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National Museum of Nuclear Science & History

Bob Carter’s Interview (2015)

Manhattan Project Locations:

Bob Carter is an American physicist who joined the Manhattan Project first at Purdue and then at Los Alamos. He worked in a group that was assigned to create an operating nuclear reactor that ran on enriched uranium. In this interview, Carter discusses how he came to be interested in physics and wrapped up in the Manhattan Project and nuclear physics instead of being drafted. He also talks about his experience at Los Alamos working on the enriched uranium reactor and how he taught several big name scientists, including Enrico Fermi, how to operate it. Carter also discusses meeting Oppenheimer and seeing the Trinity test unauthorized, as well as his interactions with spies Klaus Fuchs and Ted Hall.

Date of Interview:
June 3, 2015
Location of the Interview:


Kai Bird: Let us begin at the beginning and I think the viewers of this will want to know first about your own background. What year were you born?

Bob Carter: I was born in 1920 in Philadelphia, Pennsylvania.

Bird: On what day?

Carter: February 3, 1920.

Bird: 1920.

Carter: Yes.

Bird: Okay, 1920, what was sort of before modern physics, quantum physics was invented as such.

Carter: Well it was already ongoing, Niels Bohr and [Erwin] Schrodinger and some others in Europe had already pretty much proposed the structure of the atom and started understanding fairly well the basis of modern quantum mechanics.

Bird: So you were born just virtually at the same time as quantum physics was being invented.

Carter: A little bit later than the first successful attempts. Yes. I had nothing to do with it of course.

Bird: Of course. So what are you earliest childhood memories growing up in Philadelphia?

Carter: No, my family moved a lot. My dad had no education and no specific training or profession of any sort. We moved a lot from job to job and there were some good years and some bad years, but we moved around from one small town to another. He liked small towns rather than the city even though he grew up or maybe because he grew up in the city.

Bird: What was his profession or job?

Carter: He had no specific profession or job and that was part of the problem. He worked as telephone lineman for a while climbing telephones and doing the wiring for early telephone connections. He inherited some money from an uncle and went into the construction business and lost it all. Then he managed to acquire a grocery store as the sort of owner and manager and then he moved from one type of store to another. Eventually owned a drug store but without a pharmacy.

Bird: Where was that? What city?

Carter: Well that was in a little suburb of Philadelphia called Southampton, a little town called Southampton. Then we moved to Berlin, Maryland down near the shore, near Ocean City, Maryland. I was just thirteen when we moved there  and basically I say that is where I grew up, Berlin, because I was in sixth grade I guess when we moved there, six or seventh and then I finished high school there and went on to college from there.

Bird: Were you even in high school interested in science or physics?

Carter: I was interested in science even before I was in high school evidently and I do not know if it was science as such but sort of technology and gadgets and devices and things like that. For instance, in my senior year in high school I took my first physics course and the physics teacher had had one year of physics in college, which was probably typical in those days and maybe even these days.

I remember on my final grade in the course he gave me an A++. There is another ramification with my grades and things, but the principal with whom I was really quite friendly—it was a small town small school and he asked me, “Bob what do you think this means, this A++?”

He said, “I do not know how to interpret that.”

I said, “Why don’t you go ask Mr. Brule,” he was the physics teacher.

I said, “Why don’t you go ask him what he meant I do not know what it was.” Apparently Mr. Brule physician’s teacher told the principal, “Well Bob knows more physics than I do and I could not figure out anything else to give him.”

Then I went on and took physics in college.

Bird: Where did you go to college?

Carter: I went to a small college on the eastern shore of Maryland called Washington College.

Bird: Right okay.

Carter: I do not know if you know of it.

Bird: Yeah I do know of it. It supposed to be a good small liberal arts college.

Carter: Yes.

Bird: Were you the first member of your family to go to college?

Carter: My mother had gone to secretarial school after high school and she had been a secretary for a few years before she was married. I was the first to go to a full four year college.

