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Interview of Herbert Friedman, Talbot Chubb, E. T. Byram and Robert Kreplin by David DeVorkin on 1986 December 12,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
For multiple citations, "AIP" is the preferred abbreviation for the location.
Friedman, Chubb, Byram, and Kreplin were pioneers in X-ray space science, X-ray astronomy, and both founding and early and original members of the electron optics branch at the Naval Research Laboratory in Washington, D.C. The interview focuses on their work at NRL. They discuss their impressions upon coming to NRL, their training and how they were hired; what they were hired to do; and their work in the post-World War II era at the labatory.
We have today at the National Air and Space Museum four pioneers in X-ray space science, X-ray astronomy, who were both founding and early and original members of the electron optics branch at the Naval Research Laboratory [NRL] here in Washington, D. C. The group was and is headed by Dr. Herbert Friedman, who is at my far right Dr. Friedman came to the Lab in 1941, first in metallurgy, and then formed the rocket group after the war out of the electron optics branch. And next to Dr. Friedman is Dr. Talbot [Albert] Chubb, who has degrees in physics from Princeton [University] and from [the University of] North Carolina, [and who] came to NRL about 1950. Next to Dr. Chubb is Mr. E[dward] T[aylor] Byram, who came to the Lab in approximately '46 — but you'll correct me on that I'm sure in the interview — from the University of Toledo, who has specialities and training in engineering, [and is] also very interested in physics. Next to me is Mr Robert [William] Kreplin, who was trained at Dartmouth [University] in physics, [and] came to NRL about 1952. What I thought we'd do, gentlemen, in the beginning of this session is to ask each one of you to talk about the impressions you first had upon coming to NRL, a little bit about your training and how you were hired at NRL, what you were hired to do, and what your own personal interests were upon first coming to the Lab. We'll start with Dr. Friedman
I came to NRL almost immediately after getting my doctorate at [Johns] Hopkins [University], where my thesis work was in solid state physics using X-ray spectroscopic techniques. I spent a year as an instructor at Hopkins, and at the same time was involved with the NDRC [National Defense Research Committee] project to develop a proximity fuse. When I came to NRL, the thought was that I could contribute to the use of the new physics, solid state physics, in metallurgy, where there were important problems in dealing with magnetic materials, the basic physics of ferromagnetism, for example, and practical problems which related to the development of special high temperature, high strength alloys for turbine blades, for example. There was a tradition of X-ray work at NRL Charles Barrett and Robert Mayall are both names which have a very distinguished history in metal physics. And they left a legacy of all sorts of X-ray analytical equipment in the laboratory which became available to me right away. With the approach to the war being well appreciated even in 1940 in the Laboratory, there were a host of problems that I could select from — problems that I thought had potential solutions in a reasonable length of time which would contribute to the war effort. Those were the things that occupied my attention from then through the end of the war. But in the process of developing those applications, my emphasis at all times was on using electronic techniques for registering, recording X-ray [and] gamma ray intensities, rather than [using] photographic film, which was the traditional approach to all sorts of X-ray and gamma ray work. Now, I could go on in more detail, but you may wish to move on to the other members of our group here.
Well, you formed the electron optics branch toward the end of the war — I know there were a number of reasons for that — and there were a number of projects that you became involved in, especially in bomb testing, bomb detection, that lead directly into the rocket work. I think it would be a good idea if you just mentioned briefly how the electron optics branch was created, and how you began with the bomb detection work. Then possibly we could hear from Mr. Byram.
My special asset when it came to NRL was that I had developed an X-ray geiger counter detector which was almost 100 percent efficient, and I set about putting that detector in all sorts of X-ray analytical equipment This equipment could be used in metallurgical problems like evaluating expansion characteristics of high temperature steels. When a problem came into the lab connected with the production of quartz-crystal oscillator plates for communications sets — I should say what the problem was when it came to us. The Japanese had essentially taken all of the good well-faced quartz out of South America before Pearl Harbor. The technique in those days to prepare crystal oscillator plates was to determine the optical axis of the crystal, then orient the crystal for cutting relative to the optical axis and its natural faces. The various types of oscillator cuts could be prescribed very specifically with respect to those axes. The process was practical, if you had good crystalline faces. It was not practical if you had to start with crystals of the type that were available largely in the United States, that had shattered faces, broken to the extent that you could not use the optical methods for orientation. The process also suffered in that no matter how accurately you cut the crystals, they still had to be refined to a somewhat better cut. The problem was that if the crystals were not cut precisely according to the optical axes, that they would have a temperature drift. To correct the temperature drift, each crystal after it was first cut would be put in an oven, run through its frequency cycle, and then the face would be polished, abraded down, [and] adjusted in its position until the temperature coefficient was minimized. The method I used was to put the crystal in a goniometer, and use X-ray reflections to locate the crystal faces. Then one could immediately take the crystal in its goniometer, put it into a cutting machine, and start to make the crystal cuts. They would come out almost perfectly on the first cut. That was an enormously successful practical development It was done very quickly. The equipment was put into the manufacturing plants, and millions of crystals were made during the war. If you translate the time it would have taken previously to cut a crystal, run it through a temperature cycle, which took many hours, and make the corrections, you can see that the time saved was measured in millions of man hours.
You were still in the metallurgic division at that time?
I was still in the metallurgy division at that time. But I had already begun to make contacts with people in other divisions. In chemistry, for instance, they had a problem associated with anti-fouling bottom paints for ships. They used various forms of pigments in these paints. The one which was most successful at that time was a copper pigment, but sometimes it worked and sometimes it didn't. I immediately converted the crystal orientation equipment into a powder diffractometer, and was able to show that the pigment that worked was a cupprous oxide, [and] the pigment that didn't work was cupric oxide. Distinguishing them by their crystalline structures. These are examples of just a few of the problems that involve radiation detection In the very simplest sense, non-destructive testing of valves, castings and so on was very important. It was all done with gamma ray radiography. You would set up your dials in a circle, and put the film behind them, with radium source in the middle, and take pictures. Or you would use a large X-ray machine to do the same thing But in order to economize on time and to insure that each radiograph was perfectly exposed, I developed an exposure meter, again using geiger counters, which would automatically time the exposure or cut off the X-ray machine at the proper time and give you a perfect radiograph on each try. There were many, many problems. We developed fitness gauges that worked from one side or from two sides. The [United States] Navy tankers which went out of port with their huge tanks filled with oil would come back filled with sea water. Corrosion was a very serious problem. Before sending them out again, they wanted to make sure that the bulkheads would not collapse from corrosion, so a back-scatter gamma ray device was very useful to them. And I remember the very uncomfortable experience of testing this device in the Norfolk [Virginia] Navy Yard, where we would go down to the bottom of the tank, about 40 feet down, in mid-summer, and just die of heat prostration before we could make our tests and get out again. There were applications to such things as measuring the thickness of lead coating on condenser discharge tubing on some of the big ships — which are now sailing again, the [U. S. S.] New Jersey, the [U. S. S.] Iowa — which were built in the Boston Navy Yard. We went up to the Navy Yard again with the back-scatter gamma ray device to show that you could measure the thickness of this wiped-on lead coating. They had no way of gauging once the coating was put on, and to be safe, you always put on a lot more than was needed. That was expensive, and an awful lot of time and material could be saved by having a good gauge. It was interesting, in those days all of that work was done by women.
The coating. And to go down into the bowels of a ship as a man all alone took a lot of courage. [Laughter]. Also, it was difficult to work aboard a ship, as a non-union scientist. I remember going to the Boston Navy Yard with Captain Cochrane, who was the executive officer at the Naval Research Lab. On a weekend in frustration, we wanted to get a piece of equipment bolted down, and Joe Cochrane took the welder's torch and started to weld it to the deck of the ship He was almost physically attacked, because he was not a card carrying union member. Well, I think these examples give you a flavor of the variety of things that came into the laboratory, some of them very simple but still very important to the war effort We just picked those that we thought we could solve very quickly. Many of them gave us insights into physical phenomena which we knew only very crudely. We tried to develop a cosmic ray mine trigger, for instance, in which we used geiger counters beneath the hull of a ship, and relied on the displacement of the water by the essentially empty volume of a ship to change the penetration of cosmic rays through the hull. We tried to track the coastline from an aircraft by measuring the natural radioactivity at, let's say, a thousand feet. An aircraft coming in low would want to know whether it crossed the coastline or not, and you could tell, up to a thousand feet, rather distinctly from the change in gamma ray intensity over land and over the ocean that you had crossed that boundary. For all of these things we made very special tubes to suit the particular situation.
At that time — this was all during war — the tubes were all made in the lab shops? These were all prototype tubes, would you say?
They were all prototype tubes. The lab had marvelous shop facilities of all types. They would have a machine shop, a plastic shop, a plating shop, a glass shop, and those shops were manned by very skilled technicians. You could get your work done very quickly. We could have had a museum full of specimen tubes of all types, if we thought well of saving and preserving them.
You've given us a very good introduction to the types of applied research that you performed, all centered around the ability to detect high energy radiation, starting with your designs of the tubes. I assume that the electron optics branch was formed before any of your colleagues were on staff with you, is that correct?
So let us assume then that the electron optics branch is formed, and that you've now moved into the postwar era I assume one of the largest of your programs became the nuclear test detection project, what is called Project Rainbarrel. Is that correct?
OK. Now, Ted Byram came to work with you at first on bomb detection, is this correct? Could you give us some information on your training, background, and the interests that you had when you were applying for jobs, and how you ended up at NRL?
I'd been in the [United States] Army for three years. In the spring of 1946 I got out, and found work at Glenn L. Martin. I heard of NRL through Glenn L Martin. They had a contract to develop the Viking even back in 1946. And at that time I was working in the shops at Glenn L. Martin as a plant layout engineer, and had the run of the whole factory, and so I watched the Vikings and became interested in that. My background really was in electrical engineering, and through the Army [I worked on] radio maintenance, trouble shooting, radar trouble shooting, so I wasn't anxious to stay as a plant layout engineer. I did get into some electronics at Glenn L. Martin, but their hiring practices were so bad — they'd be hiring thousands of people one month and laying them off the next month, and you never knew when you were going to have to leave and find a new aircraft company. When I heard in 1947 in the summer that NRL was hiring, I got an interview with Dr. Friedman and Dr. [John Adolph] Sanderson, and the work sounded exciting. I was very glad to move down to NRL, and got there in early December of 1947, and immediately started working on this atom bomb test project. One of the first jobs was to develop the discriminator that would cut down the background from cosmic rays, using coincidences between the geiger tubes that were bundled together for this monitor that had been already designed and built. It turned out [to have] seven large geiger tubes, 2 inches in diameter and 2 feet long, and their characteristic was that if two tubes fire, you get a double-sized pulse, if three tubes fire you, get a triple size-pulse, so you could build a discriminator that would only be sensitive to the single amplitude pulse. That would reduce the background, [and] lower the counting rate of the detection system, which was contained in a box about the size of this table. There were about fifty of those built, and they were installed all over the Pacific and the West Coast, in Asia, in Shanghai and Manila and Tokyo and Guadalcanal, Alaska, all the little islands scattered around the Pacific The discriminators seemed to work pretty well in the laboratory, but after about a month of operation out in the Pacific things didn't seem quite stable, so I was sent out there to find out what was wrong I was selected to go because nobody else would fly in an airplane, I think.
Was the selection made by Dr. Friedman?
Yes, I think so I think I was [at] the bottom of the list If I didn't go, nobody was going. But it was a wonderful trip. I went first class as a VIP I had my own B-17 to fly around in. I visited all these little islands in the Pacific, Manila, Shanghai, and the repair job was very simple It was just to bypass this discriminator, because the geiger tubes were not stable enough to maintain this relationship of one, two, or three-size pulses.
Was this your first contact with high level radiation detectors such as —
Yes, it was my first contact with geiger tubes, first contact with almost anything It was an exciting time to be — if you didn't like what you were doing one day, all you had to do was wait two or three days and you'd be on a new job; new exciting things were going on. It was —
How would you contrast the working conditions at a place like Glenn L. Martin with NRL? You were doing two very different things. Did you sense that there was more freedom to explore the applications of these technologies at NRL?
Oh yes. At Glenn L. Martin, it was really a very routine job. You got put on one little project and that's where you stayed. There was no variety. The working conditions were entirely different. The atmosphere of working in the laboratory compared to working in a manufacturing plant, was entirely different. The laboratory environment suits my idea of working conditions perfectly.
