THE MANHATTAN PROJECT:
The American research effort had been spread between a number of widely spaced universities and directed by individual professors. To draw these diverse activities and people together required a number of organizational and leadership changes, which eventually led to the appointment of Leslie Robert Groves as the director of the project in September 1942. The activities were camouflaged under the code-name of the Manhattan Engineering District , generally shortened to the Manhattan Project. Groves was a 46- year-old colonel in the Corps of Engineers who, as deputy chief of construction for the United States Army was no stranger to supervising large-scale projects , such as the building of the Pentagon , and being responsible for spending vasts sums of money. But he was anxious to get closer to the war zone and to command troops in action so he was not very pleased with his new appointment. He knew, however , where his duty lay and promotion to brigadier softened the blow and gave him greater authority for the formidable task that confronted him.
Groves was the son of a lawyer who had entered the ministry later in life and had served as a padre on the Western Front during the first World War. He stood about 1.8 m tall, but was distinctly overweight—estimates varied between 115 and 130 kg—and while all this flesh didn’t enable him to present a very soldierly figure, particularly when wearing belt , it did nothing to quench his dynamic energy or his ego. Nicknamed ‘ Greasy Groves’ in the early days in the Army , he was not renowned for his tact , and was almost universally disliked ; moreover , he was an Anglophobe . He was , nevertheless , widely respected and, by many, feared. His second in command said that he’hated his guts’ 1 and described him as ‘ the biggest sonofabitch he had ever met’ but he still had confidence in his decisive , ruthless ability.
Groves had been trained in engineering at the Massachusetts Institute of Technology , before going to West Point , where he was fourth in his class , but he was not enamored of scientists and regarded most of them as inflexible , indecisive and argumentative. He did, however , sorely need someone to direct the new central laboratory where the bomb would be designed , and his choice fell on Robert Oppenheimer . It was a surprising , but inspired selection.
Oppenheimer was tall and skinny , less than half the weight of Groves , and always gave the impression that he would benefit from a good meal and some physical exercise. His countenance was sad and lugubrious , his posture droopy , his movements puppet—like as though his joints were not well coordinated , and there was a general air of tension and nervousness about him which was exacerbated by his chain-smoking. He was born on 22 April 1904, the son of a German Jew who had emigrated to the United States in 1898 and who had prospered as an importer of textiles. Robert was a delicate child and was a distinctly late developer; he himself referred to ‘ an almost infinitely long adolescence’. He was tormented in his early years by illness , by a lack of self confidence and by loneliness . He was never able to come to terms with himself or with the world , and he had an ascetic , poetic vision which was so unrealistic that he was always disappointed by any of his achievements . He was a perfectionist who was so clever and ambitious that his goals always seemed beyond reach. He expected everything and everyone to be extra special , but they never were.