Bird: Did you have a scholarship or how did you pay for it?

Carter: Well when I started out I did not have a scholarship but the college scrounged around to give me all kinds of benefits like there was a book scholarship for instance. My books were all free, all my textbooks were free and I had a campus job as basically the janitor in the library and I had a few campus concessions, there was a candy concession in the men’s dormitory and I was given that concession and there were a few concessions with local cleaners and dyer companies so that when men in the dorms needed a suit pressed or cleaned or needed laundry done I was the agent.

Bird: So you worked your way through college?

Carter: I basically worked through the first two years but then I got a scholarship from the County, Wooster County. It was administered through Wooster County but it was called a Senatorial Scholarship and that paid pretty much all my expenses, my last two years.

Bird: You must have gone to college and gone to Washington College in about 1938?

Carter: Yes.

Bird: Then you graduated in 1942?

Carter: Yes.

Bird: Your major was in physics?

Carter: Physics, yes. My major was physics and I had a dual minor in mathematics and chemistry.

Bird: So you were in college on Pearl Harbor Day.

Carter: Yes.

Bird: I presume you must remember that day vividly.

Carter: I remember that day in particular because it was my dad’s birthday and I had gone home to celebrate his birthday. We did not have a radio on and that was long before days of television.

Bird: Right.

Carter: I did not know about the Pearl Harbor attack until that evening when I went back to college after being home over the weekend. People were running around madly in the dormitories trying to figure out what to do and several of my classmates sort of volunteered and decided we need to get after those Japs. So some of them volunteered right out of college.

Bird: You were very close to graduating.

Carter: I was close to graduating so I had to register for the draft and in principle I was eligible to be drafted. The draft boards often deferred students who were close to finishing their collegiate career or whatever. Living in a small town area in Maryland the head of our local draft board there was a personal friend.

Bird: It made common sense to let you finish.

Carter: Yes.

Bird: So you graduated in June.

Carter: I graduated at the end of May.

Bird: End of May.

Carter: In 1942.

Bird: Did you immediately have a job?

Carter: No, I had been promised a teaching assistantship at Indiana University in Indiana to go on to graduate school in physics. My physics professor in college had recommended that he had gotten his Ph.D. there and I had applied and been accepted. When I went home after graduation from college I talked to the chairman of the draft board as I mentioned he was a personal friend. I asked him if they would defer me to go to graduate school the following fall and he said, “No way.”

Bird: No way.

Carter: “We are about to send you your greetings letter.” So I sent a telegram in those days people did not often make long distance calls and I sent a telegram to the chairman of the physics department in Indiana telling him I am sorry my draft board is not going to let me come to your institution in the fall so if all goes well I will see you after the war. I got a telegram back from him almost immediately saying – I can offer you a job in a metallurgical laboratory at the University of Chicago which would provide deferment from military service and I wrote back to him again saying thanks but no thanks I am interested in physics not metallurgical.

I of course knew nothing of the metallurgical in the laboratory at that time. Then within about a day evidently physics majors who had just graduated their names were put on some kind of a national register as being possibly available for scientific work or physics related work.

Bird: Right.

Carter: I got a telegram from Purdue University in Indiana offering me a job there as an instructor of Navy Enlisted men. Most of the big universities had educational programs for various contingencies of the military service and Purdue had one for teaching electricity, electrical wiring to enlisted men in the Navy who when they graduated from our program would go directly on shipboard somewhere.

Bird: So you went to Purdue and took that job?

Carter: I took that job at Purdue, yes.

Bird: That provided deferment? 

Carter: What?

Bird: That provided deferment?

Carter: Yes that provided a deferment and there was a cyclotron at Purdue and one of the physics graduate students that I met almost immediately when I went to Purdue was working part time as a volunteer at the cyclotron facility. Now the cyclotron is a big elaborate machine that is used for nuclear physics research.

Bird: Yes.

