but they were highly confident in their ability to turn theory into reality—to successfully build an atomic weapon despite being relatively unfamiliar with plutonium, which had been discovered less than three years earlier.

“At this point in 1943, they were talking about plutonium with certainty,” Lestone says. “But at the time of these lectures, there was maybe a microgram of plutonium in existence. But they knew that we were going to have gobs of it—that other people would bring them the plutonium, and their job was to do all the stuff in the book.”

Today, ‘all the stuff in the book’ is common knowledge—“mathematics and physics that are largely at an undergraduate level,” Reed explains. “It’s not as exotic in some ways as one might think.”

However, Reed, Lestone, and many of their contemporaries still find value in The Primer. “Read it word for word; it has so many gems in it,” Lestone says. “It’s cool to go back and look at it and remember what they were working out in 1943 and put that into context.” (Lestone drew on that context while working as an extra in the Oppenheimer film in 2022.)

“It’s a stunning document in the breadth of what it covers, the issues they anticipated, and the things they were getting right,” Reed concludes. “It’s a founding document of the nuclear age.” ★