AVS Historical Persons | N. Rey Whetten - 1998

N. Rey Whetten - 1998

Oral History Interview with N. Rey Whetten

Interviewed by Roger Young, 1998
 
YOUNG: I am Roger Young, and I am here to interview Rey Whetten, who has been a member of the Board of Directors for many years of the American Vacuum Society. He was the American Vacuum Society President in 1976, and he's been the Treasurer since 1984 and through 1999, I guess. He's now the Technical Director of AVS and has been for several years. First of all, would you be willing to tell me what the Technical Director of AVS is?

WHETTEN.JPGWHETTEN: Sure, willing to try. This is a relatively new position. I think I'm the first Technical Director. We've had it for almost five years now. There was a feeling that-- As you know, first of all, the AVS is set up with divisions representing different fields. They compose a symposium by each division, making up papers in their given field. There was a feeling that we were missing a lot of new things which were occurring partly because they were somewhat out of the existing divisions' fields. We would occasionally have topical conferences in some of these areas, but the topical conferences, if they didn't easily fit into a division, were frequently dropped. We just lost those fields, which some people felt were symbiotic with the rest of the society. 

So the Technical Directorship was formed as somebody who should try to incorporate new ideas which would easily fit in with the AVS into our program, into our structure. In order not to keep proliferating in the number of divisions, why, we formed what we called Technical Groups, which are much more flexible. They include Manufacturing Science, Biomaterials Engineering, Magnetic Surfaces, and some fields like this, which can be combined with other groups or divisions or dropped if the need seems - are much more flexible than divisions. Divisions are pretty permanent - we've been unsuccessful in dropping those that some people felt should be dropped - and have a lifetime of their own. 

So it's an attempt to incorporate both the very good features about divisions and new fields. Then somebody on the Program Committee, where I am supposed to have a certain number of sessions that I can use for new subjects to introduce them, et cetera. 

YOUNG: When did you first start working in the vacuum area?

WHETTEN: Actually, in graduate school. I worked in cosmic rays, which is not a very active field these days, I guess. But we made a number of Geiger counters. To make those, you had to have the Geiger counters pretty clean, evacuated them. We had mercury Langmuir type pumps and liquid nitrogen traps and, I expect, a pretty good vacuum, although we couldn't measure how good it was because of the limitations in the gauge. We didn't have Bayard-Alpert gauges, obviously. 

Some of the things I remember (this was at Yale) was how casual we were about some of the equipment. I remember you could walk on the floors and sometimes see mercury coming up between the floorboards where people had broken pumps and spilled it and inadequately cleaned it. Also, compared to what I found at GE, we were totally unaware of the dangers of working around a glass system. There are no shields or anything. But then we were expendable graduate students, I guess you could argue [chuckles]. 

YOUNG: What were some of your early projects in the vacuum area?

WHETTEN: I think one of the projects initially-- GE was just attempting to, as I arrived, to get into the color television field. I think Jim Lafferty had a tube in that area. But the one that I worked on was a post-acceleration color tube, and the problem was with back-scattered electrons. So another fellow, Al Laponsky, and I worked quite a bit in secondary emission and back-scattered electrons and so on. 

It was one of those cases where I think the tube was an engineering success. GE actually leased a factory building in Syracuse and had started to order equipment to fill it to compete with RCA in a big way. It was much brighter than the RCA tube was at that time. RCA cut the price of their color television in half, so overnight GE suspended the entire project. They could not make - at half price, they couldn't possibly compete. Neither could RCA, but RCA didn't mind losing money for a while to gain market share.

YOUNG: You and Peter Dawson did some work with quadrupoles. Do you want to say something about that?

WHETTEN: Sure. One of the things that, when you were with Vacuum Products, I guess one of the products was a monopole mass spectrometer. Quadrupoles were coming into use, as well as the monopole. We found that there was a type of quadrupole, which Paul had actually discovered in Europe. He discovered the field, not the mass spectrometer. But you could confine a given charge to mass ratio in a field that uses hyperboloids of revolution for the surfaces. Putting RF and DC voltages on these hyperboloids of revolution, you can contain - depending on the voltage and the frequency - a given charge-to-mass ratio. Under good conditions, this really works dramatically well. You can store ions of a given charge-to-mass ratio for weeks. We used to often set it up with ions in the trap on a Friday, and they would still be - not all of them - but there would be some there Monday when you would come in. 

