martes, 13 de diciembre de 2011

The Manhattan Project-The Development of the Atomic Bomb

Nota: este articulo está en ingles escrito por mi. Si no lo entendéis, podéis ver el documental en español haciendo click en el link de Dailymotion que esta abajo del todo


Note:this article is the final paper for the asignature "US Culture, History, Economic Development and Curiosities",with the topic of The Manhattan Project.The main purpose is to explain in 4 pages with my own words the subject in a easy way , after the considerable reseach of the necessary information. I am aware of the tens of possible errors that i have made in the writing due to my limited english expression,but I hope the main idea is clearly understandable. For more information about the subject, please follow the links in the end of this article. J.F. 

“Now I am become Death, the destroyer of World” -verse 32 from Chapter 11 of the Bhagavad Gita, quoted by J. Robert Oppenheimer while watching the test of Trinity, after the initial euphoria and as reply to the test director, Kenneth Bainbridge, for his phrase: “Now we are all son of bitches”

The rise of power of Hitler in 1933 becomes a deadly menace to the Jew community in Europe, especially in Germany. A few percent could successfully escape for the Nazis and exiled to United States of America or another countries of Europe, and some of those Jews were brilliant scientists as Leó Szilárd, Edward Teller, or Albert Einstein, and could find refuge in the American universities.

In 1938, fatal news comes from Germany. Germany scientists discovered the fission. To split up the atoms, Uranium cores are radiated with neutrons which become them unstable. During the division, there was a miss of mass as kinetic energy. If those new neutrons could successfully split up other cores as a increasing cascade process, there is an explosive chain reaction. Doing that with two masses of Uranium with a high speed inside a bomb, the effects of the explosion would be exponential. The consequences of the discover inside the Nazi Germany would be lethal to the rest of the World, so Leó Szilárd, totally worried, tried to alert in a letter to the President of America, Franklin Delano Roosevelt, but in order to increase the warning, requested to Albert Einstein his own firm to get the necessary influence to be listened.

As a reply, Roosevelt created the Uranium Committee the day 11 of October of 1939, but didn’t give a high priority because meanwhile the Second World War had begun. Another exiled scientists, Enrico Fermi, helped Szilárd in Columbia the first obstacle to create the bomb, if in a Uranium reactor it’s possible to obtain a sustained chain reaction. Without the duplication of mass in the fission, it wouldn’t be able to build a bomb.

Both scientists, with different methods of work, convinced the American scientists, which their community worked internationally, to censored their own documents to not help, directly or indirectly, the German scientist in the race of the development of the bomb. In that time, the Germans were winning the race until the attack of the Japanese to the United States in Pearl Harbor. When the United States of America entered in the War, the almost-inactive-Project obtained the expected priority and was transferred to the Army. The Brigadier General Leslie L Groves, an expert engineer and administrator, were chose to direct the Manhattan Engineer District, with the headquarters in NYC, after the built of the Pentagon. He was very disappointed and convinced that the Project was a waste of time of money.

Meanwhile in Chicago, Szilárd and Fermi built the first primitive reactor in a squash court and the fission was controlled by a pile and with Graphite as Wall to stop the atoms and forced them to continue the chain reaction when they bounced. So it was possible to do the fission in a controlled way as in a reactor, or as in a powerful bomb.

The principal matter to obtain a good fission is the strange and short atom, U-235, and same happen with the atom U-238 in a ratio of 1:39. In 1942, the only way to split up them was the electro magnetic separation. The atom U-235 is smaller and faster than the atom U-238, so they could be separated in a Magnet and be captured one by one. However, the scientist of Columbia University preferred a new and competitive method, the gaseous diffusion. That method consist in a barrier of high pressure and low pressure that separate the light and heavy atoms, but , it was very hard to build a good barrier due to the dimensions of the atoms. Both methods were needed to be development in a massive scale with an expensive cost urgently but at least, there was a small hope that the Project could finish with success.

Groves, now convinced of the success, order the development in a remote place in the mountains of Los Alamos, New Mexico. In December of 1942, 54.000 acres of terrain were bought with the excuse to use them in demolitions. To direct the installation, Groves chose an unexpected candidate, J. Robert Oppenheimer, a great talent physic teacher.Oppenheimer had fame for have a complicate temperament, and some persons considered it wasn’t a good choice for a project with a high pressure and tension. He joined in the facilities some scientist as Enrico Fermin, Edward Teller or Hans Bethe, with engineers recent graduates of the universities. The stuff increased of 235 in 1942 to 2500 in 1945.