Carter: I asked this graduate student if he would take me and at least show me the cyclotron. I had heard of them but had never seen one. He took me there and the professor in charge of the cyclotron talked to me and showed me around and then somehow or other the subject came up of my working there a little bit too even though I had this full time job teaching. Now I was also going to take an occasional course in the physics department or math department. I said oh sure I would like to come spend a few hours a week helping out down here and so that is what I did. It was unpaid, just volunteer work just to help out and learn a little bit more about physics.

Within a few months the professor told me that they were going to take on a classified project for the Federal government and I would not any longer be allowed to come. It was going to be a secret facility, they were going to have a guard on the door and probably no longer be allowed in.

I said, “Well you are still going to need the kind of help that this other graduate student and I have been providing. Why can’t you get it set up so we can keep working with you?”

I remember he looked at me and said, “You know I never thought of that.”

And a few days later he called me aside and he said, “Bob if you want we can hire you into this classified project. We will get you security clearance and we will hire you and you will get paid a little bit, this time for doing the same thing you have been doing as a volunteer.”

This other graduate student and I signed on and then it was a one year contract with the Federal Government using the cyclotron for some classified nuclear physics research that was related to problems of the Manhattan Project. It was before the Manhattan Project, before Los Alamos for instance was in operation. It was still 1942; it was the summer of 1942 about two months after I had graduated from college. We worked on that and then—

Bird: At that point you had not even heard the phrase “Manhattan Project”?

Carter: No, no. I had no idea about, well I learned about nuclear fission but I had not learned anything about chain reactions as I recall but just the basic interactions that the nuclei do not the whole thing that goes on in a chain reaction system.

Bird: How long did this job at Purdue last?

Carter: It was a one year contract that they had and two additional faculty type people, research people came from Cornell University to work at Purdue so there were two Purdue faculty people and two who came from Cornell who were the leaders of the program as research scientists basically and then there was this other graduate student and I working around and doing odds and ends on the project. It was a one year contract and then towards the end of that year in the fall of 1943 one or another of the faculty told me, “We are going to be leaving, all four of us are going to a project out west and we cannot tell you where it is, we cannot tell you what it is about, but you and Harry, the other graduate student, are suddenly going to be in charge of the cyclotron.”

It was a major research facility at the university in the physics department at that time. He said, “You and Harry are going to be in charge of the cyclotron and you are going to have to figure out what is happening.”

Bird: This is Harry? What was Harry’s last name?

Carter: Harry was Daghlian, Harry Daghlian.

Bird: Daghlian.

Carter: If you know he was the first person who was killed in a radiation accident at Los Alamos.

Bird: Really?

Carter: So he was my personal friend there at Purdue. Very suddenly these four faculty type people disappeared, Harry and I were left in charge of the cyclotron and there was no longer a classified facility, the guards went away, the doors were opened, it was just an open research facility. Within a few weeks or so, two, one of the men who had come from Cornell and the man from Purdue who was in charge of the facility there, both wrote to me from Los Alamos.

It turns out that is where they had gone and they both wrote to me separately and said “Hey Bob, we think you ought to come out here, this would be a great place you could make good contributions and we think you would really enjoy it.”

I talked to my friend Harry and they did not invite him, they just sort of invited me, but I talked to Harry and he said, “Gee I would like to go too, see if they will let me come too.”

We did not know where it was, did not know what it was about and so I wrote back and said Harry would like to come too. And the one man who had been at Purdue in charge the whole time said, “Okay if he really wants to come—we are at high altitude here and Harry had some medical problems and it might not be appropriate for him to come to this altitude.”

Then I talked to Harry and he said, “I do not care, I want to go anyway.”

Harry and I moved to Los Alamos in the fall of 1943. The four—

Bird: Do you remember the month?

Carter: Beg your pardon?

Bird: What month in 1943?

Carter: It was in December.

Bird: December.

Carter: By the time we got all the paperwork straightened out and everything. The classified contract had gone from October first to October first, the fiscal year thing.

