Roy Glauber (2016) - Some Recollections of the Manhattan Project 1943-1945

How do you do? I have gotten a slightly late start. And I hope you’ll pardon me. It’s of course a late start in describing what happened about 70 years ago. Now, what I’m going to try to do is to relate to you some of the experiences and some of the memories I have from a period when I was in fact just 18 years old. The year was 1943. I want first, however, to go back just a bit prior to that. And let me see if I can get this system working. Can you see Enrico Fermi? The year was 1938 and he had been doing a succession of experiments using neutrons. Neutrons were the neutral particle that resides in the nucleus but only discovered really in about 1931. There were many mysteries before that. That clarification led to a great many experiments that could be done. And Fermi was primary among the experimenters in discovering what it was that neutrons did to nuclei. He did a long succession of such experiments in the middle 1930s. Some of the last experiments he did would shine a beam of neutrons on uranium, the heaviest of the known nuclei at that time. He discovered quite a complex of things going on but had no time to analyse them because he not only received the Nobel Prize but used that as the occasion to himself, for himself and his family to leave Italy. After visiting Stockholm briefly he went to Columbia University in New York. And there really began a great deal of the story that I am going to tell you. He left many questions unsettled regarding what neutrons do to uranium. One of the greatest of the radio chemists of the day, Otto Hahn, began investigating that seriously and discovered that there was quite a variety of particles that emerged from these neutron-uranium collisions and they had chemical properties which were absolutely bewildering. As a radio chemist, he could verify that several elements at least that emerged from these collisions had the same properties as familiar and much lighter elements. The person who really resolved this problem was also a refugee at the time. In 1938 she left Berlin, aided by Otto Hahn, her boss, and settled in Stockholm where with a nephew of hers, Otto Frisch, this woman, who was Lise Meitner, developed the theory that what was happening was in fact a split up of the uranium nucleus. That 2 fragments, approximately half the mass of the original uranium nucleus, were emerging. And there were many chemical consequences because this was a variety of nuclei, roughly in the middle of the atomic table. Now, this idea which in fact was hers, she was never rewarded for it, did lead to quite some activity. In particular Leo Szilard, a young Hungarian who loved thinking of the future, realised that these were nuclei being produced which had a few neutrons too many. That not only would these fission fragments, these heavy fission fragments emerge but more neutrons. He was aware, in other words, that it might be possible to create a neutron chain reaction. And disturbed by the possibilities that might be opened by that, he decided that he had to communicate with Franklin Roosevelt, the president, and see to it that America was aware of the dangers involved. He wrote a letter on behalf of Albert Einstein to Roosevelt. And here he is meeting with Einstein at a summer vacation spot in 1939 at the end of Long Island, drafting that letter which Einstein was happy to sign. And that letter was then transmitted by a well-known banker to Roosevelt who was duly impressed and appointed the only technically trained person he would know who was the leader, the chairman of the Bureau of Standards in Washington, Vannevar Bush, and asked him to put together a committee to look further into this matter. Well, here you have that committee. It, as you can see, was seemingly a rather joyous occasion to these people, 3 or 4 of them Nobel Prize winners. Including in the centre you had James Conant who was President of Harvard University but who in fact was a chemist! And well, I won’t go through the naming of these worthy individuals but the truth of the matter is that besides enjoying themselves and appointing still other committees they did virtually nothing. (Laughter) So that is, I think, really the true introduction to this matter. A man who was peripherally involved was Kenneth Bainbridge who was a mass spectroscopist at Harvard and who told us the correct masses of the various fragments that were coming off in uranium fission which was thereby understood for the first time. Bainbridge also built a cyclotron. Here he is proud of his new cyclotron. The year must have been about 1940 or ’41 when the cyclotron was completed. As the interest in doing experiments with fission arose. And there was even a desire to do more experiments. Here you have someone whom you will recognise as Robert Wilson. There in the centre is Robert Wilson whom you'll recognise. I think he was at that point at Princeton University, years later at Cornell, and finally the director of the Fermi laboratory in America, the great accelerator laboratory in the mid-west. But here he was negotiating on behalf of a fictitious organisation called the St. Louis Medical Depot, trying to secure the cyclotron itself and have it shipped somewhere to the west. Where was it being shipped? Well, many people by late 1943 had learned one particular address. This was it. It was the only information I was given when I turned 18 and had had quite a few of the courses as