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Lawrence Litz’s Interview (2007)

Manhattan Project Locations:

Lawrence Litz was a young physicist when he began working on radioactivity at the Metallurgical Laboratory at the University of Chicago. From there he was transferred to Los Alamos, where he worked on casting the plutonium hemispheres for the atomic bombs and became the first person to see metallic plutonium. He recalls the twenty-four hour shift he pulled to cast two more plutonium hemispheres in case a third atomic bomb was needed to force the Japanese to surrender.

Date of Interview:
September 12, 2022
Location of the Interview:


Justin Piel: Hi, I am Justin Piel and I am in Palm Harbor, Florida interviewing Dr. Lawrence Litz for a school biography project.

Lawrence Litz: Good afternoon. I am Dr. Litz. I am glad to be able to discuss some of the work that I did many, many years ago on the atomic energy program. And I think Justin has some questions he was interested in getting answers to.

Piel: So, what is your full name?

Litz: Lawrence L. Litz, middle initial “M” for “Marvin.”

Piel: When were you born?

Litz: October 22, 1921.

Piel: What was your childhood like?

Litz: Very good. I grew up with a younger brother and a younger sister in Chicago and we always were happy with what we were doing even though we were living in the middle of the Depression.

Piel: So what was it like working in the war?

Litz: Exciting in a sense that the work itself that the work itself was very interesting. The fact that the war was going on and what we were doing was supposed to help end it was not as critical in our everyday thinking. But the programs that I had to work on were very exciting.

Piel: So what led you to become a scientist?

Litz: I guess that was just how I liked to think. I took chemistry in eighth grade, elementary school and was involved with chemistry and physics ever since.

Female family member: Stop. Ask him about when he blew up the attic.

Piel: When did you blow up the attic?

Litz: Well, it happened that we had a very nice attic with lots of room in our house in Chicago. And I had my chemistry set there and one day what I was doing happened to be a little explosive and splattered liquid all over the ceiling of the attic.

Piel: Oh, my. So what did you study when you were in college?

Litz: Well, I went to the University of Chicago. Actually, I went to a secondary junior college, Wright Junior College in Chicago, studied chemistry and just general topics. And then when I went to the University of Chicago, I majored in chemistry with a minor in mathematics. And then this was in—I graduated from Chicago in June of 1942. On June 12th I left school, got married on June 13th. 

And on June 14th, I went down to Florence, Alabama and started working at an ammonia plant in Florence, Alabama for the Tennessee Valley Authority as part of my scientific experience in industrial activities. And then, of course, while I was there, we had a laboratory starting with twelve men in the control laboratory for the ammonia plant. By a year later, that is in June of ’43, we were eleven women, one man, myself, and a group leader. And I decided that I ought to get involved in something that was more attractive to a man than being in a lab with eleven other women. 

So I left and I went back to Chicago to wait out my time while I was looking for a job, went to—one day somebody said that there was work going at the University of Chicago. And I went there and they said, “Well, you know, you have been working at an industrial laboratory, but we would love to have you.” But they would not tell me what I was going to work on, but that it was going to be very interesting. So I took the job there in November of 1943, spent some interesting time studying the effect of radiation on materials having to do with the nuclear reactor that was being built in—I forget what state—but up north somewhere. And then when that work—the act of construction started, they shut down my job because they were satisfied that they could live with what they knew about the effect of radiation, and they transferred me to Los Alamos. 

At Los Alamos I got involved with some chemistry work at the beginning, but then they needed somebody who had experience in high vacuum metal, high vacuum technology. And I joined a group that was going to work on plutonium, which was a newly conceived element. The plutonium was just then being produced in the Hanford, Washington nuclear reactor, and at the beginning we would get very tiny quantities of it. 

About—oh, it must have been—see, I started there in March of 1944 and within about, I would say, a month I had built a high vacuum system that could purify metallic plutonium. Then there was this one particular day of interest when I had the first small amount of plutonium as a salt put into the high vacuum system, reacted it with magnesium metal to form plutonium metal, and the magnesium part was boiled off in the high vacuum system. And we had a little tiny button, about an eighth of an inch in diameter, of metallic plutonium. 

So I was the first person ever to see metallic plutonium. And it turns out that my wife, Evelyne, was working in health physics at that time and she was responsible for checking the laboratories for stray radioactivity. She happened to walk into my laboratory just at the right time and I told her, “Look into this little telescope,” that looked down on the crucible containing the plutonium. And so she was the second person on earth to see a piece of metallic plutonium. 

I also developed this material, which is cerium monosulfide. It is a golden color and is very resistant to reaction with the chemical that are involved in the plutonium metal chemistry. And it’s the kind of thing in which the early pieces of plutonium were melted. 

