Andrew H. Thomas - How to Make an Atomic Bomb

Andrew Thomas studied physics in the James Clerk Maxwell Building in Edinburgh University, and received his doctorate from Swansea University in 1992.

His Hidden In Plain Sight series of books are science bestsellers.

Hidden In Plain Sight
The simple link between relativity and quantum mechanics

Hidden In Plain Sight 2
The equation of the universe

Hidden In Plain Sight 3
The secret of time

Hidden In Plain Sight 4
The uncertain universe

Hidden In Plain Sight 5
Atom

Hidden In Plain Sight 6
Why three dimensions?

Hidden In Plain Sight 7
The fine-tuned universe

Copyright 2017 Andrew D.H. Thomas

All rights reserved.

The year is 1964.

Dave Dobson was a physics student, excited to have just received his PhD. Dobson was a bright guy, and a science enthusiast. He had a good general knowledge about several fields of physics, but his knowledge was nothing spectacular.

To all intents and purposes, Dobson was Mr. Average.

This made it all the more surprising when Dobson received a telephone call from the renowned nuclear physicist Edward Teller. Teller invited Dobson to come to Washington D.C. for an interview for a job in one of the country's leading nuclear research facilities. Dobson was amazed and, frankly, wondered if they had got his name mixed up with someone else. He later described everything he knew about nuclear chain reactions at that time: "I had seen an exhibit with a model of a chain reaction made up of mousetraps and ping pong balls."

Dobson met Teller and they spent an evening together. Teller quizzed Dobson to discover everything he knew about nuclear weapons, and Dobson honestly replied that he knew nothing more than any other amateur science enthusiast. To be frank, Dobson admitted he knew absolutely nothing at all about nuclear weapons.

"Great", replied Teller. "You will be perfect for the job".

At that time the early 1960s the Pentagon was extremely concerned about the possible proliferation of nuclear weapons to other countries. Only the United States, the Soviet Union, Britain, and France possessed nuclear weapons. Britain had been the third country, France had been the fourth. Which country would be the fifth country to possess nuclear weapons? Or the sixth country? Where would it all end? Which country would be the "Nth country"?

In order to shed some light on that question, the Pentagon had started a top secret project called the "Nth Country Experiment". Dave Dobson would be one of two physics students who had been selected to work on the project.

The worry was that so much information about how to make an atomic bomb had been published in the popular press. While no classified secrets had been leaked publically, there was plenty of more general information freely available to an amateur enthusiast. Given the availability of that general information, would it be possible for a rogue state, employing nothing more than a few physicists of very average ability, to create a nuclear weapon?

Basically, the goal of the Nth Country Experiment was to determine how difficult (or easy) it was for a bunch of amateurs to make an atomic bomb.

This, then, was to be Dave Dobson's first job straight out of university. Dobson was given a desk in a corner of a laboratory in the Livermore Radiation Laboratory in California. He was introduced to another amateur physics enthusiast, Bob Selden, a 28-year-old soldier who would be working with him. Neither man had any nuclear expertise whatsoever.

Their job was to imagine they were working for a rogue state (named the "Nth Country"). They were handed a document explaining their task. Here is the first paragraph of the document: "The purpose of the so-called Nth Country Experiment is to find out if a credible nuclear explosive can be designed, with a modest effort, by a few well-trained people without contact with classified information. The goal of the participants should be to design an explosive with a militarily significant yield. A working context for the experiment might be that the participants have been asked to design a nuclear explosive which, if built in small numbers, would give a small nation a significant effect on their foreign relations."

The first thing which needed to be done was to obtain security clearance for Dobson (Selden had already been cleared because of his military background). Clearance was necessary because it was against the law to design nuclear weapons without security clearance.

Dobson and Selden would have access to none of the secret research material at the laboratory, but they would have access to the general library and its publically-available material. They were told that the imaginary "Nth Country" they were working for would have "more resources than Ghana, but less than an industrialized nation." They should assume they had access to good machinists able to shape uranium and plutonium, and also access to some engineers experienced with conventional explosives. Apart from that, they were given no more instructions on how they should proceed. They were on their own.

In the library, Selden found a book about the Manhattan Project, the U.S. project which developed the atomic bomb. According to Dobson: "It gave us a road map. But we knew there would be important ideas they'd deliberately left out because they were secret. This was one of the things that produced a little bit of paranoia in us. Were we being led down the garden path?"

If Dobson and Selden wanted to perform an experiment, perhaps with high explosives, they had to describe their desired experiment in great detail. A team of experts then calculated the result of the experiment and passed the result back to Dobson and Selden.

Ironically, one of the most useful sources of information came from President Eisenhower's "Atoms for Peace" programme, the motivation for which was to encourage the use of non-military nuclear power around the world. Atoms for Peace was just one example of the enthusiasm at the time for nuclear energy, the result of which was to distribute a vast amount of technical information into the public domain.

After two-and-a-half years, in 1966, Dobson and Selden had finally finished their design. According to Selden: "We produced a short document that described precisely, in engineering terms, what we proposed to build and what materials were involved. The whole works, in great detail, so that this thing could have been made by Joe's Machine Shop downtown."

However, after they had presented their document, everything went very quiet, and Dobson and Selden were not informed of the outcome. They presumed that they had failed in their task. So, one day in Livermore when they met a senior researcher, Jim Frank, they asked him why things had gone so quiet. Did he have any knowledge of the outcome of their experiment? Yes, said Frank, he knew what had happened. The reason why everyone had gone quiet was because they had realised that if a bomb had been constructed precisely according to their detailed instructions, it would have exploded with the same order of magnitude as Hiroshima.