Alexei Vorobyov

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ORAL HISTORIES
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Interviewed by
Joan Warnow-Blewett
Interview date
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Interview of Alexei Vorobyov by Joan Warnow-Blewett on 1990 July 20, Niels Bohr Library & Archives, American Institute of Physics, College Park, MD USA, www.aip.org/history-programs/niels-bohr-library/oral-histories/31927

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Topics discussed include: Vorobyov's family background and education; his work at Fermilab and the European Organization for Nuclear Research (CERN); James Franck; Joe Lach; Per Grafstrom; Valery Schegelsky; high energy physics.

Transcript

Warnow-Blewett:

This is an interview with Alexei Vorobyov. It is Fermilab experiment 715. I wanted to ask you before we start talking about the experiment, where you were born and the year?

Vorobyov:

That’s an easy question. I was born in 1931, not far from Leningrad.

Warnow-Blewett:

Where did you go to university? Where did you get your PhD?

Vorobyov:

I graduated from Leningrad Polytechnical Institute which is a kind of university in 1955.

Warnow-Blewett:

Is that when you got your PhD?

Vorobyov:

No. We have another system. When we graduate at the university we don’t have any degree. Later on we have degree already while working in the research institute.

Warnow-Blewett:

I see. So where was that research institute?

Vorobyov:

This one.

Warnow-Blewett:

It was, the Nuclear Physics Institute?

Vorobyov:

Nuclear Physics. The Nuclear Physics Institute [at Gatchina] was at that time a part of the Ioffe Institute in Leningrad. So we separated somewhat later. So I entered the Polytechnical Institute; I entered Ioffe Institute and started research there. And after separation I became a member of that institute.

Warnow-Blewett:

Till the end of the Ioffe?

Vorobyov:

Yeah, at the beginning there was Ioffe Institute, and now it’s a separate institute, this institute.

Warnow-Blewett:

Is this your full name, Alexei?

Vorobyov:

Alexei Vorobyov. As to degrees, you know, our system is different. We have two degrees instead of one, candidate and doctorship. So first I had candidate degree, and after a while I had a doctorship. But it was long ago.

Warnow-Blewett:

Yes. Well, okay. Now, the other thing I wanted to ask you before we talk about the experiment is your, do you keep letters, do you write letters?

Vorobyov:

Letters?

Warnow-Blewett:

Yes. Letters. Do you write to colleagues?

Vorobyov:

Oh, yes. Of course.

Warnow-Blewett:

Do you keep those letters?

Vorobyov:

Well, most of them are official letters. Yes. I have many, many such letters, of course.

Warnow-Blewett:

I’m talking about just writing correspondence to colleagues.

Vorobyov:

Yes, of course I have some correspondence. While preparing the experiment we had quite intense exchange of letters.

Warnow-Blewett:

And what about e-mail? Do you have e-mail?

Vorobyov:

E-mail is quite recently that it became available here, quite recently, so we start using it now.

Warnow-Blewett:

And do you save your e-mail?

Vorobyov:

Yes, we have now.

Warnow-Blewett:

You don’t destroy it?

Vorobyov:

Oh, I am not sure.

Warnow-Blewett:

We find that many scientists destroy it. We are hoping for future historians that some letters would be kept.

Vorobyov:

I’m afraid we are not keeping most of the information. So we are not thinking about history.

Warnow-Blewett:

Yes, well that’s difficult. What about notebooks? Do you keep any notebooks from experiments?

Vorobyov:

Yes and no. First the attitude was that any document that came to a file so we had maybe two hundred documents. But when experiment is finished then most of them were destroyed, because they occupied too much space.

Warnow-Blewett:

Too much space, yeah.

Vorobyov:

But I have no custom to use some private notebooks, some private notes. This is what I’m not used to.

Warnow-Blewett:

You don’t write private notes?

Vorobyov:

No.

Warnow-Blewett:

No. Well, okay. Now, when we talk about 715, experiment 715 at Fermilab, from what I understand, and I’d like you to tell me how that group got started. I mean, you had worked here at other laboratories, like CERN, and then there was work going on at Fermilab. So could you tell me how it got started?

Vorobyov:

I think that group was created as usual, I think. First people get acquainted somewhere. To become a collaborator it’s not easy.

Warnow-Blewett:

It’s not easy?