Bird: Right. You arrived in Los Alamos in December of 1943.

Carter: Yes.

Bird: By train?

Carter: By train yes we went on the Super Chief or whatever the big Santa Fe train was at that time on the train from Chicago.

Bird: Then did you check in in Santa Fe in the famous little Los Alamos office?

Carter: Yes. A WAC, Women’s Army Corps woman in the Army at Los Alamos, we got off the train in Lamy, New Mexico which is a little stop somewhat near Santa Fe. This WAC met us there and she was the driver so she drove us into the 109 East Palace, Santa Fe to that front office.

Bird: Right.

Carter: We checked in there and then she took us on up to Los Alamos that afternoon. We checked in and we were both unmarried so we moved into a dormitory in Los Alamos and started to work.

Bird: You spent the rest of the war in Los Alamos?

Carter: Yes.

Bird: What was your first impression of this secret city Los Alamos?

Carter: Well, the city itself was not much of a city yet at that time. I guess it was just fun to be in the new situation and then immediately the four staff people who were there were part of the group. They were a major part of a group to which I was going to work and the group leader was a professor from the University of Illinois, or Lake Champlain and he had been an office mate in graduate school at the University of Wisconsin with the lead Purdue faculty man who had been in charge of the cyclotron. They were personal friends and maybe that was probably part of the reason that the team from Purdue joined this other man and set up a group.

Bird: What was his name? The team leader?

Carter: His name was Donald Kerst.

Bird: Kerst?

Carter: K-e-r-s-t.

Bird: Okay.

Carter: He incidentally invented—what is it called—the betatron, which is another nuclear physics instrument.

Bird: What was your team specifically working on when you first got there?

Carter: I am sorry.

Bird: What was your team working on when you first arrived?

Carter: The project they were working on was design and build and operate and understand a special nuclear reactor, an operating reactor based on enriched uranium. It was going to be the first device of any sort that was built with enriched uranium. Uranium was in a liquid solution, a water solution and was contained in a thin wall sphere about a foot in diameter. Then there was graphite and other things around it as what are called reflectors to help improve the criticality conditions of this reactor.

The four staff members who had come from Purdue by the time Harry and I got there had already each taken a partial of the whole project to design equipment and the designs were in the shops. Some of it was mechanical of building devices; some of it was electronic control circuitry and circuitry to read out the nuclear conditions of the facility when it was operating. These four men had already designed those things and they were in the shops.

Then during the early winter, late January/February, these various components were finished in the shops and delivered to our laboratory. Each time when something would come the staff member who had designed it asked me to help test it, to make sure it met the requirements and the operating conditions were all adequate. So it turned out that almost by default that I was the only one in the group that really knew all of the systems including the electronic controls and offerings. Then in the spring when we were loading the uranium fuel I was the one at the controls at the facility. The whole project was an idea of Enrico Fermi. Fermi at that time was still at the metallurgic lab in Chicago but he came our frequently to visit Los Alamos.

Bird: So you meet with Fermi?

Carter: Beg pardon?

Bird: You would meet with Fermi?

Carter: Yes, yes. He was always interested in exactly what was going on and I taught him basically how to operate the facility. At the controls I did it dozens and dozens of times to verify that everything was working okay and to look at different conditions. I taught him how to operate it because he was very curious and wanted to learn. It was fairly straightforward but—

Bird: You were teaching Fermi?

Carter: Yeah. Then when the facility was finally expected to go critical we were getting enriched uranium in small batches from Oak Ridge. So it took us about two weeks to actually load a little bit of uranium every few days or so as it arrived from Oak Ridge. We had chemists in our group who had to process the uranium the way it was shipped from Oak Ridge was not in usual form for our facility. We had chemists who ran it through various stages to process it. It took the order of a day or two after they received before it was ready for us to use.

