AVS Historical Persons | Albert Nerken - 1990

Albert Nerken - 1990

Oral History Interview with Al Nerken

Interviewed by William C. (Bill) Brown, 1990
BROWN: Al, what we'd like to do with this interview is to just get some of your thoughts about the early days of vacuum technology and things like that, and what evolved. So, if you would. You just start in where you want and go.

nerken.jpgNERKEN: Thinking back to the first year that Frank Raible and I got into the business of making leak detectors, I had the responsibility for the mechanical. Looking around for valves, there were no vacuum valves, no bellows seal valves available at the time. I used a converted refrigerator valve, which had an old diaphragm. It was pretty bad, but that was the best I could do. Shortly after that, we were very fortunate in getting in touch with Dr. William Libben1 at Brookhaven National Laboratory, who pointed out that they were using a bar stock2 valve with bellows. He showed us the design, which we improved, of course. It consisted of bar stock with a bellows attached to a cap. The cap was soft-soldered to the body. If you turned the valve too hard, you would push the cap off of the body. We introduced the idea of an O-ring and four screws at the corners of the bar stock. And of course, those proved to be extremely successful types of valves. I think they were the first ones that were commercially offered. That's in '46. [Chuckles]. So, I think that these were bar stock valves, bellows-sealed, offered commercially. The plumbing was still pretty elementary.

The next thing that I can think of in the way of changes had to do with the leak detector itself. As Professor Nier had designed it, there was something called the repeller that was necessary for its functioning. It had a positive voltage on it. But unfortunately, that positive voltage attracted electrons, which caused the deposition of a semiconducting carbonaceous deposit, and that ruined the field of the repeller. You could do something about it, but sooner or later, you were forced to take the source out of the spectrometer and clean that plate. We came up with the idea of putting a DC-heated, or maybe even an AC-heated, wire rib in place of a solid plate, and that was hot enough to burn off anything that was deposited. So, the heated source came into being.

BROWN: Now, this was the mass spectrometer? The way you had your heated filament in your trap, and the gas came in, you ionized it, you accelerated it? It was all just like you said?

NERKEN: Yeah. The repeller pushed it out of the ionization chamber. That, however, released deposits of the - If you had a nonconducting film, electrons built up on there and negated your positive field. So that was one improvement.

BROWN: How about your collector? 

NERKEN: That's something I'd forgotten about. We originally were using a Victoreen3 tube as the first stage of the amplifier. As I recall, we had a drawer full of tubes that were microphonic, so about one out of ten Victoreen tubes were suitable for use an electrometer. And then, some years later - I don't remember just exactly when, but some time in the '50s - Raytheon came out with a taut wire filament, a little acorn tube, and that really solved our problems.

BROWN: Is it true that Victoreen, if you wanted to select these, they would select them for you, but they would charge you for the price of ten tubes?

NERKEN: All I remember is a drawer full of Victoreen tubes that were microphonic. The next thing that occurred, a Dr. Gerhart Lewin either wrote an article or brought to our attention, a letter to the editor of one of those physics magazines, indicating that iridium filaments would not burnout. Coated iridium. So we decided to investigate that, and I worked on it. I started looking into the manufacturer, and the only iridium I could get at the time was from a well-known company, whose name I forget now, but they were forming their wires by sintering iridium powder. We tried using that; they broke apart when you looked at them! So I was fortunate enough at that time to get in touch with a well-known wire company, whose name I forget, who had been producing wires for scientific purposes. They had just completed some development for a military outfit, and they could produce a flat ribbon of fairly ductile iridium. We got a hold of some of that and had some problems finding out how to bend it, but then we coated it via electrophoretic methods with uranium oxide, I guess. Those proved to be very, very good. They didn't burn out. They had some other defects, but this was the introduction in the mid-'50s, I guess, of the non-burnout gauge.

The next thing that occurs to me is that we figured that now that we had a gauge, we ought to have a circuit to go with it. The circuits available at that time for measuring the output of ionization gauges were highly unsatisfactory. I think there were Wheatstone bridge types of things, vacuum tube bridges. The constancy of the tubes would change and the bridge would wander. So, we had at that time a physicist named John Peters who sat down and developed a circuit, which for reasons I don't recall, did not prove satisfactory. Then a brilliant idea occurred to me, and I'll take credit for it. [Laughs] I was discussing the problem with my partner, Frank Raible, and said, "Hey, Frank, what is it exactly that we're measuring in an ionization gauge?" I said, "It's ions. Positive ions." He said "yeah". I said "what are we measuring in a leak detector, in the mass spectrometer tube; positive ions. So, why the hell don't we use the same type of negative feedback DC circuit for measuring the output of an ionization gauge?" That was the start of the DC ionization gauge circuit which really was a big help. If we go by the number of units sold, it was very much needed.

BROWN: Let's talk a little about the leak detector per se, the Veeco leak detector and some of the trials and tribulations you might have had. You mentioned the soft solder. Some of the people at that time, another company, whose name I won't mention, was using soft solder and had non-good vacuum materials but Veeco seemed to have a reputation for a better vacuum system. How did you accomplish that?