Ted reminded me of another counter story I'd like to insert. The tubes he described [were] the biggest tubes anybody had made. You couldn't find anything in an instrument catalogue bigger than that for a geiger counter, but we had built one about 10 feet long and about 10 inches in diameter, which was used to Dr. at the bay at Piney Point, the Navy's torpedo test range. They were developing torpedoes and testing them there, and more often than not the torpedo would not spin straight or would bury itself in the mud at the bottom of the bay. The problem was how to recover them. Well, we suggested tagging each torpedo with 5 milligrams of radium and dragging the bottom with this huge counter, finding the buried torpedo that way.
Why did the counter have to be so large?
They were of the original design that had the anode that was loose at one end, connected with the other?
They were a simple design, except that they were monsters.
Huge. How many people were you hiring when Ted Byram came on staff? And what kind of people were you looking for?
We were looking for good people, first of all, and people like Ted who were very adaptable, because, as he said, we were readjusting our priorities almost every week, what urgently needed to be done. We were looking for people who were skilled in electronics. We had a great resource right there at NRL. We had the Navy Materiel School, which trained about five thousand electronic technicians for the Navy. And we were able to essentially draft people out of that group to join us.
The students or the teachers?
The students. People like Rich[ard] Arnold, and several others in that category, moved right over to us from the Materiel School. They were very well trained, probably better than anybody you could find in industry at that time. And we were always looking for Ph. D.s. We had to limit the number of employees to fill the allowed billets. There was good control on billets for each branch and division of the laboratory. We always wanted to have a high percentage of Ph. D.s and [to] rely on technicians in the shops to give us the technical backup whenever we could. Well, up to the time Ted came, I think we were, all together, maybe five or six people in the electron optics branch. From there on it expanded rapidly.
How were you granted these extra billets? Was it because of the applied work?
The emphasis was on applied work, in the sense of getting money, getting space, [and] getting people, but there was never any quibbling about the basic research that we did. We were free to arrange our time to meet both requirements.
Let's move on with Dr. Chubb. You came a few years later — well, I'll let you say it I'd like to know a little bit about your training and interests.
OK. Well, I guess I started off with a general interest in physics I have two brothers who majored in physics before I did I went to Oak Ridge during the war, spent part of the time in the Army there. That did expose me to a variety of physics phenomena, especially in the area of gas discharges I worked in the electromagnetic plant for isotope separation, where the uranium hexafluoride was ionized in a strong arc, and the ion beam was separated by mass spectroscopy techniques. I had at that time the goal of going on in physics, and had more or less selected a potential study area for when I went to graduate school, namely the Phillips gauge discharge, which was used for measuring vacuum pressures and also as ion sources in mass spectrometers. So as soon as I could get out of the Army — and with the help of the GI Bill — I did go to the University of North Carolina, and eventually worked on the Hodding discharge for my dissertation, and I worked under a thesis director, Dr. [Victor] Masket, and he had worked at NRL. He knew of Dr. Friedman's work, and told me he was a very good man to work for, so I just accepted that, applied for a job and accepted it I don't believe I ever came up, did I, before we —
You came up, and we talked I took you to lunch and I decided Talbot was exactly the kind of man I wanted, so I twisted his arm.
I don't think it took that much twisting. But, anyway, I came As soon as I could finish up the commitments at the university I started in at NRL.
You came to NRL in 1950?
I guess it was '50, yes fall of '50.
How big was the group by then? You'd already had at least one rocket flight, which we'll talk about in detail later, and you were working, at that time at least, on several fronts. What did you see as your closest interest, what you wanted to pursue? And I'd also like to know what freedom you felt in choosing what you wanted to do.
Well, the electron optics branch was already an internal-structured organization, as I remember It had [Jerome Guthe] Karle working on electron and X-ray diffraction, and wasn't [Laverne] Birks separate then?
Laverne Birks was separate. He had the microscopy branch.
And I guess I was just assigned to work on geiger counters. The first BTs, with the X-ray and ultraviolet counters, had already been flown, yet there was a lot to be learned about what gave them their sensitivity and determined their characteristics. This area of work fitted in more or less with my background in gas discharge physics, although I had never really worked with a geiger counter before. My first years, a lot of them, were spent learning to use the ultraviolet monochrometer, measuring the spectral response of the ultraviolet counters, measuring the absorption characteristics of simple gasses throughout the ultraviolet, and photo ionization yields and characteristics. So I naturally was, I guess, more or less assigned the responsibility for all the sensors that we put on the rockets.
So your first few years of activity were largely assignments.
Well, I also worked on — our major contractor, you might say, the one who gave us money to do work — was the [U. S Navy] Bureau of Ships. They had the problem of detecting nuclear radiation for the Navy, and Herb had already developed the primary geiger counter sensors which were used in their main radiation detecting instruments, which they called Radiax at that time. There were some problems with those, but then they were also trying to develop a high-range instrument for measuring up to 500 roentgens per hour, for very high levels of radiation. For example, they were developing these very small tubes such as this one here, and even one that was much smaller, to work with these very high radiation levels. The geiger counter — generally when it's exposed to a high radiation field, it chokes and no longer counts.
Is there anything in the smallness of a particular design of tube that made it —
Well, the smaller it is, the less sensitive it is, and when you want to work at 500 roentgens per hour, you need a very, very insensitive tube. These were the little tubes that eventually ended up in the first U. S. satellite [Explorer I] with [James A.] van Allen's. So a lot of my work was for the Bureau of Ships, a lot of it was for the rocket program, and a lot of it was just studying the ultraviolet properties of gasses.
This was not the BS-1 tube that we know now which one —
This is the BST-12, except it's had a new window put on it. This tube here — does this have a mica window?
I can't get this off right now.
I think that one is the one that comes off. Were these the first tubes —
This is the BS-1.
And those were the first you that you encountered?
Well, we had a wide variety. There were lots of different tubes that were not — this is a standard tube that was used in the Bureau of Ships' Radiax, but there were many experimental tubes and tubes that had been used for a wide variety of purposes. But you can see the mica window is kind of concave. That made it sensitive to beta and alpha radiation that could enter the open end, and would be absorbed in the crawl of the tube. Actually, that's a fairly late generation of BS-1. There were earlier generations which had glass back ends and different kinds of seals.
You can discriminate their ages by the nature of the connectors.
Well, the early ones didn't have the ceramic insulator.
By early you mean how early? And late?
When I first came to NRL, we didn't have the ceramic insulator tubes; I don't believe. Would that fit your memory? There were the glass variety.
The tubes that were finally manufactured commercially for the X-ray diffractometers and goniometers had Lindemann glass windows, a lithium type of glass that was very transparent to soft X-rays. The Lindemann glass sealed the soft glass to the stainless steel body, and then a glass terminal to hold the anode at the opposite end. So these were the second generation, in which ceramic replaced the glass and mica replaced the Lindemann window.
In hiring Dr. Chubb in 1950, did you have anything specific that you had in mind for him? Or he was just to augment your team, to be sorted out later, you might say?
There always was a very strong need to work on the detector tubes, because they were at the heart of almost everything we were doing. My first expectation from Talbot was that he organize this work and see that the technicians did the things we wanted done, and so on. But he was allowed to let his imagination roam across the whole spectrum of what we were doing, and contribute to anything that he had an interest in. In general, that was the approach we took. Nobody was restricted to a very specific task. If anybody came along with an idea that sounded reasonable, we'd find a way of letting him pursue it.
Was this the general characteristic at NRL, or peculiar to the electron optics branch? I'd be very interested in any comparative memories.
I really think it was especially characteristic of the electron optics branch. Every group had its own, you know, particular character and characteristics, but I don't think very many of the groups gave the scientists quite as much freedom and encouraged responsibility and ingenuity as much. But there were other good groups at NRL too. I mean — it was just a very good spot. There were some groups that didn't do much of anything. [Laughs]
Well, eventually we'll get into this question of being able to choose the type of research that you were to engage in, and making choices, balancing the industry-related research to your bomb test detection research to rocket research. I want you to keep in mind this kind of a balance, and discuss periods in time when you had to make choices. I think we should hear from Robert Kreplin now.
I might make one further comment along these lines. We had a lot of important relationships with chemistry, and there were two people there who worked obviously in the same mode that we used: Bill [William Albert] Zisman who was a surface chemist, and Peter King, who was a very broad-gauged chemist. We had many cooperative programs, and they were as remote from what was typical of a chemistry division as our work might have been remote from a purely optics type of research program.
But no one ever questioned why you were in physical optics?
No. It was a matter of individual character, the nature of the person involved, whether he had this kind of adventurous approach to research. That was true of Pete King and Bill Zisman. There were people in other divisions who had that approach, too I spent some time, for instance, working on cavitation of propeller blades on ships, and I, who had never built any high-powered electronic equipment, built a very powerful oscillator to drive the magnetostrictive generator of waves that would produce cavitation effects in blades. And I worked with people in one of the radio branches then who seemed to be able to pick up on things remote from radar without any hesitation.
So there was a lot of crosstalk in the lab, creative crosstalk.
You could affect transfers of people, detail people who had special abilities, and only the superintendents of each division when you needed more power. Is that basically how it worked?
And your superintendent was [Edward Olson] Hulburt.
Yes Dr. [Robert Morris] Page, who is given credit for developing pulsed radar, needed a kind of discharge tube for the pulsing operation. He knew we were working with discharges, so he tried to bring us into that problem, and we did consult with him.
This is R. M. Page.
Mr. Kreplin, let's turn to you I know you were trained in physics at Dartmouth?
Yes, that's right.
Again we're interested in what your interests were and how you came to NRL.
Well, I guess I'd always been interested in mechanical things, but at Dartmouth. I came to know Will Raitin, professor of electricity and magnetism, radio, and other things like that I think it's under his influence that I became more interested in electronics at that time. And in the summer between my junior and senior year, there was a notification of summer student opportunities at the laboratory. I don't remember exactly how it was that I chose NRL, but I made an application for that and showed up in Washington one hot June day and went out to the laboratory. I recall I had no idea, really, what I wanted to do at that time, so they had a tour arranged for us. I remember visiting a number of different divisions, and going through the electron optics division, I remember very well how interesting things — the things that were going on there seemed to be interesting. There was a lot of electronic stuff, not radio particularly, but on different applications of things, and that seemed like kind of an exciting thing to me. When we finished the tour, I said I thought I'd like to work up there for the summer. I don't remember whether you had my application or anything else, but apparently you said yes, that was all right, so I went to work wiring up circuits and also plotting data from the Pacific stuff, in1948 in the summer. I came back in the summer of 1949, got a degree in '49, then worked with Frank Moore at Dartmouth in the following summer doing some spectroscopy [of] ionized manganese plates that he'd brought up from Princeton Then after getting my Master's degree, I re-applied to NRL and came back. That's how I got there.
What was it about the electron optics? You were still in Building 30 at that time?
Was there something about the atmosphere of the place or the problems that were being done? Did anyone give you a lecture about what they were doing there?
Yes, I presume that they did I don't remember too much about those first days, except that I remember that it looked like an exciting place to work, and it never ceased to be, in all these years.
It's interesting that all four of you came actually under different types of conditions. It looks like there are many ways to obtain a position at NRL: contact through [a] summer student, through a faculty advisor, [and] through the Federal Register, I guess would be the best way to describe it. And with you, [when] you came originally, there was an intermediary also, who knew Hulburt Is that correct?
Yes I was something of an embarrassment at Hopkins, because they never had any trouble placing their Ph. D. s. Because of the work I'd been doing, I got connected with the Rustless Iron and Steel Company in Baltimore. I was working at Hopkins but as a consultant to them, on corrosion problems in stainless steel. They were very excited about the work I was doing, but they had thirty chemists in their plant and no physicists After a lot of soul searching in the plant, they decided that they could not really employ a physicist full time. So I was desperate for a job [Augustus] Hermann Pfund, who was the chairman of the department at that time, took it as an insult to Hopkins, that any Hopkins Ph. D. should have any trouble getting a job. He had a former student of his who was head of metallurgy at NRL, and he simply picked up the phone and said, "I'm sending Friedman over to see you, and I want you to give him a job." Those were days when academic jobs were very, very rare I know when I got my degree, there were only two openings in the whole country, one at M[assachusetts] I[nstitute of] T[echnology], and one at Cornell [University], and every young Ph.D. physicist applied for those two jobs. Physicists still had very few opportunities in industry Chemists had all the opportunities, but very few industries — you could boil it down to Bell Labs, Westinghouse and G[eneral] E[lectric] — employed any physicists. When I came over to NRL for my interview, I too was intrigued with the reception I got I'm trying to recall, Canfield, Robert [Hawthorne] Canfield was the head of metallurgy. He was a very good physicist, and we immediately had a good rapport I was delighted to have the opportunity to come into metallurgy and start working with him. Unfortunately, by the time I made the transfer — the day I came — Canfield left. The man who took his place was Francis [Marion] Walters [Jr.], who was a cookbook metallurgist, I guess is the best way to describe him I had the feeling right away that he was very uncomfortable with a physicist, and especially a physicist who was into the new solid state physics. That was all very mysterious to him I don't think he disliked me, he was just very uncomfortable having that kind of physics in his division. About that time, let's say within a year, it was known that R[adio] C[orporation of] A[merica] was going to put out a commercial electron microscope. The thought was that it would go into chemistry, because the major applications of the microscope, right at the start, were thought to be in looking at pigments, looking at the fine structure of chemical materials. So it was assumed that chemistry would get the first microscope that came off the assembly line at RCA. The chairman of the chemistry division was Perry Borgstrom. By then I had made very strong friendships with Zisman and King, and they kept urging Borgstrom, "Take Friedman and let him run the microscope operation. " But he somehow could not manage to make that decision. Time went on I was unhappy in metallurgy, not able to get a decision out of Borgstrom. There was an opening in metallurgy at the [National] Bureau of Standards, which had a very good metallurgy department, much more modern than the one at NRL at that time I went to Bureau of Standards. They offered me the job I came back to NRL, and I had a rather routine date with Hulburt I was to meet him at lunch and talk about anything, from physics to music to anything, and I told him I was going to be leaving the Lab in the next few days. He didn't ask me anything, but he went in to the director at that time and got his permission to make me an offer to come into the optics division [he] came back to see me and asked if I would be willing to work with him. Well, I already had an enormous admiration for Hulburt, and that offer was just irresistible I said yes without a moment's hesitation. He had already gotten the approval of the director that if I accepted his offer, he would take the electron microscope [and] set up an electron optics branch So all of that transpired in that way.