Vorobyov:

Not easy, because you should know people, you should trust people, they should know you, they should trust you, they should understand what you can do, what you cannot do. And before you don’t have such understanding of each other, and the collaboration is not really visible. And collaboration is created always, say, from the bottom, not from the head. Not from the administration, some bosses say that you should collaborate. I don’t think this would give any result.

Warnow-Blewett:

It would not be good?

Vorobyov:

Yes. I don’t believe in such collaborations. They may be for some while, but they’re not necessary; on the other hand if people are already very good friends etc., and they have some common understanding of the problems, then that’s another story. And then of course all the officials try to help you, if they see that the collaboration is already existing and that it is good. So this was not the first collaboration we had.

Warnow-Blewett:

It was not the first you had with Fermilab?

Vorobyov:

With Fermilab it was the first, but not the first collaboration with the western groups. Before, as far as I remember our first collaboration, before it was a hassle of iron curtain, and very few relations. And somewhere in sixties we managed to penetrate — and this was the Niels Bohr Institute in Denmark. So we started with that institute, some small collaborations with some small experiments. Later we moved to CERN. And then it became more serious. And at CERN we did do the experiments WA9 and NA8(?), just when the SPS accelerator started. So this was already very serious high energy experiments, small angle scattering. So this is how it happened that I knew American colleagues. Because they started even before us. They started similar experiments at Fermilab. This was Joe Lach’s group, also small angle scattering. But very different technique. But we used very different methods.

Warnow-Blewett:

So how did you meet Joe Lach? Was it at CERN?

Vorobyov:

Well, I’m not sure. I don’t remember even the first meeting. But of course we knew each other from publications, from the letters of interns, so we were interested what was going on at Fermilab, because we at that moment we were in competition. We started later at CERN than Fermilab.

Warnow-Blewett:

Were you doing a similar experiment at CERN?

Vorobyov:

Yes. We did a similar experiment at CERN, but we used very different technique, because we suggested some new method here in Gatchina. We thought this method is much better than the previous, and we tried to demonstrate it.

Warnow-Blewett:

At CERN?

Vorobyov:

At CERN, yes. So we produced a detector, which we call a recoil detector, constructed it. Then there was a big collaboration with French people, with people from Sweden.

Warnow-Blewett:

What did you call the detector?

Vorobyov:

It has a name, a special name, ICER; but it was a recoil detector, which proved to be very effective. Even for future experiments it will be used. So we started later, but some of our colleagues were very skeptical about it, because Americans were more than one year ahead of us.

Warnow-Blewett:

More than one year ahead of you?

Vorobyov:

Yes. Because the Batavia accelerator was first in operation, before this at the CERN. Okay, but then it happened that, I don’t know, Joe Lach, maybe, if he reads this now he might agree with me, that our technique was more effective. So we finished, we started later, but we finished first and we did more, so we produced more results.

Warnow-Blewett:

At CERN?

Vorobyov:

At CERN. Not only with proton scattering, but also with pion scattering, and they proved to be very precise. So very valuable information was obtained from that experiment. And Joe Lach, of course, was interested. He came to CERN. Maybe he came to Gatchina later on. And at first we were suspicious, because we were in competition as I earlier said. But later we understand that we might be friends. So we started to discuss the problem. The problem was very interesting. So we made some suggestions to each other. We understood. We just became friends… We had no idea about some future collaborations at that moment.

Warnow-Blewett:

You had none?

Vorobyov:

No.

Warnow-Blewett:

No. You mean your group at Gatchina had no ideas about what your next experiment would be?

Vorobyov:

Yes, at that time, no.

Warnow-Blewett:

So you thought, maybe you’ll do something with Fermilab? Did Joe suggest that?

Vorobyov:

I think, yes. I think, yes. This idea came maybe from Joe first. He came to Gatchina, he met more of our people. So he understood that we had quite a strong group supported by the institute, by workshops, by electro-engineers, etc. He decided it would be useful to combine our efforts for some future activity. But again, I stressed that the first point was that we became friends, we knew already the families, the children, sending congratulations to Christmas, etc. And, of course, we were looking for other ways to collaborate. Later on we decided to start this experiment 715. But of course now it’s difficult to trace when and how these first ideas came. There was a problem — the physical problem. It was discussed in many conferences, that there was some disagreement, very strong disagreement in the weak interaction sector, but, you know, that the weak interaction theory proved to be everywhere very good. But this was a very remarkable disagreement between Cabibbo predictions.

Warnow-Blewett:

Cabibbo predictions? The theory, the model?

