Nikolaus Riehl - Session II

Walker:

Let us begin with the Auer Company. I understand that you had been with the company a long time when the war started.

Riehl:

From 1927 onwards.

Walker:

And the Auer Company had experiences with thorium and the like. My question. I understand that immediately after the start of the war, the Military Weapons Ministry started the uranium project. Did they contact the Auer Company immediately?

Riehl:

Yes. That was so. In fact, I was the initiator. The Military Weapons Ministry had, at start, some interest in the matter for a period but then dropped it for various reasons: In part because the whole matter went very slowly; then they became interested in rockets which were much simpler for them to understand. Did you by chance not see the television broadcast several months ago? It was a program on British television. several of us appeared. I was there along with Weizsaecker, Wirtz, that is Karl Wirtz, and Casimir from Holland. Casimir, in fact, said something that no one else could say. They all wished to demonstrate that they were not Nazis. It is clear that Heisenberg was not a Nazi, but scientists are often politically very naive and so it was with Heisenberg. Casimir expressed that point very clearly.

Walker:

Yes, that impressed me a great deal.

Riehl:

Did you actually see the broadcast?

Walker:

No not the broadcast, however, there was a small publication that followed the broadcast having the title "Picture of Science."^[1]

Riehl:

So.

Walker:

It did not mention you but did mention Weizsacker and Casimir. Casimir emphasized what you just said. Moreover, Casimir wrote a book in English.

Riehl:

What's its name.

Walker:

"Haphazard Reality." It is in English.^[2] In it one sees that basically Heisenberg regarded himself as a German nationalist but he was not sympathetic to National Socialism. However, he did not want to see Germany lose the war.

Riehl:

Yes. Yes. That was a problem. There was a wonderful joke that circulated a good deal in Germany during the war. The joke in the form of a question: What does a pessimist say? Example: After it has been snowing for a long while, the pessimist says, "We have had a great deal of snow this year but it is not of the same quality that we used to get." And so, there is a similar joke that goes as follows: The pessimist says, "We will lose the war but Hitler will remain."

Walker:

I have a definite question. As the war continued and you worked with uranium, did you also have other activities.

Riehl:

Yes. Yes, of course.

Walker:

Would you give an estimate of how much of your time you spent?

Riehl:

How much on uranium and how much on other things?

Walker:

Little or much?

Riehl:

Little.

Walker:

The other topics were immediately important for the war, I assume.

Riehl:

The other topics?

Walker:

Yes.

Riehl:

No, I wouldn't say that. I did not deal mainly with matters that were important for the war, but rather with matters that would be important after the war. The situation was as follows. The Auer Company supported itself on a number of things, that is, rare earths, thorium, luminescent compounds, and also on uranium. They brought money to us and that was the important thing. Since my scientific division needed money, that was very important. For an industry one states, “Investigate, investigate.” And then someone asked, “And where is the money?" That principle I know well. To continue, "last but not least,” we manufactured gas masks. For example, it was called the People's Gas Mask. That was a relatively simple mask that every German had to have in the Hitler period. That was the real business that brought money, more money than thorium, the rare earths and luminescence taken together. The Auer Company feared that when peace came, "when peace broke out" as was commonly said, the Auer Company would have lost its main business. As a result, it was the obligation of my scientific division to carry out research and development which would give us new fields of endeavor which the Auer Company could develop. People noted that I had a bit of fantasy and an instinct for specialties that could succeed.

Walker:

Viewed fundamentally, was the preparation of uranium scientifically interesting?

Riehl:

Not scientifically. The subject was, of course, as I have often said, something completely new, something exciting, the whole uranium history. We were all fascinated, including me. I was quite certain, and I mentioned this explicitly in the television broadcast, that I never believed that there would be a German atomic bomb prior to the collapse to Hitler. I was convinced of this, partly because of Hitler's primitive outlook and partly because I saw the great strain being placed upon industry through the war effort. For example, I had to wait eight months to obtain seventy kilograms of copper for a high temperature oven. Copper was in extremely short supply in Germany. You can see by this example, how weak the governmental support for this project was.

Walker:

That means there was little copper available?