Right. Quite rapidly, too.
He made me head of electron optics. At that time, there was a head clerk at NRL, May Pope, who handled all of the clerking for the laboratory, really. We needed job description, she wrote one paragraph for me, said I was going to study the application of electrons for the Navy, and —
Application of electrons?
That simple. [Laughter]
And that was it. That was my job description Hulburt immediately boosted my grade so that I was matched with [Richard] Tousey and Sanderson and [Leo Henry] Dawson, his other branch heads, and then also almost immediately allowed us to become the largest branch in the group. We always got the most wholehearted support from Hulburt.
You had already, as you say, paid your dues to the Navy by developing and applying the counter tubes, and were well along at that time on many different fronts. But I'd like to carry the group into the late forties and into the early fifties with the rocket work, and start discussing — at least with Mr. Byram, and with you, how you finally got a slot on V-2 No 49, that flew in September, '49, and what your goals were at that time. How did the rocket work develop out of all the other applied work that you were doing?
My first realization that there was the possibility for that kind of work came when Hulburt gathered me and Tousey and Dawson and Sanderson together, and said the V-2s were coming to the United States and there was going to be an opportunity to use them for research And his first thought was to take a small Hilger ultraviolet spectrograph, a quartz spectrograph, which had been used for aurora studies in the second polar year, and which was still in Dawson's cabinet, and suggested we try to mount that spectrograph in one of the V-2s and try to observe the solar spectrum. I was very heavily committed to Project Rainbarrel.
You were already in that.
Yes. And Tousey took the initiative there, along with some people in Ernie [Ernst] Krause's branch. Krause was the spark plug of the V-2 program at NRL He had gone abroad with the Paperclip group to look at what technologies were available, and in particular to look for the V-2 rockets. [He] came back with great enthusiasm for initiating a rocket program, both for military uses of the rocket and for using it as a research vehicle, and established the Rocketsonde branch, of which he was the head. But it was understood that other people in the Laboratory, particularly people in the optics division, would join with them in doing high altitude research.
Was that your own decision, that you were too committed yourself, or did you really try to break out of it in the beginning?
I couldn't get out of the Project Rainbarrel, and really didn't want to, because it was right at the time when we had made these rather spectacular observations, after Bikini and Sandstone and Fitzwilliam, that we could detect the bomb debris, and that we could actually analyze the debris and determine what kind of a weapon had been fired. And there was a very high priority put on the whole problem of monitoring Russian progress in making a bomb. There were two people who came over to NRL from O[ffice of] N[aval] R[esearch], Lloyd [Veil] Berkner and Urner Lidel. They had both been in naval uniform through the war, and they were about to move into civilian mode again, but they had this ONR task, to get around the country and see what ideas people had for doing physical monitoring of Russian progress on a bomb. We had ideas, and we were given all the resources we could ask for, to follow up on them. So it was a very exciting challenge, and I wanted to do it. At the same time the idea of doing rocket work was very intriguing, but it had to be put on the back burner. In any case, Tousey and the people in Krause's branch were given the lead to develop a spectrograph. They connected with the Baird Instrument Company to be their contractor and went ahead with that. It was only after they had had a number of disappointments — they had a very early success which fired everybody up and aroused a lot of the astronomical community to the potential of doing rocket astronomy.
October of '46.
But then things went sour. There were attempts to develop pointing controls, first a one-axis pointing control. There were always problems of recovering the film cassettes after impact. And there were a number of what really were failures, because of these difficulties — of working with a rocket, getting a good flight, getting a good recovery — it wasn't easy. And when that process went on, first of all, I realized that they were only probing the near ultraviolet, which had almost nothing to do with the ionosphere. Right from the start, because of my contacts with Hulburt, whose whole career had started with the ionosphere, I was motivated to think the way Hulburt thought, on how does the sun make the ionosphere? And his idea was that it could very well be X-rays. There was no way the people who were using spectrographs and photographic film would ever get down to the X-ray region. So it was a very natural thing to think of using our counter techniques to do X-ray photometry at the first opportunity.
Did you express these concerns and interests with the rest of your group, especially with Ted Byram, who was with you at that time? Do you recall turning over in your mind what you'd rather be working on as this continued, especially as you were touring the Pacific in the B-17? Whether your time might be better spent, more interesting, at least to your own personal interests, in rocketry, X-ray solar rocketry?
So far as I can remember, the only connection I had with that before the actual launch flight was that I always read the Institute of Radio Engineers' Proceedings I ran across in there an item — I assume it was by [Karl Guthe] Jansky — that said that their idea of the temperature of the corona was like 500,000 degrees, and I mentioned that to Dr. Friedman I knew that they were talking about looking for X-rays. But I think my main connection with the V-2 before launch was just helping to find good geiger tubes that had stable characteristics, and proper sensitivity I made some calibration measurements, with a small X-ray generator
Where did these particular tubes come from that you had available? Were these already being built by Anton [Electronics Corporation] at that time?
Let's see The X-ray tube development went from Phillips Metallix to Amperex and then to Anton Amperex was a subsidiary of Phillips [Nicholas] Anton was president of Amperex and then he slid off and set up his own company. All through that period, because my connections with them went back to the crystal oscillator plate manufacturing problems, they were very generous with us in accommodating any requests we made for special tube work or for special X-ray equipment, or whatever. Obviously it was to their advantage to have this association with us, because the crystal work had been extremely profitable to them. The diffractometer, the powder diffractometer became a commercial item, a very large business, and then the X-ray spectrograph became equally large, so it was a very compatible relationship. We could sketch tubes and within a week or two we would have tube bodies in the lab from them.
Are these side tubes an example of the modifications they made for you?
What changes actually had to be made, then, in these particular tubes? These are not V-2 era, are they? But are they similar? How are they similar or different?
On that first V-2 we used copper bodies with graded glass to metal seals, and they were not similar to anything that was being made by these commercial groups outside. But you can see the similarity there.
This has glass ends, the anode is supported at both ends.
Did you come up with this basic design?
Those were our designs. We haven't mentioned the technicians we used for glass blowing. There was a senior technician in the glass shop, Leland B. Clark. His son was also a glass blower, Lee [Leland] Clark Jr. , who came into our branch. There was another man who came to us from the glass shop, Mike McEwen. Those people were very experienced, ingenious. They knew of the availability of all sorts of special glass parts, glass technology. I could sketch a tube to them. They would convert it into a design which could be put together.
So literally a sketch, a conceptual sketch, no draftsmen in between, nobody setting tolerances and parameters, this was all directly from your informal sketch?
Mr Byram, did you have a role to play in that?
Well, it mostly was the testing I was going to mention that I remember a little bit more about the V-2 design. There was a flat spot welded across, maybe 3/8 of an inch long, just straight across there, and then the hole was drilled in there, and our window was attached to that machined flat.
So it didn't have a large flange?
No, there were no large flanges.
No large flange right there. And that was the simplest modification you could think of, I take it.
Well, it was a very easy one and it was really very effective with those tubes.
What role did Anton play? Did they provide these to you? It sounded like the modifications were made right in the NRL shops to standard tubes.
We would start using something like the BS-1, something in that general category. Then, as Ted says, we wanted to put a window in the side, so we would file away a groove that could take a crystal window, wax it on with piceine or glyptal, whatever, and have an ultraviolet counter. Or we could put a beryllium window in the side, because that would make a tube more rugged for rocket flight.
What were the problems that you worried about, as you realized that this was going to be a detector flown on a vibrating and obviously very hostile V-2 rocket?
Mostly we worried about the stability of the counter itself, was it leak tight, did it have the proper filling, did it have good characteristics, no multiple counting, good long plateau, stable threshold, a reasonable operating ability.
Did you find that these were qualities that were easy to come by?
No. I guess that by that time we didn't have too much trouble. But the truth is, we covered a very broad spectral range, and had a wide variety of windows. There was mica, I think, a quartz window tube, beryllium window, aluminum window. All of these with the largest aperture that we thought could be supported, so it was very critical that the tube be vacuum tight, and remain that way. They were filled to nearly an atmosphere of pressure, as I remember everybody in those days filled tubes and I don't really remember what the mixtures were.
You had other people who were identified as working on the V-2 49 project, which was your first rocket project [Sam] Lichtman and Nemecek, Joe Nemecek.
Did every one of you have similar duties and yet dissimilar specialties? Filling in in different areas of expertise?
I don't think Joe ever did any filling, but everybody else did, including Sam Lichtman and Dick Arnold and myself, Dr. Friedman.
How did you set your priorities, preparing for the first flight? You had a deadline, of course, when the rocket presumably was supposed to fly, and I know there was a one month delay in there somewhere. But you were still working on Project Rainbarrel, and presumably there were other projects. Did you have to carefully manage the time of each of your team members?
Well, I had gotten very itchy about doing a V-2 experiment, but they were booked up, and the only promise I could get was that if some experiment failed in preparation, and space and telemetry were available, I could squeeze something in. Now, at that point Sam Lichtman came to me. He was in Krause's group But he had gotten somewhat unhappy with his situation there. He knew that I wanted to fly, and he was an expert on the telemetry. He had been involved in developing the pulse-code modulation system. He came to me and said he would like to work with me, and in particular, if we wanted to get into the V-2, he would be very helpful in making that arrangement, since he came right out of that program. And he was… He went ahead and prepared the pulse-code modulation system for our small experiment, and kept track of what was going on in Krause's Rocketsonde section, so that at the point where somebody had to cancel his priority, we were able to move in.
So you didn't know that you had this particular slot ahead of time, until —
Very shortly beforehand.
I see. So it was a matter of getting the experiment ready to fly and simply waiting for a slot?
We knew we had all the components, and that if we were given a slot and given a few weeks, we could put something together and get it done.
Were you excited, Mr. Byram, about this?
I'm not sure I was terribly excited, but I was very heavily involved in getting the instrument ready. Things were not miniaturized in those days. The telemeter system was this big around and that high. The electronics box control — I've forgotten how many detectors we had, something between a dozen and half a dozen detectors — that electronics box weighed 300 pounds. The commutator was this long and that square, and it weighed 20 or 30 pounds, [with a] great big heavy motor to drive the slip rings — it was a mechanical monstrosity.
So the size of the tubes were deceptive, compared to the payload.
Cables were that big around. Nothing was miniaturized.
The experiment was mounted in a V-2 nose cone, the kind that was used to carry 2000 pounds of TNT, so our heavy payload really didn't make any difference. Two thousand pounds of nose cone was the biggest part of the payload.
It sounds as if this would not have been a possible experiment without the V-2. You needed something that big, because you did not have electronic miniaturization at the time.
We couldn't have flown in anything like a WAC Corporal, for instance.
Well, what were the days like once you knew you had a slot? Did you find it was kind of hectic? Did you have split loyalties to your Rainbarrel responsibilities and to getting the tubes all behaving properly?
I think my responsibility to the Rainbarrel was over by that time I may have made one or two trips in '49, but they were very short. It seems to me that I went back to Shanghai on that — I left on the day that the Communists were moving from Peking down to Shanghai. But I think that was in 1949.