Vorobyov:

Yes, Cabibbo model. And what was measured in the previous experiments. And these previous experiments were three of them. And all three of them were in disagreement with Cabibbo. Not only by the wing of this symmetry parameter, but even the sign was different. So, many people pointed out that this is a problem — how to solve it. The problem was difficult to solve because this is quite a rare reaction and the background is very severe. This was, we are speaking about sigma-minus beta decay. And this beta decay happens once per one thousand decays of sigma-minus into strong pi and neutron without electron. They are really difficult to separate when sigma minus decays, either to pion or to electron. You should separate pions from electrons. You like to detect pion. And you like to detect electron. But how to separate them, and how to kill pions not killing electrons. So this was a remarkable task, because the killing power should be about ten to four, ten to five. So there were no devices by that time that could perform such…

Warnow-Blewett:

So what year is this? This is 1980, say?

Vorobyov:

Yes, it’s around that. It’s 1980. And then we discovered problem and then we suggested a method. Okay, I should mention to you that the previous experiments were three of them. They seemed to be in agreement, but each of them disagreed with the theory. But still they were very suspicious, because only thirty events involved.

Warnow-Blewett:

Thirty events, yes, very small.

Vorobyov:

Forty events in the other one. So in such cases, you know. Also there are some psychological influence. The first experiment might influence the second and then they agree both, and the third is influenced by these two previous. So we’ve known that already by experience, that such an influence might take place sometimes, especially when the experiments are not very statistical.

Warnow-Blewett:

So you’re talking with Joe Lach about all this?

Vorobyov:

Of course, we discussed many problems, not only that. Normally how an idea comes? You should have in mind some problem. Not only one.

Warnow-Blewett:

Physics problem.

Vorobyov:

Physics problem. Of course, at the beginning you don’t know how to solve it. There are other people who tried and they were not able, so they were not clever, were they? It’s not by definition, it’s not so evident. Okay, but suddenly you come to an idea how to solve it. But the idea should contain some technical solutions because we are experimentalists. So it should suggest some new method, which can move you somewhere.

Warnow-Blewett:

Forward, hopefully.

Vorobyov:

Forward to the next step, yes. And this was our suggestion. We suggested to use a so-called transition radiation detector. And you know, electrons, or fast-charged particles, very relativistic particle goes not… Suppose you have some media which is not uniform — foil, recoil foil or air foil. And then the particle goes through this stack of foils into space by air. In some sense, you know, the speed velocity is different in different matter. But in the physical past what comes is the ratio of the real speed to the speed velocity. So, for example, what happens with the particle when you change the speed? It goes, but then you accelerate, accelerate, so you know, there is a brems(?) time. But instead you may keep the velocity constant but change the speed of the light because the ratio is V over C. So if you change not V but C it is the same. So when you change the C so that means it equivalent acceleration to acceleration theoretical, and the particle start to emit quantas, x-rays quantas. And then you may detect this. And the number of this quantas is a good measure of velocity. And so it happens that just in that region of energy, and this region was from five GeV to eighty GeV, this is the best application for that technique. Because electron already radiates in full strength, but pion is still not in that there is so much threshold. If the velocity is beyond this threshold it comforts it; if it’s above radiates. So what happened we just — not that it is ideal place to try to use this transition radiation technique. The history of this transition radiation comes, oh, it was long, so it was predicted first by theory, some solid theory by Franck.

Warnow-Blewett:

Oh, James Franck.

Vorobyov:

Yes, Franck. You know Franck is famous for describing the Cherenkov light. But using the same the equation you may predict this transition radiation. He didn’t pay too much attention, but such a prediction followed forward from his work. Very, very weak. One quanta for two hundred plays, for example. So people even disregarded that as a practical thing, it was just purely academic. But then Armenian physicists, they were very enthusiastic about it. They made…

Warnow-Blewett:

Who were enthusiastic?

Vorobyov:

Armenians. Ernie Hernald and his group. They were many years in making propaganda for that. So they made some progress. But again, not practical. They didn’t construct a real device.

Warnow-Blewett:

So it was still academic?