Later on the quantities got bigger and bigger and I had to develop the procedures to stabilize plutonium, because plutonium was a metal that had six different crystal phases as it was heated between room temperature and its melting point, which is about eight hundred degrees Centigrade or about two thousand degrees Fahrenheit. And the problem was that we could not make a bomb with a material that would change shape due to its changing crystal form as it got hot. And it finally turned out that when I mixed it with small amounts of gadolinium—and all this information is now in the open literature, but, of course, in those days it was absolutely secret. But three percent gadolinium, that stabled one of the phases so that we could make the spheres that were going to go into the atomic bomb, and they wouldn’t change shape as the bomb warmed up from room temperature to the point where it exploded, but would stay as a sphere configuration. 

The bomb itself was designed as a piece of plutonium—actually two half-spheres, hemispheres that were put together to make a full sphere. And in the middle there were some elements that would product neutrons as the reaction procedure proceeded. And these neutrons caused the plutonium to undergo fission and release very large amounts of energy.

So this sphere which might have been, oh, perhaps eight inches in diameter was put inside of a casing of high explosives that was about, I guess, maybe four feet in diameter. And when—

Female family member: The picture, yeah.

Litz: Oh, yeah, and here are pictures of what the bomb looked like. These units were built many years later to show in a program that was held at Los Alamos to celebrate the fiftieth anniversary. And I am standing beside one and my wife Evelyne standing beside the bomb in another picture. The newspaper is the first publication that released to the public the fact that we had an atomic bomb and that it was dropped on Japan. 

Actually, this particular bomb that was first dropped was dropped on Hiroshima and it was made of uranium. But we had made a plutonium bomb earlier and tested it near Albuquerque, New Mexico to find out whether the whole concept of having this high explosive mass going off and actually compressing the plutonium sphere and causing it to become explosive—was not explosive in its form as we built it. And, of course, this is a completely new concept in causing a bomb to explode. But they tested it in the desert there in southern New Mexico and found out that it had the explosive force of about twenty thousand tons of TNT, in this little tiny sphere of plutonium metal when it underwent fission.

So the first bomb that was dropped was the one that was dropped on Hiroshima and that bomb was made from pieces of uranium-235 that were shot—slugged into a solid unit of uranium-235 such as when this piece entered the whole thing became critical or explosive. 

The war of course was going on. Plans were underfoot to invade Japan. As a matter of fact, when the war ended as a consequence of our dropping these two bombs on Japan, my brother, who was in the Army in Alaska, was getting ready to board ship for the invasion of Japan. Dr. Oppenheimer, who was head of our Los Alamos project, had talked to us for about two hours the day before the bomb was actually dropped and we had shipped it to the Tinian Islands to be carried out to Japan. And he pointed out the fact that our military had estimated that had we gone through—would we go through with the invasion, which was fully under schedule then—if it happened a bit later – that we probably would have lost about a million men. And after the war ended the Japanese told us that they too had estimated that had there been a normal invasion of Japan, that probably a million Japanese would have been killed.

Now, in the two cities that were bombed—the second city that was bombed was Nagasaki. It was bombed two [three] days after the first bomb that was dropped and it was the bomb that caused the war to end—had the Japanese made the decision to give up to the Allies in World War II. And they too had estimated that had we gone through the invasion that probably a million Japanese would have been killed in, of course, the invasion—the war that would be going on during the period of the fighting.

So the two bombs and the two cities that were destroyed by the two atomic bombs lost about one hundred thousand people as a consequence. But one of the things that is pointed out in this article – and this article is the, as I said, the first public announcement that there was such a thing as an atomic bomb and that it was destroyed. But also right in the middle of the thing is an article which says that more Nippon or Japanese cities are being put into smoldering ruins by our conventional bombing. Because at that point in time, every day there were thousand-plane raids on different Japanese cities, which were completely destroying the cities. So with our bomb we did not do anything more than what was being done every single day before and would have been ongoing afterward, where we were essentially wiping out Japan. 

And, of course, the war ended and everybody was very happy, including me. And I stayed with the Manhattan Project at Los Alamos for about another month and a half or so. I left in September of 1945. I went back to graduate school at Ohio State and got my PhD in Physical Chemistry. So I became a doctor of physical chemistry.

Piel: So to be selected into the war, you like volunteered or—?

