The Los Alamos Primer was a printed version of the first five lectures on the principles of nuclear weapon

Nuclear weapon

A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...

s given to new arrivals at the top-secret Los Alamos laboratory

Los Alamos National Laboratory

Los Alamos National Laboratory is a United States Department of Energy national laboratory, managed and operated by Los Alamos National Security , located in Los Alamos, New Mexico...

 during the Manhattan Project

Manhattan Project

The Manhattan Project was a research and development program, led by the United States with participation from the United Kingdom and Canada, that produced the first atomic bomb during World War II. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the US Army...

. They were originally given by the physicist Robert Serber

Robert Serber

Robert Serber was an American physicist who participated in the Manhattan Project. He was born in Philadelphia, Pennsylvania; he was the eldest son of David Serber and Rose Frankel. He married Charlotte Leof in 1933. Rose Serber died in 1922; David married Charlotte's cousin Frances Leof in...

 after being delivered in person on April 5-14, 1943, based on conclusions reached at a conference held in July and September 1942 at the University of California, Berkeley

University of California, Berkeley

The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...

 by Robert Oppenheimer

Robert Oppenheimer

Julius Robert Oppenheimer was an American theoretical physicist and professor of physics at the University of California, Berkeley. Along with Enrico Fermi, he is often called the "father of the atomic bomb" for his role in the Manhattan Project, the World War II project that developed the first...

. The notes from the lecture which became the Primer were written by Edward Condon

Edward Condon

Edward Uhler Condon was a distinguished American nuclear physicist, a pioneer in quantum mechanics, and a participant in the development of radar and nuclear weapons during World War II.-Early life and career:...

.

The first paragraph states the intention of the Los Alamos laboratory during World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

:

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.

The Primer contained the basic physical principles of nuclear fission

Nuclear fission

In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts , often producing free neutrons and photons , and releasing a tremendous amount of energy...

, as they were known at the time, and their implications for nuclear weapon design

Nuclear weapon design

Nuclear weapon designs are physical, chemical, and engineering arrangements that cause the physics package of a nuclear weapon to detonate. There are three basic design types...

. It suggested a number of possible ways to assemble a critical mass

Critical mass

A critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction. The critical mass of a fissionable material depends upon its nuclear properties A critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction. The...

 of uranium-235

Uranium-235

- References :* .* DOE Fundamentals handbook: Nuclear Physics and Reactor theory , .* A piece of U-235 the size of a grain of rice can produce energy equal to that contained in three tons of coal or fourteen barrels of oil. -External links:* * * one of the earliest articles on U-235 for the...

 or plutonium

Plutonium

Plutonium is a transuranic radioactive chemical element with the chemical symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, forming a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation...

, the most simple being the shooting of a "cylindrical plug" into a sphere of "active material" with a "tamper"—dense material which would focus neutrons inward and keep the reacting mass together to increase its efficiency (this model, the Primer said, "avoids fancy shapes"). They also explored designs involving spheroid

Spheroid

A spheroid, or ellipsoid of revolution is a quadric surface obtained by rotating an ellipse about one of its principal axes; in other words, an ellipsoid with two equal semi-diameters....

s, a primitive form of "implosion" (suggested by Richard C. Tolman

Richard C. Tolman

Richard Chace Tolman was an American mathematical physicist and physical chemist who was an authority on statistical mechanics. He also made important contributions to theoretical cosmology in the years soon after Einstein's discovery of general relativity...

), and explored the speculative possibility of "autocatalytic methods" which would increase the efficiency of the bomb as it exploded.

The Primer became designated as the first official Los Alamos technical report (LA-1), and though its information about the physics of fission and weapon design was soon rendered obsolete, it is still considered a fundamental historical document in the history of nuclear weapons

History of nuclear weapons

The history of nuclear weapons chronicles the development of nuclear weapons. Nuclear weapons possess enormous destructive potential derived from nuclear fission or nuclear fusion reactions...

. Its contents would be of little use today to someone attempting to build a nuclear weapon, a fact acknowledged by its complete declassification in 1965. It used to be available for download from Los Alamos's website, but after the September 11 attacks, Los Alamos restricted access to all of their technical reports. It can still be found on internet mirrors, though.

In 1992, an edited version of the Primer with many annotations and explanations by Serber was published with an introduction by Richard Rhodes

Richard Rhodes

Richard Lee Rhodes is an American journalist, historian, and author of both fiction and non-fiction , including the Pulitzer Prize-winning The Making of the Atomic Bomb , and most recently, The Twilight of the Bombs...

.

External links

• The original Los Alamos Primer (LA-1) from a Federation of American Scientists
  Federation of American Scientists
  The Federation of American Scientists is a nonpartisan, 501 organization intent on using science and scientific analysis to attempt make the world more secure. FAS was founded in 1945 by scientists who worked on the Manhattan Project to develop the first atomic bombs...
  
  mirror
• A mirror of the FAS file at Wikimedia Commons
• Review of the 1992 version of the Primer