Vorobyov:

Still academic, but the theory was well-developed already, very precise theory. Due to first pioneering work and followed by Armenian work. So we already had in our hands a very good theory of this phenomenon. So when we decided to try to use this phenomenon as a detector, as a real detector, it was not difficult. So we use a couple of these equations, we calculated the optim (???) We understood that it was do-able. So we understood. It’s difficult, but still it’s do-able. It means that 200 layers followed Ksinon(?) chamber and again 200 layers and other Ksinon(?) chamber. So such twelve modules, which is some six meters long. So not all people believed us that we can do that. For example Leon Lederman. Oh, he is half serious always, as you know. So he said that he would bet that this would never work. But try, he said. Anyhow, he promised a bottle of cognac if it worked. And he did it later on. Okay, so but we realized that this would be a very effective detector for electrons, while pion would be detected, not solved from there. But still rejection power, by only one of that device was not ten to the five which we would like to provide, but it was rather ten to the three. But the advantage of this device is that the electron is not killed by the device. The electron goes strong, so the device is rather transparent, so an electron goes through and still survives. So it just radiates some quanta, and continues its way. So we can measure it, and then we may apply normal techniques recommended, for example, by Leon Lederman. Leon used many times this lead glass and to measure there, to separate electromagnetic shower from hadronic shower in a normal way, in a common way. Again, but again the rejection follows, if you use only that way, if you are very, very confident(?) you construct a very elaborated device of that kind, still you will never reach ten to three, even. So ten to the three now in our first device(?) and ten to two in the second one. And so we reached ten to the five rejection power. But still keeping the efficiency to detect electron on that kind of level of 98% was fantastic. Not killing electrons at all and killing pions by five points or so magnitude. So this was one point. So when we realized that we can do that, we suggested it to the Fermilab. Why to Fermilab? Because this is only the idea how to detect, but then I just mentioned in the beginning, that in previous experiments there were only few sigma events, but Fermilab was just famous because of many, very intense hyperon beams. So they could provide us as many as we like, sigmas, ten to the five per second for example. So really we are thinking of even better hyperon beam(?) several, but at that time it was an absolutely fantastic hyperon beam; of course, there was some background problems, etc., but the beam was there. The second condition was that we needed a lot of sigmas and they were there. So the combination of the Fermilab facility and the new method was very promising.

Warnow-Blewett:

So now we should step back and say, “How did this group get formed?” And you started by saying that Joe Lach of Fermilab came, you talked, you became friends, and then in those discussions you suggested this new detector.

Vorobyov:

Yeah, we were looking how to combine the advantages of Fermilab facility and our possibilities as physicists, as experienced in making some devices. So finally we came to a combination. Of course, there are many other ways. But we understood that here we practically, we are happy here that we combined these things in a very natural way. Not artificial way.

Warnow-Blewett:

It was a real collaboration. It was a natural collaboration.

Vorobyov:

So we started as friends, but that’s not enough. Then we had good ideas. If we didn’t have ideas, this shouldn’t work. Of course, we would have continued sending greetings, but not enough. Well, finally we discovered how to use advantages of that and the new method. As soon as we understood that in a good way, so that means according to our calculation it could easily accumulate at least ten to the five if you compare with thirty events. And then this remarkable possibility to separate that from the background. When we understood that, then we started making propaganda and inviting people.

Warnow-Blewett:

And inviting people. Are you about to tell me how you got these other institutions?

Vorobyov:

Oh yes, I can.

Warnow-Blewett:

When you say inviting people, you meant getting a larger collaboration together?

Vorobyov:

Yes, yes, because we need at least maybe ten or fifteen people — this was a relatively small experiment if compared to the now present collider teams of 400 people. So here we were I don’t know, I calculate about twenty people. It’s a reasonable group. Which I like very much. I don’t like big collaborations, by the way.

Warnow-Blewett:

How did Yale come in? And Iowa State, and the University? I’m just looking at the institutions in the proposal. Chicago… you see?

Vorobyov:

Let me see the proposal here. Yes. I can tell you one — that’s interesting also. You see this name, this is Per Grafström.

Warnow-Blewett:

At Fermilab.

Vorobyov:

At Fermilab. But how he came here? Again, Per Grafström is a very good young physicist, very, very good, one of the very best I’ve met in the West. He participated in both our experiments at CERN.

Warnow-Blewett:

Was he from Sweden?

Vorobyov:

He’s from Sweden. And he participated at CERN with us.

Warnow-Blewett:

With your group. Yes.

Vorobyov:

With our group. And again we became friends. Naturally, of course. Then I understood he is a very reliable physicist. If he analyze data, you may be sure that any… oh, Valery Schegelsky was another specialist in programming. You met him just now. Schegelsky. He also was one of the active physicists at the CERN experiment. But Schegelsky is not as reliable. He’s very quick, very quick, but he makes some mistakes. He comes back and checks, he finds it, but the combination of Grafström, who is not so quick, but very fundamental, and Schegelsky — and this works perfect.