Riehl:

There was very little copper available. Let us go back to Auer. The principal work of my scientific division was to find new areas of work for Auer. Things could be useful when peace "broke out." It was, of course, somewhat naive that peace would break out and then everything would be as it was previously. However, that was a slogan and with it went my primary mission. In this way I answer your question whether I worked on things other than uranium that were important for the war. I can answer with a flat "no."

Walker:

So you worked on more than uranium.

Riehl:

Much more than uranium. In the case of uranium, the situation went as follows. I was the initiator. When it became, clear that it could provide a new source of energy that brought my interest to focus. I first went to Otto Hahn and asked him what he thought was right. Should we begin preparing very pure uranium for nuclear reactors at the Auer Company. Incidentally, at that time we called them uranium machines. He said, "Yes, that seems right to me but please understand, the production of energy doesn't interest me. I am much more interested in the fission products since I would like to investigate them and determine in more detail which kind and how they appear. That interests me a great deal and the reason why I believe it is appropriate to work on a uranium machine, but I am not interested in the energy. I then said, "In my case the reverse is true. As an individual working for a company and a technically interested physicist, I am much interested in the production of energy." After this meeting with Otto Hahn and his blessing, I went ahead. I would not have done so if Hahn had said: "Please do not do this." After the conversation I went to the Military Weapons Ministry and obtained the first order.

Walker:

Can you remember the date when you went to the Ministry.

Riehl:

When?

Walker:

After speaking to Hahn but before the war?

Riehl:

That is easy to determine and can be readily confirmed. It was immediately after the article of Fluegge, immediately after.

Walker:

That was June of 1939.

Riehl:

Shortly thereafter, perhaps two weeks or ten days, but shortly after. I also remember that my part-time coworker, Mr. Zimmer, came to me since we had both read the article. He looked at me and I looked at him and I said, "That's a matter for us to work on." Zimmer was involved in the initiative but I was the director of the scientific division. I had influence and money and so to say power. I gave the responsibility for the first part of the work to Dr. Hoernes, that is, responsibility for the methods of chemistry dealing with this. I am basically not a chemist, whereas, Hoernes was a chemist. I am speaking here of Dr. Philipp Hoernes. He worked out the procedures very thoroughly and very well. He was half Jewish and was shielded in my organization. Earlier on he had been the director of our factory for rare earths in Oranienburg and had to be hidden somewhat on racial grounds. No one could touch him.

Walker:

Such people could not be director of a factory?

Riehl:

No. They could not be. They could not hold an official position. His wife was purely Jewish. Later on as the war progressed, we took her into our home for protection. That was, of course, dangerous but everything turned out well. Nothing happened either to Hoernes or to his wife. He did all the basic chemistry work. He did it and I followed it in the manner of a coordinator, although later on I went to Degussa to have them take over the metallurgical activities since we did not have experience there. Earlier on, Degussa, as a result of urging from me, had developed a procedure for the production of very pure metallic thorium. We had a considerable excess of thorium, more than we could sell. (Cerium and thorium are often found together in ores.) We had great sales for cerium but thorium remained unsold. I began searching for an application for thorium metal. I said to myself, thorium is an interesting metal, very pyrophoric, and acts like a getter, that is, it will absorb gases in vacuum. I also found another pair of uses for thorium. That is the kind of thing which occupied me for the most part. In order to produce thorium in metallic form, one has to turn to metallurgical procedures. We could produce oxides easily but one needs additional processing to get the metal. That was accomplished by Degussa as a result of my stimulation. Since they made such excellent metallic thorium, we decided that they ought be able to make metallic uranium. In fact, the first uranium metal was made by the same procedures. Later on, we developed a branch factory near Berlin for producing uranium. It belonged to the Degussa concern. So that is the history. It was a managerial activity. I went here and I went there. I arranged this and I arranged that. The time required to carry through the uranium story was not long. The first factory, which I arranged, was in Frankfurt itself and was part of Degussa. After the war, everything was made in Hanau near Frankfurt. Herr Wirths was there. He was the true head in the factory. He was a very good chemist. When he was with me, he began in the radiological division and then commented that it was more interesting to be working with me and asked me to transfer him. That was a very good idea since I knew him very well. Thus, he was transferred to our scientific division, but to begin with had nothing to do with uranium. Naturally, he was much interested in the progress of events but the main responsibility belonged to Dr. Hoernes. However, when I went to Russia, Wirths became deeply involved in the work on uranium there. He played an extraordinarily important role, working in collaboration with Mr. Thieme, who also had nothing to do with uranium previously. The two were among my most important co-workers in Russia.