In October of 1942, the scientists tried to calculate how much U-235 were need to build a bomb, but with a high variation and margin of error in the solution. In December of the same year, Roosevelt approved 2000 millions of dollars to build the big industrial factories .The scientists researched a good barrier in the gaseous diffusion and decided to double the necessary quantity of U-235, but in the end the amount were 10 times the necessary, as a result of the lack of the correct samples of U-235 in the calculations.

The General Groves wanted to finish the bomb to use in the War, and order in a half year term, to built the big electromagnetic calutrons of Ernest Lawrence by the facilities of Oak Ridge,Tennesse. Those calutrons, built as a race track in a zone called Y-12 and with two big
Magnets, were used to separate the atom U-235 of the atom U-238. Due to the strictest lack of time, there weren’t built factories to test the laboratory implications. It was necessary 10 calutrons, each one in its own factory, to obtain 100 grams of U-235 per day. The first Magnets were very potent and the way to obtain more U-235 was to build more calutrons, in total 1152 and 55.000 inhabitants were recruited in Oak Ridge in restricted terms of silence.

Meanwhile, in Los Alamos, there was started the test bomb,with the coded name “The Gadget“. The design of the bomb was similar as a gun. Inside the bomb, a canyon shoot a piece of radiated fuel against another in 1km/s.The neutrons were required to joined fast before they could melt the fuel and stop the reaction. Groves and Oppenheimer directed the Project and paid attention to all the levels and groups, in an excellent cooperation, despite of their opposite personalities.

At the same time, the Plutonium, discovered in 1941, was a good alternative of the U-235 in a ratio of 2:1 in the fission and be produced in a higher scale. Plutonium was produced in the 3 Hanford reactors in Washington , ordered by the scientists of the University of Chicago and built in August of 1943 by 66.000 workers and in a region of half million of acres. Another facility was built in Oak Ridge in September of the same year,the K-25 Plant. The problem of the barrier in the gaseous diffusion couldn’t be resolved until one year later. In the end of the War, Oak Ridge were the biggest city of Tennessee and the industry production for the Project was similar than the automobile, a 10% of the total GDP of the United States.

The slow process to obtain U-235 to influent the process of the war and the problems of the Plutonium, whose impurities could provoke the fission and the explosion before than expected provoked a small crisis in all the terms. Oppenheimer re-organized the Project and orders the investigation of the bomb of Plutonium. The new configuration of the bomb were created with an outer layer of explosives and forcing isometric waves to the core, increasing the density and decreasing the distance of the atoms to facilitate the explosion. It was the first time doing this very complicated engineer problem and it was resolved between May and August of 1944.




In December of the same year, it was producing enough enriched U-235 of the K-25 factories and become more enriched with the calutrons,to obtain an atomic bomb in February of 1945,called Little Boy for its small size. But due to the military predictions to use more than one bomb to defeat the enemy, it was necessary that the Plutonium Bomb also worked. In March of 1945,the design of the Plutonium Bomb was aprobed,with the code name Fat Man, for the outer layer of explosives and the sphere form.

There was also another problem, it wasn’t possible to test Little Boy before using it, due to the lack to obtain again U-235; but that wasn’t a problem for the Plutonium Bomb so there was a test in July of 1945. With the purpose to display and transport the bombs , Colonel Paul Tibbets, a veteran combat pilot with lot of experience in B-29’s ,were chose to a new Unit, the mix group 509. This Unit was trained in Wendover Field, Utah, launching trial bombs Orange, of 2500 kilograms each one.

The day 12 of April of 1945, Franklin Delano Roosevelt died suddenly in Warm Springs, Georgia, so the vice president Harry S Truman become president and occupied the Oval Office. The Manhattan Project was developed in secret and Truman didn’t know it so it was necessary to inform him during his first weeks in the Presidential charge.

Almost one month later, the German Forces in Europe surrendered, but the Japanese remained, without any intention of surrender. In June of the same year. Tibbets and his Unit went to Tinian Island, in the Pacific Sea, situated in 2350 km of Tokyo. Inside Tinian there was built the biggest airport of the world, for the new air fortress B-29, with a large runway, and the facilities to put the bomb inside the planes. The Unit was also trained in real combat with the enemy to get used to be under enemy fire and flight alone.

In the morning of the day 16 of July of 1945,in the another part of the World, in the Jornada del Muerto desert in New Mexico, 300 km in the south of Los Alamos , it was tested the first atomic bomb. Code-named Trinity by Oppenheimer , as a reference of a poetry of an English writer of 17th Century, John Donne. The paradox of the poem was about a God that destroys to renovate. However, the bomb before the explosion didn’t seem to be imposing in the tower of 30 m of height. Parts of the bomb were covered with adhesive tape. 3 days were necessary to assemble the devices, produced as laboratory devices and non industrial devices. The workers got nervous to build some parts of the bomb and revising several times discovered lot of errors, as some unplaced wires.