See, by the time we did our V-2 experiment, I thought we had done all the physics in Project Rainbarrel. We weren't going to make any great discoveries. We had detected the Russian bomb, and it was time to get out of that There were lots of things that the chemistry group continued to do that were interesting science, like trying to determine how long the radioactivity was trapped in the stratosphere. We had stations along the 80th Meridian from the arctic to the antarctic, and so we could observe routinely what the radioactivity in the two hemispheres was, and that was an interesting problem in stratospheric circulation. They continued with that. There were surveys made of radioactivity near the ground, natural radioactivity, which were interesting. For instance, we put some of our huge blower systems with filter papers on a truck, and toured the nearby states, and measured radon in the atmosphere, and found enormous variations with the geography, which could have been followed up, would have been interesting. And when I look at what we measured then, it's interesting in the context of the radon problem today. In the Washington [D. C.] area we find radon in the atmosphere at a level of something like 10-18 curies per cc [cubic centimeter], which is the level at which they're worried about radon contamination in homes today. Well, that would be normal, but the concern now is for many times that value. Anyway, for the chemist those were interesting problems, and they continued to pursue them.
Did you have the freedom to move out of Rainbarrel then and into literally anything you chose, which in this case was rocket research?
Did you go out to White Sands [New Mexico] for the actual flight?
No I didn't go. I didn't go because I didn't get along with Sam Lichtman very well [DeVorkin laughs].
Ted, I have a picture of you and Joe and Sam with the rocket at White Sands.
I wasn't there for the launch I may have gone out beforehand, because this —
It's a picture of the installation of the equipment in the rocket.
Yes, I remember going up and down on the tower with this huge heavy payload, but I'm sure I wasn't there for the launch.
The launch was delayed by a month
That might have had something to do with it.
Yes, and I don't recall exactly why, but I know that there was a problem with the rocket. It had to be delayed for a month. During that time you or members of your team had the responsibility of making sure of the care and feeding of the tubes, make sure they were still live. What I'd like to get from you collectively, though, is your feeling for what that kind of life is like. Is it terribly frustrating, constantly battling these tubes? I know you had portable filling stations, gas filling stations for them, that you were trying to make tubes work in an environment that really they weren't designed to work in. What were your major frustrations in that?
I was never frustrated I enjoyed fighting them. It wasn't a frustration, it was a challeng.e It was mind over geiger tube. [Everyone laughs]
How did you make sure it was mind over geiger tube?
By keeping at them. Just looking at them more or less constantly, checking them.
I think we started out with ten or twenty counters of the type that you wanted to fly one of, and [by] filling them, and then checking plateaus and thresholds as a function of time, day by day — pretty soon you picked out the ones that were leaking and tried to repair and refill those, and hope by the time it came to install them, you had at least one left that was good.
I think that those V-2 tubes were better than average. I don't think we had anywhere near the trouble that we had later, where we were putting 40 and 50 tubes in an experiment.
The first V-2 experiment was really very simple. We wanted that one band of X-rays. We wanted Lyman alpha, and we wanted to get a look at the Schumann region. It was only later that we went to these enormous variations on the theme by using aluminum windows and mica windows and beryllium windows and plastic windows, and so on, to discriminate different wavelengths.
But I was more involved with the data reduction than with the payload itself, I think I was given the job to determine the motion of the V-2 during the flight. The aspect information came down on three gyroscopes, made in Germany, cost a thousand dollars each. In those days I thought that was terrible. But they flew these on all the V-2s, and they had a little pamphlet giving the algorithm for converting to the actual motion of the rocket I worked on that data for six weeks, and I finally told Dr. Friedman, "I can't make any sense out of it. It doesn't seem right." So he sent me over to talk to the mathematician at Rocketsonde that had written the pamphlet, and he said, "OK, I'll look at the data, I'll give you the answer next week." And I went back the next week. He said, "You're right, it doesn't make sense." [Laughter]
The only mathematician I know in the Rocketsonde section is [Homer Edward] Newell [Jr.].
No, he had another man.
He had another man.
I've forgotten his name. But I said, "How did you do it in the past?" and he said, "Oh, we never tried to do this before."
They never tried to determine aspects.
Right. Nobody ever cared what the payload was doing.
This was the first sensor of its type flown on a — well, no, they had the calcium sulphate phosphors, and there were Burneit's film-filter combinations, didn't they need aspects for those?
If they did, they got it from something other than the gyroscope. And I think it was Sam Lichtman who actually solved the problem, and used our own X-ray data itself to — either he or he and I together did that — I'm not sure that I remember. We could determine at least crudely what the motion was.
The film blackening attempts and the thermoluminescent phosphors were really attempts to detect X-rays. I don't think they thought far enough ahead about fine corrections for aspect in their data.
Between V-2 49 where you had your first detection of Lyman alpha radiation, and Viking 9, which came in 1952 — August of '52 approximately — there were quite a few subsequent Viking, Aerobee and a few V-2 flights as well I know that you were on at least one of them, and Tousey's group flew quite a few of the film-filter combinations. But virtually all of these flights were unsuccessful, [due] either [to] rocket failure or damage to the film upon impact, or in some cases the detectors that you flew were damaged. Again, I would like to pose this question of mind over geiger tube. Did you have the same feeling about mind over rocket, something you couldn't control at all?
No. Well, the V-2s were pretty bad, after V-2 49. They were pretty disappointing, to see two of them fail in a row.
Once we got into the Aerobees, every one of them performed as predicted. Now, we were on Aerobees 8, 9 and 10. The first seven Aerobees had failed. That was why we got 8, 9 and 10, because nobody wanted them. I believe that's true.
These were the first Aerobees.
But they were supposed to go to 70 miles. Every one of them did. They all behaved differently. When we flew sets of three, one of the three was always very much better than the others, because it scanned past the sun, which is nice, perfect position. We always, on one of each of the three, had a good roll rate, good precession, cone, and got a good straight-on view of the sun when we were out of the atmosphere, and our experiments always worked. I don't think we had any failures in those.
I was reading from some of the records of the V-2 panel, and from some of the reviews of the NRL reports that indicated that there was a lot of trouble primarily with the film-filter combinations of Burnight, that there were a lot of ruptures. But I guess that was on impact, and you didn't have to worry about that.
No, but I did see one of the craters from a V-2, and it's a big hole in the ground, about the size of this room. It was about that deep and about that big in diameter. It's a wonder they ever got anything out of them.
Viking 9, before we go to the Aerobees, Viking 9 was one of your very complex experiments, as you indicated. You had some 60 tubes in that experiment. What transpired between the Viking 9 and your first success, V-2 49? There were several years there where you did design other experiments. Did they get progressively more sophisticated, or did you decide to make one incredible jump to the Viking?
No, we had V-2 failures. Was it V-2 5l?
55, which just lifted off the ground and started to walk over to the blockhouse. And fell over at the blockhouse and became a huge inferno, and that was a total loss. See, Viking 9 was 1952.
So not much time elapsed in there. And we had been promised that Viking would be stabilized so that we could point our entire array of 60 detectors at the sun for the whole flight. It had roll jets and it had the fishtail, the gimbaled motor, to stabilize it. So all of our ambitions, let's say, were focused on that Viking. It was going to be a spectacular. But the stabilization didn't work. It worked just about up to the level where we began to get signals, then the roll control failed, and it just started to spin faster and faster. We could get very little out of it. In fact it spun so fast that a lot of the equipment was just torn loose inside from the centrifugal force. So we were ready for Aerobees. We had had enough of big rockets by then.
You certainly knew that Aerobees were there, but the first seven of NRL's Aerobees, as you mentioned, were failures. Were [the] three of you — Dr. Chubb was with you [now] — were you ever finding yourself gathering around the coffee pot late at night, wondering why you were in this new way of doing research that you had no control over? Did you feel that you didn't have control over the rockets, or you were always hoping for the best?
Well, I think personally I always hoped for the best, and I expected it.
Yes, I don't think we ever had any real hesitations. You're sooner or later going to get results.
I think this says a lot for the institution you're working at, also were there ever any reviews or periods of time when people such as your supervisors, or even people in other groups would turn to you and say, "Why aren't you doing something more productive?" I know this was the case at APL, the Applied Physics Lab, in van Allen's upper air group in the late forties, where they were referred to as "the five percenters." Was there any jealousy or questioning of your goals among other groups, say ranging from chemistry to the more applied groups that were working for you, the crystallographers, people like that?
No I tried to mention early on a variety of practical things that we did. That continued all through this era, and I guess we had a reputation of doing well at both. We were in basic research. We were also into applications, and I suppose to the sponsors, we were earning our way into having complete freedom of operation
I guess what I'm trying to clarify here is that you, Mr. Byram and Dr. Chubb and Kreplin also worked in applications, at the same time that you were doing rocket research?
I think in those early rockets, I didn't really participate up until we had Aerobees 8, 9 and 10. I was working on, I remember, the pulsed operation of geiger counters, to try to develop a power supply which would allow us to make measurements at very high radiation levels just by applying a momentary pulse of voltage to the counter.
That was for Bureau of Ships. That was one approach they were following, high level radiation detectors. I remember publishing a paper, a silly little paper on just the transmission of barium fluoride crystals. You know, there were publications coming out of the group during this period of time, even when there weren't rocket results.
I know you were publishing on theoretical characteristics of geiger tubes and counters.
When was your big geiger counter paper?
The Proceedings of the IEEE [Institute of Electrical and Electronics Engineers]?
Yes, that was probably, was that in this era?
Yes, it was. It was in the early fifties About '53 or '54, paper came out. That's right. So the important thing is that in context, you weren't doing only rocket research. Other work came in as it demanded attention, or if there were slack times, or if you found that there was nothing better you could do, you were just waiting for another launch. Is that the way.
Well, the rockets in general, you know, were a year apart or so, so you had to — and you had lots of time to do other things. You worked on many long-lived experiments simultaneously, and you would work on what needed to be worked on. You weren't just focused on a single project. It would have been a very poor use of time really. There was always a lot of interesting stuff going on.
Is a good example of this the fact that even though you flew in September, '49, your first paper on that flight, analyzing the results of that flight, did not come until '51? You say there were several reasons for the delay there.
Well, the biggest reason was that we were so heavily involved with other things. We were still doing a lot of the work on Rainbarrel.
Yes, you were still involved with that.
And then also there was a problem with publication Sam [Samuel Abraham] Goudsmit was the editor of the Physical Review. When I sent him that paper, his letter back to me asked, why do you want to publish in Physical Review? Physicists weren't interested in this sort of thing. Why didn't I find some other publication like ApJ [Astrophysical Journal] or Journal Of Geophysical Research? So there was some time lost in there. I had never published in another journal, so it was kind of a shock to suggest to me that I shouldn't publish in the Physical Review.
The Physical Review was your journal of choice.
Yes. I don't know how much that delayed us. I think it was primarily that we were so busy. The story was presented at meetings. So it was well known immediately that we had the X-ray results.
As best I can recall from reading the chronologies that I put together, you remained the only group doing X-ray rocket research for quite some time. There was really no other group, until after Sputnik.
Does that say something about the uniqueness of the technology, the necessity of putting together a group that could handle these detectors?
Well, we were very good at it. I've had people comment to me in later years that they always felt they could never catch up with the NRL group, the people in X-ray astronomy, and wondered when their chance would come to get a step ahead of us. The group in England, Kent [Kenneth] Pounds, has told me this. He thought as a young man they would never get that step up on NRL. We were just going ahead and doing our thing, sort of oblivious to what other people thought.
Your counters were of course commercially produced for industrial work by Anton, but did other groups also approach Anton for counters for different regions in the spectrum? And was there any limitation — I was wondering, who held the patent on the basic design of these counters, or were there any patents for them?
There weren't any patents on the basic design.
We found that when we tried to patent the tube, the patent examiner would usually say, "Well, what's inventive about a tube that consists of a cathode and a wire anode and a vacuum-tight envelope? There's nothing inventive about that. If you put different gasses in the tube, well, other people have used rare gasses with some small amounts of quenching agents of one sort or another, so what's new about a tube that contains a rare gas and a quenching agent? We just were never encouraged by the patent office to try to cover very, very specific things, like methyline bromide with argon as a mixture. They didn't accept that. And yet from the practical point of view it made all the difference in the world of our commercial applications, because those tubes lasted, were essentially permanent tubes.
And yet there was no patent, and so other people would have been free to approach these commercial producers. Or could you not trust that a commercial producer could produce something for a rocket? Let's put it that way.
I don't believe they were ever approached to duplicate our tubes for somebody else's rockets.
Moving into the Aerobee era, then, you were looking forward to the Aerobees, but with the Aerobees there was another price to pay, and that was payload, weight. Your detectors, of course, are quite small and they always remained quite small, but what about all of the heavy commutators, all the electronics that went along with it? Did you have to build up expertise in the electron optics branch that could work on miniaturizing these electronics? Was it a chicken and egg problem? Were you ready with miniaturization by the time the Aerobees came along?