Warnow-Blewett:

How did Grafström come to Fermilab then?

Vorobyov:

I asked him to join us. I advised Joe Lach to invite Grafström to Fermilab.

Warnow-Blewett:

Where was Grafström from? Was he from Lund?

Vorobyov:

He is from Uppsala. Yes, he is from Uppsala. I know the situation was favored for that, because in Sweden they have such rules, if they send some physicist to CERN, after some while, after two, three years he should be replaced by some other Swedish physicist. They have some definite system. So he should go; and that was a good suggestion for him to go to United States. And also, he had a son, small boy, and there was a good chance to learn American better. So all this I knew. I suggested that to Joe Lach and Lederman that they invite him. And he accepted the invitation. So we have very strong guy in our collaboration.

Warnow-Blewett:

So you added him, and then you invited other people.

Vorobyov:

Then Joe Lach invited the other people. Really I didn’t know all the rest, for example, Peter Cooper was very good. I don’t know how Joe Lach found Peter Cooper.

Warnow-Blewett:

Was he the spokesperson?

Vorobyov:

The spokesman was Joe Lach.

Warnow-Blewett:

I was interested that Cooper was called the correspondent co-spokesperson?

Peter Cooper from Yale became a spokesperson.

Vorobyov:

This is a democratic process, so when collaboration was organized, then we elected our spokesman.

Warnow-Blewett:

You elected him. How did you write this proposal? What were the steps here? You went to Fermilab? Did you go to Fermilab to write this proposal?

Vorobyov:

This is were many steps. There is the first draft, and the second draft, etc. As far as I remember, I visited Fermilab somewhere at that stage, when we discussed in the organizing stage. We also hired the workshop in Gatchina, people came here, from Gatchina.

Warnow-Blewett:

You say workshop, you mean, for the whole collaboration, so that people from the U.S. came.

Vorobyov:

Yes. Maybe not the whole collaboration, because it was only part of them at that moment.

Warnow-Blewett:

I see, this was a very early meeting.

Vorobyov:

Yes, later on we had all collaboration meetings here.

Warnow-Blewett:

So what were the groups then at the beginning? At the beginning, it was just your group and Gatchina and Fermilab.

Vorobyov:

And then Yale, Cooper, and Teig also. Cooper probably invited Teig. He is also a very good physicist. And then there were some people at Fermilab, who decided to join us. Not all of them were very effective, their presence here was quite formal, I should say. This always happens with Fermilab people, they need to be in some experiments. They go to shifts, but they are not very active in the preparative stage. For example, this Ronald Winston from University of Chicago. I mentioned to you some three previous experiments, and he is the author of one of them; and it was of course for him quite interesting to join us to make this next generation experiment, and as far as I understood Anderson was also collaborating with Winston at some earlier stage.

Warnow-Blewett:

I see, Iowa State; Anderson had worked with Winston before.

Vorobyov:

Yes, this is what my feeling is, but I am not sure about it.

Warnow-Blewett:

Ah ha, but then we have the University of Iowa. Do you remember how they got in?

Vorobyov:

Yes, Anderson from Iowa.

Warnow-Blewett:

But then… see, there are two universities in Iowa, Iowa State and University of Iowa.

Vorobyov:

O-Oh! I don’t distinguish there. I always felt they were one.

Warnow-Blewett:

Okay. Well, that’s not true.

Vorobyov:

That’s not true, definitely. But you know there is some critical mass, as soon as you have enough people already to start the experiment, then we don’t wait for the others. There are some others who will join us later on.

Warnow-Blewett:

So did that happen here? You got started before every one was on?

Vorobyov:

These people were all on for the proposal. But later, I think, we have some new names also.

Warnow-Blewett:

Here’s the first publication, so a few people added.

Vorobyov:

No, this is the second publication this was, what you call a by-product. Sigma-minus magnetic moment measurements. The main paper was on beta-decay. There is a huge article in Physical Review, so this was the first and the main publication, and this is the second, which was not even in the plans.

Warnow-Blewett:

I see, so when was the first publication? I should have a reference to that, shouldn’t I? Physical Review, is there maybe a footnote here?

Vorobyov:

I think there should be a note here.

Warnow-Blewett:

So we’ll just say that the first publication was a major paper in the Physical Review and you’ll give me that citation.

