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Oral History Transcript — Dr. R. E. Kidder

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Interview with Dr. R. E. Kidder
By Joan Bromberg
August 20, 1986

Listen to R. E. Kidder discuss the differences between magnetic fusion and laser fusion.

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R. E. Kidder; August 20, 1986

ABSTRACT: This interview was conducted as part of a project to study the history of laser research.

Transcript

Bromberg:

What I'd like to do is to get an idea of what you were doing before your first contact with lasers.

Kidder:

OK.

Bromberg:

I don't know how conscious you were of the whole maser development through '58, whether that was part of your interests.

Kidder:

No.

Bromberg:

So, say around '58, what were you doing, what branch were you in, what were your main research — ?

Kidder:

Well, let's see. Just because it's a good starting point, I'll start in '56. Now, that was the time at which I left the Standard Oil Company of California's research laboratories in Southern California, and I came up to Livermore. The connection there was that there was a big project here at Livermore, run by the California Research and Development Corporation, which was — the project was contracted out to Standard Oil. They were operating the California Research and Development Company's activities in Livermore, and so since I worked for Standard Oil in Southern California, I knew quite a bit about what was going on up here. That was the project to build this gigantic accelerator, the MTA, and in fact, my boss at Standard Oil down there was a project manager for MTA. His name was Alex Hildebrand. He was the son of the famous Hildebrand at Berkeley, who I think lived to be 100, in very good health, I think. Anyway, I had heard about the CR and D operation up at Livermore, because it was Standard Oil's connection, and it sounded interesting, what Livermore was doing, and so I came up to Livermore in the summer of '56 on a job interview, and I liked what I saw, and so I accepted a position at Livermore, and I started working there in '56. Now, my training had been in the theoretical side of physics, and so actually my PhD thesis was in theoretical molecular spectroscopy, which was not an area I intended to pursue at Livermore at all. But anyway, I was also trained in mathematics. In fact, I got my Master's degree in mathematics and didn't switch over to physics until sort of the very last chance one would have for getting a PhD in math. So I was mainly a mathematically oriented physicist, which is what I worked in when I came up here to Livermore. I started at Livermore in the weapons program, the thermonuclear weapons program, essentially right away, and I worked in that field from 1956 on, essentially in nothing but that field for six years from '56 to '62. And that encompassed the period of the nuclear testing moratorium. If you remember, the United States and the Soviet Union, while they didn't have a treaty, they had a sort of a gentleman's agreement of some sort that neither one of them would test nuclear weapons, and that went into force at the end of 1958, I guess it was, and lasted until the end of 1961. There was a three year period during which there was no weapons testing either by the Soviet Union or the United States, and so I was busy during that three year period setting up methods of calculation primarily for thermonuclear weapons.

Bromberg:

And that would include working on computers?

Kidder:

Working on computer programs for this purpose, and so that was my principal activity during that moratorium period. Then, the moratorium ended in the fall of 1961, and the US had had a readiness program, so that they could commence nuclear testing on very short notice, which they did. In fact, there was the Pacific test series, called Operation Dominick, which took place in the spring and early summer of 1962, and my involvement with Operation Dominick was that I, along with Ted Merkel, who was the head of the physics department which had been formed during the moratorium, were assigned the responsibility to review the technical capability, the technical aspects, I should say the adequacy of design of all of the weapons that Livermore Lab was going to fire in that Pacific test series. So Merkel and I ran the so-called pre-mortem committee, pre-mortem, before the death of these devices, in the Pacific, and reported, my job was to report to Johnny Foster, the laboratory director, as to the status and design adequacy of the weapons that we were firing or the devices that we were firing in that Pacific test series. So that tells you I think pretty well what I was doing, up until 1962. I was totally immersed in nuclear weapons physics and design, and in particular providing the laboratory with means for computer calculations for doing the weapons design work.

Bromberg:

How did the laser first come across your horizon?

Kidder:

OK, that's what I'm getting to. First of all, people at Livermore, myself included but other people as well, were very much interested in the laser, as a means of producing extremely intense light, in particular focusing high power, high power and high intensity energy on some target. The reason for that was simply that if the amount of energy and the intensity that could be created was high enough, we knew that we could ignite thermonuclear materials in the laboratory under controlled conditions. We knew that in 1962, so the whole issue was, could you get enough power in a single laser pulse to do that?

Bromberg:

Now, here I'm a little bit vague, because is this — now, somewhere around the end of '61, the DOD got very interested in lasers, the glass lasers come in, and DOD began an extended program, more money, Project Seaside came in, so I'd like to — I would assume that once the laser was made down at Hughes, you knew about it.

Kidder:

Sure.

Bromberg:

Was there very much contact between your group and Hughes at that point?

Kidder:

Let me explain that first of all, the DOD interest had nothing to do with the interest of the weapons, the AEC. DOD was interested in lasers as weapons to attack tanks or airplanes or things of that nature. And so they were interested in lasers with totally different characteristics than we and the AEC were interested in. In fact, the DOD probably knew nothing about any interest from the AEC, or had no reason to know much about it, certainly in 1962, and it was only in 1963 when there was a summer study that was chaired by Keith Bruckner in the summer of 1963 which took place at Woods Hole, Massachusetts, and I was a member of that summer study. But again, that study had entirely to do with the DOD's interest in weapons. It had virtually nothing to do with AEC interests. In fact, I couldn't say anything, the people at that meeting didn't have the appropriate clearances to — they had DOD clearances but they didn't have clearances that would have entitled them to listen to what we were interested in at all.

Bromberg:

OK, this clears it up. Within AEC there was originating an interest quite independently in lasers.

Kidder:

Quite independent of the DOD, yes.

Bromberg:

Yes, of course. Something I didn't really know about. And that, I assume then, is going to be cross-laboratory. I mean, you talk about it at Livermore, you're also talking about it to other AEC people?

Kidder:

Well, no, not really. You see, the problem was that —

Bromberg:

— a kind of new historical thread that's coming in here, that's why I'm dwelling on it a little bit.

Kidder:

Well, the reason that everything was so isolated was the classification. See, none of the DOD contractors had any access to the nuclear weapons information, and the classification rules at that time were very, very strict about our interests, and so while we could attend, and I did, the summer study, and contribute to the study of lasers for DOD purposes, the reverse couldn't happen. None of the DOD people were allowed any access at all to the work that I was doing at Livermore, so it was all fairly mysterious as far as they were concerned. Anyway, to get back to the thread of the AEC's interest, which was, as I've said, totally isolated form and totally distinct from the DOD interest, we really couldn't care less about the DOD's weapons. The kind of weapons or the kind of lasers that they were interested in were useless for AEC purposes. We were interested in the development of laser technology in general, and so we were interested in keeping abreast of the DOD's support of laser development. But the lasers we were interested in were of a radically different kind than the DOD, and we couldn't tell them about it really. So Livermore, so what I did is, I was watching this laser development, and we were interested in short pulse lasers, that is, lasers that would produce pulses of light of durations of the order of tens of nanoseconds at the most, and of course the DOD was interested in long pulse lasers and delivering lots of energy over a long time, so it wouldn't satisfy our requirements at all. Anyway, we all of course were —

Bromberg:

When you say "we," can you give me a little feeling for this particular group you're talking about ? Who's "we"?

Kidder:

"We" is the Lawrence Laboratory and people in the Lawrence Laboratory who were interested in new concepts and new technology applications to weapons. Well, the people that were mainly involved with this, were interested in it in the early days, besides myself, were John Nuckolls. He was very peripherally involved in this but was interested in it at that time. There's Sterling Colgate, who's now at Los Alamos. He was in the magnetic fusion program at that time, as I remember, but he was interested in this idea. Let's see, I guess Teller was certainly interested in it. Teller's interested in every new idea he can think of. So there were other people who were interested in watching the development of particularly the Maiman laser. We weren't much interested in the Bell Labs helium neon laser, but the pulsed laser of Maiman looked like it would, if you could store energy in it and then release it in a very short time, then the Maiman type laser looked like some day it might be just what we would be interested in.

Bromberg:

Now, I just want to summarize something. So what I'm understanding here is that it's a kind of conversation across groups. There are groups of people who talk together, who know each other as interested in frontier technology. It's not one little group that's talking this over, it's Colgate from the thermonuclear CTR and you in this weapons analysis group, is that ?

Kidder:

Not really, because I never talked to Nuckolls. In fact, it wasn't till years later that I knew he had any interest in this, for example. Colgate I knew had an interest in it. Teller, I don't think I ever talked to him about it. So I think it wasn't true that, it wasn't a group of people, you know, talking to each other. I talked — I guess, let me see if I can explain this. In my scientific work, I seemed to be a lone wolf. Almost all the papers I've ever published are single author papers, and I tend to work pretty much by myself, and that might explain why I had very little contact with these other people. What happened specifically was that while I mentioned these other people, as I found out later in some cases, had been interested in this thing, I didn't know that at the time, and so I had been following with interest the laser development after Maiman had first shown that the laser worked, and the thing that triggered me off was when Hellwarth, who was at Hughes Malibu Research, and M. C. Quong, those two scientists, Bob Hellwarth and M.C. Quong, published a paper, maybe it was just in the BULLETIN of the Physical Society or something, anyway, they did an experiment in which they did precisely the sort of thing that would have made the laser of interest to the AEC. That is, they pumped it over a long period of time, and then prevented it from lasing by putting a shutter in the cavity, then opening the shutter quickly and dumping the energy in a short pulse. As soon as that happened, then I realized right away that this was what we were waiting for. The amount of energy that was being talked about was miniscule, by our needs, and also that the pulse length, the length of the laser pulse was far longer than anything we could tolerate. We knew all this. I mean, we were not guessing. We had very good ideas about what would be required way back in '62 and '63.

Bromberg:

By the way, I have to apologize for slowing you down this way, but it's precisely the social situation and the first germs of the idea, these kinds of things, that we can't get at except through the conversation, that's why I keep slowing you down.