Walker:

And Mr. Zimmer said to me that although he was in Russia with you, he actually had very little to do with uranium.

Riehl:

That's right. He had very little to do with uranium. He did not come to Russia at the same time as I. In fact, he was only a part-time employee of the Auer Company but more in the role of a manager. Thus, in this sense we worked together in Germany. We used to joke together, saying that we were too speculators. Back in the great inflation time of the 1920s there were two Jewish speculators by the name of Barmat and Kutisker, who were nationally famous. Zimmer said to me, "We are like Barmat and Kutisker. We go from office to office and hope to find money." He worked well along with me. He is, indeed, a very clever man and I have often sought his advice. We were very close in Germany. In Russia, however, we were not the equivalent of Barmat and Kutisker. Instead, he became interested in biological matters and worked with Timofeyev-Ressovsky. Timofeyev-Ressovsky was actually a Soviet citizen. However, he came to Germany in the 1920s at which time there were very good relationships between Russia and Germany, not as at the present time. Lenin was in power but the relationships were reasonably liberal. Well-known physicists such as Ioffe often came to Berlin and gave lectures and Springer-Verlag produced a journal that had the name "Physical Journal of the Soviet Union." It was produced in Berlin. The relations were, indeed, very good. No hostility or anything like that. It might, in fact have remained like that if Hitler had not come into power. Stalin had continued the good relationships. He was wiser than Hitler. In any case, Timofeyev-Ressovsky came to the Institute for Brain Research following the death of Lenin since they wished to have his brain examined. Professor Vogt, a brain scientist, that is, a German brain scientist, took on this request. Timofeyev-Ressovsky came to Germany in connection with this request and so enjoyed working here that he remained. He was actually a geneticist, but he enjoyed the atmosphere so much that he remained. He did not obey the request that he return to the Soviet Union. In other words, he was…

Walker:

Subject to treason.

Riehl:

Yes. Subject to treason. Later during the war he lived at peace. No one followed him. The Nazis left him alone. He lived there and we all supported him. We had very close contact. We were all good friends and then the Russians came. I said to him, "Timofeyev, you are subject to treason. It can go very badly with you." He said, "No. Nothing will happen." I said, "I am formally in order being a German citizen, but you are a Russian citizen." He repeated, "No, nothing will happen to me." He had two sons and one of these sons was murdered by the Nazis. No one knows the exact circumstances. He had made contact with the Russian prisoners and had helped them. When that was discovered, he was arrested and put in prison, disappearing without a trace. Timofeyev said that the fact that his son was lost in itself should be regarded as justification for staying in Germany. That was, of course, not the case. The Russians came into our area first and questioned everyone. I was already in Russia at this time, since I was among the first individuals picked up and taken off. The entire group was arrested. Timofeyev was given a ten year sentence and with him Zimmer, Katsch, Born, and Zarapkin, a Russian, were picked up. Zimmer joined me since he was a German citizen and was not actually sentenced. He did, however, spend a period of time in the famous Lubyanka prison as a captive. One day Zavenyagin, the Atomic Minister in Russia, called me and said, "Do you know a Dr. Zimmer and a Dr. Born." I said, "Yes, I know both of them very well." "Do you wish them?" "Yes." I said, "Of course." Then it became clear to me that the poor gentlemen were captives. I had not known it previously. I had though they were walking about Berlin as free men and envied them. I thought, here I sit in Russia and they wander about East Berlin. Perhaps they don't have much to eat but they are free individuals. Now I knew that they were not actually free, that they were indeed less free than I. Thus, Zimmer came to me, not along the uranium road, but as a friend and a scientist.

Walker:

When he was in Russia.

Riehl:

While he was in Russia in one way or another. I tried to arrange the situation so that Zimmer and Born would not actually be working directly in the uranium activity but in ways that would be closely related to it. That was, of course, somewhat of a swindle, since we had no need for a geneticist and also had relatively little to do with radiochemistry. However, I wanted to keep them busy. Then one day the institute in the Urals was founded and they went there. Later on I came as scientific director of that institute.

Walker:

Zimmer said to me that the Russians only were interested in whether the German group accomplished something. They cared little about what went on within the group itself as long as it was productive.