In his early days , then, first at Harvard and later at Cambridge and other European Universities , he was distinctly unhappy . A psychiatrist indeed diagnosed ( wrongly as it turned out) a type of schizophrenia , and Oppenheimer himself wrote he was ‘ on the point of bumping himself off’. But he worked his way through all these difficulties and blossomed forth in his thirties , by which time he had turned his attention to the studying the quantum theory and had begun to establish an international reputation in that field. He held joint professorial posts at the California Institute of Technology and the University of California where he established a world famous school. He could still use a caustic tongue , still didn't suffer fools gladly and could still appear to be very arrogant. His private wealth also enabled him to act very independently , but he had, by and large , learnt to contain what he himself called his ‘beastliness’ , so much so that his strong personality and his charm began to break through more and more clearly. They had a particularly marked effect on his students and on the opposite sex , and he began to gain a reputation as an inspired teacher and something of a lady- killer. Leona Bibby ( later Marshall) , who was one of the very few women actively engaged in the research work , described him as ‘a disembodied spirit who never expressed himself completely and left a feeling that he had depths of sensibility and insight in layer after unrevealed layer like the seven veils of Salome’.2
Without doubt , Oppenheimer was a complex character with many of the drawbacks commonly associated with a touch of genius , and not everyone thought that Groves was wise to appoint him to direct anything. He had never led a very large group of people , his interests lay in somewhat abstruse theories, he was not a good experimentalist , he was regarded by many as indecisive , and he was not a Nobel Prize winner unlike many of the people with whom he would have to work. More importantly , his political leanings were to the left and he had been associated with members of the Communist Party . His first fiancée , Jean Tatlock , whom he began to court in 1936 and with whom he had a stormy , on and off relationship , was a member of the party , and Katherine Puening ( Kitty) whom he married as her fourth husband , in 1939, had been previously married to a member who had been killed fighting in Spain. Robert’s brother , Frank , a fellow physicist , and his wife , were also former members of the Communist party. It was, however, Oppenheimer’s friendship , since 1938, with Haakon Chevalier , a Professor of Romance Languages at the University of California , that was to prove the most damaging because , towards the end of 1943, Oppenheimer named Chevalier as the man who had been involved , albeit unsuccessfully , in an attempt to introduce him to a Russian agent. To try to protect Chevalier, Oppenheimer had originally prevaricated when tackled on this issue by the security authorities and he only revealed the full truth when pressurized by Groves to do so.
Groves admitted that such a background was ‘ not to our liking’ but he regarded Oppenheimer so highly that he used his considerable authority to obtain his security clearance , writing on 20 July 1943:’ In accordance with my verbal directions of 15 July it is desired that clearance be issued for the employment of Julius Robert Oppenheimer without delay , irrespective of the information which you have concerning Mr. Oppenheimer . H is absolutely essential to the project.’ 3
Though Oppenheimer said that he had never regarded Communist ideas as making any sense , the tag of being a fellow-traveller stuck with him and he was kept under constant surveillance and frequently interrogated . In the end his past, rightly or wrongly , caught up with him and his loyalty or lack of it became a cause célèbre
In the post war years . Nor did the two main women in his life , who were partially responsible for thetag , bring him constant happiness. Jean Tatlock committed suicide in 1944 , and though Kitty bore him a daughter in that same year , she reacted to the general strain by turning to drink. But whatever crosses he had to bear , Oppenheimer was repay fully the faith that General Groves had showed in him , and the two so unlike in many ways and only formally friendly , struck up a surprisingly good working relationship as they set about their task.
Roosevelt had decreed that ‘ time was of the essence’ , there was no shortage of funds and General Groves was no slouch. It was in his nature to act first and ask questions later. He began by touring the universities where work was already going on , and by taking steps to ensure that adequate supplies of uranium would be available , while Oppenheimer began to recruit a team of scientists. The general plan was that some basic research would continue in some of the universities but that new centers would be built where the necessary personnel and facilities could be concentrated. In September 1942 a site was bought at Clinton in Eastern Tennessee, where 235 U would be separated from natural uranium ; this came to be known as Oak Ridge. Another site, for making plutonium , was purchased in January 1943 at Hanford on the banks of the Columbia River in the state of Washington. The third , acquired in in November 1942, at los Alamos in Northern New Mexico , was to provide a central laboratory , which would be directed by Oppenheimer himself , where the bomb would be designed and fabricated once the necessary materials became available. The sites chosen were remote and far apart from each other to limit any attempts at sabotage and t provide good security. Groves hoped to compartmentalize all the work so that one team would would not know much about what another was doing , with only very few people having an overall picture. This was a typically military approach but it caused a lot of friction between the military and the scientists who were accustomed to much more ope discussion . Secrecy was indeed to be a contentious issue throughout.
To push ahead as rapidly as possibly the method of parallel development was adopted . If more than one way of solving a problem seemed to be feasible they were all investigated fully without a lot of preliminary consideration of the detailed pros and cons. This was expensive and inevitably led up some blind
alleys but enough clear pathways opened up to show the way forward.