Litz: Yes. Well, I was looking for a job. Almost everything that, let’s say, a scientist would do during that period was likely to be involved with the war effort. The ammonia plant in Muscle Shoals, Tennessee made ammonia, but a larger part of that ammonia was converted into nitrates, which were used in making bomb materials. So the fact that we were working on something that hopefully would help to end the war wasn’t of great concern. And, as I say, when Robert Oppenheimer talked to us about that, he made the point very strongly that hopefully the thing we would do could bring the war to an end. And it did.

Piel: How did you first react to—when you were told that you had the job to be in the war?

Litz: Well, I was happy to have a job. As a scientist I was ready to do almost any type of science that I was knowledgeable in. And, of course, the interesting aspect of this is that most of my science had to do with chemistry and water and different types of solutions, different types of materials. I really had very little training in metallurgy, but the fact that I knew how to build and run high vacuum systems was a critical fact that, in my case, I was the right guy to take on the job of doing the research involved in determining how to purify the plutonium metal, how to alloy it. I worked, of course, with many other scientists, for example, who would do the research on what the crystal structures were and so on, tell me what was going on, see what I could do to fix things.

Piel: So how did you get to New Mexico if you lived in Chicago?

Litz: Yeah. Well, that’s a slightly interesting story. Los Alamos, New Mexico is about thirty-five miles north-northwest of Santa Fe. And when I was transferred to Los Alamos, I did not know what things were being done there, because, again, the secrecy was such that the people in Chicago did not know that we were truly working on an atomic bomb. We knew that we were working with radioactive materials. But the fact that the goal was to produce an atomic bomb was not known to this large laboratory of scientists at Chicago. And we did not even know where Los Alamos was. 

The group that I worked for in Chicago bought a train ticket for myself and my wife and our little puppy to go on the Santa Fe Chief from Chicago to Los Alamos. I’m sorry—from Chicago to Santa Fe. Well, the passenger train does not actually go to Santa Fe. The passenger train goes to a little town called Lamy, New Mexico, which is about eighteen miles south of Santa Fe. And we got off the train at Lamy and we sat down on the bench of the railroad station. And everybody else that was on the—everybody else who was on the train got on the bus that took them from Lamy to Santa Fe. 

But I was not told that I was supposed to get on the bus, so my wife and I and our baggage and our little puppy were sitting there on the train in Lamy, which was just a very tiny town built around the railroad station. And everybody had gone and we were sitting there. And then about half a block away in the parking lot, there were a couple of military cars. And after we were sitting there for almost a half hour, a man got up from one of the cars and came over and talked to me and said, “Weren’t you at the Met lab?” So the man asked me whether I had been at the Met Lab, which is what the laboratory at the University [of Chicago] for the Manhattan Project was called. 

I said, “Yes.” It turned out that he recognized me because he had worked there, had seen me there.

And he says, “Are you going to the hill?” 

Well, I did not know what “the hill” was, but I said, “I guess so.” I assumed that he was going to Los Alamos too. And so we—my wife and I and our stuff got in the car, they took us to Santa Fe where there was the entering office for Los Alamos. 

And the lady there checked out my identification and said, “Yes, you are due up there.” And so we got in another car and they took us to Los Alamos, which is up in the mountains about thirty-five miles, as I said, north-northwest of Santa Fe. 

When we got to Los Alamos, they said, “You were not supposed to bring your wife with you.” Well, they knew—in Chicago they knew I was bringing my wife because they bought the ticket for the two of us .But they said—well, they had assigned a small apartment to us, but had not anticipated her being there for another week or two. So they managed to get a couple of beds and a couple of lamps put in so that we could sleep there that night and they could furnish it the next day.

So when I first got there, I was working with some other scientists making what they called “Water boiler,” which would be a nuclear reactor with a surrounding of water that would reflect the neutrons back into the central radioactive material. This took place about maybe two months and then they finished that activity and said, “Well, we need somebody else down in the metallurgy organization and we know you had experience in the past in building and operating high vacuum systems, and we would like you to go down there.”

And I said, “Well, okay.” As a young scientist I was interested in doing almost anything that would take advantage of my skills. At that time I was, let’s see, I guess about twenty-two years old. 

Piel: Wow.

Litz: Well, I got married in June of 1942 and I was twenty years old because I got married in June. I would be twenty-one in October. And so by the time I got to Los Alamos I was twenty-two going into twenty-three. So, as I say, I was a very young man. But as my peers and my superiors determined, I apparently was very capable and that is what our director at my time at Los Alamos said, that I was unusually able to do the job, particularly for a man my age.

Piel: What was a normal day for you in the war?

Litz: Well, typically we would start—my particular program we worked just during the day. So I would start working perhaps eight o’clock in the morning and work until five with a break for lunch. I would go doing whatever experiments I had to do.Take time off and go back to our house, which was about a half a mile away from the laboratory. Evelyne also worked in the laboratory too, so we would break for lunch together, go down, make something, and then go back to work ‘til five. 