Riehl:

That is exactly right. They were not interested in what went on within the German group so that in that sense we had a great deal of internal freedom. For example, during that period I wrote a scientific book which had nothing whatever to do with uranium. Zimmer translated this book into English since he knew that language very well. I wrote it first in German and then translated it into Russian and he translated it into English. The book was sent to press and printed but then the Lysenko affair developed and the book was placed on the forbidden list. Many Russian scientists managed to get hold of the book in some way through some channel. Moreover, they cited it. However, the book never appeared officially, although it was announced — a book by Nikolaus Riehl.

Walker:

Do you have a copy?

Riehl:

No, unfortunately not. Unfortunately not. I do not myself have one but many Russian scientists have it. I know that because one of them said to me that the book was very interesting. Not everything in that book is right anymore since a great deal has developed since. However, it was interesting, contained much material and was well thought through.

Walker:

Can I ask another question. It relates to partly tense relationships between the Wirtz group and the Diebner group.

Riehl:

Wirtz and Diebner?

Walker:

Yes. In Dahlem Wirtz was working on a uranium machine which used sheets whereas Diebner carried on his own activity later under the authority of the Military Weapons Ministry with cubes that is with a lattice of cubes. While there was a relationship between these two groups which was in part friendly, there was also tension. I would like to ask what you know about it. There was a genuine concurrence between these two groups, partly friendly but also somewhat under tension. I would like to ask you what you know about them. I know, for example, that from 1943 on, there arose a question should one make sheets for Heisenberg or shall one make cubes for Diebner. Auer could make either one or the other but not both.

Riehl:

I know of a concurrence and I know of this dilemma, whether to make sheets or cubes. At the end we made only cubes. However, I saw that only from the standpoint of fabrication. The nature of the concurrence regarding the question of sheets or cubes, I know nothing, really nothing. Have you asked Wirtz?

Walker:

Yes. I have also asked Czulius. He is at the present time in Erlangen. He was at the Weapons Ministry at the time. The two are cautious, but both agree that there was a competition. Each group believed that it had the best plan and could do better.

Riehl:

That seems reasonable but I can't add anything to it.

Walker:

And how about the situation at the Auer Company.

Riehl:

We had to make the things which for which we had orders, for a large sum of money was involved. I often took risks. For example, I acquired a new factory for making metallic uranium which cost about eight hundred thousand marks. At the time I didn't have the order for the metal. There are times when one must take risks. If things had gone badly, the supervisory management of the Auer Company would have said, "Well, you are a good scientist but you don't know much about business." That would be unpleasant. However, everything went well. I obtained the customer and everything fell into the right order. I only produced what was ordered and in the original period the only orders I had were from the Military Weapons Ministry. That is the way I remember it. It is, of course, unfortunate that I no longer had the papers. Later on, the State Research Ministry took over, but I don't know more than that, that is where the money came from. I do not know more exactly what was written on the order. I believe that in the later period, that is after 1943, the orders came from the National Research Ministry. The money came through the National Bank. By that time, the matter was not important for the military.

Walker:

On receiving orders, would you then proceed with manufacture?

Riehl:

Then indeed, we went ahead and produced.

Walker:

The fact that the Nuclear Research Center was set up in Karlsruhe is an interesting facet of history. Related to it is the history of the light water "swimming pool" reactor that was developed for the Technical University in Munich. Maier-Leibnitz is involved in this. Heisenberg desired to have the central reactor station in Munich along with his Institute. It appears that Maier-Leibnitz was not enthusiastic about this. As a result, the reactor station was developed in Karlsruhe. At that time the government said, "We will purchase a reactor for Heisenberg's institute. Heisenberg, however, said, “I don't want anything to do with a small reactor.”