It took us a few weeks to gradually every few days add a little bit more uranium and tests and verify its conditions. Then we were able to predict pretty well when it was going to actually become a critical self-sustaining chain reaction. There were a lot of the big important numbers of the Los Alamos lab not members of our group but of other groups and management those were alerted this day it is going to go critical. It was one of the chief steps towards understanding more about—

Bird: What day did it go critical?

Carter: I do not remember for sure, it was early May, 1944.

Bird: ‘44.

Carter: By that time, yes.

Bird: Was [J. Robert] Oppenheimer in attendance that day?

Carter: I do not think Oppenheimer was there in the group but there were a lot of other important people of the lab who were there. Dick Feyman had done calculations to try to predict what would constitute a critical condition for our facility. He was very interested and so almost day by day he would also come and check to see how we were doing. He and I were on a first name basis, I should have given him how to operate too, but he was not particularly interested in that.

Bird: Bob, how soon after you arrived at Los Alamos were you aware of what the gadget—what they were building?

Carter: Within twenty-four hours.

Bird: Within twenty-four hours. Who told you?

Carter: The day after we arrived there, we went to work, we arrived late in the afternoon and checked in the dorm and all that kind of stuff then the next day we went to work. The people from Purdue and we met the group leader who was in charge of course and they handed a bunch of documents and said here go read these. Then they told us about the project, briefly, they verbally told us. One of the men I do not remember which one, got up at the chalkboard and kind of drew what we were working on and explained the concept of the fission bomb to us. Then they gave us various documents.

Bird: Do you recall your initial reaction that you were working on a bomb? Were you shocked? Excited?

Carter: Well, I was excited and at the time, there was a lot of uncertainty as to whether or not a fission bomb would actually work. There were about three concepts all intermingled at the same time. One was that fission had been discovered in Germany and there was a possibility highly likely that the Nazi’s were working on a similar kind of thing a bomb type device.

Bird: Right.

Carter: It was important that we find out whether or not such a device would function would actually explode and find it out before the Nazi’s. It was important to do that.

Bird: Were you told the name of [Werner] Heisenberg? Did you know the name of the German physicist Heisenberg?

Carter: I had heard, yes. I had taken an introductory auto mechanics course at Purdue and I had heard Heisenberg.

Bird: Heisenberg uncertainty principle.

Carter: Yes. I learned Heisenberg, Schrodinger, Niels Bohr and the atom concept.

Bird: When did you first encounter Oppie?

Carter: Well, there is an amusing story about it. Within a few weeks, after I arrived at Los Alamos, I wrote to my parents to tell them where I was almost right away. I could not say very much about it and then I got a letter from my mother after about two weeks that asked a bunch of questions: Where are you? What is the name of this city? What are you doing?

You know typical mother kind of letter. I got it from the mailroom at the lab. I opened it up and there were pieces of it cut out.

Bird: They censored your mom’s letter?

Carter: Yes. I held it up and showed it to one of the staff members who had been at the Purdue project was there in the room. I held it up and said, “Look what they did to my letter!”

And he jumped up and he grabbed me by the hand and said, “Come on.”

We ran at full speed from our office to Oppenheimer’s office and Oppenheimer had a secretary in the outer office and then his personal office was in the back.

The secretary looked up and said, “Can I help you?”

And this man his name was Charlie Baker, he said, “Yes, we need to see Oppie.”

We walked right on in.

Bird: Oh.

Carter: He looked up and said, “What is going on?”

We showed him the letter and he grabbed his hat and said, “Come on.”

The three of us—Oppenheimer in the lead—went to a different building actually and a military officer who was in charge of security. Oppenheimer showed him the letter and said, “Don’t you dare ever do this to anybody’s letter again.”

Then he said, “Find the pieces that you cut out of this!”

Bird: Whoa.

Carter: I think he was a Major maybe a Lieutenant Colonel, I do not remember the rank but he was the resident guy in charge of the security or censorship. He said, “I have no way of finding that it almost certainly is in some trash basket.”