The Oak Ridge site , where 235 U was to be extracted from natural uranium , covered 250 sq. km of impoverished , sparsely populated , rural land consisting mainly of red clay which meant that there was generally a lot of mud about when it was wet . Initially, a new town to accommodate 13,000 people was planned but a peak population of 75,000 was reached , during the summer of 1945, making Oakridge the fifth largest city in Tennessee. It was a closed military area, surrounded by barbed wire , and all the services associated with a large town —housing, water , drains, electricity , schools, hospitals , churches, roads and railways —had to be provided , as well as all the special technical buildings and plant.
Although 235U had been separated from 238U on a small laboratory scale , the task of ding it on a large industrial scale was Herculean . Natural uranium contained on 0.7 per cent of 235U, and it differed in mass from 238U by only 1.26 per cent.
There was too little know-how for anyone to predict which would be the best method of tackling the problem so at first two methods were adopted : electromagnetic separation and gaseous diffusion ; later, a third method, the thermal diffusion was also tried. All three processes took bold steps into unknown territory , and because of lack of time, research , development , construction and operation , all had to go on more or less simultaneously. In such a rapid build up of new technology it is not surprising that there were formidable hurdles to be overcome. The recruitment and training of staff ; the procurement of all the vast amounts of necessary materials; the design and the building of the plant ; and the successful operation of the new processes , all provided many head aches and many setbacks.
In the electromagnetic method of separation , which had been developed mainly by Ernest Lawrence at the University of California , the vapor of a uranium compound is electrically charged and then passed through a vacuum surrounded by a very strong , 4,570 tonne, oval shaped magnets. The magnetic field deflects the electrically charged uranium atoms , but it deflects the lighter 235U ones more than the heavier 238U ones, so that the two are separated. The set-up was known as a coultron or racetrack , and some 500 of them were planned to provide the right amount of 235U. Construction began in February ,1943, and the plant was first operated in November of that year, but, by the end of the year , there had been so many faults in the magnets that it had scarcely produced 1 gram of 235U. It was not until September 1944, after all the original magnets had been stripped down and rebuilt , that more promising amounts began to be made.
In the gaseous diffusion method , natural uranium was converted into uranium hexafluoride (hex) , which is a gas consisting of a mixture of 235UF6 and 238UF6 molecules. When the gas was pumped through a porous filter or barrier , the lighter 235UF6 molecules passed through slightly more rapidly than the heavier 238UF6 ones, so that the gas emerging from the filter was enriched in 235UF6. Only very slight enrichment was achieved by one filter so that the process had to be repeated over and over again through a cascade of thousands of filters. The main problems were the handling of the very corrosive uranium hexafluoride gas and the manufacture of suitable filters. All the hundreds of kilometers of pipes in the plant had to be plated with nickel to withstand the gas , anda special , new sealant ( now widely used under the trade name Teflon) had to be developed for use in the thousands of pumps because hex attacked any normal greases. The difficulty in making satisfactory filters arose because they had to have very fine pores and yet be strong enough to with stand the gas gas pressures to which they were subjected. The first type of filter was replaced by an improved design , but this caused some delay so that it was not until early in 1945 that the gaseous diffusion plant began to produce reasonable amount of enriched uranium.
In the thermal diffusion process, isotopes are separated by feeding the mixture into a vertical , cylindrical tube, which is cooled on the outside and which has a heated , concentric cylinder inside along its axis. The lighter isotopes move to the hot , inner surface and then to the top of the cylinder . The heavier ones move to the outer, cold surface and downwards to the bottom of the cylinder . One One cylinder produces only very little separation but racks of thousands of cylinders achieve the desired results. Construction of the plant began in June 1944 and, despite many problems with leakages, it was operating reasonably well at the start of 1945.