Kidder:

Right. Well, yes, I figured, I understand that, but I have to get to where I'm going and then we can come back again, because then you'll understand how all this happened. OK, as soon as that happened, I went to the director of the laboratory, or very shortly thereafter, as soon as I knew about this short pulse business. I don't, I'm not aware that I discussed this with any other scientist at the lab. I was in charge really. I was in the physics department. I was working for Ted Merkel in the physics department, and I — as I say, my recollection is that when I found out about this, I went pretty promptly without any encouragement by anybody else, and I think the reason that I'm saying that is, I probably had as much of a knowledge about thermonuclear ignition problems as anybody at the lab, and it wasn't as though I needed to talk to anybody. So I went to the director right away, Johnny Foster, and I told him, I said, "Look, I don't know much about lasers, but it looks to me as though this development at Hughes Malibu will ultimately, if we can make the laser of shorter pulse duration and tremendously increased energy, we could use this for igniting thermonuclear materials, namely deuterium and tritium, in the laboratory. And I don't know whether this thing could be scaled up, but I don't see any reason why it couldn't. Let me go down and talk to Hellwarth and Maiman and see what they say." And Foster said, "Fine." So I went down to see Maiman.

Bromberg:

He must have been already gone from Hughes.

Kidder:

He may have been. I went to Hughes, Malibu, and I talked to Hellwarth at Malibu. I don't remember whether I talked to McClone(?) or not. I forget whether he was around. But I did talk to Hellwarth, in fact I had lunch with him at Malibu, and we discussed this idea of scaling up the laser, and he said he didn't see any reason why it couldn't be scaled up. Sort of the obvious scale-up was just put a whole lot of these little things in parallel and shoot them all at the same target. But the question was brightness, could you keep a good beam, keep the divergence low, and he didn't see any reason why you couldn't. I didn't when I was at Livermore, but I had nothing to do with lasers, and so I wanted to talk to the then experts, and Hellwarth didn't see any reason why you couldn't scale these things up. When I went down to see Hellwarth, I had a guy from Livermore go with me. His name was Ken Trigger. He's at Livermore now, I think, I'm pretty sure he is. Anyway, Ken went with me, and the reason that I took Ken along was that he was a personal friend of Ted Maiman's. They'd been school chums together, I think at Stanford. So anyway, and Ken may have been working in my group or something at that time, I just can't remember, anyway Ken and I went down to Hughes, and after we talked to Hellwarth, we went over, we met Ted Maiman somewhere, I forget where. We went to his house, and I think Maiman had had a big argument with Hughes or something at about that time, and he may no longer have been working for Hughes at Malibu. I don't remember clearly. It seemed to me — we met him at his house, though, not as I remember, not at Hughes, or at least he took us to his house. We may have met him at Hughes and he took us to his house. And I think we had dinner in his house there, and I talked to him about this discussion with Hellwarth and about lasers in general and short pulse lasers, and the scaling problem, and Maiman didn't see any reason either that things couldn't be scaled up eventually, with the appropriate materials and so on. So I went back to Livermore and I reported right away to Foster, and I said the guys down there didn't see any reason either that these things can't be scaled up, and I think Livermore ought to start doing a little work in this field. So Foster said, "Fine, let's go ahead." So that's the way the program started. And I don't know who else Johnny Foster talked to besides me. I have no recollection. He didn't make any indication that there was anybody else involved with these decisions other than me, and you'll notice in that letter to General Betts, the cover letter to General Betts, copies were not sent to anybody in the laboratory except me and Merkel. Ted Merkel has died a good many years ago so he's not around anymore. So the social aspect of the thing, it's my — I was isolated essentially from these other people who, I later found out, had been interested in this. I talked to Foster and no one else. I went to Malibu and talked to those people and reported back to Foster, and we started the program, so —

Bromberg:

Now, when you say started, what does that mean? Did you start on it part-time in some way?

Kidder:

Yes. The physics department was formed, I forget whether it was before or after I went down to Malibu. I think it must have been before. And a project was formed called Q Project, and I was in charge of Q Project, and one of Q Project's responsibilities, in fact it’s main responsibility, was to look into and do some work, both theoretical and experimental work, on short pulse lasers for this purpose.

Bromberg:

Q switching or?

Kidder:

Well, sure. That wasn't the reason we called it Q Project. Q just happened to be a letter that was left over. There's a lot of the lab, the lab goes by letters, there's A division, B division, and so forth.

Bromberg:

Did you recruit anyone into this at this point, or this was still a one person —?

Kidder:

No, we had maybe a half a dozen senior people involved, not all of them directly involved with lasers. We had other responsibilities besides lasers in this project. But it was an actual group with a budget and a secretary and so forth. It wasn't a one man operation at all. So that's the way the laser project at Livermore started, and I think that's described in Betts's letter, that we put this thing together, and so that is the best evidence for exactly what happened and what the goals and things were, because it was written at the time.

Bromberg:

Actually the organization isn't described in here, just some of the conclusions. Now, at this point, were you thinking at all in terms of fusion reactors, or only in terms of simulated weapons?

Kidder:

It was 100 percent simulating weapons. The idea of using this for fusion reactors was not regarded as — well, I was going to use the word sensible, but I don't think that's right. We had no ideas of making things efficient enough or having enough gain in these capsules to make it at all interesting for power production. So that idea simply was absent. In fact, General Giller, who was the head of the DMA for many years, quite a few years, not too long ago, said in an article in SCIENCE MAGAZINE that the goal of the program of laser fusion at Livermore and Los Alamos as well, because he was speaking for the DOE, not the labs individually, was military right from the beginning and it always has been. That's been the primary goal of it. Now, when there was the Arab oil embargo in 1972 or something, there was a big emphasis on the possibility of using this to produce power. But that was never a primary activity, and prior to 1970, it wasn't an idea at all. There was simply no interest whatsoever in anything but the military applications all the way to 1970 or maybe '72.

Bromberg:

Well, for example, in '63, you were reviewing this paper by Dawson you showed me.

Kidder:

That's right.

Bromberg:

Now, he's immediately interested there in using lasers in some aspect of controlled thermonuclear reactors, but that did not transfer to your group.

Kidder:

I thought that was nonsense. It didn't seem to me that it made any sense at all to talk about this as a power source in those days. It just didn't —

Bromberg:

You didn't tell Phyics (?) that you thought the whole idea was nonsense? Maybe you did in some indirect way.

Kidder:

Well, no, I didn't have any objection to Dawson's ideas of publishing that paper. He had no access to any of the classified stuff at that time anyway, and I mean, I thought for a person on the outside, as he was, as you saw, I made some criticisms of his work, but I had no reason to — I mean, if people wanted to think that there might be some application for power, I would have regarded them in those days as indulging in fantasies, but fine, I mean, I don't have any problem with people — that simply, when I was making my advice to the AEC, I was not selling this in any sense, quite the opposite, as a source of power. And General Geller says that, as I say, in this thing in SCIENCE, which wasn't all that long ago. He makes it very plain that not just from my standpoint but from headquarters' standpoint, this was always a program that as primarily related to nuclear weapons research, and of course that's borne out by the fact that it has never received a dime of funding from anything but the Division of Military Applications.

Bromberg:

So I'm going to also conclude that before 1970 you weren't having much to do for example with the magnetic fusion people at Livermore?

Kidder:

None whatever, no. I participated in an in-depth review of magnetic fusion, but it was quite a bit earlier, I guess, than 1970. But no, we had no connection. There was no interest either way. We weren't interested in magnetic fusion, really, and they weren't interested in us.

Bromberg:

OK, now you started to do a considerable amount of work...

Bromberg:

I want to come to some of the early researches you did on lasers themselves, because you've got this paper with Bleck on spiking phenomena, and you've got a paper on chemical lasers, and it seems as if there's a period here between the start of the program and the disk system, for example, where you're looking at a variety of laser media.

Kidder:

That's right. Yes, the ruby laser was the one that we worked on for quite a while, on a very small scale, as opposed to the neodymium glass one, and I'm really not entirely clear just why that was where the emphasis was in those early times. It's hard to explain, because the glass laser had been invented and operated by Snitzer, I think it was, at American Optical, very early on, and I'm just not clear why we elected to do all our experiments at least with solid state lasers, with the ruby systems.

Bromberg:

There were other systems. The carbon dioxide started coming out and so on. Those were not?

Kidder:

No, we needed, the CO2 laser, the first indication that the CO2 laser would be useful was when the Canadians came out with this so-called T laser, this transverse electric atmospheric pressure, the A was for atmospheric pressure, and prior to that time, the CO2 laser had been mainly used as a continuous wave, CW laser.

Bromberg:

That's about 1970, isn't it ?