Oppenheimer said, “Our agreement is that you will not censor any incoming mail, if you have concerns about it, you will send a note to the recipient, but you will NOT ever cut out anything from someone’s incoming mail again.”

Bird: Wow. That is a pretty dramatic story.

Carter: I was not much of a historian in those days so I did not keep that letter. It accumulated with some other mail and stuff.

Bird: But they were censoring your outgoing letters occasionally.

Carter: Yes, well outgoing mail, we were not allowed to seal it and it went through the mailroom unsealed and they looked at it. If they had concerns with it, they would send it back to us and tell us you cannot say this.

Bird: I see.

Carter: Change it somehow or other. That was the way outgoing mail was handled.

Bird: When Oppenheimer dragged you over to the security man, was he angry?

Carter: Yes. He was furious that they had done this because evidently his agreement with [General Leslie] Groves was that this censorship of that type was not to be done to people’s mail.

Bird: You are twenty-three/twenty-four years old and Oppie grabs you and takes you, that quite a performance, you must have been pretty impressed.

Carter: It was before I was twenty-three.

Bird: Wow.

Carter: No, no I was twenty-three.

Bird: Twenty-four.

Carter: It was either before the end of 1943 or early 1944. I do not remember.

Bird: So that was your first encounter with Oppie?

Carter: Yes.

Bird: Wait was the second?

Carter: Well, directly with him I guess I was in meetings where he was speaker or in charge or moderator or something several times. I guess the next time I was in direct personal contact with him was in the summer. A woman graduate student had come to work in our group and her name was Joan Hinton, you have probably heard that name. She wanted to bring her mother and sister out to New Mexico for a vacation in the early part of next summer, 1944.

Evidently she decided that Oppenheimer had a ranch some place out there and that she would ask him if she could use his ranch. She was about my age, actually not quite as old as I, and she worked in the group. She came and joined the group I was in. She did not hesitate to say what she wanted.

Evidently she somehow had contacted Oppenheimer and asked him if she could use his ranch to bring her mother and sister for a little vacation and he agreed. Then I had a motorcycle in those days and I would take her, this woman, over to Oppenheimer’s ranch which was the other side of the Sangre de Cristo.

Bird: Forty miles away.

Carter: Beg your pardon.

Bird: About forty miles away?

Carter: Well it was a fair amount further than that. You went through Santa Fe and the further east around and up on the east side of the Sangre de Cristo Mountains it was over in that—

Bird: I visited that ranch.

Carter: Oh you did.

Bird: On horseback.

Carter: Okay, alright. Well near a little village called Taos.

Bird: Yes.

Carter: Okay. Well one time and I went with her and we cleaned it out it was just an empty building at the time and kind of dirty. We cleaned it out and washed windows and fixed doors and I do not know did a bunch of repairs. There was a little creek beside it and I dammed up the creek and there were some pipes there that evidently had been used for water transport.

Bird: I see.

Carter: I dammed off this little creek to make a pool and connected the pipes together so I had a little stream of water running up of the pipe right by the house from this little stream. Anyway, one of the times after we had started doing this, she and I stopped in at Oppenheimer’s office to tell him what we were doing to his house. That was the next time it was one on one, the connection with him.

Bird: Did you ever meet Kitty [Oppenheimer]?

Carter: Yes. I met her at some kind of social function. We did not talk or much but we met and said, “Hello, who are you?” Things like that.

Bird: I am jumping around here a little bit but coming back to your graduate school student friend, I am sorry, what was his name?

Carter: Harry.

Bird: Harry, tell me about his accident that must have been a shock.

Carter: It was a shock. He stayed in the same group I was in until a month or two after we achieved criticality and did various measurements on the conditions of that operating facility. Then another group was set up—

Bird: We have five minutes left.