It might seem profligate to operate three different processes simultaneously , but, in the end , they all earned their keep because it was only by using the partially enriched uranium from one process as the feed stock for another as the feed-stock for another that the required product was made in sufficient quantities. Planning was exceptionally difficult because , particularly in the early stages , neither the actual amount of 235U required for a ‘Little Boy’ bomb , nor the desired degree of purity , were known with any certainty . estimates of the amount began at around 100 kilograms but , in the end, around 40 kilograms of 235U of about 80 per cent purity was found to be satisfactory , and slightly more than this amount was delivered to Los Alamos by 24 July 1945. It was less than three years since General Groves had arranged for the purchase of the Oak Ridge site.
To make plutonium , which was required for ‘ Fat Man’ , it was necessary to build a much larger version of the pile that Fermi had constructed in his Chicago squash court. Some development work was carried out in the Argonne Forest , close by Chicago , and at Oak Ridge , but the final production site which was chosen was at Hanford in the state of Washington on the banks of Columbia River. The availability of large supplies of water from the river for cooling purposes , and the proximity of the Grand Coulee Dam with its associated hydroelectric scheme , made the site very satisfactory. The original Hanford was a tiny ,riverside village with a sparsely populated hinterland of storm-ridden , scrubby desert. General Groves inspected the site on 16 January 1943 and about 2,000 sq. km of land was acquired in February . As at Oak Ridge, a new town was spawned and, at its peak , it had a population of about 60,000.
The manufacture of plutonium involved two stages . First, it had to be made within a pile , or a reactor as it was sometimes called, by the bombardment of 238U by neutrons. But as only a small part of the 238U was converted into plutonium , this had to be followed by a chemical extraction process to obtain pure plutonium. Three piles were built , at 10 km intervals , alongside the Columbia River . These were on an altogether different scale from Fermi’s original oe : he called them ‘ different animals’. Not only were they much bigger , they also used purer uranium and graphite and they incorporated extensive cooling and shielding arrangements so that they could be run at much higher power. Thousands of aluminium tubes , embedded in cylinders of solid graphite , 8.5 by 11 m in size, contained slugs of uranium , themselves clad with aluminium. When the pile was operating , the slugs were kept cool by passing water over them through the tubes. At the peak 350,000 litres of water per minute were used , the heated water being returned , after treatment , into the river. To avoid ill-effects from the extensive radiation which was emitted , the pile was shielded by surrounding it with steel plates , concrete , and special high –density compressed wood.
After the pile had operated for about seven weeks , the slugs of uranium , now containing about 250 parts per million of plutonium were simply pushed out of the aluminium tubes into tanks of water and replaced by new slugs . After being stored in the water for about eight weeks to allow time for the short-lived radioactivity to decline, the slugs were ready for chemical treatment to extract their small plutonium content. The extraction process , which had been worked out by Glenn Seaborg , involved some complex chemistry and, because the slugs were still highly radioactive , some complex technology. The process , beginning with the solution of the slugs in hot,concentrated nitric acid , was carried out in three vast plants erected 16 km away from the piles. Each plant consisted externally of massive concrete structures, 243 m long , 20m wide and 24 m high. The walls were made of 2.1 m thick concrete and the roof was 1.8 m thick. They were called ‘Queen Marys’ , after the huge ship of that name. There were various cells within each ‘ Queen Mary’ in which the different chemical operations were carried out , but the radiation was so intense that they all had to be done by emote control through the concrete walls , using periscopes , television cameras and automatically operated handling equipment.
Construction of the first pile began in August 1943, and it was first operated in September 1944. The other piles were also in action by the end of 1944 and the first supplies of plutonium to Los Alamos were delivered at the start of 1945. By the middle of that year enough had been provided to make two ‘ fat Man’ bombs , and much more was in the pipeline.