Kidder:

Yes, that's right. Quite late. And when the T laser came out, and not until the T laser came out, was there a substantial interest at Livermore in the possibility of using the CO2 laser for short pulse purposes. And that interest at least at Livermore — well, I'll say this and then we can go back to earlier times — what happened was that in about 1972, or somewhere in that vicinity, and I think it had something to do with the oil embargo and things of that kind, it certainly didn't have to do with a great resurgence in military interest, but again, there were developments in laser technology that made the possibility of thermonuclear ignition I think come much closer to realization. Anyway, around '71, the DOE or the AEC, I guess it still was, decided they were going to put more money into the laser work at Livermore, and one of the reasons for that was that — well, there were two programs that were terminated, both of which had a good effect on the laser program. The first one was the Pluto Project at Livermore, which was a project to build a nuclear ramjet, and the guy who became the head of the physics department, Ted Merkel, used to be in charge of the Pluto Program at Livermore, and that went along, I think it was until 1964, and then it was terminated very suddenly, primarily because the next step would have had to have been testing the air frame for it, not just testing the ramjet engine, which had been tested then in Nevada, but testing the airframe for it, and making a big increase in funding would have been required, on the one hand. On the other, the ICBM was coming up, and so people decided an air-breather, particularly a nuclear-driven air-breather, didn't look like a good thing to push through. And so the Pluto Project was very abruptly cancelled and cancelled totally. Well, that meant that there were people around the lab who were available to do something else. And of course Merkel was one of them, because he was the head of the Pluto Program, and he started the physics department, and he was favorably inclined towards this laser program and me. So that was helpful. Then the other program that went down the drain, this was in 1972 I think or somewhere around there, was a weapons type program that I can't, classification won't allow me to describe in detail. Anyway, it bit the dust, and its budget then was available, its budget was research money and it was a very substantial budget. That is to say, at that time the laser budget was about a million a year, and this program was a four million a year program, research program that collapsed, so suddenly four million dollars a year or thereabouts became possibly at least available. And so that was decided by the lab, to put that into a much expanded laser program in'72. And so that's what they did, and then the program grew from that point on, and I might say, in '72 I bowed out of the laser program pretty much, and it was taken over by John Emmett, who was at NRL, the rationale of that being primarily that my capabilities are not in running big programs but in early research phases of innovative programs, and that was clearly going to go from what it had been, a fairly small scale innovative research program, into a big, let's build a big laser, program, and so Emmett was brought in from NRL to take that project over, which he did, and which he still is in charge of. So from '72 until '86, he has been in charge of going ahead, one step after another, and producing these enormous lasers, glass lasers that you've probably read about or maybe even seen at Livermore. OK, to go back then to earlier times, —

Bromberg:

Earlier times, you were working on ruby, and you also did some, you were talking about why rubies seemed the most interesting. I guess there were YAG lasers coming up. I don't know the properties of these lasers well enough to know if I'm saying something ridiculous. Maybe you can use YAG lasers for short pulses.

Kidder:

No.

Bromberg:

You were interested in chemical lasers, I understand.

Kidder:

That's right. The chemical laser, I can describe that I think fairly clearly. Again, the kind of laser that we were interested in particularly was a laser that was first, I think it was first demonstrated in Germany, and that as the iodine laser. It was my conclusion that the iodine laser and the neodymium glass laser had very very similar capabilities, and the iodine laser had certain advantages because since it didn't have to have a glass host to so to speak hold up the lasing ions, it occurred to me that the quality of the beam that you could get out of a, the brightness of an iodine laser beam could conceivably be a lot better than the brightness of the neodinium glass laser. So we worked on the iodine laser. One of the people who worked on that in my project, in Q Division, was David Gregg, and we wanted to be able to make an amplifier out of the iodine laser, and the iodine laser has very high gain, so it's hard to make a system that stores energy and doesn't lase before you want it to, and so we used a method of spoiling the gain of these amplifiers with an inhomogeneous magnetic field. That is to say, we spread the lines out by having them in a fringing magnetic field. And that worked OK, and we published a paper on that, Dave Gregg did, on that. Then in Germany, Karl Kompe who was at the Max Planck Institute —

Bromberg:

I guess he started out with [???] didn't he?

Kidder:

OK, maybe he was. Anyway, instead of using a magnetic field, he simply mixed in with the iodine some inert gas to broaden the line and reduce the gain, and that was a much more practical way to do things, and it worked OK. So we dropped our work on using the magnetic method for, the inhomogeneous field for broadening the line. But we decided that Kompe was a very competent guy, seemed very interested in pursuing the iodine laser, and so we decided that we'd let him sink or swim on the iodine laser, and if things looked good, we'd adopt that as our high powered pulse laser approach, and if it didn't, if our neodinium glass looked as if it were more favorable, then we would adopt it.

Bromberg:

Now, we're going along toward the middle sixties. Do you still have your half dozen people and are you still called Q Project?

Kidder:

We went from being called Q Project to Q Division. That was at some point, but it's really not even clear to this day when that transition really occurred. I think Carruthers and his historical people figured that out finally, but I don't remember just when that was. As I say, we had eventually, we were running at a million dollar budget, which would mean that we had probably something like ten senior people involved. We ramped up from zero to our ten people fairly abruptly after 1963, and then we stayed at a level rate from then until 1972, until we got this additional four million out of this other project, and then the whole nature of the project changed. So it went up and stayed that way for a long time. I tried to increase the budget for the program, and would have succeeded, I think, had Ted Merkel lived. He died, and Edward Teller became the head of the physics department.

Bromberg:

When was that?

Kidder:

I'd have to look that up. My memory for dates is not good. Anyway, I'm guessing it's mid-sixties.

Bromberg:

These things obviously I can look up…

Kidder:

Well, yes, OK, I have a note here. All it says is "Merkel, 8 August '66." Whether that means, that's when he died, I think it does, but anyway, let's say that Teller took over in late '66 probably, and his attitude towards the program, the laser program, was one of continuing to do the work, but he wouldn't support any growth in the program at all, so once he took over, any further budgetary growth simply stopped.

Bromberg:

That seems a little surprising.

Kidder:

It does. I don't know. I never did figure that out. But he put the clamps on that program pretty thoroughly, until 1972.

Bromberg:

So in the chemical laser business, you really didn't have much to do with the Berkeley people.

Kidder:

None. Not really.

Bromberg:

Did you have much to do with Compa(?) himself?

Kidder:

No. He visited us, but we didn't have much to do with him. We elected to pursue the neodinium glass development, and watch the iodine development. We did some work, as I said, in iodine lasers ourselves, but we simply said, well, the Germans are going to go ahead with this. They're very competent. They're very interested. We don't have to do this work on the grounds that they won't do it right. Let's let them go ahead with it and watch them, and that's what we did. As it's turned out, even to this day, the neodinium glass and the iodine lasers are still thought to be somewhat competitive. The Germans have right now, right up to the present time, continued to pursue the iodine laser, for their own research purposes with laser fusion. And they're building a bigger one, and it's going into operation this fall in Darking. And it has advantages and disadvantages, compared to the neodinium glass systems. Livermore elected to go the neodinium glass route, and I advocated that strongly, in '72, and Los Alamos, who had gotten into the laser business I think in '67 or somewhere around then, I'll describe that, how that went about, they had to take second best. The other big laser — oh, DOE or AEC said, "We're not going to build two big neodinium glass lasers. Just not going to do that." Since Livermore had already built this system and was in the process and knew all about them and was way ahead of Los Alamos in the whole area of this work, we sort of got first choice on which big laser we would build, and we said, "We'll build the neodinium glass laser." Since the AEC wasn't going to build two neodinium glass lasers, Los Alamos was, I don't know whether they would put it quite this way, but I would say they were stuck with the CO2 laser. We simply didn't want that as our first choice. So Los Alamos had to build the CO2 laser, and that's how that split occurred. Then the guy who started the Los Alamos program, at least in any substantial way, was Keith Boyer, and Keith, I don't remember the date now, it's probably late sixties, '67 or somewhere in there, maybe even a little earlier, I don't know, anyway he came out to Livermore to see me. As I say, until 1972 I ran the program for Livermore. I ran it for the first ten years of its existence. So Keith came out to see me, with this idea in mind that he was going to start a program of laser fusion at Los Alamos. Prior to the time he came to see me, there were one or two people at Los Alamos whose job it was, I gather, to kind of watch what we were doing, but not actually to start as program. Well, what precipitated Keith's interest was very clear. He had been in charge of the nuclear rocket program at Los Alamos, Rolar (?) and that bit the dust, so he was looking around for new and novel things to work on, and he thought that lasers — laser fusion might be an interesting thing to look at. So he came up to see me, and I showed him all around what we were doing, and I told him, I said, "Yes, I think as far as the AEC is concerned, I think this is something that we certainly feel should be worked on, we're working on it as hard as they'll let us, " and I told him I thought Los Alamos ought to get in on this too. And he agreed with me, and so he went back to Los Alamos and convinced, I guess it was Agnew, who was the director, that Los Alamos ought to start a program, and they did. So Boyer was in charge of the Los Alamos program right from the beginning, and that built up to some level or other.

Bromberg:

I understand that at some point around here, maybe '66 or '67, there was a meeting with you and, I've heard it from Lubin, and some other people, and this was a discussion of laser fusion, some of the early ideas on inertial confinement. Does that ring a bell at all? And in fact, it really is around this time, around '68, that you're beginning to publish in NUCLEAR FUSION. Here's the first, Paper # 20, "Application of lasers to production of high temperature and high pressure plasma," you've got in NUCLEAR FUSION.

Kidder:

Yes.

Bromberg:

So it sounds as if here somewhere there's at least some idea going on about controlled fusion, because —

Kidder:

Well, not really, you see —

Bromberg:

Isn't NUCLEAR FUSION a controlled fusion magazine?

Kidder:

No. Papers on inertial confinement fusion are published there.

Bromberg:

Yes, but I mean a magazine that's devoted to fusion reactor physics. Or is it wider?

Kidder:

It's wider than that.

Bromberg:

So if you publish this discussion, it's not necessarily going to be because you're interested in —

Kidder:

No, and I can explain that. Again, to the outsider, things must have appeared somewhat mysterious. See, we knew right from the beginning, meaning before lasers were even invented, that if you wanted to ignite thermonuclear fuel, you could confine it inertially but you had to compress it, because it wasn't enough just to heat things up to some modest density as a gas, but you had to compress it to extremely high density, before you could succeed. Now, the problem was that the Atomic Energy Commission did not allow us to ever mention the word compression. So in that paper that you just referred to, I was only allowed to publish that because I was simply heating a gaseous sample, this was a theory paper, but heating a gaseous sample of deuterium, I think it was, no compression involved at all. It was heated up, a shock wave went in and came out, and I couldn't say a word about what we knew to be an absolutely crucial requirement from the very beginning, and that was this compression of the fuel. Now, it's interesting how ultimately we were able to talk about that. One of the key things that happened was that there was a paper, something published by Basov, in — I'm going to look at my notes, I think when I was looking through this I saw the reference to this — and this was a very key thing, because it allowed us finally, or gave us the foot in the door, shall we say, to finally get something declassified. Yes, here it is. "Basey Basov, for example, has estimated that values of compression between 100 and 1000 can be achieved by means of spherical hydrodynamic plasma implosion." This was a paper presented at the European Physical Society meeting on laser plasma interactions, September 1971, Harwell, England. Now, that was a tremendous bomb shell to us, because we knew for the preceding ten years that you needed to compress things by this kind of — to this extent, in order to succeed in inertial confinement fusion, but we were forbidden to say anything about that. So when we saw Basov say this, then we thought, aha, maybe now we can get the AEC to let us say something about compression. And what happened then was, let's see —

Bromberg:

But you know, still —

Kidder:

— this was mentioned, I think I was allowed to say something about compression at a meeting that took place in Iran, (?), Iran in 1971. I'd have to check that, but that's what I seem to have here. On this paper I seem to have referred to this thing of Basov's. And I was allowed to do that, so — right up until 1971, the activities, for people who didn't have clearances for weapons, nuclear weapons information, were very mystified as to what was going on, because the whole idea of compressing fuel by means of lasers was something that they wouldn't have known we were working on.