Carter: Another group was set up and they dealt with the fission cores of the bombs of both the Hiroshima and Nagasaki bombs. They were the ones who verified that it was the right amount of material in these cores to be used, did other measurements related to those nuclear measurements. Harry for reasons that I do not know, decided one evening to do some additional tests on one of these cores. Now they had the ones to be used on Japan had already been sent. I do not think they had been used yet, it was a day or so before or about the same time.

Harry decided to do an additional nuclear measurement, he was not careful enough in the way he handled the material, and he accidentally caused a super-criticality of the thing. He had it on a table a little table, he was leaning over, the super-criticality occurred, and he told me he saw a flash of light and realized what had happened.

And he disassembled the rods, the reflector material and he disassembled it and went running out of the building so he would not get additional radiation from the residual radioactivity. This young woman who I mentioned, it was in the evening after dinner, we often worked ten or twelve hours a day. I was in an office on the other side of the shield wall and was not aware of anything happening. He ran out of the building and this young woman that I mentioned in the Oppenheimer situation, Joan Hinton, she was just arriving. Our building was isolated from the main technical are in the town site so you had to drive to get there. She had just arrived and she was getting out of her car in the parking lot and Harry ran out and said, “I just killed myself, take me to the hospital.”

They got back in the car, she took him up to the hospital and then she came back later and told me, I was still there in the office, I was not aware that anything had happened. She came back and told me what had happened. But I do not think we went to the hospital that night to try to see him, but we did the next day and he was seriously irradiated.

Bird: He died how much later?

Carter: He lived less than a month, I do not remember exactly.

Bird: Very sad. Jumping ahead, were you at the Trinity site?

Carter: Yes.

Bird: In July of 1945?

Carter: Yes, I went to the Trinity site. Now do I have another few minutes to tell about that?

Bird: Sure.

Carter: This young gentleman and I our group leader at that time was Percival King and he was involved in some measurements to be done at the Trinity site but Joan Hinton and I were not. We were involved in interpreting the measurements they were going to make there but we were not involved directly in going there and doing the tests. We asked him Percy King to tell us what the geometry looked like and where we could go and watch the Trinity test unofficially. He drew a little guide on the chalkboard and said here is a hill go on this side of this hill and you will be able to see it.

Joan and I went on my motorcycle to the Trinity site and after dark we went across the desert fortunately on a motorcycle partially pushing it and found this hill and got on there. It was raining a little bit which was unusual in that part of the desert. It was raining a little bit and we got up on the side of the hill and sat there and there were a few other people there with us also from the same group. My concern was mostly with my friend Joan Hinton and I. So we sat on the little side there and then the detonation occurred and it was overwhelming to see it and to experience the shockwave when it came and the sound wave about a minute after.

Bird: How far away were you?

Carter: We were about fifteen miles away. I never did go back and get—

Bird: Shockwave?

Carter: It was a very strong shockwave.

Bird: Did you feel heat?

Carter: We felt heat, yes. Now we had ridden the motorcycle during the day, mid-July, the sun was out of course in New Mexico so we got some windburn and sunburn on our cheeks. Our cheeks were somewhat sensitized to the heat that did come, but we felt the heat from the detonation.

Bird: Were you wearing goggles?

Carter: No, no, we did not have goggles.

Bird: This is an unauthorized visit.

Carter: We were totally unauthorized, yes. Occasionally I thought back if the MPs or somebody had found us there, we probably would have followed the Rosenberg’s [Julius and Ethel] or led the Rosenberg’s.

Bird: That causes me to ask: did you ever meet Klaus Fuchs or any of the other spies?

Carter: Yes, I met Klaus Fuchs. One time early in 1944, I asked my group leader to explain something to me about the functioning of a chain reaction and a bomb. He said, “Bob I do not understand that either. Go talk to Klaus Fuchs, he is an expert.”

Being sort of an innocent young guy I called Klaus Fuchs’s number and asked if I could come over to his office and talk to him. He invited me over so I went over, went in, and asked him my question and he got up to the chalkboard and gave me a fairly simplistic but adequate answer. As far as I was concerned, he was just a very knowledgeable scientist.