Los Alamos was set among rugged , forested country in an isolated region of extinct volcanoes. The whole area was split up by deep canyons into long, thin plateaus, called mesas , which were often at a height of 2.3 km . Access to the mesas was extremely difficult and the area could only be reached after a hazardous , 56 km drive from Santa Fe , the nearest community of any size . When the site was first inspected by Groves and Oppenheimer , it was occupied only by a few ranchers and bya private school for boys, and it was the school buildings that provided a base from which to expand oppenheimer was particularly happy with the choice of site because he knew the area well , having shared a cabin some 100 km away with his brother for a number of years.
Los Alamos was officially opened o 15 April 1943, but many of the planned , new buildings were far from ready and there was a general air of chaos and confusion as Oppenheimer set about getting the show on the road, travelling all over the country recruiting ‘the men who could make a success’ of this venture into the unknown. It was not easy to persuade scientists who were already fully occupied in jobs of their own choice to move to a place they had never heard of to work on a project , closely linked with the military , about which most of them knew very little. ‘ There was a great fear ,’ oppenheimer wrote , ‘ that this was a boondoggle which would in fact have nothing to do with the war we are fighting.’5 But in the end his persuasiveness was such that he succeeded in gathering together what Groves described as ‘the greatest collection of eggheads ever’.6
It was an international cast , with many native Americans supported by others whose origins lay in Italy , Hungary, Poland , Austria, Germany and Russia. As G.P. Thomson wrote :’It is noteworthy, and I hope will be noted by future Dictators , how dominating was the part played by physicists who had fled from Fascism and Nazism.’7 And at the end of 1943, after an agreement on the mutual exchange of atomic energy secrets reached between Roosevelt and Churchill at a conference in Quebec , they were joined by many British scientists from the ‘ Tube Alloys’ project. Akers, Frisch , Peierls, Chadwick , Oliphant , Penney and Niels Bohr , with his son , Aage, were among those who went to work across the Atlantic. So, too, was Klaus Fuchs, a German who had become a naturalized British citizen , and who slipped through all the security screens to become infamous for passing secret information to the Russians.
Much basic work had to be done on the chemistry and metallurgy of uranium and plutonium and on how they would be handled safely , but the major problems that had to be resolved were the critical sizes of the two materials and the details of how they could be made into a workable bomb. The critical masses were measured in a series of dangerous experiments in which subcritical masses of the materials were brought together into a supercritical mass for a fraction of a second. The necessary work was carried out by what was known as the Critical Assembly Group operating in a building in canyon remote from the main laboratories . In one set of experiments a piece of uranium hydride enriched by 235U was dropped through a ring of the same material.As it passed through , the assembly became supercritical for a fraction of a second , simulating a small bomb , and it was possible to measure the output of energy . Otto Frisch, whose idea it was , referred to the experiments as ‘twisting the dragon’s tail’. Other experiments involved building small blocks of the materials into a small pile until the critical size was just reached , and it was such an operation that caused the only wartime death at Los Alamos. Harry Gaghlian , working alone at night contrary to agreed regulations , accidentally dropped one of the blocks into the pile and the resulting surge of radiation lead to his death twenty –four days later. A fellow worker , Louis Slotin , was killed by a similar incident after the war.
The first idea for making a bomb was to assemble two subcritical pieces of material at opposite ends inside a sealed gun barrel. To set off the bomb , one of the pieces would be fired into the other, using an explosive charge , to form a supercritical mass and, at the same time , to trigger off a source of neutrons. The two pieces just come together at just the right speed; it it happens too quickly they might just disintegrate on impact before the chain reaction could get started ; it too slowly , the chain reaction might build up too slowly and simply produce enough heat to cause the mass to expand without exploding.