NERKEN: Mainly, I never did feel that the leak detector required the kind of vacuum that made stainless steel a necessity. If you weren't going to bake out, brass was good enough. We just kept everything very clean; we had very thorough cleaning methods and that was about it. 

I will also say that, in the line of valves, one of the early things that happened was I had been asked by Argonne National Lab to develop a stainless steel bellows-sealed valve. That proved to be quite a problem because you are trying to take a thin bellows, several thousands of an inch thick, and braze it to the heavy part of the valve and it didn't work out very well. Again, one of these minor engineering feats. I had found from a magazine, looking at new products, that there was an outfit, I think in Chicago, that did nicrobrazing, that was brazing in an oven with a compound which kept everything at the same temperature and so you didn't have the problem of burning the bellows in order to get enough heat to braise it. So I think we were the first. At some time in the '50s, the first stainless steel bellows seal valves were being offered. I don't know how they're manufactured now. Probably by some form of oven nicrobrazing, I suspect.

BROWN: How about some of the techniques and things that were developed? I remember using some of the Veeco leaks for standard leaks and things like that.

NERKEN: I don't like to use the word "Veeco." This is not an advertising session.

BROWN: That's all right.

NERKEN: Makes it a little bit difficult, but…I don't know who was responsible for the glass leak. I know that we made them early on. It was an obvious thing to do. The copper tubing leak was a holdover from the wartime project, from the Manhattan Project. I will say I took a lot of pride in the fact that my company was one of those that helped found the Committee for Vacuum Technology4 I think was the name originally. For one thing, I was very interested in the possibility of having! some standards. We still need them. [Laughs]

BROWN: Just to get back a little bit, I'll just mention the name that I've heard. I hope you remember a fellow named Herb Zuhr.

NERKEN: Oh, Herb Zuhr? Yes.

BROWN: He worked, I think, with you.

NERKEN: I think that was before the era of Veeco's existence.

BROWN: Yes. But a lot of work was done. Collaborative work.

NERKEN: Well, if you want to talk about that, that was before we were in the business of making leak detectors. It's something that I'm going to discuss today at two o'clock. The so-called diffusion plant at Oak Ridge had to be leak-tested, and a section was set up under Dr. Jacobs. Jacobs hired a man named Herb Zuhr, and then Al Nerken, another fellow named Lyle Liebert, and finally, Frank Raible. We were his four lieutenants. He tried out a number of different ways of detecting leaks sensitively; none of them worked out. And finally, since he knew Professor Nier at the University of Minnesota - they had done postgraduate work at Harvard together - he went up to see Alfred Nier at Minnesota and said, "Al, how about making us a little mass spectrometer with great sensitivity to pick up helium?" Nier did that. And some time in early 1944, I guess, we started receiving leak detectors made out of glass with, I think, mercury pumps. They were a disaster when they got into the manufacturer's premises, I assume. Big manufacturers like Allis-Chalmers and Chrysler were making huge vessels for this diffusion plant. The men were at war. They had women workers. Somehow or other, they managed to break the glass. You didn't have any glass blowers. There was a disaster. The women would get yelled at and threaten to strike. Finally, Chrysler said that if the project didn't straighten the situation out, they were going to drop their contract. So Jacobs approached Nier to do something, which Nier didn't think was doable, namely to make a mass spectrometer with a metal body, because all the work in physics, even today probably, is done in glass to minimize out-gassing and to permit baking. So Niehr did it, and sure enough, he came up with something, which later on was handed on to General Electric to manufacture.

BROWN: They made mass spectrometers and actually worked at Oak Ridge and the whole bit with Nier's design?

NERKEN: Nier's design went up to Schenectady, I guess, but I'm not too sure where they were manufactured.

BROWN: Talking a little bit, and I know you don't want to get commercial and this is not a commercial, but generally, coming through the years with the mass spectrometer type of leak detectors, I reckon there have been about three or four what I would call big players. That was Veeco. Consolidated Electrodynamics, I think, was the original.

NERKEN: Was the original kind, yeah.

BROWN: And then GE kind of got into it a little bit when they started with their VPO5 operation. And of course, Varian came along with it, and some of the general manufacturers.

NERKEN: But there are some things that have happened.

BROWN: Yeah. You know, you kind of pioneered through that, survived, and - 

NERKEN: The Nier tube, one of the things I forgot - You do forget these things. Of course, they happen in the course of your work. We had the 60-degree Nier tube, which had somewhat limited resolution, and that leads to background, unless you have a very, very clean system. So somewhere along the line, we decided that we would use a double-field design, and we had what you called a C-tube instead of a B-tube, where you had two magnetic separations. That increased the resolution very substantially, which meant in the end that you really had more usable sensitivity. As I say, if you get sensitivity with a lot of background, you really don't have anything. I don't know that we were the first ones to do it, but Veeco did it through this high-resolution C-tube somewhere along the line.

