AVS Historical Persons | J. Harry Leck - 1991

J. Harry Leck - 1991

Oral History Interview with J. Harry Leck

Interviewed by Len Beavis, Feb 11, 1991
BEAVIS: I am a member of the Society's Historical Archives Society. As part of the Society's historical archive project, today I will be talking to Dr. J.H. Leck. It's February 11, 1991, and we are in Clearwater, Florida. I'm sure most of you who have been concerned with measuring vacuum are well aware of Professor Leck's indispensable book, Pressure Measurement in Vacuum Systems, now in its third edition. Presently, Dr. Leck is Professor Emeritus at the University of Liverpool. 

Harry, it's a real pleasure to have you with us today. How did you get started in vacuum?

leck.jpgJ.H. LECK: Thank you for inviting me. It's a pleasure and I'm surprised to be here. But I'm very delighted to be here with you. How did I get started? Well, I took a degree in electrical power engineering at the end of the war in Europe, and went to the Metro-Vickers Company, and went through the factory in there. And one of the departments I went through was in the vacuum science department and got interested in vacuum equipment there because they were making cyclotrons and such like equipment. I saw that it was the research department which was run by Jack Blears and found that interesting because it applied to electrical engineering and physics and chemistry, bringing all things together. And it was a nice group of people working there. I thought they were a nice group of people working in that laboratory; that's why I went to work with them.

BEAVIS: Interesting. Why did you make the decision to study pressure measurements? 

LECK: That was one of their problems in the laboratory at the time. Ionization gauges, hot cathode gauges were just emerging from the laboratory into the factory. Penning gauges were comparatively new. Penning had just brought out the cylindrical cathode gauge which looked attractive down to 10-6 millimeters of mercury, as it was in those days. The thermocouple gauge was also interesting. Leak detection was a real problem still. In fact, it was an interesting problem. As I say, it involved some electronic engineering, building, measuring circuits, stabilizing circuits, and physics and chemistry as well. I just found it interesting, and somebody was prepared for me to do the work.

BEAVIS: You mentioned Jack Blears, and I know you remember many other of the original people in vacuum, or what we consider the original people - guys like C.R. Burch and Dushman and Burrows, and people like that. Maybe you can reminisce a little bit about your experiences with these people.

LECK: Yes, of course. I was very impressed by these people because I came across them at a very early age, and they were the experts in the field. I think 1C. R. Burch - Charlie Burch as he was known to his friends, not by me - was, I think, the character amongst all these people, Burch was an extremely able person. He was only in the vacuum field from about 1925-1935, and then moved into optics, classical optics. He became a fellow of the Royal Society through his work in optics; not at all in vacuum. He died quite recently. When he was over 80 years of age, he was still considered the expert in Europe for classical optics. A number of companies employed him to test check on telescope lenses made by Taylor Hobson. Many people would not accept their lens until Charlie Burch had okayed them. I talked with him about seven or eight years ago when he came to Liverpool to give the Burch Prize for the British Vacuum Council. He said, "Some of these modern mirrors are very poor; they are getting very slack. There are great big hills ten-millionths of an inch high on some of these mirror surfaces." He worked very hard. I recall I invited him to come and give that prize, and he said, "Well, I may be late. I'm coming on the train from Birmingham, from Bristol. I know we have to change at Birmingham. Sometimes when I get off the train I forget where I'm going and have to ring back my secretary to find out which town I need to go to." [Laughs]  But as you know, he made a big contribution to the Vacuum Society because he invented the oil diffusion pump. Up till his day, in 1928, all good diffusion pumps were made of glass and they operated in mercury. If you wanted high vacuum, you either needed cardice2 or liquid nitrogen. These were days of the depression, and he, as a physicist at Metropolitan Vickers, was given what he called "a bloody boring job," which was to find a simple way of cleaning transformer oils, recycling transformer oils. He went to the vacuum department and got the idea of cleaning the oils in the vacuum. It took him about two weeks to realize, because he replaced the mercury in the diffusion pump by the oil he was supposed to clean, he would get better vacuum without liquid nitrogen. And that was it. Being a classical scholar, of course, he called these apiezon oils - oils without pressure. That's where the name comes from. He and Burke set up a still in the basement in one of the labs at Metropolitan Vickers making oils. That served right through the World War II for the large demands in valve use in radar transmitters. I suppose it was good for the radar world with all these radar sets down the east coast of England operated by oil diffusion pumps, not mercury diffusion pumps or liquid nitrogen. So Burch made a real contribution.

He was a person who would turn up at the laboratory at two o'clock in the morning because he'd got a good idea and would be sitting, working there in his carpet slippers and dressing gown. In those days in the factory one had to clock in and clock out. His time card was quite irregular. He once received a rather curt note of fault, saying could he explain this irregular time sheet? He wrote back and said, "You might be the guardian angel, but you're not God Almighty." [Chuckles] He ignored it from there on. He got into trouble with the chief salesman, a certain Captain Maxwell - no relation to Maxwell of Maxwell Press. He would write all kinds of letters to potential customers saying, "Don't buy this equipment. It's really not very good." The order that came down that every letter that Burch sent had to be vetted by Captain Maxwell. He arranged that on the Christmas dinner he would say grace. He said, "Good Lord, send down your blessings to us with a copy to Captain Maxwell, please." [Laughs] I well recall telling the stories-- But I must stop talking about Burch. I can go on and on for hours. [Laughs] 
One thing I'd like to mention, and somebody ought to mention here, was a man called Bancroft, who worked with him, and designed himself the rows of vacuum pumps that were made by MetroVicks, so-called DR1 pumps, that lasted us about 25-30 years, from 1930 right through into the '60s. It was a modern pump. It was a very, very popular pump in Europe, and that was all due to Bancroft. Frank Bancroft did all that. 