Vorobyov:

Of course, the very first publication was some Letter, some similar letter, in Phys. Rev. Letters, and then it was followed by a fundamental paper, but later…

Warnow-Blewett:

…a second Phys. Rev. Letter. So this is really the third one, I have here. Is this the full list of collaborations?

Vorobyov:

Yes, I think so.

Warnow-Blewett:

OK, so just a few people added.

Vorobyov:

Yes, just a few people, like Newsom, for example, Newsom.

Warnow-Blewett:

Newsom, he was at Iowa. The one thing I see new here is Swallow, which looks like it’s another department from University of Chicago, isn’t it? These are all Enrico Fermi Institute, and he was Department of Physics. It doesn’t matter.

Vorobyov:

For example, Newsom. I mentioned the CERN collaboration, but we also collaborated with Saclay Nuclear Center and made some experiment there. And Charlie Newsom, I met him first there, in Saclay. In the restaurant. Because we spent all nights and days on experiments. French people don’t like to work much, and they were disciplined, their wives control them very strictly. So they disappeared early. We were alone, sitting in a restaurant, and Newsom he came from America, so he was in the similar situation, and so again, we became friends there, and so when we moved to Fermilab, and then Newsom heard we are going to suggest an experiment, he joined us.

Warnow-Blewett:

So he tried to get on, and so you said, that’s fine.

Vorobyov:

Fine, yes, and learn more. Now we are running the second experiment at Fermilab, which is E 761. Just now. And many of these people are in that second experiment including Charlie Newsom, he is again with us, Peter Cooper, and some other people, so this collaboration is, of course there are some changes, but it continues.

Vorobyov:

We have new people, of course, we are losing some.

Warnow-Blewett:

Why do you think you that add a new institution to the collaboration? You have made a point about people liking each other and respecting their work.

But is it also true that you sometime add an institution, so there will be more money because you need enough money to do the experiment?

Vorobyov:

Yes exactly. Of course, we are calculating everything. So we should have enough money, but also we should have enough experienced people to make different experiments, to go to shifts, for example, we should provide at least four shifts. This is a huge amount of experimentation to keep it in operation it is quite a hard job, so if people are not experienced…

Warnow-Blewett:

You say four shifts, that means, you go around the clock, and it is what, 6 hour-shifts?

Vorobyov:

No, it’s normally eight-hour-shifts, and one is a reserve.

Warnow-Blewett:

I see, I see.

Vorobyov:

So there is some back-up shifts, but this theoretical. Normally life is much more difficult, because when it’s absolutely smoothly running, then it is like that. But normally we always have some problems, and then people are coming and they spend much more time there. I remember when we started running this experiment, we returned to our village at three o’clock in the morning regularly.

Warnow-Blewett:

This was when you were at Fermilab?

Vorobyov:

Yes, and mostly sleep until nine o’clock and then (???) and especially difficult in the first part of the experiment, the running.

Warnow-Blewett:

We’ll talk about the set-up in a moment. Okay. And you helped write this proposal, right?

Vorobyov:

As we say that money — we understood that such and such pieces of equipment should be provided by manufacture. Okay. Then Fermilab might provide maintenance and beam, etc., but normally Fermilab preferred that most of the equipment except these fundamental pieces would come from outside. Because Fermilab is providing beam, so it would cost a lot. So they also insist on collaborations, saving money for Fermilab and invite more universities. So we invited some other people, for example we needed a neutron calorimeter.

Warnow-Blewett:

A calorimeter?

Vorobyov:

A neutron calorimeter. And this calorimeter practically existed and was standing somewhere but it should be rebuilt and reactivated, and people from Yale University said, okay, we can do that, so this way, you know, that’s practical. But that’s already minor thing. The main problem is to have some brilliant idea.

Warnow-Blewett:

Yes, of course.

Vorobyov:

Because I found that from the instance when you understand this combination of good fellows, nice fellows, beam and this method can give… So these people and other people that’s already a minor thing. We have some initial group, we have good ideas, and I think this is already the most crucial, but the remaining — how people are coming and complete the collaboration, that is already some minor thing, it depends of course just friends, relations.

Warnow-Blewett:

Hmm, but meanwhile you had to complete the full detectors. You needed the various parts, like the calorimeter, and so forth?

Vorobyov:

Yes. There are some pieces, maybe trivial, but they are needed, so we are looking around so who is in a position to provide that.

Warnow-Blewett:

Yes, and so they joined. So now when you make these decisions, as to who is going to do what — and earlier on for the Leningrad group, it was decided what they would do. But then how did you make the decision for the other parts of the detector? Did you meet at Fermilab? Was that during that period?