I think we were ready.
How did you get ready?
Well, I'm sure I had very little to do with it. I think it was Sam Lichtman and Bill Nichols.
Bill Nichols. See, our shops were working on miniaturization, in a very general way, like how to weld contacts rather than solder them, and also, the IGY [International Geophysical Year] concept was now gaining momentum and we were thinking ahead to what kind of instruments would fly on the Vanguard satellites. See, by 1954 I think there was the van Allen symposium.
Yes. And we were proposing things to do but also thinking of, how do you instrument this 20-inch sphere, with very light weight equipment, 10 or 12 pounds, to do your experiment? So the whole philosophy of miniaturization was moving ahead very fast, and there was a lot of expertise in our shops, as well as in the divisions, that we could draw on.
It seems to me just in general components were getting smaller too. Vacuum tubes were in smaller shells.
Our people were continually abreast of whatever was happening in industry, and at that time we could just buy parts, components and things, just to see what they were like. So whenever we needed something, they had the background to go ahead and select the best components to do it.
They finally got those triggered thyrotron tubes for the rate meters, which were something that came out of the electronics industry at that time. Certainly condensors got smaller. I mean, World War II surplus condensors were huge things. So I don't think it was all that big a struggle for the l5-inch Aerobee dimensions.
We only had four detectors or something like that.
Four detectors? So you were running simpler systems now.
It's only when we got to the small rockets that had 6-inch diameter, then we had to really get things more miniaturized.
These are the Nike Deacons and Nike Asps that were running in '57, '58, in your expeditions, San Diego High and Puka Puka, the eclipse expeditions and so forth? I'd like to get a sense of what daily life was like, now that all four of you were in the group with others, in the early to mid-fifties. Could you synthesize a day in the life of the group, let's say as you were getting a payload ready? What were your different responsibilities? Were you still in Building 30? Were you all together working at different tables within earshot of one another? Was it a lively place? I'm trying to get a flavor for the group and how you really did work together.
Well, it was certainly lively! And I believe that the whole branch got together for a coffee break around nine o'clock in the morning. That was certainly true when I first came.
I know a lot of us would go out for pizza on Tuesday afternoons.
That was later.
That was later. But we would eat lunch frequently together, some of us would.
But up in the penthouse it was all open, everybody was within earshot of everybody else.
Except in the corner where Sam was.
I don't know.
We were a very good team, and we worked very hard.
We spent almost no time at meetings.
That was my philosophy, for one. I avoided getting on any of the committees that organized these activities, like the IGY committee, and the rocket panel. It seemed like such a drain on time which could be used so much more effectively by being right in the laboratory. It was just easy to let somebody like Homer Newell or Jack [John William]Townsend [Jr.] represent the Lab, and count on them to take care of our interests, if it came to finding us places in the program.
I was trying to determine, and I think I did, that you later on were a member of the working group on internal instrumentation.
We can get to that, but in the nature of the flavor of the lab, I'd like to have all of you refer to the cartoon that you kindly provided me a few days ago, and try to get a sense of what's behind this cartoon, the various personalities. I'd like to offer this to you. Who would like to work on interpreting the cartoon, each one of you, starting here with I guess it would be Commander Stecher and Commander Deal. Would you mind giving us a running commentary? [Eagerly peers over his shoulder]
Talbot was talking recently about these boosters coming down, and you're getting a feeling looking up as though each booster was coming right down on the blockhouse. There were warnings — stay in the blockhouse until the booster impacts. That cartoon shows — which one is it — Commander Stecker with beads of perspiration, having narrowly escaped being hit by the booster coming down. [Laughter]
What we should do is try to turn this around and maybe have one of you walk us through it, give us a sense of personalities. Is there a way we could put it down on the table?
Oh yes, like that.
Here you are, Dr. Chubb. You're looking at, what is that?
That's a display, a real-time display of the telemetry signal from the rocket that was developed
This one here.
And set up by New Mexico State University. New Mexico State University was doing all our telemetry at that time.
You have to realize the situation in the blockhouse. You would have all of your instruments displayed on that tube, and then the rocket would fire, and everything would go wild, everything would disappear, and you'd await with your heart beating rapidly to see the telemetry come back on in a stable fashion. Then of course the rocket is flying, and you've got a dozen lines of telemetry, maybe Talbot would know what was on each line. He could tell you when the sapphire tube came in, or the lithium fluoride tube came in, or the X-ray tube came in, and...
So you're saying, "Wang, bang, look at that sapphire tube respond!" Is that it?
The others are saying, "Well, the rocket has already come down to the ground." [Laughs heartily]
Has this ever happened or is it apocryphal?
I don't know. It probably did.
It's exaggerated, somewhat.
But I think it does speak to Talbot's enthusiasm, and Nichols was a very pragmatic sort of fellow.
Talbot has a very healthy voice and a lot of enthusiasm, and you could hear him all over the blockhouse.
What about Ted Byram down here in the lower left hand corner? "I thought this was supposed to be such a red hot beacon your sms had." What does that refer to?
I always thought that the beacon was a wasted 20 pounds or so of payload, and I let everybody know what I thought of them.
Actually we stopped flying them, didn't we?
We quit as soon as we had any authority to make them take them off. The radar beacon. The beacon would be triggered by the radar, and then send an echo back that was very much enhanced so that they had a good signal-to-noise [ratio].
This was only to amplify the telemetry.
Only to amplify the radar.
It was a transponder for the radar.
They used radar tracking to get the trajectory.
And it was for range safety. Their principal argument was that they absolutely had to track that rocket for the first 60 seconds, in case it had to be cut down. My own opinion was that the radar was not going to have any trouble at all picking up the flame from the rocket. The thing was burning, they were going to track it, whether there was a beacon or not.
Usually the beacon would burn out anyway.
It frequently did.
The beacon was placed on pins?
No, it just...
Well, the antenna was in the pins, but the beacon itself was up in the nose cone.
OK. Who are Rickets and Baumgardner here?
Rickets worked for the college and was the head of what they called the physical science lab. It was really just a contractor to NRL to support NRL's rocket work.
He's saying, "Ah well, another 142 percent recovery." Is he an optimist?
I imagine he was. He was very good at his job. He started off as a telemetry expert. And it may be that he's referring to telemetry recovery rather than to physical recovery.
Recovery of the data.
Down here below is Herb Friedman, and he's standing on a soap box — is that a soap box?
I guess so.
I always thought it was a marble pedestal. [Laughter]
A marble pedestal? "Yes, I say to you, fellow members of Sigma Xi, we stand today on the veritable threshold." Veritable threshold of what? Was that just a general opening you were well known for?
Well, I guess I was recognized as a good salesman. And I used to go over to the college and give them a lecture, when we came there for a set of shoots, [to] tell them what we were doing and what the physics was, what we were after. And in that case it was a meeting of Sigma Xi.
And where is the person who actually drew this cartoon?
He worked for the college.
With apologies to Pogo. Is this a unique document or is this the sort of treatment that you all got continuously?
Every rocket had its own cartoon, as far as I can remember.
Every rocket, every shoot?
Every series, anyway.
I see. This is one that survived.
I have one in my file somewhere. It may be identical to that.
I've seen this before.
How well does this sort of exaggeration characterize your personalities, how you worked together as a team, getting back to this sense of, what is a day in the life of your group like? Trying to reconstruct it.
Well, I would say that Byram was a perfectionist. He was tough on anybody who worked with our experiment, and they knew it. That's what that cartoon reflects. If they goofed, they would have to pay for it. Talbot was a great enthusiast. He was always bubbling over with enthusiasm. And it was my job to see that people understood what we were doing and why it was important.
It was part of my job, I always thought, to look for things that other people had overlooked.
What kinds of things did you find that other people had overlooked most frequently?
Oh, things like leaving the lens cap on. Things like not checking up on — in fact, once we'd gotten into the days of pointing controls, not looking over the shoulder of the person who programmed the pointing control.
What do you mean by that?
Oh, people, they would frequently get their geometry mixed up, and lined up pointing 180 degrees away. I think that was a very frequent failure.
You weren't as dependent on pointing controls in the beginning as were the disperse people, say in Tousey's group.
No, they were dependent from the very start. We didn't get into it for quite a while.
As the Aerobee era developed and matured, after pointing controls became available — which was in late '52, '53, when [William A. ] Rense made his first photographic detection of Lyman alpha — Tousey's group started flying multiple spectrographs, or designing grazing-incidence machines to go deeper into the ultraviolet, to try to get down to Lyman alpha as well. You started piggybacking small ionization chambers onto his spectrographs. How well did your two groups work? You mentioned that Lichtman came from Krause's group. Did he always remain in Krause's group, or was he detailed?
He was in our group. He was part of our group.
What about liaison with Tousey's group? Did you have any official liaison there?
It was very close.
I worked with Tousey's group very frequently. And with Rocketsonde too.
Were you all in Building 30 together?
No, we were in neighboring buildings. Rocketsonde was east and Tousey was west of us, but just by one building. They were all connected.
In scheduling for flights, did you have to work through the Rocketsonde group or through Tousey's group in order to get a flight, or were you pretty much independent by then?
Well, for the first one, the V-2 49, we had to do it through Krause's group. Afterwards it became more formalized at a higher level. We would make our request, and it would get approved, not by, let's say, any of our competition, but by the administration of the Laboratory, and by the administration of the program out at White Sands. The limit on what we did, once the Aerobee program started, was just our own capability to put together new payloads, attack new problems, on our own schedule.
Who decided, and how were these decisions made, to attack or define new problems? I know you started out in ionospheric physics, determining what part of the solar spectrum was responsible for the ionization balance in the F-2 region, in the D region, and these types of problems, but in the mid-fifties you started flying ultraviolet sensors for non-solar work. I'd be very interested to know if you worked as a group defining problems, or if it was all completely your initiative, Dr. Friedman?
We always had the idea that if there was an unexplored region of the spectrum, we should get at it as soon as we could, because all of our experience showed that we would make discoveries if we looked where nobody had looked before. So we did that early Aerobee to look at the luminescence of the sky in Lyman alpha. We got something there. We kept following up on that. It immediately became clear that we could fly small telescopes and do photometry of stars. A very obvious thing [was] to try to get the first map of the brightest ultraviolet stars in the sky, which we did.
What I'd like to do is carry you through a series of these visuals, talking about how you developed the ultraviolet program, the stellar ultraviolet program. As far as the detectors go, my understanding is that it was again using these side tubes, is that correct? Did you always use these side tubes?
Well, there are some pictures there that show the tube.
That's right. Possibly you could use them to point out what their characteristics were.
See, there we are. And that's the kind of tube we had on the table, with a window put in the side.
One of these.
And these were all sensitized to the Lyman alpha line?
For this experiment. In this schematic, we show these tubes on that metal block, and the collection of hypodermic tubing which defined the field of view. In these pictures of the tubes, as seen from outside the rocket, you can see the tubings looking out in different directions. There's an image that shows the collimators poking out of the side of the rocket.
Did you produce these plates and sets of collimated tubes at NRL in the machine shops? Again, was this simply a matter of sketching something out for a technician who would then machine it up to your specifications? Even by the mid-fifties?
Yes. I'm sure of that. It was more than a sketch, but —
We had our own small shop, and so we could do small things like that by direct contact with the machinist in the small shop. And even do it ourselves if we wanted to.
But major hardware was still.
This big block was made in the main shop.
That was made in the main shop. What was the procedure like for getting this built? Was this a laborious problem of internal memo writing? Trying to get this work done? Could you specify a date and have a reasonable assurance that it would be done by that date?
You could always specify a date, if the shop agreed that it would do it, it would get done. If they thought this was a reasonable request that they could accommodate.
I see. Did you have an astronomical interest yourself in any of these early Lyman alpha projects, stellar Lyman alpha? Or was this still another case of brain over tube?
Yes, I think it was still brain over tube as much as anything. My interests were different than Dr. Chubb's and Dr. Friedman's. I was interested in the mechanical performance of the rocket, because I knew nobody else would be. In general, that was the way I worked. I did things that nobody else wanted to do. But usually things that had to be done. We had to know how the rocket was pointing at the sun. Somebody had to go out and calibrate the aspect detector that looked at the sun.
Right. To what degree did any of you take part in the actual writing of papers, the analysis of the data?
I usually helped with the analysis of the data, but had nothing to do with writing the paper.
Well, I certainly did some writing, you know. It depends on which paper, how far along it might have been, what year.
I usually did just the analysis, you know, in the early days — just handed Talbot a bunch of plots of things that he would suggest, and he'd go ahead and write it.