Bromberg:

OK, now I still want to harp a little bit on this '66 or' 67 meeting, because you said you weren't really interested in lasers for fusion reactors before the seventies, but Lugen (?) says that there was this meeting in which the ideas of inertial confinement for fusion reactors were discussed, and you were the principal idea man for the meeting, and he says Dawson was there, and that was apparently a very pivotal meeting from his point of view, in getting him interested.

Kidder:

OK, I'm trying to —

Bromberg:

And in fact, if you're telling Boyer in the late sixties that Los Alamos should be interested in lasers and fusion —

Kidder:

Yes, but for weapons purposes. I never suggested to Boyer that I felt this would be useful, at least in those days, for laser, for the production of power, because frankly I didn't think it would be. Now, let me say, there was a crucial idea that came into the picture, and again, this idea wasn't — didn't come about until l970 or '71, in there. You see, the idea that came about was a way of making one of these capsules into a high gain capsule. In other words, that means that the amount of thermonuclear energy that would be released when the capsule burned would be very large compared to the amount of energy required to get it to burn. And the trick that Nuckolls, John Nuckolls and Lowell Wood, those were the two guys that came up with this idea, was that they would heat only a very tiny amount of this capsule, but compress the whole thing, whereas the idea that I had been looking at did involve essentially heating and compressing the entire thermonuclear material. Now, for weapons purposes, for our research purposes, the idea of having a high gain capsule was not important. If we could get thermonuclear ignition to occur, whether the thing had high gain or not was a matter of rather small moment. On the other hand, if you were interested in the possibility of using this for power production, it was absolutely crucial, because in order to get this thing to burn, the efficiency with which you could do that couldn't possibly be more than about 10 percent, probably a lot less overall, with lasers anyway, and that meant that even to get back the investment of laser energy you had to have a gain of 10 in the capsule, but to make a power plant, where you're going to sell power to a customer and make up for lots of other losses in electricity — you know, you only can make electricity with 30 percent efficiency or something — you're going to have to have gains on the order of 100 or more. Well, unless — if you heated the entire mass of fuel that you were going to ignite, you couldn't get gains that high. At least it would be very improbable. So Nuckolls and Wood said, well, let's not do it that way, let's play the game in such a way that we only heat the very center of a bunch of this fuel, and compress the whole thing, then the center lights, and then propagates and ignites all the rest of the fuel. Very good idea.

Bromberg:

Were they in your group at this point?

Kidder:

No, neither one of them was.

Bromberg:

Where were they?

Kidder:

Nuckolls was —

Bromberg:

— how did they get into this?

Kidder:

Well, Nuckolls was interested in laser fusion. He was one of the people I mentioned in the very beginning.

Bromberg:

He was over in the fusion group?

Kidder:

No, I believe he was in the weapons, one of the weapons divisions, all that time, and Wood — I'm not sure. I'm just not clear on where Wood was connected at that point. However, they were essentially non-interacting with my people. Nuckolls had very little contact if any. In fact, I didn't even know he was interested in laser fusion for years.

Bromberg:

But he must have brought this idea to your attention.

Kidder:

He did. Yes, he did.

Bromberg:

Someone must have.

Kidder:

Eventually. He and Wood and I went to Washington, I remember, and this was in '70, I guess it was, and he presented this idea to the President's Science Advisory Committee, and this was '70 or '71, somewhere in there, and it wasn't until this idea came up that it made any technical sense to talk about using laser, inertial confinement fusion for power production.

Kidder:

It was worse than no information, just those papers that were published seemed to me to put people on false leads about what the AEC was doing, more than no information would have.

Bromberg:

One of the things that did surprise me in these documents that you showed me here is that you were thinking in terms of 10 to the 4th lasers in these early documents. Now, that seems to me silly. I mean, my first reaction is, it's silly to think you're going to get 10,000 lasers all focussed on a part, point of the plasma. Is that a reasonable idea?

Kidder:

Well, let me say that that idea was used only as a demonstration that at least there was a theoretical possibility. Now, whether that would ever be practical is a totally different question, and I didn't attempt to, I hope, indicate that putting 10,000 lasers and aiming all of them at one place would be a practical way to do something. It just showed, sort of as a mathematician would say, it was an existence proof. That's all. Now, in fact the Russians, when they built the big glass laser, did something fairly close to that. I don't think they came up with 10,000 rods, but instead of building large aperture systems, which we decided to do with glass right away, with the disks, which was the only way you could go to large aperture systems, the Russians instead elected at the [???] Institute to build a rod system which was, it didn't have 10,000 rods but it had several hundred, I believe, that they were using, and I think some people would say that that was not a particularly sensible or practical way to proceed, but that's what they did at the [???] I forget the name of that place. They may still be trying to use it or something, I haven't kept up with that. No, I would say that the 10,000 lasers was simply to show that at least conceptually, the thing wasn't impossible. Whether that would be practical or not. We decided right away that you had to have a small number of large aperture systems, and that's why we went to glass disks.

Bromberg:

We should talk about the glass disk system, and its origins and the experimental work that went into it.

Kidder:

I have a picture of — I don't know whether this is the very earliest one that was built, but — this is the earliest one built, I think.

Bromberg:

OK — Dr. Kidder is holding a photograph of a tilted disk, a glass disk, one of those light purple glass disks that takes such a beautiful picture.

Kidder:

Yes, they do.

Bromberg:

And this was built, it must have been around '66, '67?

Kidder:

That's too early. I'll look at my — around, let's see, does it say in there anywhere?

Bromberg:

Here in '69 already you've got an article in the JOURNAL OF APPLIED PHYSICS, on the glass disk laser system, so it must have —

Kidder:

It says here, the article on the glass disk thing was received September, '68, so I would assume that this thing you're looking at, you see it has these — let's see, that was a funny thing that happened. I'll explain that to you. This was September, '68, so I would assume that that picture you're looking at was probably taken in early '68 or somewhere around there, possibly late '67. Probably early '68. There was a funny sidelight to this. I hadn't been following the design progress on this as carefully as I guess I should have, and when I finally discovered that they were going to use the flash tubes, here, this is the optical direction of the beam, this way, and a whole bunch of them, instead of lengthwise, I was flabbergasted, because it seemed to me that that was a terrible mistake to have done that, because you couldn't pump as hard that way. The ends of the flash tubes of course aren't terribly useful for pumping, and the efficiency of the thing, I thought, would clearly have been much better if the tubes had been lengthwise instead of this way. You can see in this laser, they're this way. Of course, the very next lasers that were built were all built with the tubes lengthwise, and they have been ever since.

Bromberg:

I see, I didn't pick up these transverse — those are your tubes.

Kidder:

The guy who was principally responsible for putting this thing together was Jim Swain. In fact, he's one of the authors I think in this — yes, Swain is the first author listed on this Large Aperture Glass Disk Laser System, so he was the guy that really put this whole thing together and got it going.

Bromberg:

Well, I've read that article, maybe skimmed it is a better word, and you lay out the factors very clearly, as to rods versus disks, and the reason for tilting them and so on, so it all seems a very logical result of thinking. Is that the way it came about?

Kidder:

Yes. It was very logical. The logic of this thing is really transparent and simple. If you want to make something of large diameter, then you have to get the pump radiation inside of it to the middle of it. It doesn't do any good just to pump the outside. You have to pump the middle. So if you're thinking about a large diameter rod, if you make the diameter large, you have to decrease the doping all the time, so that the light can get in and pump the center of it. Well, what that means is that for each useful element in the mixture, namely, the dopenion(?) that's going to do the lasing, you've got more and more useless glass. So, the mental process you go through is, you say, well, let's imagine we had this great big rod that was this big in diameter, with all this glass in it, what would we do to it? Well, what we could do is slice it up like this, then squeeze out all that extra glass and throw it away, but keep on the ions, all the lasing ions, and then tilt it so that a, it would have big faces looking at the source of pumping, and b, tilt it at the booster's angle so that you wouldn't lose any light by reflection. That's about all the thinking it took, and that's almost a logically airtight argument for going this route.

Bromberg:

This was an idea of yours, or this was an idea of a group of people?

Kidder:

Well, the idea of using disks as opposed to rods was thought of by almost everybody almost immediately, when people thought of laser systems. In fact, American Optical Company had a patent on disk lasers that they filed quite early, long before we built this system they had some kind of a patent — I don't remember whether they had a booster angle tilt to them, but they had disk systems. General Electric did also. General Electric filed a patent application on solid state disk laser systems, again very early, and I think there was some kind of a fight between GE and AO about the patents. So the idea of using disks was certainly not original with Livermore or with me. It was what I would term an idea that was obvious to anybody. The idea of tilting it at the booster's angle and things like that, I don't remember whether those were in the early ideas of American Optical or GE. Maybe they were. I just don't remember. So I would say, the concept of the disks would have to be assigned to General Electric, I don't know who in their labs, and American Optical and maybe even other people.

Bromberg:

What were the elements in this which — I mean, nobody else did this, so what were the elements in it that were novel?