they existed at the time, most of the graduate courses, and was asked to go to this place. Well, this place was Post Office Box 1663. And I shortly learned, you know a post office box in America is about the size of a shoe box. And it might have had some difficulty accommodating the 2 trunks of books and belongings I sent there. But just imagine the difficulty that it must have had accommodating the moving vans and freight cars full of materials that everybody else was sending to this location. We were not even sure it was in New Mexico – but that was where we were being sent. In fact it turned out to be not Santa Fe, but Lamy, which is a tiny wooden rail station about 15 or so miles from Santa Fe. Well, there was a man who got off the train when I did. He wore a Derby hat and a navy blue overcoat and he announced that his name was Mr. Newman. Well, when we got to Santa Fe, where there was a small office run by the project, and signed the register I could see that his name was in fact John von Neumann. He was in fact the author of one of the famous texts I had been reading at just that time. He was met, I should say, by someone who looked for all the world like a cowboy. He wore inevitably dungarees, a checked shirt and in fact a ten-gallon hat. He seemed to be a cowboy of some sort, hired as a chauffeur. And there started a conversation, a really remarkable conversation, between Mr. Newman and this 'cowboy', whom I later discovered was in fact Jack Hawking, a member of the theory group and a mathematician at the laboratory. The trip up to the laboratory was geographically remarkable. This is a picture taken a little later. The original bridge across the Rio Grande, which runs north-south there, had been in fact washed out and you can see it in the background here, that’s the original bridge. This was a bridge that appeared about a year later on the way up to what we call 'the hill' which was back here behind these great bluffs. We had to drive north some distance to Espanola in order to cross the Rio Grande and go back south and this was the sort of vista. There were magnificent vistas that began to unfold as we climbed up into the Jemez Mountains. That’s the main chain, the Sangre de Cristo Mountains, you see, literally looking across the Rio Grande in the bottom of that valley. Here is where we got to the entrance to the project area such as it was. It was on a plateau which was high above the Rio Grande valley, about 7,000 feet of altitude. It turned out that this plateau was crossed by a great many canyons so that the country would be virtually impassable, except by the 1 or 2 roads that led to a nearby pueblo ruin. Well, that’s the entrance. When it got a little busier a few weeks later there were many MPs examining the credentials of people wanting to get in. And many stories conveyed back out by the truck drivers and various individuals not bearing any responsibility to the project but just telling about bizarre things they had seen up there on the hill. This is something called 'the big house'. What was up there was the Los Alamos Ranch School for Boys. In particular several parents, whose sons had tubercular problems and were sent to this school to get a high school education and at the same time breathe the fresh clean air of New Mexico. And if I jump ahead now, it became a laboratory. It became a laboratory with a fenced area which was quite considerable in size. It had many buildings, laboratory buildings within it. And when finally they made the place look much more respectable – this is the way the gate looked but this was not there, I would have to say, for the first 2 or 3 years. Here is how people’s credentials and baggage were examined entering the technical area. I just happened to get hold of this picture because the man being interrogated is Robert Marshak who was a group leader in the project. After the project was going for a year or 2 there was a fair amount of construction and in fact much of it rather awkward. The technical area had begun on this side of the road but had soon filled the area up to the fences. And they decided they had to move to the other side of the main road. And the only way of managing the problem of examining people’s credentials was to construct elevated passageways across the road to take you from one part of the technical area to another. This happened eventually to be E building or the seat of the theoretical division which I was made a tiny part of. Now, to move further ahead, this was typical housing for 4 families. Most of the people at the laboratory were very young. They were families just beginning with the result that the hospital, for example, had quite a high birth rate relative to the population. These young families were producing more people than virtually any other army-run hospital. (Laughter) The housing varied quite a bit. I like this particular picture, not just because it showed the way people live but a forest fire in the distance. The country was very dry. Virtually no water at all, except for a carefully managed pond in the middle of the Mesa, and it was a devil of a job trying to put out even those very tiny forest fires. Here is more housing. Here is some housing unique in that it had all the single women in the laboratory, about 12 or 14 of them. This is what a dormitory room looked like - not mine but you couldn’t have told mine from this one. It was a single room in a temporary structure which at least kept people out of the elements, out