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History and Development of the Atomic Bomb
The devlopment of the atom bomb converged from many fields of research.
The development of the atomic bomb has its roots in several converging technologies, including the understanding of the elements, isotopes and the nature of radioactivity. The atomic bomb would not be possible except with developments in metallurgy that allows for the extraction and purification of a specific element in a concentrated form. With most metals, this is done by heating a source in a blast furnace containing the metal and allowing the desired metal to separate out due to specific gravity. The slag is then removed and disposed of and the concentrated metal is cooled off in forms to produce raw ingots. With Uranium, the process is much different. Uranium, due to its radioactive nature, has to be processed from tailings using water. This means that the whole bulk of slag and traces of uranium therein has to be crushed to a very fine powder so that the uranium can be separated out by a mass spectrometer or centrifuge in a water base. To process uranium in the traditional metallurgical way would risk the chance of producing a critical mass of radioactive uranium and a radioactive meltdown. This was theory that was later confirmed in nuclear accidents like at Chalk River in 1952. There was an accident before this when the Oppenheimer team was experimenting with Plutonium in 1944 during the days of the Manhattan Project. This ended in radiation sickness and the death of a scientist. So it has to be processed in sub critical batches. Uranium 235 and uranium 238 both occur together naturally in ore containing traces of it. It is found in Northern Canada and Africa. Uranium 235 is the more unstable of the two, spontaneously emitting neutrons, which can trigger further reactions in other uranium atoms in a chain reaction. But Uranium 238 forms 97 percent of the two, so extracting Uranium 235 is much more difficult as they occur together. This is one line that had to be perfected.
Another line that needed development was explosive techniques in order to create the desired chain reaction that would produce a catastrophic explosion from a run away (critical mass) chain reaction. This took considerable experimentation. Initial ideas involved the concept of a gun firing one sub critical mass of uranium toward another sub critical mass of uranium. But the weight of the gun was prohibitive, especially for planes and rockets of the early days. Another idea was needed and this came from shaped explosives around sub critical lumps of uranium. The explosives in the Fat Man bomb were modeled on a classic geometric form of the dodecahedron. Little Boy was designed using the classic gun approach. But without exact timing in the implosion device of the Fat Man, the explosive train would be just random enough to just scatter the uranium without detonating it in a critical mass.
The understanding of electronics and how electricity behaves over distance in various metals is crucial in the development of the firing mechanism. The physicist J. J. Thomson was instrumental in determining that the electron could be separated from the atom in 1897. Einstein's seminal work in 1905 on the photo-electric effect lent support to the discovery and explained how it worked. Tesla's experiments around the turn into the 20th century also gave us tremendous understanding of the nature of electricity. In addition, he gave us remote control and wireless power transmission. The works of Edison and Westinghouse also contributed, largely from Tesla's help. Experiments done by Faraday and Maxwell also gave understanding into the relationship between electricity and magnetism. From these works the knowledge of the electrical properties of the various elements were derived. Assembling this information into a klystron switch that timed explosive impulses to nanosecond accuracy was accomplished using a combination of specifically measured wiring and a neutron reflective shell. This allowed the development of the implosion triggered A-bomb.
Another line in the development of the A-bomb is the discoveries of radioactivity, which of course, needed the advent of the radio. But before this, Madame Currie was experimenting with radon. Exposure to radiation eventually led to her death. Several scientists experimented with controlled reaction in graphite piles and in pools of heavy water. These lines of research led to the development of controlled nuclear reactors, some of which were designed to "breed" the desired ingredients of A-bombs. Most nuclear reactors today are used in producing electric power. But some are deliberately designed to manufacture bomb grade material o the atomic level.
The allies were afraid that the Nazis were developing an atom-bomb and began their own researches in earnest in the early 1940s, When the Nazis were defeated in 1945, Operation Paperclip was set up to smuggle 1,600 nuclear scientists, rocket scientists, physicists and engineers into America. Some of these wound up in Los Alamos, the experimental nuclear facility that was developing the A-bomb. It turned out that the Nazis were not that advanced in A-bomb building, but had the best rocket science of the day. The first successful critical mass leading to an explosion was on July 16, 1945 at Alamogordo, New Mexico. By August 6th of the same year, Little Boy, the gun fired device was dropped on Hiroshima. A few days later, on August 9th, the Fat Man implosion bomb was dropped on Nagasaki. Both firings were successful, but resulting in death on a scale unimagined before for a single bomb and a new disease; radiation sickness. The US had hegemony in nuclear weapons until the Soviets developed the A-bomb and fired theirs in a test in 1949. By the mid 1950s The H-Bomb which was an implosion-explosion-implosion device was successfully fired by the US under the development of the Teller team. In 1959, the USSR had the H-bomb, thought to have been given to them by domestic spies in the US. Development was extremely rapid from there. This began an age of hundreds of atmospheric, underwater and near space detonations.