Kidder:

Well, first of all — I think I get what you're striving for — I realized, anybody in this business realized that for the purposes of the AEC, we were going to have to have an enormous aperture or a number of apertures, each one of large size, in order to get the kind of pulse energy through the system that we would need, the limitation there being the pulse would damage the laser material itself if it was too intense, so to get the total energy, you had to have a large area. Well, if you're going to make a large area with hopefully a relatively small number of laser beams, each one had to have a large area, so you are now talking about a material that would have to be able to be produced economically and in big quantities and large size, and it seemed that glass was the ideal material for that. So we could visualize very large disks of glass. But as soon as you talked about a large size, it immediately was clear, as I've explained, that you couldn't use rods. You had to squeeze all that glass out of there. And you used the disks, tilted them at the booster angle. So for reasons that are really quite fundamental, we decided that we had to use tilted glass disks of large aperture.

Bromberg:

In some way it's the particular application that you had in mind that brought together all these ingredients.

Kidder:

That's right.

Bromberg:

And the novelty came through bringing together the technology of the day with the application.

Kidder:

Right.

Bromberg:

And also is it correct that it was with the tilted disk laser that you also came simultaneously to the decision that glass was what you wanted?

Kidder:

Yes. We decided that it had to be glass. We couldn't expect to have crystalline materials that size and good optical quality. And there was no reason to. Glass was a marvelous medium because there are so many different kinds of glass, and it's flexible to do different things with. So then the only question remaining was, what do you dope it with? Well, glass had been doped with all of the rare earths and those had been tested for some time to see which lased best, and neodinium had the best lasing properties of any of the materials that glass was doped with, so we simply decided to use neodinium, and so that essentially determined the whole architecture, the materials at least, and laser concept, to the present day. I mean, we're building use neodymium doped glass laser disks tilted at the booster angle. That's exactly what's been done ever since. So that decision I think was very compelling. It wasn't one of those situations where there are seven different ways of doing something and it's hard to decide which way to go. By this logical sort of explanation that I've gone through, it was pretty clear that there was only one way to go, with one exception, and that was the iodine laser. The iodine laser had always been a close competitor to the neodymium glass. It can be made in large aperture. It has very good optical qualities, because there's no glass in it at all, and the lasing ion, the iodine atom, has cross-sections for lasing and atomic physics characteristics that are very similar to the neodymium ion in glass, so it's a very close competitor, but as I say, we elected to go the neodymium glass route and let the Germans pursue the iodine route, and that's the way it's been ever since. The Germans are still pursuing the iodine route.

Bromberg:

By the way, if you want a break... Now, the codes — I've got three codes here, Magpie, Laser, Glassniks. We talked a little bit about the codes last night but didn't get anything on tape really. I don't really know what to ask you about that, because I don't know what kinds of breakthroughs are involved in designing a new code. I don't know what the creation of a new code really involves as a scientific act. Now, should we begin with Magpie?

Kidder:

Well, I guess the best way is just for me to ramble on a little bit, and then we can zero in more. First of all, Magpie essentially is a code which has nothing to do with the laser fusion business. Magpie, I put together the Magpie code. I didn't do the programming for it but I did all the physics and mathematics for it. That code is a one dimensional magneto hydrodynamic code, which we developed for a number of reasons, one of which, though, we were designing high explosive driven electric generators, and the Magpie code was — one of its important uses was in designing these. The Russians call them Magneto Cumulative Generators. What they are is, basically the idea is, you have a coil of wire. You put an electric current through it, so there's a magnetic field generated, and then you change the inductance of this coil. You decrease it essentially by squashing the coil with the high explosive, and as you do that, the high explosive does work on the magnetic field, increases the electrical energy in the circuit, and so you have a means of converting high explosive energy into electricity. That was one of the main reasons the Magpie code was written and used. It has nothing to do with laser fusion or lasers. So then, now, the Waser code was specifically for the purpose of doing these implosion calculations that were of interest in the laser fusion context. And so you say, what are the challenges in a code like that? Well, the first challenge is to make sure you put in all the physics that's important, and don't leave out any important physical processes. You first have to think about that. Once you think you know what physics is important and what you can leave out, then the question is to from what amounts to the differential equations that describe the physics and hydrodynamics and so forth, to a difference equation, and then from the difference equations to a computer program. Now, as I say, there's an intermediate step even there. So I would do the physics on quasar or its predecessor, the weapons code predecessor. I did the physics on that, not that I invented all the physics by any means, but I selected the output of a lot of other physicists, people like Bethe and Fermi and people like that who had done a lot of the basic calculations long before I got into the business. I collected what I thought to be the necessary physics together, wrote the equations, the differential equations that described the system. Then I converted those to difference equations in an appropriate way. Then you have to get an algorithm for solving these difference equations, and that's — in this case, that was a tricky business, because if you solve these difference equations in a sort of — well, the technical term is explicitly as opposed to implicitly — the method of solution would become unstable under some circumstances, and the whole computational process would blow up and stop. It couldn't go any farther. So I had to come up with a means of solving these difference equations that was stable under the conditions that we needed to operate the program, to do the weapons calculations we needed to do, and also the laser fusion calculations. So I came up with an implicit method for solving these difference equations, which was stable, and so what that meant is that instead of these calculations blowing up in your face, so to speak, we could now run through these calculations lickety split and everything would be just dandy. And it took me a while to

Bromberg:

— that was a real mathematical —

Kidder:

Yes, it was a mathematical —

Bromberg:

— innovation.

Kidder:

Innovation. But once that was done, then we programmed the equations for the computer that we had at that time, and from then on we had a perfectly good tool for doing these implosion calculations in the weapons context. Then when lasers came along, of course we had to add a package, a computational package to the code, to introduce the laser light to the problem, and its absorption in the plasma and so forth, so that that required what could be called a sub-routine added to the weapons package, in order to take account of this new thing, namely, now you are putting laser light into the system.

Bromberg:

Would you be able to do that anywhere, or were the computing facilities of Livermore, the fact that you were at Livermore an important factor here?

Kidder:

Well, I guess the fact that I was at Livermore in those days was important, yes. We had — I won't say it was absolutely unique, but I think, I'm trying to remember what computer it was that we initially ran this code on. It was, I think it was the IBM 704, but it may have been even an earlier computer than that. The 704 was — that was before they went to transistors. It was, the 704 0 I think was the transistorized version of the 704. But yes, I think the fact that we had rather exceptionally good computer facility here at Livermore, of course they had the same at Los Alamos, that probably was an important factor.

Bromberg:

Is there anything else that has to do with the kind of facility Livermore is, that we should add in at this point, as being important for the way your research was going in the sixties?

Kidder:

Well, let's see. We had the computer capability, and we had right from '62 a clear idea of what would be needed, OK.

Bromberg:

I assume you had — well, we talked about the money, how much money you had. The possibilities in that, the possibilities for expanding it.

Kidder:

Let's see.

Bromberg:

It might be that the steadiness of income, it sounds as if income is more steady than it is in an academic environment, where you're continually going back for grants, but maybe that's wrong. The AEC can also be pretty shifty.

Kidder:

Yes. Well, as I say, we were, the laser program was very small at Livermore, for all the ten years I ran it. As I say, the budgets I think never exceeded a million dollars a year. But they were steady. I mean, we weren't feast or famine from one year to the next. What happens, there are abrupt, of course, as we all know from the plight of the magnetic fusion program at Livermore now, where they abruptly cut out funding for the magnetic mirror —

Bromberg:

— oh, I didn't know that.

Kidder:

Yes, they mothballed this big mirror machine that's been —

Bromberg:

— the tandem, or…?

Kidder:

Yes, the tandem mirror.

Bromberg:

What a shame.

Kidder:

So that was a very sudden decision. The most sudden decision I know of in my history at Livermore was the cancellation of Pluto. That was, I mean, one day they had a 20 million dollar a year program going, and in those days 20 million was the equivalent of an awful lot more today. Six months later, you couldn't find a trace of the program. That's the way that thing — it wasn't tapered off, it was just terminated, and everybody transferred out of it and everything shut down.

Bromberg:

OK, so I'm barking up the wrong tree there. We might leave that tree alone. There are a couple of things that you got publications, and of course I didn't see the reports on your list. One was, I guess, a long path laser, plasma X laser. Are those things we should be —

Kidder:

Well, yes, the long path is kind of interesting. What that is, is that you put a laser amplifier in the middle of a big long room, basically, and then you generate a laser pulse from an oscillator, Q switched oscillator, or mode-locked oscillator maybe, and then you propagate that pulse through this laser amplifier many times, so that with using even mirrors or prisms to reflect the beam back and forth through this thing. Now, I mean —

Bromberg:

That's the one you showed me last night?

Kidder:

Right.

Bromberg:

You said that you had an economic reason for doing it.

Kidder:

Yes. The problem there, the reason that we had to go that route was that we found that building the first disk laser took an awfully long time. The delivery schedules on glass were not really met very well by American Optical. We bought the glass from them, and it was a slow, slow process, getting those disks from AO, and not only that, our budget was very small too in those days, so both for reasons of expediency and time, getting somewhere quicker, and saving money, we thought, well, why don't we buy a bunch of prisms, and use those to reflect the beam, and instead of having several of these amplifiers stacked up, one after the other, we'll just make it look as though they're stacked up with mirrors. So that's what we did. And that laser was the work horse then for the program, for quite a long time, I forget how many thousands of shots we used that thing for. It was very reliable. We never damaged any glass with it or anything. It ran very nicely and put out a good beam for several years. I guess we used that until, from the time we put it together until '72. So essentially all of the laser research that we did on plasma formation and so forth was done with that laser. So it was a real work horse. It ran very nicely for quite a long time. Now, we discovered things, of course, that the people who were not in the program really didn't know about. That has to do with the fact that Nuckolls and Wood were not really part of this effort at all. We had found out, for example, that when you eliminate these targets with intense laser light, that you generate very unexpectedly hard X-radiation from the fact, we were in the process at that time of looking for neutrons from deuterated polyethylene targets, and we thought we'd seen neutrons, but we found out that they weren't neutrons at all. We were seeing neutrons but we were also seeing very hard X-rays, and we found out that those X-rays were being produced, as they had to be, by very energetic electrons, so that the first idea that there was a problem with laser fusion, namely that you would produce hot electrons, was experimentally discovered in about 1970. Now, Nuckolls and Wood didn't seem to know much about that, because the scheme that they proposed for laser fusion took no account of hot electron production, and a number of other things, and so it was an idea that had a great deal of appeal because of the high gain idea that they had, but in many respects was very impractical, and wouldn't come anywhere near to producing the results with the energy input that they were talking about at the time. See, they thought that you could get ignition of thermonuclear material, with this idea of theirs, with an input of energy of — get what was called break-even, the amount of energy out equals the amount of laser light absorbed or in, with a kilojoules of laser light, which made everybody very excited, because that was a small amount of light, and it meant something you could presumably put together in a reasonably short time. I mean, when I was asked about this, and I said, no, that was impossible, I made the statement very officially to the then chairman of the Atomic Energy Commission, who was Dixie Lee Ray in Washington, she asked me at a meeting, I forget when this was, in the early seventies, whether I believed that in these ideas of... (off tape )

Bromberg:

…that you told Ray it was simply out of the question. That didn't get on the other tape.

