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National Museum of Nuclear Science & History

James A. Schoke’s Interview (2014)

Manhattan Project Locations:

James A. Schoke was a member of the Special Engineer Detachment at the University of Chicago during the Manhattan Project. He worked for the instrument group, inventing instruments to detect uranium and alpha emitters and travelled around the country to train scientists to use and maintain his instruments. In this interview, Schoke discusses his encounter with George Koval, a health physicist and Soviet Spy who infiltrated the Manhattan Project’s top secret facility in Dayton, Ohio. Schoke recalls meeting with Koval several times at Dayton to help train him on instruments that were used to detect radiation at laboratory facilities.

Date of Interview:
November 7, 2014
Location of the Interview:


Kelly: Okay, this is Cindy Kelly. It is Friday, November 7, 2014 and I’m in Delray Beach, Florida with Jim Schoke. First question is please tell me your name and spell it.

Schoke: James A. Schoke. James, J-A-M-E-S A. S-C-H-O-K-E.

Kelly: Great. We have a wonderful interview with you about your Manhattan Project days and your role as an inventor. This session is to catch up with you about a man who was not too long ago awarded a medal by Russian President Putin for his work as a spy in the Manhattan Project. And this is something that really—

Schoke: Came as a surprise to me.

Kelly: Good. So let’s talk about that.

Schoke: George Koval—I met him, he was in Dayton, Ohio at Monsanto Operation, which was concerned with producing polonium with beryllium, making triggers for the plutonium bomb. And he was an instrument technician there, maintaining instruments that I had worked on considerably to substantially improve from the pre-war designs.

And polonium is an alpha-emitter. This isotope of polonium, I think it was polonium 210, is an emitter of alpha rays. And the equipment that I had improved were alpha-ray detectors. So they had a lot of them there.

George Koval, when my equipment was installed there, I went there quite often and I had to train him on how to maintain this equipment, which included polonium. That isotope of polonium had a fairly high vapor pressure, which means it would float around in the air and deposit on things. So when the samples that they were measuring, which were usually thin platinum disks with the sample on it. The platinum disk may be an inch and a half in diameter or an inch in diameter and the samples would be put into a chamber that had two parallel plates, each about two inches in diameter. One above the other. And the polonium, when it was on these disks, had a tendency to contaminate the chamber so that you constantly had to clean the chambers in order to be able to measure new samples.

And so one of the things I had to find sandpaper, a light sandpaper that could be used to sand the two plates, one of which the sample sat on and I had to go through get samples of sandpapers from all the companies that made sandpaper in order to find a sandpaper that would do the job without also contaminating the plates. In other words, one that did not have alpha ray emitters or had very little.

At any rate, George Koval was a very nice guy. We became friends because I was there quite often. And from time to time continuing to make improvements on the equipment. And having to show him what the improvements were and how to maintain and so forth. He was an excellent technician. He knew his job very well. And he was very friendly.

Of course, I had no idea he was a spy. In fact, not until Cindy told me that he had been a spy. The amazing thing to me is that he wasn’t detected at all and he got away with it. They went through great pains when I was transferred to the Manhattan Project to investigate my background in great depth. Many members of my family and many friends, old friends of my family were questioned by the FBI. So I don’t know how he got by with it. It’s amazing to me. At any rate, he did. And I don’t know what more to say about him.

Kelly: Well, that was very helpful. Let’s see. Now did you know him at Oak Ridge or did you ever meet him there?

Schoke: My memory says no.

Kelly: Right, because he was a health physicist.

Schoke: Right. And he was involved with instruments for measuring radiation levels and which I also, my group, instrument group, development group was involved with. And I did liaison for that group. So I might have been in contact with him, but I do not recall it.

Kelly: Did he have many friends?

Schoke: I don’t know the answer to that, I’m sorry. He was a very friendly type, so it wouldn’t surprise me if he did. But I don’t know. We only had business together. We may have had lunch or something like that, but other than that, we didn’t socialize.

Kelly: Can you describe him?

Schoke: Well, he was a nice looking guy. I think he was a little older than I was. I don’t remember his height. But I know he had a nice looking face. And that’s about all I can recall at this point.

Kelly: How old were you at the time?

Schoke: At this time, I was twenty or twenty-one.

Kelly: So he could have been how old?

Schoke: I’m guessing mid to late twenties.

Kelly: Did he have any accent when he spoke?

Schoke: No.

Kelly: Can you say that?

Schoke: I do not recall any accent. I think he was raised in the US, that’s my impression. That he may have told me where he came from, I don’t specifically recall now.