In the event , this ‘gun’ method was found to be satisfactory for 235U used in ‘ Lttle Boy’ but it would not work for plutonium as two pieces of that material could not be fired together quickly enough in a gun barrel. This was due to the presence of too high proportion of 240Pu atoms among the predominant 239Pu atoms. It was therefore necessary to use a much trickier implosion method in making ‘ Fat Man’. The idea was that two touching hemispheres of plutonium , forming a sphere which was below the critical size and which had neutron source at its center, would be surrounded by explosive charges which, when detonated, would compress the sphere into about half its original size. The corresponding increase in density of the plutonium would mean that that the atoms were brought closer together so that the neutrons responsible for carrying on a chain reaction would have to travel much shorter distances before colliding with other plutonium atoms. The smaller sphere of high density plutonium would, therefore, be supercritical.
The necessity of developing two rather different types of bomb —the ‘gun’ for 235U and the ‘implosion’ for plutonium —meant that the research effort had to be two pronged and this threw still greater burdens on Oppenheimer’s organizing ability and severely stretched the facilities of Los Alamos. There were also very difficult decisions about priorities for , at that stage, it seemed likely that 235U , which could be made into a bomb rather easily , would not be available as early as plutonium , which was clearly going to be more difficult to make into a bomb. Nor was the situation helped when Seth Neddermeyer , a fine scientist but a poor organizer , who directed the original work on the implosion method , had to be replaced by George B. Kistiakowsky because progress was being made too slowly.
It was an almost completely new field of research work , which because of the lack of any basic background work, involved a god deal of imaginative , intuitive guess work. The idea was to surround a central plutonium sphere with a layer of natural uranium and to have an outer layer of specially designed , shaped explosive charges. These charges would concentrate the explosion towards the center of the sphere and as this concentrating effect was similar to that of a lens on light the charges were referred to as lenses. The lenses , which had to be made with a precision of a few thousandths of a centimeter so that would fit together accurately enough , were cast in moulds and finished by machining . There were two components . One contained fast—burning explosive mixture , called Composition B, consisting of TNT, RDX and a wax. The other was a slower-burning mixture , called Baratol, containing TNT, nitrocellulose , barium nitrate and aluminium powder . The two together were intended to build up a smooth , symmetrical detonation wave which would first compress the natural uranium layer and then the central plutonium. Within a period of about two years , over 20,000 castings and 50,000 machining operations were carried out to try to achieve the desired results , but, after all the tests, there remained some lingering doubts as to whether the radically new design for ‘ Fat Man’ would work satisfactorily . It was therefore decided , during 1944, that any uncertainty should be resolved by carrying out a full scale test firing on a prototype ’Fat Man’ . The decision was made easier in the knowledge that thee was expected to be enough plutonium available by the summer of 1945 to make two, or even three, bombs. It was lucky that similar testing of the simpler ‘Little Boy’ bomb was not regarded as essential , because the supply of 235U was distinctly limited.
The test of ‘Fat Man’ was carried out in the south of New Mexico on a 30 by 39 km site on the edge of the Alamogordo bombing range. It was an area of flat , desert scrubland in the center of a sun drenched valley, so dry and hot during the day that it had been christened Dead Man’s Trail by early Spanish explorers. The test and the site were code-named Trinity, a suggestion originating from Oppenheimer’s imaginative mind and inspired by his recollection of lines from one of John Donne’s ‘Holy Sonnets’:
Batter my heart, three person’d God; for you
As yet but knock , breathe , shine , and seek to mend.
That I may rise and stand ,o’erthrow me , and bend
Your force to break , blow, burn and make me new.8
The new site , like those at Oak Ridge , Hanford and Los Alamos required the creation of still another new township from nothing.
The test bomb was to be exploded at the top of a 30 m high metal tower, built on a spot nicknamed ‘Ground Zero’. Between 8 and 10 km away , to the north, west and south , there were observation posts built of earth with roofs of concrete slabs supported on strong wooden beams. The base camp was situated 6.5 km further to the south , and there was a viewing platform for VIPs on a hill 32 km from Ground Zero.