Kidder:

Yes. The question was, there was this belief that was expressed by Keith Brueckner, KMS fusion, and also by Lowell Wood and Nuckolls at Livermore, that one could expect to get break-even at relatively low input energies from the laser, namely something on the order of a kilojoule, did I agree with that? And I said, "Not at all." I said that I felt that it would require enormously greater energies than that. In fact, I had estimated in '62 I think it was that it would take a hundred times that much to get ignition, and subsequent calculations indicated that it was even more difficult than that. So, no, I didn't agree with the conclusions, these optimistic assessments that were being made by either Nuckolls, Wood or Brueckner. And that's what I told Dixie Ray at a meeting in Washington of the AEC. So that was where that stood, and as of today, of course, the Nova laser is putting out on the order of 100 kilojoule, and they're not getting break-even at that level, and I think they're now, the belief currently is that it would take maybe as much as a good fraction of a kilojoule to break even, so I'm not even sure what numbers the laser people are advertising these days, but in any event, through either good luck or good management, the number I was giving Dixie Lee Ray has proved to be exactly right. It's taken an enormously greater amount of energy, for reasons that I knew at the time, but I don't think these other people did. I was worried about the decoupling effects in these plasmas and I was worried about hot electrons. And there's no evidence that either Bruekner or Nuckolls or Wood took this into account. In fact, the method they were proposing postulated extremely high laser light intensities on the target, which would have generated, would have caused this decoupling effect and a number of other high intensity effects that would have vastly degraded the performance of the system. I don't believe they knew that, because they weren't really — Nuckolls and Wood were not part of the laser program. They were out of it, and so weren't current, I don't believe, on the things that we knew about limitations having to do with the laser-plasma interaction, on the one hand, and Brueckner of course came into it as pretty much of a johnny-come-lately as far as the laser fusion was concerned. He was involved with the laser part of it for the DOD in the summer studies and so on for a long time, but I don't think he was — I think he was tripped up by the same kind of lack of information, plus the fact that both Brueckner and Nuckolls and Wood had an unrealistic idea of how uniformly you could illuminate one of these targets with lasers. They seemed to think you could do this with very great uniformity which would be required, but there was no evidence at that time, from anything we knew, we were doing experiments, that would suggest that that was indeed feasible, and that was —

Bromberg:

You're always making these assumptions in your theoretical papers, you're assuming uniform illumination.

Kidder:

Yes, in the one dimensional calculations, that's all you can assume. But when you actually go into thinking about reality, you have to take into account that you can't do that.

Bromberg:

Now, I actually want to go back to one thing. You said that the long path laser is something that put you onto the existence of high energy electrons. Does that lead to the plasma X laser, to the studies that you did?

Kidder:

I'm trying to remember the plasma X, what that refers to. I think that was the short pulse mode-locked.

Bromberg:

That was the one where you were using the laser to make a study of X-rays.

Kidder:

Yes, I guess —

Bromberg:

I think that it's this one, 27, that I was thinking of, but — I also have some notes here.

Kidder:

OK, I think this one was with the long path laser. Reference 27. I'm pretty sure. Too bad I didn't —

Bromberg:

Well, it was both. you talk about both lasers there.

Kidder:

Now, the guy who ran the so-called plasma X laser was George Kachen. And incidentally, George is almost a neighbor of yours, I think, from where you told me you live. George works for Avco Everett Research Labs, and he was in my laser division for a long time at Livermore, and he lives, I think, it's in Andover. Marvelous fellow. If you have a chance to meet George, you should. He's a delightful guy and he also knows a lot about the isotope business, because when he left Livermore and went to work for Avco, he was Avco's scientific liaison between Everett and Jersey Nuclear's operation out in Washington. So Kachen knows all about that too. Kachen ran the so-called plasma X laser. It was a mode-locked laser that produced a very short single pulse, and isolated that pulse. They make a train of short pulses. This was a mode-locking scheme invented by A.J. DeLamaria, (?) at United Aircraft, to make a mode-locked chain of these pulses with a neodymium glass laser, and then they switch one of these pulses out of this train, and then use that to amplify, and the plasma X laser had what's called a switched-out mode-locked pulse which was then amplified and then used for plasma experiments. The amount of energy involved was fairly small. It was not a big laser. But that, as I remember it, was what the plasma X laser was.

Bromberg:

I see. I want to take a minute off, and then I have a bunch of other questions. …We have not really talked about the movement from laser fusion in its weapons context into the energy context, although we've alluded to it in your conversation with Dixie Lee Ray or with discussions about Nuckolls and Wood and Brueckner and so on, so let's talk about how that went from being simply a part of a weapons program to an energy program at Livermore.

Kidder:

OK.

Bromberg:

It's not that this happened abruptly in 1972, is it, with the four million dollars?

Kidder:

No. There was a confluence of two important events. Not the four million. Although of course as a practical matter, that helped. No, the thing that really made the difference was the high gain concept that Nuckolls and Wood came up with. I mean, until you could talk even theoretically about much larger capsule energy gains than we were talking about prior to the idea of this central ignition, as it's called, nobody could be serious about using this to produce power. So the Nuckolls Wood concept of central ignition was one of the very important ingredients in this, and the second important ingredient, in terms of actually getting money to do something and go places in a much bigger way, came from the Arabs. See, and those happened about the same time, the Nuckolls Wood idea of central ignition, and Brueckner may have had a similar idea too, I'm not sure. In any event, the Nuckolls Wood idea came about in 1970, I think, somewhere around in there. I could even say when this meeting took place with the President's Science Advisory Committee. I think I have a note on that somewhere. No, it's not here, it's somewhere else. Ah, here we are, January of 1970, I have listed here, "LPP meeting, laser plasma physics, " I guess that must stand for, " at AEC headquarters." So Nuckolls and Wood disclosure, I have here. Now, this was not the meeting before the President's Advisory Committee, I don't think, I'm referring to here. This was AEC headquarters. So that was in January of '70, so —

Bromberg:

And that would mean disclosure to you or disclosure to AEC?

Kidder:

That would mean disclosure to the AEC headquarters people. Then I have another note here, and this may be what Luben was referring to. "February, 1969, laser produced plasma, AEC headquarters, K. Brueckner, chairman of this meeting. "I believe Luben was there. OK. Now, that again is where I have to be very confusing, because again, as I — I don't remember exactly what happened there. I'm remembering that at some much later — years later, Brueckner, who's a very good friend of mine that I know very well and have worked with a lot, told me, he said there was something I said at that meeting which threw him way off about something, and again, it was this business of saying something that wasn't classified that then turned out to produce just the wrong effect on whoever was listening to it. That often happens. It's a very pernicious thing. Anyway, and again, I don't recall the details of what that particular problem was. It's just that Brueckner mentioned it. But anyway, in this '69, '70 time frame is when these new ideas, new meaning high gain ideas about getting high gain out of capsules, were being thought of by certainly Nuckolls and Wood and I think Brueckner also independently, and neither Brueckner nor Wood were familiar with either some of the physics of laser plasma interactions that we'd discovered, notably this decoupling effect and the not electron effect, and certainly I think in both cases, the fact that you couldn't get uniform illumination of these targets anyway with lasers. I don't think either Brueckner or Nuckolls and Wood were familiar with that. You see, what had happened was, in all three of these gentlemen's cases, you had people who were bright guys, who had a very good idea, but didn't realize that it wasn't practical because of limitations of which they were not aware. And I was. And so people, of course, advocated these ideas at this meeting in Montreal, of the I Triple E, I guess it was, International Quantum Electronics meeting in Montreal in 1972, I guess that was. Nuckolls and Wood gave this paper on this high gain stuff, and the Arab oil embargo then put fire under Congress to put more money into other sources of energy, and between the new idea for high gain capsules that Nuckolls, Wood and Brueckner came up with, and the Arab oil embargo, which meant money was available, the emphasis of the program became strongly oriented towards power production.

Bromberg:

Now, KMS of course is coming forward in '69 and '70. Did you get any feeling of pressure on you because of the KMS business, from AEC, to take your program in the direction of energy?

Kidder:

No.

Bromberg:

Did you think that was a factor?

Kidder:

No. The pressure to go in the direction of — well, I guess I would have to say that at that time, whether we were going for energy or whether we were going for weapons physics didn't really change what one would do. You still had to get thermonuclear ignition either way. And there was only one way that we were pursuing to do that. That would be tilted disk glass lasers. So that what your ultimate goal was didn't change your research effort at all. I mean, if you were interested in power production, you might have some people begin to think about that specifically, and think about reactor design or something, but as far as the main line laser development was concerned, the requirements of either system were such that you did the same thing. So it had no impact in a technical sense on the program.

Bromberg:

But I just meant, in a political sense.