Kelly: Now what kind of access do you suppose he had as a health physicist? Did he have any secret clearance?

Schoke: Oh, as a health physicist, he had great access to lots of—wherever people were working, he potentially could have access. Now exactly what his access was, I don’t know. Or if I did, I don’t know now. He probably had access to the X-10 reactor and the chemical facilities for processing the uranium after it was taken out of the pile. And he would have great access, yes.

Kelly: So can you just help someone who’s new to this—explain a health physicist’s role.

Schoke: A health physicist’s role was to look for radiation that would be damaging to a human being. The sources could be contamination of a table or a chair or it could be a device that was being operated, like a glove box in which people were working with radioactivity by putting their hands in to rubber gloves that were sealed and inside of a box. But the box, if it had gamma ray emitters in it, the gamma rays would go out of the box and they could irradiate people. So, well some boxes were shield more than others.

So their job was to look for sources of nuclear radiation that could be damaging to workers. That’s what a health physicist did. And then take steps to correct it themselves or get somebody in maintenance or whatever, whoever was assigned to do that kind of work to get rid of the contamination. It was a big job, health physicist was an important job everywhere on the project where radioactive materials were being worked with or on.

The theory was that you were only supposed to have access to what you needed to have access to. And for the most part, that was watched. Now instrument people in general had more access than some others because instruments were used all over the place. There were portable instruments and instruments on desks. So that if you were maintaining instruments you had good access too. And the thesis was that you only were told what you needed to know to do your job. It didn’t quite work out that way, or at least for the instrument group. I can’t speak for others.

For the instrument group, we developed and serviced instruments for so many different fields of endeavor on the project that we had to have broad access as a group. So you never knew where you were going to be sent the next time to service an instrument that was made by your group.

Kelly: So you yourself, that was your role, right? Servicing these instruments?

Schoke: My role was primarily developing and doing liaison later. But early on, I did service instruments.

Kelly: And your liaison would be to train others?

Schoke: Yes.

Kelly: How to use them and service them.

Schoke: Maintain them, right.

Kelly: So in your course of the Manhattan Project, what sites did you go to? What sites in the Manhattan Project did you travel to?

Schoke: Oh, I went to quite a few. I went to Dayton. I went to St. Louis where Mallinckrodt Chemical was. I went to Site B once, Hanford—not Site B, I’m sorry, Hanford. Site B was—we had several sites on the University of Chicago campus, one of which was called Site B. And Site B was where they machined an aluminum-clad uranium for the piles, particularly for the X10 pile at Oak Ridge, which was not the first pile, but the first production pile for making plutonium. And it was an experimental pile, its purpose being to find out the most efficient way to make plutonium. And where else did I go? Well, of course, Los Alamos many times, New York once or twice, Boston once. That’s about all I can think of right now.

Kelly: That’s a lot. Three major sites and then some.

Schoke: Right.

Kelly: And you were stationed where?

Schoke: University of Chicago in Chicago.

Kelly: So in New York, what—

Schoke: The project there was called the Metallurgical Laboratory or Met Lab for short.

Kelly: In New York, what sites did you visit?

Schoke: Just one. I think it was at NYU, somebody, I can’t even recall who now, someone there had one of our instruments that was made by our group. Yeah, by our group. And needed some training or had a problem with it. So I was sent early on to go there.

Kelly: Could it have been Columbia?

Schoke: It might have been Columbia. I really don’t recall for sure.

Kelly: That was where the vast majority of the work happened.

Schoke: Well, there was a lot of work at Columbia, yes. But I’m not sure. I don’t remember.

Kelly: We’ll have to look that up. Let’s see. Well, you went to a lot of places, so in terms of the level of security, did it differ from site to site?

Schoke: Definitely.

Kelly: Tell us about that.

Schoke: Definitely differed from place to place. The security at Los Alamos for what was called the tech area, was much higher than, for example, at the University of Chicago at any of the sites. Although at Site B, it was a pretty secure site. In fact, at Site B I developed—I probably mentioned this in a previous interview—I developed a device for detecting uranium. Because it was a unique kind of material, they didn’t know it was radioactive, but it oxidized and got black, had a dark blue dust on it. When it was machined, it gave off big sparks because the parts coming off were hot and they were oxidized very easily by the air, by the oxygen in the air. So you saw these sparks and they were being machined.