Vorobyov:

Oh, yes, so we negotiated with these people, and then we understood that all the pieces for the set-up already were there or we have people to make it.

Warnow-Blewett:

…have people to make it.

Vorobyov:

And then we say, okay it’s enough. And then some new people came to help us. They became even more active than the first group, so it changed but that does not matter.

Warnow-Blewett:

You mean the new people that added… came on.

Vorobyov:

When Charlie Newsom came, he came later, but he was very active, very valuable.

Warnow-Blewett:

Yes, yes. So… now your…

Vorobyov:

So it does not matter, that the first initial group, it doesn’t mean necessarily that…

Warnow-Blewett:

…it’s the most important.

Vorobyov:

It is only initial.

Warnow-Blewett:

Your money from this Institute is just straight Government money, right? Do you have to make a special request to the Government?

Vorobyov:

Now, yes, now we are coming to a very interesting point. It is the combination of money, western and eastern, because it is very different from a combination of money from western. We had no hard currency, practically no hard currency. But we discovered even before the Fermilab experiment, we discovered that it is very profitable to combine our efforts — not only in money-but what I mean is that our background is different.

Warnow-Blewett:

Your physics background?

Vorobyov:

Physics, yes and also as experimenters, our possibilities are different. I understand that, for example, for all western physicists and Fermilab physicists it’s much easier to buy something, but to buy something standard, which is for sale. Of course, now more and more things are for sale, but when we started that was not so. But the experiment normally requires not only standard things — also standard things give you standard experiments — but we wanted to have no standard experiments, so we always have at least part of the set-up which is not standard.

Warnow-Blewett:

That must be unique.

Vorobyov:

…must be unique.

Warnow-Blewett:

…and made by hand.

Vorobyov:

…and made by hand. Not industry. Of course, industry can do this, but it would be extremely expensive, because it is unique. For example, the system which we provided was estimated to more than one million American dollars, and it cost us less. Because it’s made here at the Institute.

Warnow-Blewett:

So you not only design it, but you also build it in your own shop.

Vorobyov:

So we understood that the combination of western and eastern possibilities is very simple. All the standard things is easy to be provided by the western groups. It’s stupid to make parts supply here when they could be bought…

Warnow-Blewett:

…off the shelf.

Vorobyov:

…not expensive, but all the unique items which require electronic engineering, for example, we have maybe thirty electronic engineers here.

Warnow-Blewett:

Thirty just for the High Energy Physics Institute? That’s a lot.

Vorobyov:

Yes, that’s a lot, and so they may develop, and construct some unique things. Le Croy was only started at that time.

Warnow-Blewett:

What was?

Vorobyov:

Le Croy. A specialized electronics firm, Le Croy.

Warnow-Blewett:

Le Croy.

Vorobyov:

He had no big choice at that time, now it is much more. Interesting. It suggest a lot of things, but it did at that time not. So we could really compete with Le Croy. Okay. And also material. Some materials are much cheaper here. For example Ksinon(?). We needed a lot of Ksinon(?), which is extremely expensive in the United States, and it is inexpensive here. So we provided ksinon(?) very easily. If we should buy [in the west] it should again cost us some several hundred of million, and so on. So there is the combination of two rules you should look at — they are very different really. Now they are becoming more and more similar.

Warnow-Blewett:

At that time.

Vorobyov:

At that time, and even now still there are some differences, and if we understand how to use the differences in an effective way, it works very well. For example, an odd example, in the experiment the most valuable people are electronicians.

Warnow-Blewett:

Electricians?

Vorobyov:

No, electronics, specialists in electronics.

Warnow-Blewett:

Electronics specialists, ok.

Vorobyov:

Because, we have, I don’t know, thousands and thousands of channels, bubble-chamber experiments, nowadays bubble chamber is already old-fashioned, but this is electronics, so thousands, many thousands of channels, maybe twenty thousand electric channels, very different. Physicists are not very good here, of course, they must do what should be resolved, and how it should work, but if doesn't work, they are helpless. We need some help. And to find some electronician in the Fermilab is not possible. There are several for the whole Fermilab. But in our experiment we sent five of them, I think, so most of them were these specialists.

Warnow-Blewett:

Did Leningrad provide most of the electronics specialists?

Vorobyov:

Many, many electronics and also we provided people who are experienced electronicians.

Warnow-Blewett:

So was Tkatch one of those?