We sort of took on different things. Now, you did all that study of Lyman alpha, and also X-ray variations, that was presented at [unintelligible]. As I remember, you wrote that up completely.
Yes, that's right, I did. That was 1960. So I got kind of side tracked there in the beginning, because I began working on solar flares. I remember, one of the things we wanted to know was what would be the probability of a flare occurring if we were ready to launch a rocket at the time.
You also did all that radio fadeout.
For those receivers.
Yes. Well, in general, we wanted to study the ionospheric effects of flares, and the phenomenon of the short wave radio fade out. We spent a lot of time working on that. But this was not, I mean, it was different from the astronomy work that they were doing, night-time astronomy work that they were doing from rockets.
Well, once the night-time astronomy, as you put it, started, you had at least a minimum of two very different scientific agendas within the group. I'd be interested to know how you allocated manpower and support, and, in terms of your own interests, your evolving interests in both stellar astronomy and still solar astronomy and ionospheric physics. In fact there were three ongoing issues here. Possibly we should take this up in context of the IGY, because all of you were very much involved in it. All of your expeditions were done in the context of IGY, is that not right?
Well, everything we did under IGY auspices was solar physics; nothing in the IGY that related to galactic astronomy. And the biggest problem, from our point of view, was determining the mechanism of sudden ionospheric disturbances — was it X-rays or ultraviolet from the sun that produced the SID? The general idea in the community of astrophysicists and ionospheric physicists was that it was ultraviolet — in the most naive way. The strongest emission line on the sun was Lyman alpha. We knew that in the optical range H alpha brightened by a very large factor in a flare. Lyman alpha produced the D region. That's where absorption would take place to produce an SID, so why not expect a very large burst of Lyman alpha in a flare? We made some calculations, and Talbot and I published a paper which showed that that was kind of absurd, that you would require an increase in Lyman alpha that was astrophysically impossible, but it would take a rather modest increase in X-rays to do the trick. To us that seemed very simple, and we went ahead and designed these IGY experiments, the San Diego Hi and St Nicholas Island to prove it, and we did. I remember when we published our first results out of San Diego Hi, immediately there was a contradiction by [James Walter]Warwick and [Harold P. ] Zirin in Nature, said that these fellows are absolutely wrong, Lyman alpha is an entirely reasonable explanation of the fadeout. It took a while, before our results persuaded the community that the flare mechanism was an X-ray flash.
It really took Solrad.
Yes, it was Solrad that …
Nailed it down, anyway.
Yes, they could always say that we never got up there in time to see the ultraviolet flash, it was over before the...
That was one of the arguments.
So the ultraviolet flash, in the life of a flare, preceded the X-ray?
But we showed theoretically that the kind of X-rays, the intensities we were measuring, at the levels at which they occurred, were exactly right to produce the ionospheric effect. A rather simply theory.
What effect, if any, did this outside criticism have upon the institutional support at any time, say, from someone like Zirin who was well established as well at Mount Wilson [Observatory] at that time?
They very quickly became a small minority, I think within a year, as we repeated observations. The case got very strong.
Does the X-ray realm still sound unfamiliar to most traditional astronomers, that they would reject out of hand anything that was interpreted as an X-ray event?
I think that's true.
How did that make you feel, as far as being part of an intellectual community? Did it bother any one of you or concern you at all?
Up to that point, we thought of ourselves as physicists. We worked in solar physics and ionospheric physics, and we hadn't moved up into galactic astronomy, so we had a community of physicists of that type who reacted sympathetically to what we were doing.
Even Goudschmitt who questioned your publishing in the Physical Review — did you continue to publish in the Physical Review, or was it in the geophysics journals, that sort of thing?
I think we went over to Geophysics and APJ and just stayed with those journals.
Yes. You were working, developing an interest in night sky or galactic Lyman alpha emission, beginning an interest in solar flare phenomena, ionosphere physics — your group was obviously growing. Did each one of you become managers of subgroups within the astronomy-related or scientific or basic research-related activities of the branch? How did things evolve?
I don't think it really worked that way. I think we just developed teams, addressed individual projects. A person would be a member of a team, and be a floating member coming in and going out depending on what the needs were. When that project was over, he could become a team member in something else. Now, that doesn't mean it didn't evolve into different sections; eventually Bob became the head of our solar physics section many years later, but that grew out of the satellite work and reorganization within the lab. But this team structure, where you might well be a member of several teams, is really the way projects were done.
Could you identify, let's say in the mid-fifties, as you started the night sky work, which teams were in existence?
Well, I guess there was really only one team then, I think, wasn't there?
That's what I remember.
I think things were simple enough that there was really just one team doing rocket work.
We started to focus in smaller units. Out of the San Diego High observations we got an inkling of the possibility of a galactic X-ray background, and Jim [James Edward] Kupperian [Jr. ] and I wanted to follow up on that. There was another group, [Albert] Boggess [III], [Richard] Milligan and Kupperian, who wanted to do ultraviolet astronomy, and they got this early result that seemed to indicate the existence of large Stromgren sphere around Alpha Virginis, Spica. Ted Byram and Talbot Chubb were already doing these surveys of the ultraviolet stellar brightnesses, and they immediately were uncomfortable with that result of Kupperian, Milligan and Boggess, so I think their focus was concentrated on proving or disproving the correctness of that observation
Did that create any kind of tension within the group, one part of the group disagreeing with the interpretation of another?
Well, that group moved out to N[ational] A[eronautics and] S[pace] A[dministration]. To Goddard [Space Flight Center].
Well, that's true, but I'm thinking of the period of San Diego Hi, which is 1956. The Lyman alpha night sky work which was started in '55 and continued after that all of course developed during this period.
I'm not sure that Boggess and Milligan were in on the '55 work, were they?
Because I presented that at the, at an [United States] Air Force meeting.
It was Kupperian and Chubb, Byram and myself, who were the principal spokesmen for the astronomy area.
The thing is, I think, this was an era really of exploration and adventure. I'm not sure we're really getting that across. Every time you flew with new detectors or new eyes, under new circumstances, you would see something different. It was really a very exciting period, and going to the night sky was just — here was an opportunity to fly at night. We just had a fly-along experiment, as I remember, on the first time. And we had also developed these detectors where they were much, much more sensitive than required to do solar work, and so it was a chance to open up a new frontier. We didn't know where it was going to lead. We didn't know we were going to find a night Lyman alpha glow all over the sky. In fact, we didn't know what to think when we saw all these high signals. Our tubes were saturated about 30 times, I would say, that first one.
Is this exploratory mode well represented by the fact that as I look out at the tubes here, I see no two alike, virtually. Very few, from what I see. There are differences in every single one of them.
Well, I think that's more of an evolutionary sequence. On any one rocket flight, most of the tubes would have been more or less of one kind. The Viking flight, they were almost all that small pillbox type.
Why was that?
Why? It's a very compact arrangement that permitted a lot of tubes to be flown together, and they were flown with a free-flow arrangement which avoided a lot of the aging problems, as I remember.
Free-flow. We kept supplying a gas — was that right? I think it was.
There were a certain number of them.
I mean, they weren't flowing out through the windows, but even with the windows — some of them had windows, most of them had windows — but even the ones without windows, I sort of feel maybe we flowed gas in and out, I'm not sure I remember.
Is that what this appendage here is?
No, that's a filled-off tube.
This one was actually filled and sealed off. That's the filling — the free-flow type tubes whould have an inlet and an outlet so the gas could be continually flowed through.
Of the tubes displayed. This is a small sample of the devices, the variety. This is nothing compare to the stockpile we had, of all sorts of shapes and geometries.
I'm fascinated with how you came to all of these different shapes and geometries. Every time you planned a new flight, you would re-design your tubes, literally?
We kept trying new designs and improving things, and just changing things for the spirit of changing, sometimes. Somebody would have an idea and he would try it, and that would generate a pool of an odd geometry.
The thing is, a geiger counter works if nothing goes wrong with it, basically. When the switch from the pillbox to the cylindrical tube — which is in a sense a switch back to a cylindrical tube, because the electric—the geometry inside the tube is more favorable and it's easier to build a better counter. The fact that we did not use end-window tubes in a lot of our work in the early days, like the BS-1, is because of the dead zone in the front of the tube. For X-rays that doesn't make much difference, but in ultraviolet, much of the ultraviolet radiation may be absorbed within the first fraction of a millimeter of the front of the tube, so if you want high efficiency, you go to a tube like these side-window tubes.
So what you're saying is that the anode, just below the mica window there, there's a few millimeters of gas in there that would absorb the Lyman alpha.
Would absorb Lyman alpha, and in ultraviolet, you're talking about a single electron being produced. In X-ray you maybe get 20 or 30 electrons produced, so you can have some inefficiency in a geiger counter tube in X-rays and still get a count. But you really lose in the ultraviolet, and for the star work you had to go to this other kind of an approach But there was always a lot of unfinished business. The first V-2 49 X-ray results indicated that the sun was a strong X-ray source, relatively speaking, and when we started firing Aerobee 7, 8, 9 and 10 and 14, 15 and 16, we just didn't receive. We didn't get those strong X-rays. We got X-rays, but they were very, very weak compared to what was recorded in V-2 49, so this really left a lot of unfinished business. What it meant was that we were seeing the solar cycle dependence, so all through the fifties we were learning about the solar variation of X-rays, with the solar cycle and with solar activity. All our flights would be coordinated with observations of the solar corona from Sacramento Peak Observatory, so it was—and then in the ultraviolet program, after the nebular glow was published by Kupperian, Milligan and Boggess — part of our group — a lot of our efforts were to really again clearly show the right situation, which was that there was no glow. There again, just like the argument on the flares that Lyman alpha flash occurred before the rocket got up to altitude, in the nebular glow case, it was a question of, well, maybe this glow existed only in a very narrow wavelength band right next to the Lyman alpha line. It took us several years to get a recording of a star in a tube that was sensitive right across the Lyman alpha line, and showed that there was absolutely no halo around that star. And these focused telescopes that we went into in that era were just ideal for showing that point.
These are the ones you're talking about that had the 4 and 6-inch mirrors?
Dr. Friedman, this is you?
That's Joe Nemecek.
What exactly are you doing at this point? You have one of these concave, presumably parabolic mirrors, and all of these openings here were intended to.
To accommodate those mirrors.
The mirrors not only give you a collimated beam or at least a focused beam, they collected light from the area far greater than the detector size.
That was the purpose of these larger ones?
I think there are some other pictures in that folder, with Ted Byram.
Yes, there are.
Installing some of the very first ones.
There's the very first telescope that we flew.
Show it to the television people.
About when was that? What are you doing at this point here?
I was installing an ion chamber at the focus of a Newtonian telescope. It was an off-centered Newtonian telescope.
Oh yes, I remember that.
This is the outside of the Aerobee.
This is the part, and the mirrors would be back in here?
And the Newtonian focus would be right here, and you're putting in the connectors.
Yes. About those.
Is that one of the tubes, right there?
Yes, that is, see, one of these.
These are end windows again, but by that time we'd made them sensitive in the front.
Yes, but they're gas-gain.
Gas-gain ion chambers.
They're very stubby.
I think there was never anything published from that, but it actually worked and was very well focused. I still have a picture of the response.
Now, when you look at one of these tubes, there are a lot of things to look at and I'd like to ask you about them. This one has a very long copper appendage to it. This one is very short, comes out from the side.
They were all short by the time they got to flight. The length was so that you could re-fill it a dozen times or so.
Every time you filled it, there's a crimp in the...
And it got shortened. For flight you pinched it off much shorter. For various — that's a recovered one, that one flew, and this one flew.
How can you tell that they actually flew?
Because they're all covered with glyptal, and that was a fitting that was only used in flight.
I think that's pretty well.
Did you have the same problem stabilizing these tubes as you did the others, especially when you worked with eight to ten of these in one Aerobee?
Did they all have to have the same response?
They all had to be calibrated, and they were not identical, but they were stable.
Who decided what kind of seal was correct for this, and what the geometry was for these kinds of tubes?
Well, Bob really pioneered the silver chloride seal, which is the reason that the tubes are stable.
Would you talk a little bit about that whole process?
On one of the early experiments with the small rockets, when we went into the arctic, on the Atka, we found that the lithium fluoride windows, which we were trying to use to look at ultraviolet from the night sky, cracked, and pulled off. We had, I guess we had 100 percent failure in that flight. The next year, we had another flight scheduled, so we adapted a design of a — someone else had developed, for our particular use, and this was the first type tube that we put it on. It's a chromine, short chromine shell. This is a silver spinning, which is — a cross-section of the edge is in the shape of U, so it's cemented to the outside here. It kind of re-enters then in a tapered fashion. The lithium fluoride window is in turn tapered and coated with liquid bright platinum, which is baked on, and then silver chloride is used as a cement, to cement the platinized lithium chloride to the silver. That was quite successful. We were able to subject this to liquid nitrogen temperatures and it maintained the seal. So from that, we flew them the next year and they survived, and went through a couple of alterations and finally ended up with a simpler silver seal, but the principle is the same. The outer part is silver, and the lithium fluoride window or crystalline window is platinized and sealed with silver chloride. Silver chloride decomposed, though, and so we usually painted the silver chloride with epoxy, just to protect it in the air.