BROWN: Generally, as a I say, I don't know all of it, but it seems that Veeco kind of stayed right in the forefront. And you're still there. I mean you're still in competition. How many years, Al, have you been in this company?

NERKEN: Well, the partnership was formed in December of 1945 between Nerken and Raible. It became a public corporation in '61, and it went out of existence, sort of, in 1988. In 1990, it came into being again as a continuation of the original Veeco Instruments. That's a little bit of a story. I don't think it's pertinent to -  

BROWN: I think it is.

NERKEN: It is? Oh, well, what happened is the company had by that time two divisions. They had an Electronics Division making power supplies, and then the original Instrument Division. The English company that bought all the stock of Veeco Instruments was more interested in the power supplies than the instruments, and offered to sell it back to whoever was interested. A gentleman named Ed Braun, who had been in charge of the Instrument Division, got together his managers of various divisions and a large bank gave a loan, got me and several other parties interested in investing, and bought back the company from the English purchases. So, there are people in Veeco right now who've been with Veeco for 25 to 30 years and are still there. I think the original company is still in existence.

BROWN: Okay. I know we're going to wind up here a little bit, but I'd just like to ask just a couple of questions, and I hope I don't put you on the spot too much.

NERKEN: No way.

BROWN: What would you think, in your career and, primarily, your whole life in vacuum technology, the service industry and that sort of thing, have been the most exciting things to you? Does anything stand out? Any breakthroughs? Anything that really stands out in your mind? In the whole field of vacuum technology.

NERKEN: Well, I think the development of good valves was very mundane, but probably more important, basically, than almost anything. Of course, diffusion pumps -- we made our own diffusion pumps and Veeco made some, but we did not contribute anything to any radical redesign. Certainly, other companies pioneered in improving. It went from one-stage, I think, to two-stage to three-stage pumps and so on. And then, of course, there have not been any fundamental changes in leak detections. All have been engineering changes. Nothing has changed fundamentally with the exception, and I mention this in my talk, of this counter-flow procedure. That is a basically different way of testing. It had nothing to do, really, with the engineering of the leak detector. The leak detector has not changed except to be improved engineering-wise. A lot of electronics now.

BROWN: And as you say, some things to get backgrounds down. Cleaner systems. That sort of thing.


BROWN: And of course, you don't have to bake leak detectors, but as you mentioned, the valves, such as the Pullman6 valves. You remember the bakeable valves? You have to bake them open, and then they came and developed the material where you could leave them closed to bake.

NERKEN: We have never used bakeable views in our leak detectors.

BROWN: I know. No, no, that's what I say, they're not needed.

NERKEN: They may be necessary if people get interested in really, very, very small leaks and such things may become desirable.

BROWN: Well, you certainly seem to be still interested in the technology and the business.

NERKEN: Oh, yes.

BROWN: For 45 years. Is that right?

NERKEN: By way of interests here, I'll talk about what struck me. Not technically, but technologically. For every one of the first five, six, seven years of these main leak detectors, I was saying, "When is this market going to saturate? This can't keep on. Where are these things going to go?" Well, it definitely hasn't saturated yet, and it's rather remarkable that this device has been around for 45 years and is still in high demand.

BROWN: I think with one of our space vehicles that we've got down at the Cape, that they keep having a fuel leak somewhere. I think, Al, we've got to get you down there and see if you can help them out a little bit.

NERKEN: Friends say, "Are these your leak detectors that are failing on the job?" I say, "Oh, no, nothing to do with us." [Laughter]

BROWN: Well, you certainly must have had an enjoyable life.


BROWN: I doubt that you would change any major parts of it if you had a chance, would you?

NERKEN: No. I think that it struck me, as I look back on it, that I never had the idea where we were going to end up as a company. But as problems cropped up, we took care of them. I called it putting one step in front of the other. So, it was just gradual developments.

BROWN: There were no big, great breakthroughs that you can recall?

NERKEN: No. I don't think so. I think the feedback circuit for ionization gauges was probably as much of a breakthrough as anything.

BROWN: You were, of course, very instrumental in the old Vacuum Society4 and the new Vacuum Society, and apparently, you are still very interested in it because you're here. We all know of the Al Nerken Award, which is a very coveted award now. Is there anything you would like to say along those lines before we go?

NERKEN: Well, yes. As an engineer rather than a scientist, I wish that the Vacuum Technology Division got a little more prominence and attention. [Laughs]

BROWN: Okay. I think some of us feel that way. Well, thank you very much.

NERKEN: You're very welcome.

BROWN: I think that will conclude it.

1. Spelling is uncertain
2. The valve body was made from standard brass bar stock, approximately 1 1/2 inch square by 4 inch long, which was drilled through.
3. Victoreen Radio Corporation
4. Committee on Vacuum Techniques, formed in 1953, became the American Vacuum Society in 1957.
5. Vacuum Products Operation
6. Granville-Phillips Type C valves, made in Pullman, WA

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