Riehl:

Heisenberg wasn't very interested in reactors after the war. I know that because at that time I was in Germany. Maier-Leibnitz wanted me very much to be with him, and as a result, I settled and remained in Munich. We built the reactor together. The issue had, in part, the following basis. The Bavarians had the ambition to play a role and there was a strong desire to have the center in Munich. That was at the time in which Adenauer was the head of the government. I wasn't involved in that but I have heard about the general situation. Adenauer believed, however, that Munich was too far east, that is, too close to Moscow. That was very naive of him. But this is the way people think sometimes. For example, I knew an elderly woman that did not want to live on the right side of the Isar, a river that flows through Munich. Rather she wanted to live on the left side because it was farther from Russia. People can be that naive. Adenauer was perhaps not that naive but he did say that Munich is halfway to Moscow so that Karlsruhe is safer. Everything gets mixed up, research, military consequences, and money. So short and good, it was decided that the official station should be in Karlsruhe. On the other hand, the Atomic Minister was Strauss, an outspoken Bavarian national and a strong willed man. He succeeded in obtaining some compensation for Munich because the Bavarian Ministry was much interested. The Bavarian Minister President was Dr. Hoegner, a Social Democrat, and a very clever man. The Education Minister was Professor Rucker, a professor at the Technical University. He was also the Bavarian Minister of Culture. This group naturally wanted to do something that would benefit Munich. Shortly thereafter, Maier-Leibnitz was brought to the Technical University of Munich as a nuclear physicist. As a result, he became the person who was put in overall charge. In the meantime, I joined his group. I wasn't then officially a professor but in a transition position. It took place in 1955 when I was just out of Russia for a month or so. We knew we would get a reactor and the question then arose from whom should we order the reactor. While we could build much of it ourselves, it was essential that the core of the reactor be purchased from some American firm.

Walker:

An English firm did not come into the issue?

Riehl:

No. Only American. Every few days we received a special offer and Maier-Leibnitz and I broke our heads trying to decide which would be the best one to take. It was difficult to tell the difference, whether one was better than the other or the reverse. We agreed it should be a swimming pool reactor. That had been true from the outset. One day during the period when Strauss was still Atomic Minister, it was decided that Maier-Leibnitz should go to New York and finally make a decision, signing a bilateral agreement between the Bavarian government and one of the American firms. He came to me in my room and said, "Mr. Riehl, I don't know what I should do in order to make a selection. Which is the best? That is very difficult to judge on the basis of what we know." "Listen, Maier-Leibnitz." I said, "As you know I have had a great deal of experience with such matters in my life and when matters reach this situation, it is best to flip a coin. You then have a fifty percent probability of being right." He replied, "That is what you say." I was then ten years older than Maier-Leibnitz and was not afraid to offer him such advice. Sometime later he came to me and said, "Herr Riehl, I don't need to make any decision. Everything has been decided." And, indeed, that is the kind of world in which we live. Strauss had gone to China and obtained an order for the Boelkow Company and that is the way the decision was made. There is an international lobby. A person who had been the counsel, I believe his name was Freund and who is no longer alive, worked through this lobby and made the decision for us and that settled that. Maier-Leibnitz went also, completely at ease, to New York since he now knew the firm to which he should give the order. We were very pleased with the result. Everything went very well.

Walker:

One firm was as good as another?

Riehl:

Yes, about. There were four or five and they were all about equally good. That is why I said flip a coin. That, however, was a little too simple for Maier-Leibnitz. He was essentially ordered what to do, purely formally. Period.

Walker:

Tell me about your activities in Munich. You say you helped Maier-Leibnitz in the construction of the reactor. Tell me in more detail what you have done. You were partly scientist, partly manager at the Auer Company, then for ten years in Russia, and finally you came to Munich to obtain a university position. Is that right?

Riehl:

I had, indeed, a good scientific background, for example, in the field of luminescence and in applied radioactivity. I was, indeed, in industry, then later with the Russians, however, I also had a good background for university work. If I had not come to Munich, I would have looked for another academic position somewhere.

Walker:

What would you have done if you had not gone into reactor science and technology.

Riehl:

Principally solid state physics, that is, luminescence of one kind or another. That was my old field. I could also have focused on the solid state aspects of radiation damage, an important specialty in the field of reactor technology. One is concerned about the behavior of the component of reactors.

Walker:

Did you have many students?

Riehl:

I had, as matters progressed, very many students.

Walker:

I believe that Munich was the first place where a nuclear reactor was built in Germany.

Riehl:

We had here a very good basis. Along the way we had Maier-Leibnitz and me and a great many postdoctoral and I doctoral students. Indeed, it was a wonder that we ever got through all this. Maier-Leibnitz and I were alone for a very long while handling all of this. Then later, other colleagues joined us as faculty members.

Walker:

And it was necessary to give lectures?

