The Legacy of Los Alamos

THE LEGACY OF LOS ALAMOS

A Conversation with General Tibbets

A number of years ago, I chaired an evening dinner featuring General Paul Tibbets as our speaker. A film crew from Hiroshima flew to Atlanta to capture the remarks of General Tibbets that evening. An Air Force Color Guard was on hand as the dinner meeting was called to order. It was a dramatic event.

Prior to his formal remarks that evening as we sat having dinner, the question arose as to whether dropping the atomic bomb on Hiroshima was really necessary. Without hesitation, the General remarked that “someone had to do it [drop the bomb].” It was the clear conviction of General Tibbets that dropping the atomic bomb on Hiroshima was necessary to bring the war to a conclusion.

While representatives of the Japanese government were pursuing initiatives to end the Second World War before the first atomic bomb was dropped, leaders of the Japanese military opposed an uncon- ditional surrender even after the second atomic bomb was detonated over Nagasaki. Having recently visited Albuquerque, and Los Alamos, visits to museums in these cities shed light on the story of scien- tific progress that culminated in exploding two nuclear devices over Japan in August of 1945.

Two Museums – Two Similar Perspectives

The National Museum of Nuclear Science and History in Albuquerque and the Bradbury Science Museum in Los Alamos answer a number of questions about the dawning of the nuclear age:

A. How close were the Germans to developing an atomic bomb?

B. Who were the actors in the drama as America raced to develop two atomic bombs?

C. How was it possible for the American nuclear project to succeed where the German project failed?

D. Was dropping the bombs on Hiroshima and Nagasaki necessary to end the war?

A. How Close Were the Germans to Developing an Atomic Bomb?

In 1938 Otto Hahn and Fritz Strassman bombarded Uranium Atomic No. 92 with neutrons expecting the uranium to capture a neutron and grow into something larger. They were shocked when the experiment produced Barium Atomic No. 56. It appeared that the atom had “split,” but this was thought to be impossible.

Lise Meitner, an Austrian-born physicist of Jewish ancestry was head of the physics depart- ment at the Kaiser Wilhelm Institute. With the German accession of Austria, Meitner was no longer safe in Germany and fled to Sweden in 1938. Discussing the Hahn/Strassman experiment with Otto Frisch, they gave the correct interpretation to the experiment. The Germans had discovered nuclear fission. The fission of each Uranium atom would release 200 million electron volts of energy in accordance with Einstein’s equation E=MC2.

While the German scientists were the first to split the atom, they appeared initially to lack a complete appreciation for the significance of their experiment.

Frisch took the conclusions reached by Meitner and himself to Neils Borh in Copenhagen, Denmark, and Borh found his way to the United States.

B. Who Were the Actors in the Drama as America Raced to Develop An Atomic Bomb?

In September of 1939, Neils Bohr and John Wheeler published their article: “The Mechanism of Nuclear Fission.” They hypothesized an isotope with a high mass number, an even number of protons and an odd number of neutrons would fission easily. U-238 with an even number of protons and neutrons would require fast, high energy neutrons. On the other hand, U-235 with 92 protons and 143 neutrons only required slow, low energy neutrons. Hence U-235 could more easily produce a chain reaction.

It was theorized one pound of U-235 would be needed. The problem was how to produce the isotope as U-238 is only .07% U-235.

It was further theorized Pu-239 would serve as an effective fissile material with 94 protons and 145 neutrons. However, there was no known man made process to produce it.

Albert Einstein dispatched a letter to President Roosevelt on August 2, 1939, relating that there was the potential to develop an atomic bomb. The President referred the pursuit of such a project to the Army Corps of Engineers with offices in Manhattan. Hence, it became known as the “Manhattan Project.” J. Robert Oppenheimer, an American-born physicist of German-Jewish descent was selected to head the team of scientists working on the project while Brigadier General Leslie Grove would be in overall command of the project.

Due to poor health, Oppenheimer had spent time recuperating in New Mexico in his youth and early adult life. A school owned by Detroit businessman Ashley Pond in what is today Los Alamos, New Mexico, was condemned by the United States government in the interests of national defense. In no time at all, Los Alamos – the town that never was – was born.

Los Alamos was shrouded in secrecy. Drivers’ names did not appear on the state issued driver’s licenses. Rather, the driver was identified by number. For purposes of the U.S. Post Office, Los Alamos did not exist. Mail was delivered to an address in Santa Fe and all mail was subject to being inspected and censored.

C. How Was it Possible for the American Nuclear Project to Succeed Where the German Project Failed?

While the Germans were first in splitting the atom, America was first in creating a nuclear chain reaction on December 2, 1942. The honor goes to Enrico Fermi who accomplished the feat at the University of Chicago employing the Chicago Pile (CP-1). The CP-1 employed 500 tons of graphite and 50 tons of Uranium and Uranium Oxide stacked in a matrix until the pile reached 48 layers. Elements had been machined into blocks the size of a loaf of bread. It took over one month to build the pile. Forty people witnessed the chain reaction.

America devoted enormous resources to producing two atomic bombs, one based on Uranium 235 and the other based Plutonium 239. The price tag was about Two Billion Dollars in 1945 dollars. While Germany was the first country to split the atom, America, aided with data made available by scientists in the Allied community, most notably Britain and European exiles, forged ahead in the race for the atomic bomb. Germany, on the other hand, experienced internal political struggles over which government arm should control atomic research. Further, Hitler’s vision was limited. He wanted a lightning war (Blitzkrieg) with quick victories. Germany was not prepared to expend the quantum of resources required to develop a nuclear bomb, especially when the Russians began their assault along the Eastern Front. Finally, the Allied air bombing campaign bombed German cities into ruins. After Hitler invaded Russia, Germany’s realistic prospects for developing an atomic bomb were very poor.

D. Was Dropping the Bomb on Hiroshima and Nagasaki Necessary to End the War?

Both the military and political calculus reinforced Truman’s order to drop nuclear weapons on Japan. From a cause and effect perspective, it appears the explosion of two atomic bombs over Japan motivated Emperor Hirohito to override the Japanese General Staff and insist on accepting America’s terms on an “unconditional surrender.”

Without doubt, the outcome of the war was a foregone conclusion. America had won. However, the Japanese High Command ignored this reality. How many more people both Japanese and American would have to die in a bloody invasion of the Japanese Home Islands to prove the point?

The harsh realities confronting Truman in 1945 confirm Tibbet’s assessment, “someone had to do it.”

In the years following Hiroshima and Nagasaki, Oppenheimer became increasingly concerned about the ominous implications of nuclear power. In time, a victim of the McCarthy Era, his security clearance was revoked.

Edward Teller, who worked on the Manhattan Project with Oppenheimer joined with Stanislaw Ulam in developing the Hydrogen Bomb which is a fusion weapon employing Hydrogen isotopes and generating extremely high temperatures.

Eight of the scientists who worked on the Manhattan Project were Nobel Prize winners and twelve more would go on to win the Nobel Peace Prize.