The means to deliver an A-bomb developed in the airplane and rocket. Both of these have their history of development that lead to the use of the airplane as a means of delivery in 1945 and the rocket later in many tests launched from ground bases, jets and subs in hundreds of atomic tests by the US and USSR. Rocketry became reliable by the early 1960s and this culminated in the Cuban Missile Crisis of Oct. 1962 that brought the world to the brink of nuclear holocaust. All kinds of tests were conducted in the Pacific Ocean at Christmas Island, Eniwetak Atoll and Bogon Island by the US including several in outer space in low Earth orbit. Others were detonated underwater, on the surface and in air bursts. Many tests were also conducted in the Nevada desert north west of Los Vegas. All were heavily monitored. It was not long before others joined the nuclear club and could rattle the nuclear saber as a political threat like the US and USSR. Among the nuclear club are France, Israel, N. Korea, Pakistan, India, S. Africa and the UK. Khadaffi attempted to obtain the bomb during the 1990s without success. There is wide held fear that Iran is on the brink of having the bomb. Iran does have a working nuclear facility and can process uranium. In the spring of 2008, Iran demonstrated that they had rockets to deliver explosives by firing a salvo of several rockets. Israel and the US have expressed grave concern.
There are now several breeds of nuclear devices. The A-bomb was declassified and anyone can obtain information on how to build it. However, getting the materials is a different story, being almost impossible. Both uranium and klystron switches are both extremely difficult to come by. There is the H-bomb that has been tested up to 57 megatons. The small suitcase A-bomb exists that can take out a city center. The US experimented with and developed the "dirty bomb" that leaves real estate intact but showers the population with high does of neutron radiation which kills them all. The US also developed the EMP (Electro-Magnetic Pulse) bomb which can be powered by nuclear or conventional explosives. The EMP bomb destroys everything electrical, putting populations into the dark and the Stone Age. The conventional form of this bomb was used in Iraq in 1991 during Desert Storm.
In a nuclear world, it is helpful to know just how powerful these devices are and it is recommended to research this area by following links to US nuclear tests. This is some of the history that is made available to those who are interested.
A time lapse of every nuclear detonation
Atomic Tests, Benchmarks to Catastrophic Force
The study of atomic explosions is useful in establishing a benchmark for catastrophic force. One of the very few positive benefits of atmospheric testing in the 40's to 60's in the 20th century is the establishment of clear and definitive measures for explosive force in a variety of conditions. Whether we wish to know the results of air bursts, ground level explosions, under water, outer space, or sub subterranean blasts, the information exists as to what kind of damage results and the range of that destruction. We can assign a definition as to the cause needed to produce specific levels of destruction. Much exists in the way of declassified materials as to what kind of destruction results from various configurations and types of explosions in a wide variety of environments. This can be useful in comparing this with bolide impacts of various sizes.
The video, "Trinity and Beyond" is a compilation of numerous experiments with atomic and hydrogen bombs from Hiroshima sized detonations all the way up to 57 megatons. Most of the experiments were very carefully rigged and monitored so accurate information exists on what kind of damage can be expected in a wide variety of environments. These basic conditions consist of;
Low yield kiloton bombs detonated in the air
Low yield kiloton bombs detonated on the ground
Medium megaton yield bombs detonated in space
Medium megaton yield bombs detonated in the air at various heights
Medium megaton yield bombs detonated on the ground in various types of terrain
Medium megaton yield bombs detonated under water
Medium megaton yield bombs detonated underground
High yield multimegaton bombs detonated in the air at various heights
High yield multimegaton bombs detonated on the ground in various terrains
High yield multimegaton bombs detonated under water
Specially rigged experiments
All of these configurations have been tested and the results of each carefully recorded. A useful benchmark thus exists from about 1 Kiloton up to a range of 57 megatons.
The US DOD supplies information of various explosions and the results of the tests. Some tests and the resulting craters are detailed here. Complete information exists at US nuclear tests. Some of the experiments are detailed below.
"The device used (designated "Johnny") was identical to the Ranger Able device, chosen for its predictability and its limited yield (to minimize contamination). It was Mk-6 bomb using an all uranium core. The test name (Sugar) was a mnemonic code for "surface". The test left a crater 21 feet (6.4 meters) deep and 90 feet (27.4 meters) wide. At this time an 83 kiloton surface burst implosion bomb was being considered for use as a crater making and bunker-buster weapon. The test indicated that such a weapon would produce a crater 300 feet (91.5 meters) in diameter and 70 feet (21.3 meters) deep."