of the rain, and where we occasionally held dormitory parties. There were other features there. A great many young men who were being drafted and whom the government - there was no established means of determining people’s talents when they entered the army. So people with quite a variety of different talents were thought perhaps to have engineering skills or something of the sort and were sent to Los Alamos to live in these barracks. The assignments they had were, as war time assignments go, pretty interesting and kept them very busy. But unfortunately the army felt that this group of privates ought to have some officer leadership. These officers were people who had no technical training whatever and could see no purpose in their being there other than to give drills to these engineers. Getting them up at 6 in the morning, having them line up and exacting from them whatever calisthenics or drills were considered beneficial. It led to a great deal of complaint. These were men who had, as far as the army is concerned, very safe and useful positions but you never heard so much complaining in your life. In later years - there’s this little monument which was not there. This is where the original faculty of the Los Alamos Ranch School for Boys lived. There were several such stone houses. Now, of the people who were there the man who headed the theory division was Hans Bethe. He was a remarkable choice in that he was unbelievably versatile. He could give you a 2-significant-figure estimate of virtually any ridiculous problem that you could invent on the spur of the moment. He was an extraordinary leader for the theory division. Here is the leader of the entire project – Robert Oppenheimer. And he too was an extraordinary leader. For one thing, of course, you never saw him except with a cigarette in his mouth. He was a great teacher but didn’t believe in making things easy for anybody. He expressed himself in literary, at times almost poetic, terms and in that way he had the admiration of a great many rough-and-tumble scientists who were really very impressed by him. Wherever he went, and he visited every part of the project including all of the experiments, you would see his porkpie-hat as a kind of calling card. Now, another figure, who was away when I first came there in January of ’44, had gone off in a huff. He had left and, in fact, abandoned the project for a month until Oppenheimer talked him into returning and promised him a certain sector of the project as his own fiefdom as it were. Edward Teller had done a certain amount of work on thermonuclear reactions, possible astrophysical thermonuclear reactions, and he had adopted as his primary interest securing a burning process of some sort in among the light hydrogen isotopes, in particular deuterium and tritium. He was persuaded that somehow the nuclear bomb could be used as a match to light that continuing fire. He believed in that passionately and felt that he had been altogether neglected in the original organisation of Los Alamos. Oppenheimer had at that point to persuade him to come back. And come back he did. And you have heard a great deal about what he did subsequently. This is Emilio Segrè, Segrè had been a collaborator with Fermi in Rome. He was already in America and he had been given a remarkable sort of assignment in the early days in Los Alamos. Which was to go to an isolated place in one of the canyons where the neutron background would be minimal and determine whether the newly created element, plutonium, in particular the form in which it was created in the nuclear reactors in Chicago, to determine whether that particular nucleus underwent spontaneous fission to any considerable extent. That was important because spontaneous fission meant that there would be neutrons bouncing around within the material whatever materials you were using. And the original plan for creating the bomb was a relatively simple one of shooting a cylinder of, it was in that case uranium 235, shooting that cylinder into a hollowed-out cylinder in a spherical mass. And neither of these 2 masses of uranium 235 would be above the critical point. They would not individually support chain reactions. But when amalgamated, when joined together, they would indeed. Now, there was a difficult period of time while you were assembling these pieces and if, indeed, a chain reaction started in that period it would be pre-detonation and you’d get a much smaller explosion. In uranium 235 the spontaneous fission rate was slow enough so that that was not a serious danger. If one used a canon to thrust the cylindrical projectile into the hollowed-out volume one would have milliseconds to do that in. And that was just possible with a canon. However, Segrè discovered very quickly that the spontaneous fission rate in plutonium which was even by that time being produced more rapidly than uranium 235 which required isotope separation, that the spontaneous fission rate and the background of neutrons would mean that you would have to assemble the plutonium bomb in microseconds rather than milliseconds. A microsecond is millionth of a second. And that was the principle problem that the entire project had really to deal with in the subsequent years. Now, here is the rest of Segrè’s group. And I just show you what a group looked like and what the background and the technical area looked like. But here in the back behind Segrè you have Owen Chamberlain who was inseparable from him. And the 2 of course