But a particular day that always remains in my memory is the day that we were getting ready to melt and purify the metal for the third atomic bomb. The first bomb, as I said, was uranium. The second bomb that was dropped was plutonium. And we had just enough metal to make one more bomb. And at that point in time, when the second bomb was dropped, we did not know whether the Japanese were going to surrender or not. And so the military wanted to have a third bomb ready in case the Japanese refused to surrender. And so I actually worked twenty-four hours on units and high vacuum systems in two adjacent laboratories so that I would produce one hemisphere in one and then go on and produce the second hemisphere in the second laboratory. And this took actually just about a full twenty-four hours to do because the military said that if the Japanese did not surrender, they wanted to have that third bomb ready to drop on Japan. 

Of course, we didn’t need it. And there was an incident, which was an unhappy incident, involving that third plutonium bomb in that the scientist there wanted to do research on the radiation characteristics of the plutonium. And they melt the system—were the sphere of plutonium, which as I say was about maybe eight inches in diameter, was inside a large array of material that would reflect the neutrons that would be produced and would come outside of the sphere – reflect these neutrons back into the sphere. And also would keep those radiation—the neutron radiation particularly—away from the scientists who were doing the experiments. And the man who was working on that accidentally bumped that array of shielding material and, as a consequence, exposed himself to the radiation from this sphere of plutonium. And he died two weeks later from the radiation. So that was sort of rather an unhappy memory. And this was shortly after the war had ended.

Piel: What was the most challenging thing you came across in the project?

Litz: Probably the most challenging part was to find the right materials to stabilize the plutonium sphere so that it was not changing shape during the explosive process.

Piel: Were you ever worried that you might be exposed to toxic materials during the work on the nuclear testing?

Litz: Oh, we were always concerned. We tried to be safe, but in my case, I had to handle all this metal. The radiation was not very severe, just as I was working with it. And so I was reasonably protected with rubber gloves and we worked in what was called a dry box, so that the dust and so on would not get out. But I also had to clean up the high vacuum systems in which I was doing the experiments and I must have received some plutonium because they would test us about every three or four weeks. And it turned out that when the war ended, I had what was called the maximum tolerable dose of plutonium in me. And I will have this long after I die because plutonium only decays to half of its quantity in over five thousand years. So I do not know whether it will be in my skeleton or not, but it will be there. 

Piel: So what was life like for you and your family while you were working on this project?

Litz: The project was really very pleasant from a social point of view. We made a number of very good friends. It is interesting that one of the men who became very famous had actually wrote a book, which is entitled You’re Joking, Mr. Feynman, happened to be our next-door neighbor. And, of course, the very pleasant thing that happened while we were there is that my first daughter of four was born on April 21, 1945. And so we had a very pretty little girl to keep us company and make us happy also. 

Piel: Do you keep in touch with any of the other scientists that you worked with?

Litz: We were not allowed to correspond at all and it turned out that probably maybe in late 1944 when Evelyne, my wife, was pregnant, we got permission to take a trip back to Chicago to see our family. And I was told that I was not to talk to anybody in the scientific field while I was there. And I know that I was followed by probably G-men or somebody, who was going to make sure that I did not spill any of the secrets that I carried around with me. But the fact that we were doing this very important secret work made me confident that I would not talk to people that I should not.

The information on the atomic bomb was probably declassified in terms of the full details four or five years after the war ended. But there were many secrets that were not released until, I guess, about ten years ago—two years ago? My daughter says some of the work was not declassified until just two years ago, which, of course, was interesting.

Piel: How did you feel about the way Oppenheimer was treated in the fifties? And did you have any contact with him after he was freed [inaudible]?

Litz: No. Dr. Oppenheimer was, in terms of how he interacted with the group in Los Alamos, was extremely pleasant, jolly, and very caring. And, of course, as I said, made sure that we had a complete understanding as to the importance of what we were doing and to the fact that it was undoubtedly going to kill many people, as the normal bombing raids were doing. But the fact that we did this and we had to carry out this loss of life was likely to save, as both the Japanese and our people had estimated, would probably save almost a couple million lives. And he spent about two hours just before the bomb was dropped telling us exactly what was going on, where the bomb was going, where it was probably going to be dropped on certain critical cities of Japan. And that we should understand even though we were not pleased morally about the end consequences, how important it was, how many lives we were really going to save.