After some postponements because the bomb was not ready , 16 July 1945 was chosen as the fateful day , and Groves and Oppenheimer , together with other senior scientists and distinguished visitors , arrived on the 15th. By then the bomb had been largely assembled on the top of the tower , but not without much difficulty because a desert hailstorm , with high gusts of wind and much thunder and lightning , had severely hindered the work. The poor weather continued to cause much concern so that the planned timing of the test was changed from 2.00 a.m. to 4 a.m. and then to 5.30 a.m.
It was a long , almost intolerable wait , which seemed like an eternity , particularly for the majority who had no active part to play in the final preparations. Some managed to snatch some sleep , but many just wandered around in the darkness. Groves tried to keep everyone calm , and was particularly helpful to Oppenheimer , but as the moment of truth approached the general tension mounted.
Observers had been told to smear their skin with anti-sunburn cream., to close their eyes and to cover them with their hands , and to lie down on the ground, or in a shallow trench , with their backs and feet to the tower. A green Very Rocket was fired at 5.25a.m. ; then there was another 1 minute warning rocket ; and with only 45 seconds to go , an automatic timing system came into play which was under te control of Donald Hornig, who had designed the mechanism which was to fire the bomb and who had been the last man down from the top of the tower after making the final adjustments to the bomb. He, alone, could still have stopped the test at any moment by pressing a knife switch, but it was not necessary , and the first atom bomb in the world exploded 15 seconds before 5.30 a.m. on 16 July, 1945.
It was still dark and the first effect was a burst of brilliant , searing light which lit up the whole area far more brightly than the midday sun. The flash was seen 290 km away , and the closer observers sensed the enormous intensity of the light even through their closed, covered eyes. They also felt the heat as the door of a very hot oven had been opened. As they turned to see what had happened , using smoked glass to look through , they saw an enormous ball of red, orange and yellow flames of fire rising upwards out of the desert. Almost immediately they felt a blast of air , which knocked over some of those who were standing up , and this was followed by the thunderous roar of explosion . Thereafter , the fireball developed quite slowly into a mushroom-shaped cloud of dust, which rose to height of almost 11 km before being blown in many different directions by the variable winds at different altitudes.
The explosion made a crater 350 m in diameter in the desert floor , and, immediately below the tower , which had all but disappeared , there was another hole 36 m wide and 2m deep filled with a glass like substance because the temperature had been high enough to melt the desert sand. A 10 cm iron pipe , 450 m from Ground Zero had evaporated; 800 m away , a 21 m high tower built of 40 tonnes of steel set in concrete foundations , was flattened and ripped apart; and plate glass windows 300 km away were cracked. Measurements showed that the bomb had been equivalent to almost 19 k tonnes of TNT, which was almost four times more powerful than the Los Alamos designers had expected. What those present had seen and felt was quite unprecedented and they found it difficult to put their observations or emotions into words.Sensible comment and discussion after the event, was not really possible , because everyone was stunned and giddy. Some found the sheer elation that their efforts had been crowned with success difficult to cope with ; others were overcome by what Dr Kenneth Bainbridge , the director of the test , called ‘this foul awesome display ,’10, yet others were already beginning to be fearful of what they had unleashed.
General Groves maintained a cool military composure , and he congratulated Oppenheimer , saying , quietly ,’I am proud of all of you.’ Oppenheimer replied with a simple ‘Thank you,’11, but his deeper thoughts were perhaps better expressed in a line he recalled from the Hindu Bhagavad –Gita :’ Now I am become death , the shatterer of worlds.’12 Bainbridge echoed the sentiment by saying that ‘they were all now sons of bitches’,13 and even the ice cold Fermi was so affected that he had to ask a friend to drive him home.