Blears, of course, I knew best of all because he was my boss and I worked with Jack Blears since, what 1948, till the present day. Jack's in his eighties now and over there at the University of Liverpool. He's moved his field from vacuum but still works very hard. Of course you remember him from the Blears effect. He developed a sort of mass spectrometry. He worked closely with Al Nier. In fact, my first mass spectrometer was a Nier-type mass spectrometer. It was in fact made by Nier; he actually made it himself. It was sent to Liverpool for work by Chadwick3. Of course Chadwick had moved to America before the instrument was unpacked. So I unpacked it. I spoke to Nier years afterwards and he said, "Yes, I can well remember doing the glass-blowing on that particular instrument. It was quite tricky." So my first mass spectrometer was actually made by Nier himself.

BEAVIS: It's certainly apparent why you became involved with these esoteric pressure measurements with all these very famous individuals who were well known, I think, by a lot of people anyway. Some not so well known, of course. You've had some students of yours who have made important contributions to vacuum and related fields of study. You possibly could reminisce a little bit about some of them and your interactions with them.

LECK: Yes, it's a bit difficult; you might forget an important name at this stage. But I remember George Carter well as a student. He came to Liverpool from industry. According to George and his colleagues, George's only interest at school was playing football, not science [laughs]. He left school rather early and went to work at Dunlop and took a degree externally, which is pretty hard going in the UK, an external university degree. Then he came back and did three years research with me on ionization gauges. I recall that the first paper we wrote was at the Namur4 conference. It was a bit controversial, that paper, but I do recall Alpert getting up and saying he agreed with us, which tended to silence quite a lot of the opposition. [Laughs]  John Colligon, of course, I worked with. John, I remember, was an undergraduate student at Liverpool. I well remember him in his first year as an undergraduate. He stayed an undergraduate at Liverpool and then stayed on as a post-graduate. He, George, and I worked together.  We were associated with several people from Yugoslavia. Branka Cobic I remember worked with us there, and she's just retired in Yugoslavia. I can remember she arrived a little bit before we expected her. We were setting up an a plant for her to work with, and it needed an oven so she could bake the glass system. George Carter and John Colligon, I remember, and somebody else whose name escapes me, going down to the workshop for about two days and making these ovens with hacksaws and everything. And of course they're made from asbestos, so we were covered in asbestos stuff for about three days. We're all three going now! [laughs] We didn't realize asbestos was - and trichlorethylene we used to use a great deal as well, and that's just as deadly, isn't it? 

BEAVIS: Yes. We've learned a lot.

LECK: [Laughs] I think it's just as well. It horrifies me sometimes to think of what we did in those early days. 

BEAVIS: Yes, even carbon tetrachloride was used as a useful solvent. 

LECK: We didn't have computers or faxes, but we had carbon tetrachloride. 

BEAVIS: [Laughs] What has been some of your most recent work that you're concerned with?

LECK: Recently, I've been working with mass spectrometers, I think, quadrupole mass spectrometer. I became interested in those when I went to work at Washington State University with Ed Donaldson for a year. We had a marvelous year out there. Of course, we took over a lab that Dan Bills had occupied, so we were never short of C-valves because everywhere you looked, you could open a cupboard and find three or four C-valves. I think it was Dan who first interested me in quads, because he was a research graduate student building up his equipment. He was building a quadrupole mass spectrometer. We got it going, and I was interested in them ever since. There's still a lot not known about them. I could go on about that, but I don't think this is the time to talk about customer-manufacturer relationships in quadrupole mass spectrometers. 

BEAVIS: [Laughs] Off the record, maybe. 

LECK: On the record, I think it's the customer's fault rather than the manufacturer.

BEAVIS: [Laughs] Interesting. What were some of the, in your estimation, important milestones in vacuum over the past years?

LECK: In my lifetime, the thing that immediately comes to mind is the work of Alpert and then Paul Redhead. You remember Dan Alpert and Paul Redhead very well in the field. For introducing ultra-high vacuum, I think of them. Dan was the Bayard-Alpert gauge, I think is on everybody's lips. Then Paul introduced the cold cathode gauge, in effect, for ultra-high vacuum. Paul and his group, Peter Hobson and Ernie Kornelsen started to work down to extremely low pressure. I well remember going to a meeting in London and I had to give a very short review. I think I'd been to an AVS meeting and they said, "Well, could you talk about the AVS?" And I said that ultra-high vacuum was becoming popular. People were talking about the 10-10 torr. Pete Hobson and Paul Redhead were working down at the 10-13 torr, but they were using liquid helium, which I considered was cheating [laughs]. Somebody got up after the meeting and had a serious talk about how it wasn't cheating to use liquid helium [laughs]. 

That pops up immediately. And then of course what comes to my mind quickly was the development of the ion pump, which meant for the first time one could have a vacuum system that was pumping but sealed off from the outside world. So you could leave it over the weekend knowing that a power failure wouldn't affect it, that it would always be in good shape on Monday morning. A capture pump was separate from the normal atmosphere. 

BEAVIS: You're referring to the real pump, the Hall pump?

LECK: That's right, yes. The Hall pump, which I suppose was a technical trick of putting 25 Penning gauges in parallel, wasn't it? But then Paul thought of it, which nobody else did. 

BEAVIS: Thank you for taking the time to be with us today and contributing to the American Vacuum Society's historical archives. 

LECK: Thank you very much for having me. 

1. Cecil R. Burch
2. cardice; solid carbon dioxide (dry ice)
3. James Chadwick, Nobel Prize in Physics, 1935. Lyon Professor of Physics, Liverpool University, 1935-48, spent 1943-46 in the USA
4. The First International Congress on Vacuum Technology was held in Namur, Belgium in 1958

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