I did not correspond with Oppenheimer after I left. The areas that I worked in many fields subsequently—fuel cells and many other things—silate—did not be of the type that he would be concerned about or particularly interested in. But I was very interested when the McCarthy hearings were taking place in the fifties in which he was being accused of doing things badly and of being a Communist. And, of course, there was no indication whatsoever during the war that he had any inclinations toward communism. He was certainly an extremely devoted American citizen. And the consequences of the hearings in the 1950s where he was really destroyed mentally and morally were so bad and so out of context that I know—I am sure everybody who had been with him in Los Alamos and I am sure later on when he was at Princeton, were very disturbed. And certainly I was.

Piel: Did you receive any awards for your work in the project?

Litz: Not at Los Alamos because the activities being so secret they would not have—at least they did not have programs to give awards to people. But afterward, after I got my doctorate degree and I worked at the Battelle Memorial Institute on high temperature materials and created some procedures for producing ultra-pure silane, which is a technology currently being used today to make silicon and silicon carbide and high purities. And we have an award picture that shows me down here among a number of other scientists who were the pioneers in the silicon chemistry that led to the ability to make semiconductor materials from silicon.

Female family member: Why is that important?

Litz: And, of course, this is extremely important in that almost all electronic things today are made with the high purity silicon and silicon carbide that is made by this procedure. And then I also worked on fuel cells and have awards. This is an award that was given to me at Battelle—no, I’m sorry, it was subsequent. I left Battelle and I went to work for Union Carbide and this is a merit award from the Union Carbide Corporation for Chemical Engineering Achieving in developing a new membrane support system that extends ultrafiltration. This is a technique that is used to get high purity materials and also it was related to the type of membranes that I built to make fuel cells to drive probably one of the first fuel cell-driven cars in the mid-sixties. I built the fuel cells. General Motors converted a Chevrolet van to electrical drive and they put them together and they drove the van up and down in front of Carbide’s corporate headquarters in New York. And then the van was taken back by General Motors and the fuel cell was given to the Smithsonian Institute. And they still—I have a letter which congratulates me for that work and they told me that this letter was just this last year—that they still use that fuel cell to demonstrate what a fuel cell is. And it is, of course, a way to get electricity from hydrogen, oxygen, or other gases.

Piel: And then the last thing that my hockey coach wanted to tell you is when I told him that I was going to miss games to come here and interview you, he told me to tell you to thank you because his father was in the U.S. Army and was preparing for the land invasion of Japan when the atomic bombs were dropped on Hiroshima and Nagasaki. So because of your work, without that my hockey coach might never have been born. 

Female family member: What’s his name?

Piel: C. J. Kneehof.

Litz: And it is interesting that this coach had the same background in that context as my brother who lives in Alaska, ready to go to Japan for the invasion. And he also could have been killed. But he is very happy now. 

Piel: And these?

Litz: All right, these are a few of the patents that I am either the author or co-author. This one is of a mixing device that very efficiently mixes gases with liquids and is used in many types of chemical operations where you might use oxygen or hydrogen particularly to react with something in a liquid phase and this gives you very efficient means of getting the gas bubbles mixed with the liquids. We call this [inaudible] gas reactor. And then this patent, which—by the way, I have actually about forty United States patents where I am either the author or co-author of the patent. 

This one is an interesting one in that it is a technique for providing oxygen to fish that are being grown in fish farms where many fish are now being grown. They need oxygen to live and before I got involved with this, the oxygen was provided back in their location by taking the water and spraying it through the air to pick up oxygen from the air. Well, air contains about twenty percent oxygen and the balance mostly nitrogen. And so you could get about eight parts per million of oxygen in the water and so they would have to circulate a lot of water to provide oxygen to the fish through these spray areas. Well, I was working through for the Linde Division of Union Carbide at that time, and we decided that that ought to be a place to sell oxygen, which was produced by Linde, instead of having them use air. Because if they could use oxygen, they could get forty parts per million using pure oxygen. If you get forty parts per million—five times as much in the water per gallon as they would the air spray. And so they could grow many more fish per gallon of their tanks than if they used the air. And all this is a simple well in which the oxygen is fed into the water going down to the bottom of the well. And as it goes down and then comes up around the side of well, it dissolves—the oxygen dissolves in water and it produces a water with a high oxygen content. And so this is used very generally now in most fish farming applications.

Female family member: And one of your biggest awards.

Litz: Okay. And then one of the awards that was gratifying to me is my award to become a corporate fellow within Union Carbide. At the time I got this award, I think of these one hundred thousand or so employees of the corporation, there were only twenty-eight corporate fellows. So I was number twenty-nine and becoming a corporate fellow was equivalent to becoming a corporate vice-president in terms of salary and stature. And, of course, that was very satisfying.

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