The success of the Trinity test in 1945 had a catalytic effect on events .In Europe Adolf Hitler had committed suicide , the German armies , had surrendered in the early hours of the morning of Monday 7May , and General Eisenhower the Supreme Allied Commander , had announced in a radio message on 8 May —VE DAY –that ‘the sounds of battles have faded from European scene’. It was estimated that around forty million lives had been lost—directly or indirectly —in the six year carnage. Ironically , and surprisingly , it transpired that the idea of a German atom bomb , which had been such a driving force behind the British and American efforts was but a myth. The Germans had never undertaken any serious long-term project to make such a bomb even though they were well aware of the possibilities . In the first two years of the war , a group of scientists , led by Werner Heisenberg and known as the Uranverein( the uranium society) , had made considerable progress in devising methods of separating uranium isotopes and in making an experimental atomic pile , but in the middle of 1942 it had been decided to direct the main research effort into flying bombs and rockets.
Unhappily , President Roosevelt did not live to see VE-Day .He had collapsed while sitting for a portrait , on 12 April , and died the same day. He had served as President for thirteen years and contributed so much to the successful outcome of the European conflict.
But the war in the Far East was far from over .The Japanese had overrun many far flung islands in their early , successful days when they almost reached Australia and, when the counter attack took place , they fought to death to maintain their hold on them. Recapturing the tiny Island of Iwo Jima cost the Americans over 4k dead, while at Okinawa over 12.5k Americans and 100k Japanese were killed in 3 months of fighting. Estimates suggested that the Americans might suffer over 200k causalities if they went remorselessly on their way and attempted a direct assault on the Japanese home islands.
The new President , harry Truman , had to face up to this challenge . It is a measure of the level of security surrounding the Manhattan project that, although he knew of its existence , he knew nothing of its purpose. So, at the same time as he was being briefed about the atom bomb , he was having to begin to decide what to do with it. All the arguments , some of which seem more powerful now than they did at that time , were expressed with great vehemence, and few national leaders can ever have been confronted with such an agonizing decision. In the event Truman decided , though not very positively , around 1 June that the atom bomb should be used against japan. Groves remarked that’he did not say “Yes” as not say “No” . It would indeed a lot of nerve to say “ No” at that time.’ After all , nearly two billion dollars had already been spent on the Manhattan Project so it could not be discarded lightly. British approval for the use of the bomb , which was a necessary part of the Quebec Agreement , was given on 4 July . Churchill’s attitude was distinctly pragmatic . He wrote:
There never was a moment’s discussion as to whether the atomic bomb should be used or not . To avert a vast , indefinite butchery , to bring the war to an end, to give peace to the world , to lay healing hands upon its tortured people by a manifestation of overwhelming power at the cost of a few explosions , seemed, after all our toils and perils, a miracle of deliverance.15
Later in July Churchill and Truman met Stalin in conference at Potsdam , and Truman , in full knowledge of the success of the Trinity Test , took the opportunity of casually informing the Russians of the Americans intention of using a special weapon to force a Japanese surrender. Stalin showed no great surprise or interest because, unknown to the Americans or British , Karl Fuchs had been feeding secret information to the Russian for many years , though his activities did not come to light until 1950 when he was back in England as head of theoretical physics at the Atomic Energy Research Establishment at Harwell.
At the end of the Potsdam Conference , on 23 July , an ultimatum on behalf of the governments of the U.S., the U.K.; and China was issued to Japan . It became known as the Potsdam Declaration and laid down the conditions under which the war could be ended , concluding as follows :” We call upon the government of Japan to proclaim now the unconditional surrender of all Japanese armed forces , and to provide proper and adequate assurances of their good faith in such action. The alternative for Japan is prompt and utter destruction’.16 General Groves had already drafted a directive to General Carl Spaatz, the Air Force Commander , on 23 July . It began :’ The 509 Composite Group , 20th Air Force , will deliver its first special bomb as soon as weather will permit visual bombing after about 3 August 1945, on one of the targets: Hiroshima, Kokura, Niigata, and Nagasaki.’
The Japanese government decided to fight on ; Colonel Tibbetts’s men did their duty ; and the nature of warfare —and even, of life—was never to be the same again.
Dr. I.R. Durrani
MANHATTAN PROJECT