"The device used (designated "Frankie") was identical to the Ranger Able device. The test name (Uncle) was a mnemonic code for "underground". The test left a crater 53 feet (16.6 meters) deep and 260 feet (79.3 meters) wide. The 17 foot depth of burial was designed as a scaled down test of a 23 kiloton ground penetrating gun-type weapon also being considered as a crater making and bunker-buster weapon. The test indicated that such a weapon would leave a crater 700 feet (213.4 meters) in diameter and 140 feet (64.9 meters) deep."
"The Bassoon device, measured at 3.5 Megatons, fired in Zuni was the first test ever of a three stage thermonuclear design. Surprisingly, this substantial innovation was also the first successful thermonuclear device design ever fired by Lawrence Livermore (then known as UCRL, now LLNL). The configuration fired in this test was a "clean" (low fallout) version that used a lead tamper around the thermonuclear third stage. Only 15% of the energy yield was from fission. A "dirty" version of this design, the Bassoon Prime device, was later fired in Redwing Tewa. The predicted yield for Zuni was 2-3 Mt. The Bassoon device was 39 inches in diameter, and 135.5 inches long. It weighed 12,158 lb. Crater dimensions were 2330 feet (710.4 meters) wide, 113 feet (34.5 meters) deep."
"A 360 kiloton UCRL thermonuclear device used a boosted "Swan" primary and "Flute" secondary. The device was 15 inches in diameter, 46.2 inches long, and weighed 1116 lb. The primary was 11.6 inches by 22.8 inches and weighed 105 lb. The yield was at the high end of the predicted range. A wide but very shallow crater was created (mostly due to pressure collapse of the porous coral soil) - 1340 feet (408.5 meters) by 8 feet (2.4 meters)."
At Eniwetak Atoll, Bogon Island, a bomb of 13.7 kilotons was detonated. Considered a surface burst, it was stationed on a rig elevated at 7 feet, (2 meters). "Seminole was one of the most peculiar weapon effects tests ever conducted, as well as one of the most spectacular. This was a combined weapons development/effects test in which the device was exploded in a large tank of water to couple the shock wave to the ground. In effect the above-ground water tank simulated an underground nuclear test. The device was housed in a circular chamber inside the water tank which was accessible by a corridor through the tank. The chamber was 10 feet off center from the tank center, which led to a significant asymmetry in the crater produced. The crater produced was 660 feet (201.2 meters) wide and 32 feet (9.76 meters) deep.
The shot was designed so that by the time the fireball reached the wall of the tank, it had transitioned from thermal radiation-driven growth to hydrodynamic (shock wave driven) growth. As can be seen in the images available, the shock wave front of the fireball is still quite luminous.
The device being tested was a TX-28 primary/implosion system. The device was 20 inches in diameter and 55 inches long. The boosted primary had a predicted yield of 10 kt. The total device weight was 1832 lb; the primary itself weighed 143.5 lb." 
Perhaps the most frightening explosion that was ever detonated was the underground Cannikin shot on Amchitka Island in the Aleutian chain of Alaskan Islands on Nov. 6th, 1971. The shot was a five megaton device exploded deep underground in the one of the west most islands in the Aleutian chain that is close to Russian territory in the Bering Strait. It took miners and engineers well over a year to bore the deep shaft for the detonation. The blast generated a 6.8 Richter earthquake with a thousand aftershocks, the largest of which was a Richter 4 quake. The shot raised the immediate area overhead by 25 feet, which then dropped after the shot. Within days immediately after, a lake about 1 mile across was formed. Film shot by Hollywood of the event displayed equipment and buildings jumping and hopping violently in response to the initial shock. It created coastal landslides and a small tsunami. Underwater changes saw the permanent raising of the sea floor by a few feet. The shot was seminal insofar as it stands as the watershed for the inception of the Greenpeace movement. It produced the largest human triggered earthquake in history and proved that strategically placed weapons could be used as an earthquake weapon. The whole thing was filmed. Fortunately it was a largely uninhabited area (except for fishing crews, wildlife and Eskimos). It was an important lesson as it was detonated on Pacific the ring of fire. This tells us that strategically placed detonations can trigger greater destruction than the bomb alone is capable of doing. If a bomb were to be detonated on the main Hawaiian island in the main fissure of the shield volcano, the result would be an enormous land slide and tsunami that would wipe out everything around the Pacific Rim. Those who fired the shot in Alaska are probably aware of such possibilities. It is likely that the "other side" is also aware and has redefined their primary targets in accordance.