The epoxy is the dark brown material?
Yes, that's the brownish material. The silver chloride would turn black, you know, like photographic emulsion, turn black after a while.
Are all of these then characteristic not only of the ultraviolet tubes that were flown, but the ones that you flew for the various expeditions? San Diego High and later on? Was this a major design refinement?
These gas-gain ion chambers, which were an NRL specialty, were only used in the ultraviolet telescope experiments, and some of George [Robert] Carruthers' work subsequently, but not much there, and only for calibrations. But these gas-gain ion chambers are devices which operate with an internal gain, gas-gain of about 3000 or so. So for every photon, every free electron produced inside, you talked about 3000 on the internal wire, and that's kind of a unique type of photon counter. The thing was very well adapted to this usage.
The same type is used for solar work, too, but because the solar Lyman alpha is so much more intense, gas gain wasn't required, and so we used, say, this type of detector, which does not have a ceramic back, the special ceramic back.
These had one other characteristic. Besides having gas gain, this sleeve goes all through the ceramic, and forms a guard ring, so that there's no leakage from where'd we apply the high voltage to the cathode, and the anode, and the guard ring operated at ground.
Right, sort of like a co-ax system.
Yes, and that eliminated any leakage current from that high voltage.
It was a very thick insulator.
Well, no, the guard ring actually collected whatever leaked.
That was the ground.
This was very important for the [???]
And this did not have that.
This one did not have it.
No, I made it.
Doubt if we could have used it on that.
Well, at this point, you were building these tubes for the ultraviolet detectors, and they continued to fly for a good number of years in Aerobees. I know that the Aerobees — we see some of your first large stellar X-ray experiments on the collimated ones in the sixties — still have the UV sensors on them as well. Did the purpose of the sensors change? Did what you intended to do with UV sensors change, as you got through the H alpha glow problem? What problems did you attack?
Well, these were used to do stellar photometry — how bright are the stars at 1500 angstroms, 1300 angstroms, and 1080 angstroms? And after we had completed that study, and also cleaned up the nebular glow problem — during this period of time, we had a [E. O.].Hulburt Center fellow, George Carruthers, who had come in and spent about two years in the laboratory developing a series of image converters, so [???]
This is already about 1960?
I guess so. So as soon as his converters were really in a position to fly, we sort of felt that the next greater progress would be done with UV imaging, and we sort of turned over the ultraviolet stellar program to George.
And you concentrated in X-ray.
Yes. George was in our group. But he was the team. Actually he and Dave [David Thane] King and Harry Merchant.
In finishing up the ultraviolet, then, we should still talk about the geocorona, the series that led to the identification of the earth's hydrogen corona. As I understand it, it started with the first detection of the sky radiation in Lyman alpha in the early fifties — I mean the mid-fifties, '56, '55 — and continued on as you identified on various flights the fact that even as your Aerobee sensors looked down on the earth, you were still getting some Lyman alpha. And then there was the question as to just how extensive hydrogen was in space, and whether this is what you were picking up, or whether it was the nebular glows that you were picking up, and [the role] F[rancis] S[everin] Johnson played in the final interpretation. I'd like for you to carry through as a group to talk about how you developed different experiments, and your different analyses of what this radiation was, right up through the Ranger program that you had in 1960. I would be very happy to have your recollections of that. Maybe you could lead it off, Dr. Friedman.
Well, the first experiment was purely exploratory. We had a Lyman alpha detector with no collimator on it, and it showed an enormous signal in the night sky. We then put the hypodermic needles in front of the window.
So the very first one had no needles at all.
Had no collimators.
And as soon as we put a collimator on, we could map the distribution, and then it turned out that there was a shadow in the anti-solar direction, as though solar radiation flooding past the earth into the night sky was being back-scattered into the dark side. But that gas in the cone on the dark side of the earth was not being excited, so that the distribution actually showed a minimum in the anti-solar direction. The question then was, where was this hydrogen? Was it close to the earth? Or was it interplanetary hydrogen? I believe it was Frank Johnson who immediately took the position that it must be a geocorona, and the way to settle that question was to look at the profile of hydrogen Lyman alpha from the sun, and see if there is an absorption minimum in the middle of the solar line, which would indicate that hydrogen in the vicinity of the earth was absorbing the core of the Lyman alpha line from the sun. Now, Dr. Tousey's group, with DeWitt Purcell, I believe, preparing the instrument, went ahead and did that measurement and found the self-reversal in the Lyman alpha line, and it fit with the geocorona distribution.
Wasn't there also a question if it was interstellar, if it was all-pervading hydrogen medium, that there would be a Doppler effect that would reduce the ability of the hydrogen to recombine in one direction as opposed to another — if you actually traveled through the hydrogen, rather than having it carried with you?
Yes. If it were interstellar, we'd see a Doppler shift, which would carry it outside the bounds of the emission line.
That could only be determined by looking at the profile of the solar line, with great resolution.
So again, this was a problem in traditional spectroscopy.
That you could not solve yourself.
Well, we had the choice of how to make this measurement, and even at that time Tousey's mode of operation was photographic, and ours was electronic. We thought that we could electronically scan the profile of the line with great precision, but we deferred to Tousey, let him go ahead and make the photographic observation. [We] decided if it worked, that was fine, the problem was solved. If it didn't work, we would go ahead, and I think it was Don [Donald Charles] Morton and Tom Winters who had to do that measurement, but the instrument that Purcell put together worked very well, showed an excellent profile.
This was not anything that stimulated you to get into dispersive systems like the Bragg crystal spectrometer that you built for an Aerobee in 1960? This had nothing to do with it?
It wasn't connected with this. The X-ray problem was an old one. [Bengt] Edlen in Sweden had tried to explain the forbidden lines of the solar corona, the green line, the yellow line, the red line, in terms of forbidden transitions from highly ionized states of iron, calcium, nickel and so on, iron 14 and iron 13, and so on, and he indicated in that theory that the transitions from these highly excited states allowed transitions in the X-ray part of the spectrum, should be observable and could be resolved with a Bragg crystal spectrometer. So we flew a Bragg crystal spectrometer, and observed lines of oxygen 8 and iron 17 and so on, and they fit Edlen's calculated spectral lines very closely, with a very clean comparison. Before we did that spectrometer experiment, other people were trying to get at this business. I can't recall the name of the man at A[ir] F[orce] C[ambridge] R[esearch] L[aboratory].
[Hans] Hinteregger, probably.
No, it wasn't Hinteregger. There was somebody else who designed what seemed like a very simple X-ray camera, X-ray spectrograph, and he got a result which he immediately assumed was valid, and showed a solar X-ray spectrum, but it turned out that what he saw was a crazing in his film, and what he thought were spectral lines were entirely artifacts. Otherwise we knew immediately that the efficiency of his camera was so low that he couldn't possibly see a resolved spectrum out of the photometer fluxes, integrated fluxes that we had observed.
[Philip Chapin] Fisher did something like that.
Well, he did that with the stars.
Phil Fisher, yes, he had every hot star as an X-ray source, and that was just statistics, I think.
The AFCRL experiment consisted of wrapping a crystal on a cylinder, and letting the parallel light from the sun come in and hit this crystal, then at all the various angles around the circumference, and it would reflect those discrete wavelengths to a film that surrounded it. It was a very simple idea, and in the laboratory it was demonstrated that it worked, but it was entirely too insensitive to the sun.
That's different than what Hinteregger was doing. He was building spectrometers using his tungsten high work function tungsten cathode at that time.
But he flew it first on rockets as well. Let's finish up on the geocorona, though, because there is the story about how you got involved in Ranger, and I'd like to hear that story from you, and some of the interesting anecdotes of working with J[et] P[ropulsion] L[aboratory], and with others, in being able to piggy back onto Ranger, 1960, and as Ranger flew out to the moon. I guess you had an experiment that was to look back at the earth and to look at the geocoronoa. I imagine you, as the salesman, let's say, got your group onto Ranger. Is that a correct guess?
Well, I talked to Bill [William Hayward] Pickering at that time, and he was very sympathetic to doing the experiment, but the philosophy at JPL was that they were the only ones who knew how to do anything right, and we should simply let them do the experiment. We could provide the Lyman alpha detector to go at the focus of their mirror. Well, we did work out some accommodation with them, so that we could monitor the design of the instrument, and [???]
It seems to me, not long before flight, we found that they were putting negative high voltage instead of positive high voltage on the detectors. Do you remember that?
Do I remember it!
Were you the one that found it out?
Ted found it out.
What went on there?
Well, it seems to me that they were supposed to launch on a Thursday.
This is in 1960.
Yes. And they cancelled at the last second, and we got a telephone call telling us that our detectors were no good, and that we'd better get down there and fix them. Bring them some fresh detectors. Dr. Chubb spent the weekend refilling and testing ion chambers, and I went to Florida with a couple of detectors that had been around for a while and were known to be stable, and I probed around in the instrument, and it wouldn't — it certainly didn't work. I finally took the detector out, and aimed a hydrogen lamp at it to see if it had any sensitivity, and it seemed OK. And I put everything back together again, and was checking to see if I had the high voltage on, and I was just using an ordinary Simpson meter — I didn't have an electrostatic meter. I just touched the meter to the high voltage to see if it was there, because it was going to go off scale. It did go off scale — in the wrong direction! So JPL spent the rest of that weekend rebuilding the experiment, putting the high voltage where it belonged.
How did they manage to reverse it? This is positive to negative, you're talking about?
Yes. They said, well, it's a lot easier to make an electrometer sensitive if the polarity is the opposite of what we wanted to use.
I see. But they never checked back with you as to what the detector required?
No. We told them what it required. It required a negative high voltage on the cathode.
Who were the people you were working with, what level?
I don't know their names. They were engineers with JPL. It's been so long, I don't remember any of that.
This is the camera, the detector.
It's a beautiful device.
Yes (crosstalk). They did a good job.
…that it cost a million dollars. We had never played with that kind of money before.
It was quite a large device. I think if one were to look at it in the Ranger itself — is this it, right here in the middle? As the Ranger went out toward the moon, this would look back at the earth?
So was it very much like your ultraviolet Aerobee detectors, with the mirror and a detector.
Very much like that.
Mapped the sky. Didn't it rock?
It rocked, yes.
It rocked back across and mapped the earth.
Mapped the earth, that's what I meant.
That's this adjustment here.
It was essentially the same device, except that it was 10 inches in diameter, and the largest ones that Ted Byram had flown were 6 inches.
It was sort of a cultural shock for us to work in that kind of an environment.
What was different?
Well, documentation, paperwork, not much experimenting with the hardware so much. It's just a big operation, compared to what our little rockets were.
This wasn't your first contact with a satellite or probe?
Well, working with the Solrad satellite program, you know, that was in-house, and sure, there was a lot of testing — there was a lot of testing with that but one was sort of intimately associated with it. And there was not a lot of paperwork in the early days, was there, Bob?
No. The philosophy was just to test it and test it and test it until you were convinced that it was going to work.
There was no real philosophical conflict there. In the early days of the JPL space program, everything was defined very tightly by specifications, and not in a necessarily best manner. I mean, the way of keeping away from trouble was to put very tight specifications on experimental systems — that they not generate any noise on lines, rather than having the specifications that a system work in the presence of a certain amount of noise. They were in the learning process, too, and we just were approaching it, I guess, from opposite ends, [and] had a little trouble with communication.
They had not been building instrumentation for rockets during the fifties, not to any degree.
I don't think so.
As NRL did. I'm curious, though, you said that they insisted on building it. Did they also design the entire system? They designed it. You simply gave them a detector and they designed around it?
That's what I recall.
Did you have input?
I don't know. I guess we started with the telescopes.
I think all we required was that they make a 10 inch mirror and accommodate our detector at the focus.
With an ability to scan.
Provide high voltage and metering.
Now, from my records, at least that I found, both of the Ranger flights in 1960 were launch failures. Did this fly on a later Ranger?
No. It was one of those that you just mentioned. As I remember, the Aegena went into a parking orbit and never came out.
So it never got away from the earth.
We never got any.
There's another interesting thing about this that I just recalled, and that is that they wanted to sterilize these mirrors, did they not? Because they felt this might impact the moon and cause some contamination from earth-generated organisms, and it seems to me we went around and around about the best way of sterilizing that thing.