And they knew it was a secret project of some kind. So it was very tempting and guys took chunks of it home, which was actually dangerous for their family because if they handled it, they could get this dust on [them] and ingest it. And alpha rays inside of you aren’t good. And uranium was an alpha ray emitter. Uranium itself may not have been, but one of its by-products—no, it probably was an alpha ray emitter. It probably was to begin with.

And, yes, that was security. I’m trying to remember. Dayton’s security was pretty good too. Yes, to get in and out of Dayton, they were careful, yeah. The operation that I went to was in a school that had been taken over, an old school, an empty school that had been taken over for that purpose in Dayton. It’s kind of interesting, you know, like classrooms a lot of the work went on in.

Kelly: I’ve seen photographs. It’s a beautiful red brick kind of Victorian seminary it used to be.

Schoke: Oh, was that what it was? A seminary?

Kelly: Yes, yeah. Unfortunately, it’s no longer. But it was quite an interesting building. I’m wondering about Oak Ridge, how did the security there compare?

Schoke: Well, the only place I was permitted to go was X-10, the reactor, and all the related chemical facilities where some of our instruments were used. And the security was good in the areas I was at. Yes.

Kelly: One of the things that people at Oak Ridge who either were part of the Manhattan Project or came shortly after and knew how things were in terms of security and so forth. They were surprised that George Koval would have had access to a vehicle to drive from site to site.

Schoke: I have no knowledge of that at all.

Kelly: How about yourself? When you had to go from place to place, how did you get around at Oak Ridge?

Schoke: I didn’t have a vehicle. They would send a vehicle to take me where I had to go.

Kelly: They did?

Schoke: If it required a vehicle.

Kelly: If it did, you would have some driver and a vehicle?

Schoke: Yes. Yes, usually a military guy. I mean, I was not in uniform for most of the war. About the last eight months or a year, it was very surprising, one day we received, on a Thursday or something like that, we received an order to show up Monday in uniform. All of a sudden, the whole campus bloomed—went from very few uniforms—guys in the Navy who were going to medical school or things like that—to a whole campus full. It was crazy. But the military, those things can happen. Yeah, we were all very surprised.

Kelly: Did you have to when you traveled, were you then expected to travel in your uniform also?

Schoke: No, no, not until we went back into uniform. No, I’m trying to remember—no, I was no longer in uniform. I was on active duty but not in uniform. Yeah.

Kelly: So it was just the Chicago campus and facilities that had this new rule.

Schoke: You mean, back into uniform?

Kelly: Yeah.

Schoke: I don’t know. I know it happened there. I don’t know if it was limited to there. It probably was limited to the University of Chicago campus.

Kelly: Right. But I just thought because you traveled to other sites, that you would have to stay in uniform if you went to Oak Ridge.

Schoke: No, no. Not until—I will say this—there were many more people working that were in uniform at Oak Ridge and at Los Alamos. At the University of Chicago, there were none, unless they were visiting, somebody in uniform came. Until that order came out, “Get back into uniform.”

Kelly: But Koval wasn’t—I’ve forgotten, was he a member of the SED?

Schoke: Yes, he was.

Kelly: So did he wear civvies or did he wear his uniform?

Schoke: I’m not sure. The memory doesn’t say. You know, if he was in uniform, could easily have been in—oh, I can’t remember the name for it—dungarees. There’s a name for them.

Kelly: Khakis?

Schoke: Off duty. No, the off duty.

Kelly: Oh, off duty, oh, I see.

Schoke: Type of stuff. Like overalls or blue jeans, but not blue jean material, another cloth material, not like the khaki, but more of a cotton. There’s a name for it, but I can’t remember it now. My ninety years old is showing.

Kelly: Hardly, hardly. Well, so do you know any other spies?

Schoke: No, not that I know of. No.

Kelly: Maybe Doc.

Schoke: It’s kind of interesting, my group leader, Wendell Bradley, who was a fantastic instrument man, knowledge of electronics and instrumentation, had been a member of the Communist Party when he went to college for a very short period. But he was approved. And, of course he was not a spy, that’s for sure. So it’s strange. Some people were not approved and others were, even though they had some questionable affiliations. Of course, when he went to college was in the deep Depression and it was not unusual for people to be looking for answers elsewhere. And the same thing with Oppenheimer and his wife.

Kelly: It’s also the time of the Spanish Civil War.

Schoke: Yes, yes.

Kelly: And that captured people’s imagination.

Schoke: Absolutely, yes. Some people. Yeah, some people got involved politically in that situation here in the States. But they were older than I. They were people in their thirties probably when I was in my twenties, early twenties.