won the Nobel Prize several years later in Berkeley for using the Bevatron to identify the anti-proton. That’s Martin Deutsch. At that point I’m afraid I can’t recognise the other faces too easily. Well, here is another familiar figure, Dick Feynman. Feynman was not only an extraordinarily creative mathematician for theoretical problems, he was also a bit of a clown and a performer. Whenever you saw a cluster of a few women who were around, you would discover that they were clustered around Feynman who was performing. Feynman was always performing. And some of us got to hear his stories, later collected by Ralph Leighton, the son of Robert Leighton. It was Leighton who wrote the books “Surely You’re Joking, Mr. Feynman!” and the subsequent ones. Anyway, he was certainly one of the most prominent characters at Los Alamos. Here is the way we heard colloquia, sitting in canvas chairs which were put out in the gymnasium after the place had been searched down thoroughly for any lurking gymnasts or spies. And here is our friend, the Polish mathematician, whose name slips me at this moment but you probably all know better than I, who actually solved the problem of how to ignite the 'Super', as it was called, the thermonuclear reaction in the light elements. And here he is on a bench sitting in the Plaza of Santa Fe with von Neumann and Feynman. Now, presently I’ll run through just some pictures of individuals. This is perhaps the most famous individual we had in the place whose name was Nicholas Baker. At least that’s the name that was broadcast on the PA system, because one of the most unspoken names in the place was 'Niels Bohr'. Bohr always spoke up but never said very much. And whatever it was he said you could not really resolve because Danish is a language not given to high resolution (laughter) and because he was forever puffing on that pipe. Now, what he would do is to scratch matches, take a deep draft of match smoke and strike one match after another. That would go on all day. I have here a picture of Bohr with his son Aage who accompanied him everywhere. This is a picture which does not come from Los Alamos. It’s very typical of Copenhagen. Anyway, the 2 were an inseparable pair. Aage, who by the way also received the Nobel Prize, not for the most effective nuclear model of the day in the early 1950s, not for anything that necessarily related him to the Bohr family. Now, the man who directed the project officially was Leslie Groves. He was a rather heavy-set man with a very military mind and remarkably little understanding of science considering the nature of the project that he was dealing with. Here is a rather idealised painting that was made of him (laughter) and which now is to be seen there. General Groves and Oppenheimer often appeared together. They were not pretending to be the Gold Dust Twins. They represented really the 2 things that went on: Military authority which was in a sense the propulsion what made the whole thing go, and the intelligence that directed it on the other hand. Well, the one thing one could do in the winter was ski. There were many ski parties, rather primitive ones, they were wooden skis as a rule and the simplest of poles. This was a group that included Fermi, Bethe, Weisskopf and a couple of others. I won’t delay you with all the names. This is a photo I’ve included because it dates from about 1931 and it involves many of the same characters. They all knew one another. There is Heisenberg. And if there was such a project, and on a certain plane there was such a project as this in Germany, it was Heisenberg who was the principle authority. But sitting next to him is Rudolf Peierls who ran the project, and who really initiated the project in Britain. And in the background you have people from several other locations. Victor Weisskopf was a young student at the time. And Felix Bloch, fairly young himself. George Placzek. A man who worked on the same sorts of things in Italy was Gian-Carlo Wick in the background. These people all knew one another. Now, it was a large project. This is the electromagnetic separation plant in Tennessee. Here in Hanford, Washington, is the reactor complex that actually produced the plutonium. And there are many stories connected with that which there is no time for. Let me introduce a couple of stories which you probably never did hear about Los Alamos. There was a need to calibrate the explosion that was planned for the Trinity test. How would one calibrate that explosion? What did you have to work with? Well, the inspiration was another explosion. So this is the platform from which that would be created. Here is literally 100 tons of TNT on a wooden platform which was in fact exploded well in advance of the Trinity test in order simply to calibrate their instruments. Here is another strange thing: a piece of steel, a steel tank, as a matter of fact. And we were assured that it was the largest ever fabricated. It was quite thick steel. This was as it was being shipped to Los Alamos. The reason for this was that the original tests would not have involved very high explosives for the assembly of the bomb but it was thought that the material was infinitely precious uranium 235 or plutonium had somehow to be saved. You couldn’t just let that be dispersed everywhere. So you had to try, given whatever explosive means you had, to use in order to assemble the bomb. The idea was to be able to collect the pieces and salvage the fissionable material. So this was