AVS Historical Persons | Rudy Koehler - 1991

Rudy Koehler - 1991

Oral History Interview with Rudy Koehler

Interviewed By Jim Lafferty, November 6, 1991
LAFFERTY: This is the 6th of November, 1991. We're in Schenectady, New York. We're privileged to have as our guest today Rudy Koehler. Rudy was the second President of the American Vacuum Society, and is also an honorary life member. Rudy, I'd like you to ask you, as a founding member of this organization, how in the world this organization got started. I understand originally it was called the Committee on Vacuum Techniques. Perhaps you can tell us something about that.

koehler.JPGKOEHLER: Jim, you're correct. I was a founder of the original Committee on Vacuum Techniques, but since I've not been associated with the activity since 1956 and actually retired from an active career since 1981, I will issue a disclaimer in the sense that some of my statements may be hopelessly obsolete. I think the reason for CVT to come into being was the fact that, during World War II, the Manhattan Project, involving nuclear research, involved, very heavily, vacuum equipment and instrumentation. Both the magnetic separation techniques and the gaseous diffusion techniques involved massive vacuum equipment. As a consequence, there was technology developed, which was by and large classified, as was some of this equipment - in fact, most of it - during the actual development period of '41 to '45. With the end of the war, the suppliers of this equipment, which included General Electric, were all interested in expanding this know-how and equipment into new commercial areas.

LAFFERTY: So that was General Electric's interest was it, then? In vacuum? That's how GE is interested in vacuum?

KOEHLER: Yes. Specifically, the interest was applications of vacuum techniques. Secondarily, the pumping equipment and leak detection that went along with it. But it just seemed reasonable to expect major opportunities for the application of the techniques. Now, at the time, GE's interest was primarily in the mass spectrometer line that had been developed for the Manhattan Project, and my own role involved that of leak detection using the basic DC mass spectrometer tube invented by Professor Nier at the University of Wisconsin.

LAFFERTY: You were involved in the mass spectrometer leak detection part of the work?

KOEHLER: Exactly.

LAFFERTY: That was developed in the General Engineering Laboratory, wasn't it?

KOEHLER: That's correct. Now, with regard to who was involved in the founding, I think, at the risk of maybe omitting a few names, but in the interests of brevity, it was Joseph B. Merrill who first approached me on the desirability of getting some kind of an organization going. Joe was associated with NRC1, not to be confused with Nuclear Regulatory Commission. It was a company in Cambridge that made vacuum equipment. And then there was, of course, Dar Welch of Welch Scientific, big in mechanical pumps and other devices; Dr. B. B. Dayton of CVC2, another supplier of equipment out of Rochester; and myself. I think we have to give credit to Joe Merrill, who, being a salesman and the only salesman in that group, had occasion to make the rounds and get other people interested. So that famous meeting in New York involving about 50 people, who decided to form an organization, owes a good bit to the late Joe Merrill for getting the initial communications out.

LAFFERTY: Rudy, what was General Electric's interest in the original Committee on Vacuum Techniques?

KOEHLER: The organization got going with considerable help from industry. In the case of General Electric, I was in charge of the application and the technical aspects of our helium tracer mass spectrometer leak detector. But what isn't often recognized is that, in many areas, GE was its own best customer. For example, the question of making a lot of money on leak detectors was not foremost. We needed leak detectors in connection with the vacuum tube work, which was significant in the company, and this was the era of the initial sale of pumpless mercury-arc rectifiers. Imagine metal containers the size of a garbage can, which were used to convert AC to DC for aluminum pot lines, chlorine, and other applications; and they also had to remain vacuum tight for years!. And then our management in the lab was not as sophisticated as today, and we were allowed to dabble in any sort of activity which didn't cost the company too much money, such as atom smashers, a betatron, a couple of synchrotrons, liquid metal pumps for pumping sodium and so on, all of which required vacuum techniques in the processing of the equipment, and later on in the leak detection of the equipment, to make sure that it would survive. Again, the specific product line that was involved: the mass spectrometer series, both large analytical instruments, and then the helium tracer leak detector.