Kidder:

In a political sense, the laboratory began strongly advocating that it was primarily an energy program, even though the AEC in Washington, the Division of Military Applications, was somewhat horrified by those statements.

Bromberg:

I see, so you would continue in the same direction, but the gloss that the director's office was putting on this began to be a little bit different. Is this Toronto meeting the CLEA meeting, because the CLEA paper from Montreal —

Kidder:

Montreal.

Bromberg:

'71, Montreal

Kidder:

It's the International Quantum Electronics meeting at Montreal.

Bromberg:

OK, because there was in a paper that you co-authored, I guess that you gave in August 1971 at the CLEA meeting, there's a call for more study of laser-matter interactions, and my attention was drawn to that, and now as you say it sounds like a reaction to Brueckner and Wood and people like that who had already been looking at that. That's just a guess. It was a kind of programmatic statement which caught my attention. I wondered whether it called for — you say, "As important as getting high energy," this paper said, "are goals of getting an understanding of the laser-matter interactions, and also getting better ability to control the pulse characteristics."

Kidder:

That's right. Yes. The thing that was very apparent to me and other people in the trenches, so to speak, was that the interaction of the laser light with the plasma was a very complex process, and there were a lot of things going on which people like Nuckolls and Wood and Brueckner were not taking into account at all, that were very important and needed to be studied experimentally and theoretically. The idea of stimulated Brillouin and Raman scattering was something that we were worried about, again, in 1971, and the hot electron production, we didn't know what the mechanism was that was producing the hot electrons, but they were there. We could see those because of the hard X-rays that were being produced. And so it was clear that there was an awful lot of work that had to be done to understand this laser-plasma interaction before you could make any really sound judgments as to how much of anything it would take to succeed, and what would be the best way to proceed, and so that was the — that was in some sense a reaction to what in some sense were dilettantes in this field, who were selling an idea without real understanding of the problems that were involved.

Bromberg:

Was Emmett in this group at this point?

Kidder:

No. Well, Emmett came out, I don't remember when. I think it was in '72. Emmett has a very different relation to the whole program than either Nuckolls or Wood. Emmett's involvement with the program has been almost exclusively from the beginning in laser development. He's never claimed to be an implosion physicist or anything of that kind. He's a laser man, and he has pretty much stopped, as far as I can tell, with the idea that, I'll build you the lasers, and if you want a laser that will produce so much energy in such and such a pulse duration, I'll build it for you. It's up to you whether the damn thing works or not, as far as imploding the capsules or making neutrons or anything else. So he's really a laser man only. He has no particular knowledge or interest, I don't think, in the actual implosion processes or anything of that kind. And he's been very effective at doing what he says. He builds the lasers and they do what he says they're going to do. But that's where his responsibility generally ends. If the laser puts the pulse out on the target with the right characteristics, he's done his job, and if the thing works, fine, if it doesn't work, that's your problem. That is I think John Emmett's involvement with the program, is with the lasers, not with the targets.

Bromberg:

Well, tell me a little bit more about this switch. This was a pretty abrupt switch. Who at Livermore, who were the actors at Livermore in deciding to move into this very large program? Was this your idea?

Kidder:

No. No, I had been trying for years to increase the scope and size of the program in a very gradual way. There wasn't any reason to suddenly increase things, that I could see. No, there were a number of factors involved, two of which I've mentioned, that is, the oil embargo and this high gain capsule. Now, the actors involved, the people who were involved actually with the decision-making here were Edward Teller, Carl Haussmannn, he was — Carl, there was an accident that happened here too, and I have to mention that, an accidental occurrence that was important but accidental. The director of the laboratory all during the time I was — well, the first part of the laser program at Livermore, Foster was the director of the lab, until 1966, I believe it was. Thereafter, I have that — yes, Foster was the director until September, '65. Then, Foster was succeeded by Mike May, and Mike May was the director until this crucial time that we're talking about, which was 1970, '71, I think it was, not '70, '71, possibly even '72. Anyway, Mike May had been the director at that point longer than anyone else at Livermore, and he decided that he had been director long enough, and he decided to resign his directorship, and he was going to go to Princeton for a year and work in their Institute for International Studies or whatever it is, which he did. He resigned, and the resignation was, we had to find another director, so after he resigned, Carl Haussmann was made the acting director of the laboratory. Now, Carl had taken a great interest in the laser program, and just as a — not for any particular reason, just he liked the laser program. He thought it was an interesting thing. So by this accident, accident meaning the fact that Mike happened to resign at this time, a new director came in, acting director, Carl Haussmann, who had this rather exceptional interest in lasers, and immediately began to move and push things around, me being one of the people he was moving and pushing around, and so he was involved with this business, and this was at the time the four million dollars came in, so the program was much bigger, and what that meant was that there was a period where the program was in really a shambles. I had run the million dollar aspect of the research program for ten years. Then when the four million came in, that money was money that had been in a weapons division budget, namely B Division, and rather than put me in charge of the whole works, which might or might not have been a good idea, since I'm not noted for running big programs at all, what they did, which was definitely a bad idea, was to have three people in charge of it. We used to joke about it, we called it the Troika. The three people were me, and I was running the one million dollar program essentially I had had, but there was Jim Wilson, who was in B Division, who had had no previous experience with lasers at all, bright guy all right, but no previous experience with lasers or any management experience really either, and John Nuckolls, because Nuckolls had gotten into the act via the high gain capsule concept. So Nuckolls and Wilson and I were supposed to run this program, and Wilson had the most money, he had three million. Nuckolls didn't have much money but he was one of the three of us who were going to decide what to do. I had a million, and Wilson came in with three million, and the B Division people started going off on their own track.

Bromberg:

What track did they choose?

Kidder:

Well, there was interest in pursuing a CO2 laser at that time. Remember, the T lasers had just come in. And so they were trying to — one of the things they were working on was a high field emission electron source to drive a CO2 laser, and there were other things they were doing too, and I don't even remember what they all were. Anyway, it became pretty clear, within a fairly short time, that this idea of having three people run this program just wasn't working. The B Division people weren't cooperating with me, I wasn't cooperating with them, Nuckolls couldn't make any sense out of what anybody was doing, and it was simply a management fiasco. So Carl Haussmann — Mike May was still director, I'm sorry. Mike May was still director. Carl was not the acting director yet. Because Mike May, I remember, came to me, and I remember a discussion with Mike in the parking lot. This was before Mike resigned his position as director.

Bromberg:

You're in the parking lot.

Kidder:

I'm in the parking lot, OK. And Mike came to me and said, "Look, this troika way of running this program is just terrible," and I agreed with him, I said, "Yes, this isn't the way to do it at all." He said, "What I'm going to do is, I'm going to put Carl Haussmann in charge of this whole program, and his job is going to have to be to pull this thing together in one cohesive program, " and Mike said, "Do you have any problem with my choice of Carl Haussmann?" You know, "Would you have any problem working with him?" And I said, "None whatsoever. I think that's an excellent choice for a person to do this." Then I was later to regret those words. Carl took over then, Mike put him in charge, and immediately Carl began — Carl has very great management skills, but his interest in lasers led him to begin making technical judgments that he had absolutely no competence to do. So he began putting his fingers into the pie, and really, I thought, messing things up. And that wasn't my view alone. And so it became clear to everybody that the program still wasn't on an appropriately even keel. There was no question that Carl was a very good management guy, but somehow they needed to bring somebody in who was technically competent to run this program, and would be able to take an expanding and growing program and push it hard. Well, that's where John Emmett came in, because John Emmett was known as — first of all, he had been working on neodinium glass lasers at NRL. That's what NRL was building, and he'd been working on those successfully, and it was also known, believed and correctly that Emmett was a very energetic — he was the head of the NRL program then. He was already in management. He was technically very knowledgeable about the lasers, particularly glass lasers, had very good connections in Washington, in places that counted, and was thought to be a very aggressive go-getter type of person to run a program. And so he was approached by the laboratory, and hired to essentially take over the program, and he did. And that combination then worked very well. Emmett had just the kind of no-nonsense, let's get this program going together attitude about him that was needed at the time, and he brought Bill Kruppe(?) along with him, and Kruppe was a very good guy to have with Emmett. And so finally the laser program, with Carl Haussmann still in as the associate director in the upper management end of it, which Carl was good at, and Emmett as the honcho running the program, with Kruppe, which Emmett was very good at, then the program really got down to , was well organized, and Emmett was able to sell his program very effectively in Washington, got money for it, and the program has been essentially going along at a great pace ever since.

Bromberg:

And what part of it then did you work on? I notice you have a lot of theoretical papers coming out after this point?

Kidder:

Well, what I wanted to do, and what I didn't succeed in doing, was, I wanted to bow out of the program in terms of the major laser development end of it, because that wasn't the sort of thing that I was interested in at all. On the other hand, I did want to keep a small research program, some theorists and some experimentalists, but a very small effort, to pursue innovative ideas and things of that kind. But when Emmett came to the lab, he made, as a condition that he would come, and I could understand his reasons for this very clearly, that he — that I not be given that part of the program. He felt it would be very unfair if he came in and hired people and everything, and they were supposed to do all the dirty work, so to speak, build the big lasers and all this, whereas I was going to have the fun of doing a lot of the innovative research and things of that kind, and so he said, nothing doing, he wasn't going to come in unless he had the whole thing. And the laboratory was sufficiently interested in getting him to take the program over that they agreed to that. And so I then had no further management responsibility for the laser program. Q Division, which I had been in charge of for ten years, was dissolved, and I went to work in the theoretical division of the physics department, and I've been there ever since. Now, when I went to the theoretical division, I continued to have an interest in laser fusion, and I wrote papers and so on, but I was no longer — I mean, I was essentially part of the laser program in the sense that they paid my salary, even though I was in the theoretical division, and I had a lot of contact with them, but I had no administrative management responsibilities for any part of the laser program from then on. I was essentially a totally free agent to work on whatever I wanted to, and that was also true of the laser isotope program. As I pointed out, I built up the idea, and got Livermore started on that program, but I was never involved with the isotope program as a management person or even as a working in the program itself. So ever since 1972, I've had a position of what might be termed — well, I had the title of associate division leader at large, of the theoretical division, the at large being the important words. That meant that I could work on essentially anything I wanted to at the lab. I had no particular boss.