Riehl:

Lectures. That was a very depressing issue which we did not handle very honestly. Maier-Leibnitz did not like to read very much, as is necessary if you prepare general lectures, Relatively speaking, he was a very poor reader. When I lectured I did very well, however, for most of my life I have not been a professor but a research investigator. I have made and discovered many important things, all carried out properly, but I never had much experience preparing the lectures. If, however, I spent the time preparing them, I didn't have the strength left to carry on research and research was of great interest to me. The basic lectures, the elementary lectures for students, could be handled by others, but if I prepared myself properly I gave good lectures. In actual fact, I did not give very many and Maier-Leibnitz essentially gave none. We were both better by nature as research investigators than as teachers. We passed over the responsibility for the basic lectures to the other members of the staff. Then subsequently, the physics department was established and the system prospered with the arrival of money. I should emphasize, however, that until the end of my period as a faculty member, I did give lectures, for example, on the applications of radioactivity and solid state physics, the technology of producing light. They were all good lectures, not very general. All was in a very definite area. When Maier- Leibnitz lectured it was the same. He dealt with a very definite area. His lectures had titles such as "Selective Issues in Solid State Physics or Nuclear Physics." The great advantage of that procedure was that one discussed matters which one knew from personal experience that one had carried out himself. I obtained from students some letters indicating their level of inspiration. For example, they used words such as "fascinating lecture," and so forth when I dealt with a topic in which I had had personal experience, or had actually carried out myself. That is, of course, much more interesting for the students than general lectures. Students we had in abundance. Let me talk about radiation protection, a topic that is very important to speak about. In our work we followed the American standards. Maier-Leibnitz had never in his life built a reactor. I had a great deal of experience with radioactivity, particularly in industry. Indeed, even today, I can carry on many operations involving radioactive materials better than the young people. All was with regard to personal safety. It must be admitted that in our earlier work we were unknowing violators of the best rules. In fact, it is somewhat of a miracle that I am still alive, that I never developed Schneeberger Krankeit [a form of lung cancer] or lung cancer, or what is even worse, skin cancer. However, bone cancer is even worse than skin cancer, that is, osteosarcoma. One obtains the latter as a result of alpha radiation, for example by the ingestion of radium which is deposited in the bone. That I don't have any of these things is, indeed, a wonder. Essentially all of the individuals who worked in the radioactive division of Auer are long since dead. I and my predecessor head are the only survivors. Perhaps we understood the danger and took care in critical situations. I remember well how I handled the first radioactive preparations when I first came to Garsching. I usually operated with a cigar in my mouth. But I was very careful what I did with it since I knew it could get contaminated and took great care. I never touched the mouthpiece of the cigar with my hand because my hands could be contaminated. That is the way experience teaches. One must have a scientific attitude in the first place and then have experience. I never trusted anyone else. I always did everything myself. Nothing harmful ever occurred in spite of the cigar. When one smokes a cigar, you occasionally take it out of your mouth to lay it down. I always did this in such a way that the mouthpiece remained entirely in the air. One must pay attention to such details.

Walker:

I have an unscientific question at the end. I imagine that people often came to you and said, "Mr. Riehl, won't you die young if you continue smoking?"

Riehl:

That's absolutely true.

Walker:

I presume that you now say, having survived so long, I am going to do what I want.

Riehl:

Exactly. The situation is as follows: A cigar smoker, but actually I am really a bit of a puffer, rather than a heavy smoker — I smoke the cigar only halfway. That is expensive but one often spends money in senseless ways. When the cigar is half smoked, I toss it away. The nicotine collects near the mouthpiece so that the amount of nicotine I absorb is probably not very large. Moreover, I never inhale cigar smoke. For the most part I blow the smoke out of my mouth, allowing a little to trickle through the nose. There is, of course, in all of this a certain amount of self-deception and here I am no different from others. I have both read and experienced that if one sits in the dark and smokes, one gets no pleasure from smoking since the entire ceremony of cutting the tip, lighting the cigar and watching the smoke is missing. When an individual smokes in the way I do, and I am eighty-four years old and do not have lung cancer, people look at me and say how about your heart. I indeed have a bit of an insufficiency and, as a result take two pills a day. That is all. It is remarkable how these matters go. Why does one individual have a heart attack at age fifty and another lives to be ninety without any significant heart trouble?