I don't remember.
It was ethelene oxide I think that they were trying to use. I think that was it.
Used on Martian missions.
Were you consulted at every stage of development of this thing, then? Was that something that concerned you or concerned the efficacy of the instrument, to worry about its sterilization?
I don't think we were — I know I wasn't consulted. The first I heard that there was anything going on really was that the detectors didn't work.
I think the sterilization was just something that descended upon us. We had nothing to say about it.
No. I was indifferent to the sterilization problem, but the pressure out of the biological community was growing very rapidly.
When did you first get a picture of the geocorona? Was that not until Apollo?
That [was] George Carruthers' Apollo 16 camera.
From the moon.
From the moon.
Quite a few years later.
Of course, we did, we knew almost from the beginning that some of the hydrogen was from the earth, because we would see a segment looking down, and that had to be backscatter, so that had to be hydrogen in the earth's atmosphere.
So you knew it was there, but...
We knew it was there.
Let's move back into San Diego Hi, and talk about what you might call your rugged individualism, of shooting these rockoons off, and the whole problem of coordinating a system that was designed to detect solar flares. Here you provided a set of very interesting photographs of the rockoons. I'd be interested in how the rockoons came to be developed by your group, based upon designs. Here's a shipboard photograph of your group. How did you modify the payloads and the detectors for the rockoons? Because there you were talking about extremely small rockets.
Yes. The rockoon technique was developed by van Allen, and we simply used everything that we could learn from him. The idea of the rockoon was that it could carry the rocket to about 80,000 feet and then fire it from that altitude, and it wouldn't require any really dynamically clean nose cone, so we were able to build it in this form.
This entire package here is the telemetry and the electronics, everything. Is this very small — is this the tube itself? This little small tube?
No, that was an entrance to a pressure switch, that had to do with arming it and firing the rocket, so that it could not be fired until it reached a certain altitude.
These inside-looking tubes? These were the tubes. What was the whole procedure like in developing the San Diego High — might I call it an expedition? Was this the first of your major expeditions?
Yes, it was. It was the first time we went to sea to launch rockets. And we had never flown a rockoon except for some experience that Bob Kreplin had up off Greenland, with the launches from the ice breakers, [U. S. S.] East Wind and Atka and the LSD Ashland. In a sense Bob and Jim Kupperian initiated our group into that kind of activity, and got us ready to go on San Diego Hi.
The name came from the location? I take it you were off San Diego?
Well, it was the wind system. Meteorologists called it the San Diego Hi.
It was supposed to be nice clear weather.
They had it all wrong, it turned out.
The winds blew in the opposite direction from what they predicted.
I think out of the two weeks we were there, we saw the sun one day.
We had a solar telescope on board which we were going to use to monitor the sun, and never got a look at the sun.
That wasn't designed to compensate for the vibration of the ship, and...
That's a slight oversight.
As soon as they started the engines, we found out that it wouldn't work at all. But we did do something which saved — Sacramento Peak Observatory and the High Altitude Observatory would talk to each other by short wave radio, once a day, and compare notes on the sun, what was going on, and so we somehow arranged to operate some of the ship's transmitter, no, just a receiver, I believe, at that same frequency. I don't remember whether we talked to them or not, but anyway, they agreed to give us flare reports and give us an alert if a flare was imminent, and it was on the basis of one of those reports that we were able to fly, I guess, the one rocket that we flew in a solar flare.
Ted Byram was at Mount Wilson during that period.
That was the St. Nicholas, that was the next year.
Yes, the St. Nick. I'm sorry.
Were the purposes of the two expeditions the same, to get a solar flare?
Was the San Diego Hi the one where you found the residual 50 KeV background?
That's right, in 1956.
Did you design your experiments so that you would pick up these things, or was that just pure serendipity?
No, we designed to see what we expected a solar flare to produce. And we were close to being correct.
But you found something you also didn't expect.
Oh, in the high-energy X-ray range we found signals on days when there were no flares, while the rocket was hanging, while the rocket was launched to cut it down. We couldn't let the rocket disappear, get out of range, for fear that it might land on some inhabited property, and so any time the rocket was beginning to drift toward the end of our firing range, we had to fire it, and on those occasions, we got what seemed to be a background radiation, with a spectrum that was rising very rapidly to soft wavelengths, and we couldn't be sure that it was not solar radiation, even though it was clear the detector was not looking directly at the sun. But it could have been looking near the sun. These were firings during daylight. We thought when we saw these results that we could only make a clear-cut case if we did the same thing at night, and saw the same flux of X-rays. We didn't get around to doing that.
You did not?
Who actually went to the trouble — I know, because you were doing a lot of different things at this time, but who would go through the trouble of looking at data that you would be returning from a rocket sent up just to get rid of the rocket?
We always examined it. That's typical.
Is this a typical scene? This was aboard ship.
Yes. And that's the instrument payload there.
This is on the left.
That wouldn't normally be sitting on the table you were working with.
So this is…
…but this is typical. I always wanted to see what happened.
I don't recognize everybody.
Who are some of these? Dr. Friedman is here, who are some of the others?
And this is Talbot, here. Kupperian, [Douglas P. ] McNutt.
No, the other fellow is a fellow who worked with us I think for a while, and ended back in the lab in a different position. Maybe I've got the wrong fellow.
Would you traditionally, after a shoot, get the telemetry, spread it out on the table and all of you have a look at it?
That was the nice thing about those experiments. The record came out on an S-line Angus paper recorder. You roll it out on the war room table, and you scan down the record, and you could see exactly what had happened, almost a visual analysis in a few minutes.
What was the [plan] on the San Diego Hi, and also for the St Nicholas? You sent up a rockoon and let it sit there until hopefully you had report of a flare? Did you do this every day?
Yes, that was the idea. In the morning we'd launch one, and the winds would be generally unfavorable, and the [U. S. S.] Colonial would race along at flank speed trying to keep up with the balloon, and eventually when we came within, about to lose it, we'd have to fire it.
The Colonial could do about 15 knots. We had a destroyer, the [U. S. S.] Perkins, which could do about 25 knots, so the Perkins would get way out front after the balloon, and we would come along at a slow pace. We learned that the winds would reverse during the day, so that we could let the balloon get quite a long distance away from us and then it would come back to us.
In a rockoon you have a good number of different components. You have the balloon. Are these telemetries?
No, those are radar reflectors.
Corner reflectors. The rocket itself, a Deacon, and …
The firing box hanging below the Deacon
And the batteries. They had to be kept warm, so that was a big insulated pack.
I see. Who had responsibilities for all of the different units, the Navy people primarily or people from your group? Worrying about the balloon.
We had a balloon contractor, Winzen Corporation.
Now, you didn't follow up on the night time observations. Why was that?
Well, we did follow up. In 1957, we put an X-ray detector on an Aerobee, and judging by the way the spectrum was climbing, to longer wavelengths, we felt that if we had a detector which would look at the 10 angstrom range, 1 to 10 angstroms, we would be able to see this effect with a small detector. So we flew one of our typical X-ray counters with, I imagine it was a mica window. Do you remember, Ted?
I think it was a mica window.
A mica window on that Aerobee. This is the same one that did the ultraviolet experiment we were talking about earlier. We got a good X-ray signal. It was well modulated. We had no collimator on that detector. But Talbot's recollection is that the signal was in the direction to the south, and we suspect now that we were seeing Sco X-1 in that early experiment.
This is '57?
I don't think we ever thought of ourselves as being in a race with anybody at that time either, you know. We didn't publish things unless we had pretty much confidence in them.
We thought we were all alone. Now, it turned out that the group at American Science and Engineering [A. S & E.] had this contract — but that came later — with the Air Force to look for X-ray fluorescence from the moon. And that was the earliest inkling we had that there were some other groups looking at X-rays, and my attitude was, well, that's absurd, they're never going to see any fluorescent X-rays from the moon. So I wasn't concerned that we were being too slow to follow up.
This was already 1961, '62.
Yes. Now, in the interim, we did the eclipse expedition, which kept us all very busy in '58. The group that had the ultraviolet experiment, Kupperian, Milligan and Boggess, transferred to NASA. And they took the telemetry records with them. There was some friction between our groups at that point, those who went to NASA and those who stayed behind. And I can't recall now why we didn't keep a record at NRL. They took the telemetry with them. Why we didn't insist on hanging onto it.
This is the record of the 1957 flight.
Yes. Which we know had a good X-ray signal. And our attitude was, well, if they've gone off with the telemetry records, we'll fly another experiment within a year, do it again. My recollection is, we did it again, and didn't get a signal.
Do others have similar recollections, is that the way it sort of falls out?
I'm very vague.
I'm very vague too, but we probably did.
I think for one thing, Talbot and Ted were terribly concerned about the ultraviolet experiment. They wanted to get that straight and get that published, which they did, but it took most of their time during that period. I became rather seriously ill in '58, which sort of put me out of business for half a year, and that was another time loss. I did, in 1959, talk with Fred Hoyle about the '56 observations, because by then he and Tommy [Thomas] Gold had published a very interesting and insightful paper about the possibility of X-rays from clusters of galaxies. Their idea was that — rather from intergalactic gas — their idea was that the decay of the neutron in their continuous creation theory.
Steady state theory.
Would produce X-rays of the type we had on our record in '56, and that these X-rays would force a condensation of galaxies into clusters.
Of course, the other thing is that in 1959, we had small rockets at Point Arguela, and they did show increasing soft flux when there were no flares around, not looking at the sun, no flares on the sun.
Yes, we got these data.
So we had that other continuous X-ray data in '59, which you published and you talked about at one of the — a couple of meetings.
I presented that meeting, that data. Let's see, we had results from '56 which I gave at the I[nternational]A[stronomical] U[nion] general assembly in Moscow in '58. And then we had repeated observations in the [???]
We had the simulator work in '59.
And there was some ionospheric group that you presented. When was that?
There was an A[tlantic] G[roup] A[dvanced] R[esearch and] D[evelopment].
AGARD, that's right.
Yes. And I wrote a paper there in which the conclusion was that these X-rays we observed could be within the magnetosphere. That was '59 and we already knew of the van Allen belts. That they could be from a cosmic source, and Phil [Philip Warren] Mange at my request did a calculation of what the X-ray intensity might be from particles in the van Allen belt, and it came out by a factor of 100 too short of what we observed. So I think we had made the case for possibility, a strong possibility that these were X-rays of cosmic origin.
But not necessarily discrete.
Those were not discrete those were just a continuous distribution.
But that's of course what you could see.
Yes, that's what we saw in '59.
Now, I also wrote a paper for Scientific American then, in which I suggested that we might find discrete sources like the Crab Nebula and said then that we would undertake a program to look for discrete sources. And in that time frame, we did try to develop much more sensitive counters, and the one which we finally flew in '63 was of that type.
We had that array of Amperex counters.
This is the one you're referring to.
We had another approach, remember those end-window Amperex counters that had mica windows?
Isn't that it?
No, those, isn't that the one with the common, no, that's where we had a common window over the whole.
A beryllium window, yes.
That's the one that was the Sco XR-1 measurement. But either on the same flight or an earlier flight, we had arrays of end-window.
It was on the same flight.
I think it was the same flight.
Were these built after the A. S. & E. observations were made, or pretty much at the same time? Parallel to it?
Probably pretty much at the same time, because I think we flew this experiment about three months after they announced their results.
And it took us much longer than that to prepare a rocket schedule and build all the detectors, so we were on our way to doing this before they announced their results.
This is a close-up of the Aerobee you had at — would there be four detectors, all the way around?
Just two. And then your UV detectors above it. What were they used for primarily?
Those were these experiments.
They were continuing the photometry survey of early type stars.
So you in fact were, both of you, Mr. Byram, and Dr. Chubb, were still working very much in the ultraviolet. Who was preparing the tubes and working here in the X-ray? Were you doing that as well, or was that you, Dr. Friedman, or others?
I suppose I was pushing that, although my recollection is that Talbot did work particularly on these point anode counters.
Yes, I remember that.
We had, you know, we had a graduate student, Stu [C. Stuart] Bowyer from Catholic University who, we sort of had him put this thing together, because as I remember, that design was pretty much what we had outlined, but [???]
Is this the same honeycomb type of collimator as on this?
How well did that collimator — what kind of a field of view did that provide?
About 7 degrees.
There was a fill width, 3 degrees half maximum. But it was good enough so that we could identify Sco X-1 to within a quarter of a degree.
How did you make that identification? I know that you were again responsible for aspect. What was the division of labor there? You were using the ultraviolet data for aspect, or am I wrong?
Yes, we used the ultraviolet data, and one of the other pictures showed, we had a — there's a small visible-light photometer [that] sticks out and picks up all the visible stars, down to about 5th magnitude, and we used that.