Bromberg:

Like being a senior scholar.

Kidder:

That's right, yes. So in terms of being in the trenches and running things, I was retired, shall we say, from those responsibilities, in '72. Which, from the one exception that I would have liked to have a small continuing — and the people who worked with me wanted this too, I mean, they wanted to work for me, they didn't want to work for John Emmett, whom they didn't know — but I can understand why the lab didn't want to do that, and I can understand why John Emmett would have felt that wouldn't really be fair, so that didn't bend me all that much out of shape.

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Bromberg:

Did CTR group lay any role at all? They sound as if they pretty much weren't involved in all of this. The magnetic fusion people. I would just think that they would look a little bit askance at this rival fusion program growing up around them.

Kidder:

No, they didn't. There was no contact between — there never has been, between the magnetic fusion community and the laser fusion people. The only exception to that is, I don't know if this is still of any interest, but sometime in the past, the magnetic fusion people were interested in filling their magnetic bottles with plasma, produced by injecting a pellet of solid deuterium and then evaporating that with a laser. And so to that very limited extent, some of the people in laser, in ICF, Inertial Confinement Fusion, particularly in Japan, worked on schemes for, laser schemes for making these pellets, as a source of plasma for the MFE people. But with that exception, which is really very peripheral sort of thing, there wasn't any. The ICF people certainly were never interested in the MFE work. And I don't think, outside of the MFE's interest in filling their bottles with plasma this way, they never had any interest in the ICF work either. It was two entirely unconnected paths to a somewhat similar goal. The difference, of course, was that the magnetic fusion had no military significance whatsoever, never has, so they never got a dime out of the military people, either the DOD or the DOE. The advantage of inertial confinement fusion was that it's always had this military source of funding, plus at least, the plus part, it's had its ups and downs, the possibility at least of getting money on the basis of power production. So ICF has had always two possible hats they could put on. Magnetic fusion has never had but one, and that's been a tougher thing.

Bromberg:

Well, I want to check this name list with you…

Kidder:

When Carl Haussmann, when a director was selected for the laboratory, Carl succeeded Mike as the acting director, so as it happened, the guy who Mike had put in charge of the laser program not only had the clout of being an associate director but now had the clout of being acting director, so he would have been hard to argue with if you didn't agree with his handling of the program. Anyway, the search committee finally came up with Roger Batzel as the new director of the laboratory, and then Carl Haussmann became the associate director for lasers, and he's been that until fairly recently, when he became an associate director at large, and John Emmett was made associate director for lasers. That's the management chain of events right up to the present time.

Bromberg:

Now, are there other things that we should be talking about, that we haven't talked about ?

Kidder:

I don't know. I suppose. Well, the one area we haven't gotten into very much, which isn't nearly as long a subject, from my standpoint, to talk about, but the one area we haven't done nearly as much with is the isotope thing.

Bromberg:

That's right. Now, you gave that one report at the meeting, I mean you presented your results at the meeting in Germantown, that are incorporated into this paper. Then you said that you didn't continue, but did you continue somewhere or what? Or should we go back before the meeting and talk about that?

Kidder:

Before the meeting, I think, is most important. Before the meeting, and I don't remember now, again, I'd have to look it up in some old notes that I have, but I was interested in using lasers for isotope separation rather early in the whole laser development time, the idea being that you could tune a laser to a specific molecular or atomic transition, and make use of the fact that those transitions, the frequency of those transitions depends on which isotope of the atom or molecule you're talking about. So what that meant was, if I had an atom of uranium-235, mixed with atoms of uranium-238, the absorption spectra of those two atoms would be slightly different, because of the different mass of the nucleus and different size of the nucleus, and therefore, I could tune a laser to excite one of those isotopes but not the other.

Bromberg:

Now, tell me, what got you into this in the first place? Here you are going along doing one problem, how did you get interested in this other possibility.

Kidder:

Isotopes. Well, I suppose one reason was that I worked on the Manhattan District Project in 1943, having to do with the gaseous diffusion part of the Manhattan Project, so I was interested. Way back in '43, that was 13 years before I came to Livermore, I was somewhat interested and connected with the isotope end of the nuclear weapons business. That may have had something to do with it. But in any event, the idea that you could undertake selective chemical reactions, perhaps, by exciting one isotope but not the other with tuned laser light was a pretty obvious idea, I think, to people, again pretty early in the laser business.

Bromberg:

In France they were already interested in that from the mid-sixties.

Kidder:

Well, we were too, we meaning me and Edward Teller. I discussed some ideas with him in the mid-sixties. We were, at that time, when I was talking to Teller, we were looking at initially uranium hexafluoride, which is what Los Alamos ultimately concentrated on. But Teller and I decided that the right way to proceed was not to look at the practical side of uranium enrichment, or plutonium, at all, but to prove out these methods with much simpler schemes. In other words, if we could enrich carbon isotopes, for example, for medical purposes, or something of that kind, we had CO2 lasers for example that could be usefully tuned to carbon CO2 and so it seemed to Edward and me that we'd like to do experiments of a more fundamental nature on isotope excitation, selective isotope excitation, and worry about more difficult problems of using these heavy elements like uranium and plutonium later, and so Edward and I decided that was a good idea, but when we proposed that work be done along those lines at the lab, the lab said, no, they felt we ought to start right in on uranium and plutonium and not worry about carbon and sulphur and things of that kind.

Bromberg:

Who was "the lab"? You went to Haussmann?

Kidder:

No, Mike May would have been in charge at that time, but then there were other associate directors also that would be involved with this decision. One way or another, we wanted to do sort of the more basic research on this, and the lab wanted us to do work more immediately directed towards high fissionable isotopes, which we didn't think, and I didn't think and I guess Teller didn't either thing, was really the right way to proceed. We just dropped it. I guess we didn't have enough gumption to go ahead and try to push for it. We didn't want to — we didn't feel we had ideas at that point which were good enough to pursue on the uranium, plutonium level, and the lab wasn't interested in funding work on this other level, so that sort of stopped it. So then nothing — I mean, I thought about these things some, and I guess Teller did, and we discussed these ideas with Montgomery Johnson, who was a very good friend of Teller's, and Johnson died recently, but he was a very bright guy. I think he was a vice president in charge of research or something for Ford Aeronutronics down in Newport Beach, and he didn't work at the lab but he was a consultant at the lab and one of Teller's very closest friends, and he was up here at the lab very frequently, and Teller and I discussed some of these isotope concepts with Montgomery. Anyway, nothing came of any of that, as I've said, until 1972, when I came back from Europe, and Haussmann called me up. He said, "There's going to be this meeting in Washington. If we can possibly come up with something as an idea for presenting at this meeting for isotope enrichment, let's do it. "So I said, "Well, I'll think about it," and I came up with what I thought was this marvelous idea of not using molecules but uranium atoms themselves or plutonium atoms themselves.

Bromberg:

It sounds as if you were able to do that in a considerably short time.

Kidder:

Yes. I came home from Europe, I think it was towards the end of September, and I presented this at the meeting in whenever it was, in November, so that's how long it took me to come up with the idea. And I liked this idea better than the Los Alamos one, because it was a physics idea, and I always thought of the molecular idea as more of a chemical idea, and atoms seemed to be much more calculable. The whole idea seemed, from a physicist's point of view, much more predictable, calculable scheme, than the molecular scheme Los Alamos was proposing, although I felt then and feel to this day that ultimately molecular schemes may beat this atomic scheme. Maybe not. But the atomic scheme seems particularly well suited to plutonium work, not quite so well suited to uranium, and so, it wouldn't surprise me — see, the Germans are still working on, at a very low level, on the method of uranium enrichment using uranium hexafluoride, the molecule, the same approach basically that Los Alamos originated and dropped. So Euronet I think is funding some work in Germany on — or Eurenco, one of the two — on the molecular process. So the molecular way of doing things is by no means, as far as I'm concerned, a dead issue. There are some aspects of it that I think would beat out the atomic process. But I felt in 1972 that even though the molecular scheme might work best in the long run, that in the short run, there wasn't much doubt that the atomic process would win. And so Livermore was in the process of winning, I proposed that scheme, and was pretty convinced that we would beat Los Alamos, and of course we did.

Bromberg:

And did you do anything more on that, or just handed it over?

Kidder:

Practically nothing more on it. I handed that over, and we hired a guy by the name of — let's see, from Eastman Kodak, what the heck was his name? To take over that program. I knew him very well too. He's back at Eastman Kodak. In fact, he has a pretty big position in their research lab. Well, I forget his name now, anyway —

Bromberg:

I guess the only person is Tuccio(?), is he?

Kidder:

Yes, Tuccio came with this guy. There were three of them, Tuccio and two people, to other people, neither of whose names I can remember. One of them was the head of the program to start with. And —

Bromberg:

With Tuccio in my head goes Snavely.

Kidder:

Snavely, that's it, Ben Snavely. Ben Snavely was hired from Eastman Kodak, along with Tuccio and another guy, to head up the isotope program. So they were brought in from outside right off the bat, and Snavely took over the program, and I consulted with Snavely all the time, but I didn't work for him. I was at large. I consulted with all kinds of people at the lab, and still do. So I'm sitting here, but I work here and here and here and here, in a sort of informal way. So Snavely was hired very promptly when the program got started, and he was in charge of it for the first couple of years or two, I think, it was in existence, and then he got into some kind of a row with Teller and somebody else at the lab. I don't know the details. I don't think it's important. But anyway, he was eased out of that position, and they brought in this fellow who's still or I guess until very recently was in charge of it, whose name I can't remember either. Anyway, I think that gives you a pretty good idea of the isotope thing. I had very little to do with it other than consulting with Snavely, on the thing as it was getting started.

Bromberg:

Well, thank you very much.