A team of scientist was 35 km of distance of the atomic bomb and some of them worried if the bomb could reach the sky and destroy the World. Another thought the opposite, the bomb wouldn’t explode for a failure test in a lab some days before. Teller put sunscreen to protect his skin of the UV and alarmed everybody, despite the distance.

At 5.30 the bomb exploded provoking an intense flash, with a sudden fireball and a shock wave. The fireball occupied an extension of 12 km . The power of the bomb was similar of 20 tons of TNT. The bomb tower was vaporized and a region of 800 meters of desert becomes crystal. The scientists understood the real use of the bomb wouldn’t be experiments. Groves went to Washington with the results of the bomb to the Secretary of War, Henry Stimson, to initiate the preparations for use the bomb against Japan. Someone suggested using the bomb in Tokyo, but Groves didn’t look that possibility and looked to another place, meanwhile there was taken a pic of him looking to the map to use in the publicity . Probably he was looking Hiroshima in that moment.

Although Trinity was a successful, there were doubts with Fat Man. It wasn’t the same to detonate the bomb in a tower than to launch it out of a plane. And Little Boy wasn’t impossible to test, just to be revised and hope that all the calculations were valid and correct.




In June of 1945, 155 scientists of the Manhattan Project signed a petition to test the bomb in an uninhabited area before using it against Japan. Groves listened the petition, stopped it and asked in a probe the opinion of lot of scientists. However, an 83% were in accordance to test the bomb before using against civil and Groves blocked it until the end of the War in Oak Ridge .

By the other side, in the highest levels of the Government and the Army the idea to use the bomb without tests were accepted, to force the Japanese to surrender, before the Russians would invade them as the Postwar Settlement . There was the fear that Japan could be spitted up in two parts as in Korea, one communism and the another capitalist. And to use it before the planned invasion in November of the same year with an Allied Army of 1 million and half of soldiers to avoid large losses as in the Pacific War Theater.

During the Spring, the General Groves chose some possible Japanese cities to use the bomb. Once chosen, the cities didn’t become a target of the Allied Raids of bombing to preserve them intact before the use of the atomic bombs. On June, the President made his choice after a talk with his Secretary of State James Byrnes, about to use or not the bomb and the possible charges, implications, and public opinion in the case of not use it. Truman was a soldier in the First World War and wanted to stop it by any way. In the end he decided to use the bomb and give the choice to Japan to surrender and accept the American’s terms, if not there would be a high destruction over Japan.

At 2.45 am of the day 6 of August of 1945, Paul Tibbets thought off the Tinian Island with the Enola Gay. At 8.15 am, Enola Gay was flying in a height of 10km and the gates of the plane were opened to launch Little Boy to Hiroshima. 43 seconds later, the bomb exploded in a height of 600 meters over the city. The 90% of the city were razed for the winds of 800km per hour that provoked the explosion, calcined the skin of each person in a ratio of 3 km, and incinerate the persons under the explosion. 135.000 Japanese died as a consequence of the explosion or the radiation. That day Truman told to the whole World the success and referred Hiroshima as a military base.

3 days later, the another bomb, Fat Man, more powerful, exploded in Nagasaki with similar results. Another bombs were ready to use in the next months against another cities but due to the result of the atomic bombs, the Allied Raids of bombing and the Russian Invasion, Japan surrendered the day 14 of August of 1945.

The monopoly of the atomic bomb for the United States didn’t longer much. In 1949, The Soviet Union detonated one, and both potencies obtained the Hydrogen Bomb in the 50’s and another types of bombs in lot of nuclear arsenals. Some scientist aprobed as the Progress to build these bombs but Oppenheimer refused it and protest against the development of the Hydrogen Bomb of Teller. He was processed and his work finished but his contribution is still debated. All the deaths of the Wars of the last 200 years until 1945 were increasing exponentially and later maintained in 1 million per year until the end of the century.


Links:

http://en.wikipedia.org/wiki/Manhattan_Project
http://www.atomicarchive.com/History/mp/index.shtml
http://inventors.about.com/od/astartinventions/a/atomic_bomb.htm
http://europaenguerra1939-1945.blogspot.com/2008/10/el-exilio-de-los-talentos-alemanes.html (in Spanish)
http://www.youtube.com/watch?v=xwpgmEvlRpM
http://www.dailymotion.com/video/x11gta_el-proyecto-manhattan_shortfilms#rel-page-6 (in Spanish)
http://en.wikipedia.org/wiki/Trinity_(nuclear_test)
http://en.wikipedia.org/wiki/Bhagavad_Gita

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