a tank promptly named 'Jumbo' - it was the name of a mystical elephant at the time. Here it was being shipped to Los Alamos. Now, was Jumbo ever used? Well, it was realised that the explosive means that was necessary to assemble the bomb was going to be a bit too much even for that tank. And so it was never used. Whatever it cost and whatever it involved getting it from Pittsburgh all the way to the New Mexican desert. Someone after the war – this is a post-war development – decided to find out what would happen if he put several pounds of TNT inside this tank. (Laughter) And that’s the result. Let me move on very quickly to Trinity. I’m afraid we’re running a bit late. This is a 100 foot tower that was set up, the bomb to be placed on the top. The point was to keep its detonation away from the ground so that the ground not contaminate the explosion. Let the explosion take place up 100 feet. Well, here it is. There is the bomb. Not quite assembled yet but sitting atop the tower. Here exercising his curiosity to see the thing is – you can see who that is, can’t you, just from the silhouette. Oppenheimer wouldn’t have missed going up the tower to examine the bomb before it was detonated. Here you have a much more complete assembly of the bomb. These were all detonation devices to detonate in effect a sphere of high explosive. And this was a very complex sphere because it was a sphere which had not simply to explode outward but to create a blast wave that converged spherically upon the material in the centre. It was an extraordinary development that and probably the central one at Los Alamos. Here is the explosion after the first couple of milliseconds. This is the explosion at Trinity. Here it is a second or 2 later. Here is what was left seen from the air. The sand surrounding the tower was turned to a greenish sort of fused glass. And every last bit of it taken up by souvenir seekers presently. The circle you see here, this is where the 100 ton explosion was set off, just ordinary TNT in order to calibrate the instrumentation. And here are the first individuals coming in and looking at the stumps left over from the tower. The tower above had of course been completely evaporated. And this was one of the 4 supports of the tower. There, inevitably again, is the inseparable pair, Oppenheimer and General Groves. This is Victor Weisskopf off on the right. I don’t immediately recognise any of the others. Well, when we saw that - and I happen to have seen that explosion take place. As a theorist I was not welcome at the Trinity site, and so some of us managed to drive cars, which were even pretty scarce then, to the top of a peak, Sandia Peak near Albuquerque, where we had quite a distant view. And I managed by staying there all night and waiting until 5.30 in the morning, which was about 4 hours after we expected the blast to take place. I saw what amounted to a sunrise in the south. A very short time later there was a sunrise in the east. Well, here is what went on in the 3 weeks following the mid-July Trinity test. This was on Tinian Island. This is the implosion bomb, the spherical one. And also, by the way, that was the one tested at the Trinity site. And as you know it worked and that was a cause for celebration by 2 people out of 3 in the Potsdam conference. Truman had been informed about the test immediately. Stalin was probably not informed immediately, but he was surely informed. And there was a bit of a celebration when the war ended, involving of course General Groves and the President of the University of California who formally directed and oversaw the project. But President Sproul had never set foot in the place and never seen, it’s not even clear that he had known about the existence of the project. Oppenheimer, of course, became something of a celebrity. And a year later in the Harvard commencement you had this collection of people: Conant again sitting in the centre, General Marshal who was about to unveil the Marshal plan, General Omar Bradley and here somewhat lost off in the corner is J. Robert Oppenheimer, a Harvard alumnus. And I must say this was quite a reunion seeing him there again. He became something of a celebrity. Now, I don’t know how much further to go with all of this because there are a great many pictures and it’s gotten a bit late for the end of this talk. Maybe if there is a slide machine where we will be talking in the afternoon? It's said I will be with some students, and maybe we can put the slides, the remainder of the slides together. There are a few interesting ones. But they have entirely to do with post-war matters. This is a collection of theorists who gathered at Shelter Island 2 years after the end of the war. But there’s a considerable number of names you would recognise in that. Let me cut it off here in order not to run too substantially over and I’ll see if we can do more this afternoon. Thank you.

Roy Glauber (2016)

Some Recollections of the Manhattan Project 1943-1945

Roy Glauber (2016)

Some Recollections of the Manhattan Project 1943-1945

Abstract

Late in 1943 my undergraduate education was interrupted by my transfer to an unstated and distant location. It proved to be an improvised but huge laboratory complex, unaccountably remote, isolated, and difficult to reach.

Content User Level

Beginner  Intermediate  Advanced 

Cite


Specify width: px

Share

COPYRIGHT

Content User Level

Beginner  Intermediate  Advanced 

Cite


Specify width: px

Share

COPYRIGHT