LAFFERTY: Why were you involved in all this, Rudy? 

KOEHLER: [Laughs] That's a good question. Actually, I was a trained as an electrical engineer, majoring in power. So, the ingredients I grew up with were magnetic steel, copper, and insulating varnish or insulation in general. But during the war, of course, that took second place to the weapons development. In 1945, I had the chance to go into the laboratory and take on this mass spectrometer leak detector area. Now as it turned out, I had taken an elective in college in electron physics. Just to reminisce, the text was called Electron and Nuclear Physics by J. Barton Hoag, dated 1938. So here we have a case where we were fooling around, bending electrons in vacuum systems as the laboratory work associated with that course. I never expected to use them. But when the chance came to get into the mass spectrometry area, I figured that it might prove to be interesting, and of course, I accepted that opportunity. It was a switch. I stayed in it, by the way, until 1956, when I had the chance to go into the power area. This marked the time when I sort of tiptoed away from the areas of interest of AVS.

LAFFERTY: What changes do you think had occurred between the original Committee on Vacuum Techniques and the present American Vacuum Society?

KOEHLER: Major. The original challenge was to apply vacuum processes to commercial or industrial areas, and to further the use of vacuum equipment. At the time of the first meeting, the major contributors to those meetings were people that were indeed associated with vacuum technology; measurement of vacuum; vacuum metallurgy; to some extent, plasma phenomena; and the thin film activity was, with due respect to the scientists, largely motivated by the deposition of vacuum films on plastics and cheaper metals in the area of junk jewelry and so on. So the emphasis was on the vacuum; application of the vacuum techniques; the technology, which had been built up the previous five years; and the use of some of the equipment. Now then, under the banner of AVS, this has broadened considerably, and you now have major interests in people who accept vacuum as a given. Their interest in applied surface phenomena, electronic materials, the solid-state materials and the processes involved, surface science on materials, and thin film from the perspective of very, very sophisticated technology.

LAFFERTY: Rudy, back in the days when you were actively involved in the Society and were elected President, I think the membership at that time probably was only a few hundred members at most. Today, the American Vacuum Society membership exceeds 5,000. I think it's close to 6,000 now. What do you attribute that growth to?

KOEHLER: Well, the first aspect of the growth was the combining with American Institute of Physics, which gave us a broader base and broader interest. But, in my opinion, and this may reflect an electrical engineering bias, I think the actual growth has been the development and application of solid-state electronics. Many of the areas I mentioned, aside from the academic perspective, gets its motivation from the application of solid-state devices, electrical devices, integrated circuits, memory cells - the entire silicon cell wafer activity. Certainly, the electronic developments have been largely based on the ability to condition, to process materials under high vacuum conditions.

LAFFERTY: Yes, I think that one of the things that's unique about the American Vacuum Society is that it has given a home to all of these people who use vacuum, and not only taught them how to use vacuum in their own particular work, but they also allow them to present papers on their accomplishments using vacuum. Do you agree to that?

KOEHLER: Oh, yes. Well, these days, a good bit of the reported information at the conferences is by people who take the vacuum for granted and who primarily use it in connection with their research and investigative activity. But I agree with you in principle. As far as I'm concerned, I would much prefer to abandon the idea of a space station for carrying on processes, materials-handling processes, and see it done right down here on Mother Earth inside of large vacuum systems where I'm sure the risks would be much lower and the expenses would be much lower. As to what else might develop in the area of vacuum techniques, I am not sure. It's possible that, some day, the biologists might become active in this area for some of their handling of materials, but I'm not up to date on that, and I think I'll let that be discussed by others.

LAFFERTY: Well, Rudy, it's been nice having you here with us today to talk about the old times and also make a little prediction for the future. I want to thank you for your cooperation and being with us here.

KOEHLER: My pleasure.

1. National Research Corporation
2. Consolidated Vacuum Corporation.

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