Bird: Did you ever meet Ted Hall?

Carter: I met Ted Hall. Ted had come from Harvard, he had just finished his Bachelor’s Degree at Harvard and two or three other people came at the same time. One of them was assigned to our group and he and Ted were friends. The man joining our group introduced me to Ted and we did not quite pal around but we associated somewhat socially a little bit. But I never particularly liked Ted; I did not like his personality so I did not pursue that at all.

Bird: Now, I remember in the spring of 1945 there was a meeting called with leaflets, people put out leaflets and Robert Wilson was involved to discuss the question of how to use the gadget. Germany was already virtually defeated.

Carter: Yes.

Bird: So there was a debate about why are we continuing to work so hard on this? Do you remember attending this meeting?

Carter: No, I did not, but I heard about it. There were some people who left Los Alamos at that time because they felt that the project should not continue now that Germany was defeated, the Nazi’s did not have a bomb and Germany was defeated.

Bird: But you did not feel that way?

Carter: No, I felt that it was important to really verify that whether or not a bomb could be made. I was still a little skeptical in the back of my mind as to whether it was going to work or not and I decided well if it works we better discover it. Then if we discover it and it works we should publicize it to the rest of the world.

Bird: I think that was Oppenheimer’s argument.

Carter: That was basically Oppenheimer’s argument and I guess maybe I derived it partially from him. I do not say that I initiated that concept.

Bird: Were you in Los Alamos on August 6, 1945 when you heard the news about Hiroshima?

Carter: Yes. Incidentally, on that the people from Los Alamos who were connected with the core itself were people who worked in the same group that Harry and I did and they worked in the same building as we did and they were all friends. In fact, I kind of helped them package up the core that was used on Nagasaki. We knew approximately when the Hiroshima bomb was going to be dropped but not exactly. I remember I wrote to my dad and I told him in a day or so there is going to be some important news about the war and I would like you to save me a copy.

Bird: Of the newspaper?

Carter: Yes of the newspaper, a copy of the newspaper.

Bird: Wow. So you gave your father advanced notice.

Carter: I gave my father advanced notice, yes. I did not know within a day or two of exactly when it was going to be dropped, but—

Bird: You knew something was going to happen.

Carter: Yeah.

Bird: As you look back what are your thoughts about the use of the bomb?

Carter: I am disappointed still that the government decided, our government decided to bomb a city with primarily civilians and not much of a military objective. There were several of us who hoped that somehow our government would figure a way of demonstrating to the rest of the world and in particular Japan, threaten Japan with the use but demonstrate one somewhere so that the world could see that they were functioning bombs.

Bird: Right.

Carter: Perhaps threaten Japan if you do not stop this war, unconditional surrender we are going to bomb you. If you made the threat of course, you would have to follow up.

Bird: Right, but they did not do that.

Carter: They did not do that.

Bird: Bob, we could go on and on. I think there is another person waiting to be interviewed but I know you had something you wanted to show us.

Carter: What did I do with it? I put it in one of my pockets.

Bird: Okay. Is it still there?

Carter: Yeah. This is a little piece of the soil from the ground in New Mexico under the tower where the test bomb was set off. It is embedded in polystyrene plastic.

Bird: Right.

Carter: A small group after I guess it was probably after the bombing in Japan. A small group made a bunch of these at Los Alamos and sent pieces just like this embedded in the plastic to the mayors of most large cities in the United States with a letter that said – this could happen to your city if there is a nuclear war. So do whatever you can to avoid any future wars that involve nuclear weapons. It was a simplistic kind of thing.

Bird: Right. This is the famous ‘green glass’.

Carter: This is the so-called ‘green glass’ yeah.

Bird: Hold on to the camera near your face then people can see it.

Carter: I do not know if they can see it but it is about an inch and a half in diameter and a little bit of green glass from melted soil from below the tower in New Mexico where the first test bomb was set off.

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