Kelly: Yeah, but you were still pre-adolescent probably in ’36.

Schoke: Oh, yes.

Kelly: Yeah. So you were not engaged yet.

Schoke: I’m twelve years old.

Kelly: Right.

Schoke: Yeah, in ’36.

Kelly: Right. Do you know people that were rejected from service or from the Manhattan Project because of pasts?

Schoke: No, I didn’t know any. But I knew—I may have discussed this in a previous interview. This young lady who was on campus who befriended many of the people on the Manhattan Project and then one day disappeared.

Kelly: A nice looking young woman.

Schoke: Yes, yes. And one day [she] disappeared from campus. The word was that she was picked up as a spy or as a potential spy. I don’t know. But that’s as close as I got to knowing somebody who might have been a spy. Except perhaps like Koval. I had no idea he was a spy.

Kelly: A very few people at Los Alamos had any clue that Klaus Fuchs was a spy.

Schoke: Yes.

Kelly: He was giving a tremendous amount—

Schoke: Or Greenglass. 

Kelly: Right.

Schoke: Fuchs, however, was much more effective as a spy than Greenglass, from what I’ve read. He was much more knowledgeable. He was a Ph.D. So he was much more knowledgeable. And what he saw, he could grasp more easily.

Kelly: I just happened to finish a biography of him by Mike Rosseter The Spy Who Changed the World. He was brilliant.

Schoke: Yes, that’s what I’ve read.

Kelly: Right. And he was highly recommended by and worked very closely with Jacques Foral [PH] and Kakof [PH] and Chadwick and the other leaders of the British.

Schoke: In England, yeah.

Kelly: In England.

Schoke: Yes.

Kelly: And he called himself a controlled schizophrenic that he actually, when he was charged finally in 1950 by the British of violating the Official Secrets Act, he confessed. He confessed not only to this one incident of which they were able to trace, but to seven years worth of spying. It was flabbergasting. They were floored by the magnitude of what he had given to the Soviets. And yet, in his own mind, he confessed in part because he just didn’t think there’d be any repercussion, that he was much too valuable. So at any rate, everybody was very surprised by him.

Schoke: What was his—

Kelly: He was in the Theoretical Division.

Schoke: No, but I mean, was he a Communist?

Kelly: He was a Communist.

Schoke: He was a Communist.

Kelly: He was from East Germany, or what became East Germany. And he just hated the Nazis and their repression. And he joined the Communist Party and the Nazis sent 60,000 Communists to concentration camps.

Schoke: Oh, yes. Oh, yes.

Kelly: So they were equally hated, Jewish and non-Jewish. The Communist Party was on their list.

Schoke: Right.

Kelly: So he fled. He left to get his Ph.D. working with Max Born in Edinburgh and then joined many of his former German compatriots in Cambridge. But he didn’t seem to think that it was a double-crossing involved in giving the Soviets information.

Schoke: He thought that—I don’t understand. If he was Communist, he knew he was doing wrong. There’s no question about that.

Kelly: Yeah, he was.

Schoke: There were people in this country who felt the Russians were Allies in World War II.

I don’t know that George Koval learned anything from me that would be useful to the Soviets, to the Russians. Because he only maintained the operation of the instruments. He didn’t repair them if something went wrong. So he did not know what the circuitry was that was in the chambers. He could have opened one up and traced perhaps. He might have done that. But there was no reason for him to do that.

That, it seems to be, might have attracted attention, if he had. I would think it would have because he was not supposed to repair those chambers. He was only supposed to maintain the operational aspects of it. So they weren’t contaminated and so forth. And the contamination was determined—when there’s no sample in the chamber, no sample to measure, what’s called the background of the chamber, in other words, the emission of alpha rays or sometimes cosmic rays going through the chamber, would cause a pulse that would be detected. And that was the background. So whenever you measured samples, you always had to measure the background before and after and subtract that from the measured quantity.

As I said, there was no reason for him to deal with the circuitry. He was told if the circuitry stopped working, then you put a new chamber in and send a chamber back to Chicago for a repair.

Kelly: And maybe he sent a few to Moscow.

Schoke: Pardon me?

Kelly: Maybe he sent a few to Moscow.

Schoke: [Laughs] That’s possible. I think somebody would have known that, I hope.

Kelly: What would you say to George Koval if he was sitting here instead of me?

Schoke: Oh, wow. I don’t think you’d want to hear what I’d say to him. Yeah, I wouldn’t be very friendly. Would not be very friendly, yeah. I have no tolerance for that, none at all.

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