We thought this would revolutionize things. One possibility was to make-- A mass spectrometer is extremely small, because you could make these little volumes that were no more than, say, oh maybe a cubic inch. But the real reason was because we had thought and hoped that the, I guess you'd call it the dynamic range of the mass spectrometer, the partial pressure that you could measure, was limited in most mass spectrometers to one part in 106 or one part in 107. But if you could store a given mass or have an electron beam that ionized it and stored it for a day and then pulsed out that given charge-to-mass ratio, why, perhaps you could double or triple the sensitivity of it that way. 

That turned out not to be true. You're storing these things, but the neutral gas, the background gas, tends to scatter the ions out. So what we had hoped was the big thing turned out not to work. The other thing is that ordinary quadrupoles for space applications, which is one of the things we were looking at, got shorter and shorter and shorter. So the fact that ours was extremely short proved to be less of an advantage. And ours was considerably more complicated, I would say. You didn't have a continuous beam coming out; you had to pulse it out - although as an ion trap, it is used quite a bit in individual experiments. But commercially, it was not the big success that we were expecting. 

YOUNG: It's not uncommon.

WHETTEN: [Laughs] It's true of 90% of the things I've done!

YOUNG: You were also involved in the Auger spectroscopy.

WHETTEN: Yes. That was kind of an exciting time. It was at exactly the same time as I was working on the three-dimensional quadrupole. I think I discovered, really, the first Auger spectroscopy of a given-- I was looking, with a mass spectrometer, at plasma energy losses of different materials, looking at the energy that an electron hitting it would lose because it created plasmons in the material, a characteristic energy of the material. I found that there were some peaks of energy in the reflected electron beam which depended entirely on the material. They had the energy, which turned out to be Auger peaks of carbon and oxygen and so on. We knew it was a surface-sensitive material, but I had no idea how surface-sensitive it was. 

At this time, we were working for Virgil Stout. He was our boss. Larry Harris was looking for a project at that time. Virgil thought it would be best if I continued with the three-dimensional quadrupole project while Larry worked on the Auger spectroscopy. Which was quite successful. He got the Welch Award for Auger spectroscopy some time ago. 

YOUNG: Any other projects you'd like to talk about?

WHETTEN: The one that was a commercial success - perhaps the only one that was really amazingly so, was computerized tomography. I was in charge of the X-ray detector for computerized tomography, CAT scans, which used a high-pressure xenon detector with a lot of little ionization chambers inside it. It turned out that it was in a single body and used 25 atmospheres of xenon. Xenon becomes very much like a liquid at these pressures, so it's very heavy, very dense and absorbs the X-rays very well. 

The advantage of that detector was in part that you could easily decrease the size of the ionization chambers in order to increase the resolution of the CAT scan and compare it to individual photomultipliers. Scintillators and photomultipliers, they were pretty limited in what you could do. You just couldn't put enough of them to increase the resolution. So GE's resolution after the first year, when they made the ionization chambers much smaller, was tremendous. GE had an extremely good business, sort of a half-billion dollar a year business, in CAT-scanners for quite a while.

YOUNG: I noticed in the paper this morning that they have increased the speed at which they can run a CAT-scan considerably.

WHETTEN: Okay. Yes, they keep trying - they would like to stop the heart and things of that sort to see how the valves and the heart work. When I worked on it, a half-second was the fastest possible scan. 

YOUNG: That's been a very successful business for GE.

WHETTEN: Yes. Let's see, I was going to mention some others. I worked for a while in VLSI. GE had a one and a quarter micron process, which they later sold this business to Lockheed Martin. I worked on flat panel displays in a group where we used amorphous silicon. I was in charge of a number of technicians that actually made the flat panel displays using amorphous silicon. We made a number of them. At the time, I thought they were extremely successful. They were eight-inch by eight-inch displays that were spectacular, I thought - great color, great brightness. They were used in military applications. They were put into F-18 fighter planes and a number of others. 

But the Armed Forces didn't come through with large enough contracts fast enough for GE, so GE sold the business to Thomson of France. The only part of it that is left is something that is coming out now. It's a large panel for x-ray detection where you have a photo-diode with, essentially, a field-effect transistor of silicon underneath it. This can be made in an array with millions by millions of chips wide so that you have high resolution. It's a shadow-gram x-ray like ordinary film is, but it replaces ordinary film and has the advantage that then it's all digital. It's on a computer. You can enhance areas that are not bright enough or you can change the contrast and so on. GE is going to produce that in cooperation with EEG? With another company. 

YOUNG: Very interesting, Rey. Quite a career. Thank you.

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