Vorobyov:

Yes, Tkatch is an electronician, yes, a specialist in electronics, Grachev same thing, Denisov same thing.

Warnow-Blewett:

Denisov was also an electronics… He is at Fermilab right now, isn’t he?

Vorobyov:

Yes, he is there right now.

Warnow-Blewett:

Who is the groupleader for the Leningrad? Were you the groupleader?

Vorobyov:

For Leningrad?

Warnow-Blewett:

You were the groupleader for the Gatchina.

Vorobyov:

Yes, yes.

Warnow-Blewett:

But nevertheless, what I wanted to know is that within Russia, within the USSR, how are you funded? What I mean is — in addition to your regular funding — do you have to make a special appeal to do a special experiment?

Vorobyov:

Yes, that’s regularly the case. Once we understood we are going to such an experiment, then we apply for Academy of Sciences’s special funding. And we had such a special funding for that experiment. I don’t remember the exact figure, approximately I million rubles per year. And we have a similar funding now.

Warnow-Blewett:

For the new experiment.

Vorobyov:

For the new experiment, one million rubles per year, but this a special decision, really, in the Academy.

Warnow-Blewett:

Yes, and so you write a proposal, just very much like we would do.

Vorobyov:

We present the same proposal.

Warnow-Blewett:

Yes.

Vorobyov:

Same proposal and we say we need support.

Warnow-Blewett:

Yes, and that this is a good idea, a good experiment, so you’ll want to fund us, and the whole thing.

Vorobyov:

I think it is very similar.

Warnow-Blewett:

Yes it is. Did you make the presentation to the Fermilab, by the way?

Vorobyov:

Oh, yes, of course we were obliged to go through several committees.

Warnow-Blewett:

And so were you the person who spoke for the Leningrad group?

Vorobyov:

I gave a seminar, I remember, on this transition radiation physics, so first there was a discussion with Leon Lederman, trying to convince him. For the most important to convince was Leon. That’s the mark of him. He was more or less convinced.

Warnow-Blewett:

He was more or less convinced, even though he made a bet.

Vorobyov:

But, of course, it really means this bet means to stimulate the job, but not to reject. But for the formality we were obliged to go to present this to the panel, and we were approved there.

Warnow-Blewett:

So who made the presentation?

Vorobyov:

Maybe Joe Lach or Cooper, not me.

Warnow-Blewett:

I see.

Vorobyov:

Because I think we had already elected a spokesman.

Warnow-Blewett:

So that would have been Cooper probably.

Vorobyov:

Yes probably Cooper. For our next experiment, E761, I am a spokesman.

Warnow-Blewett:

Oh, you are?

Vorobyov:

Yes, so I am still sitting here with — I’m a spokesman.

Warnow-Blewett:

Elected?

Vorobyov:

Yes.

Warnow-Blewett:

Now I think we talked quite a bit about the piece of equipment you were mostly involved with.

Vorobyov:

Yes.

Warnow-Blewett:

And we also discussed the fact, that it was made in this Institute, designed in this institute and made in this institute. While you all were building the various pieces of equipment here in Leningrad, in Iowa, at Yale, how did you communicate? Did you meet very often?

Vorobyov:

At that time the best communication was phone.

Warnow-Blewett:

By telephone.

Vorobyov:

By telephone. So it was quite easy, proved to be quite easy. Nowadays it’s becoming more difficult, because the lines are always busy.

Warnow-Blewett:

Always busy.

Vorobyov:

But at that time there were not so many people, so for us it was…

Warnow-Blewett:

So it was easiest with the telephone.

Vorobyov:

It was not very expensive, so we could easily communicate and speak for half an hour or so.

Warnow-Blewett:

So did you speak from one person to another, or did you have a conference call with many people?

Vorobyov:

Normally from one person to another, but at Fermilab there is such a facility, that many people can…

Warnow-Blewett:

…can talk at the same time with the speaker on. And so, let’s see. The proposal went in in February and it was accepted soon afterwards. And how long did it take to build the detector?

Vorobyov:

Yes, I see here the dates February 19, 1982, but I remember very well the date of the starting of the experiment, that was October 1, 1983.

Warnow-Blewett:

So it took a year to build the equipment.

Vorobyov:

Yes, to build equipment, to transport it, etc. So, of course, in fact this was very tough. One year is very short period really for that. I mentioned only one piece of equipment, this transition radiation detector, but we provided many proportional chambers and other electronics, etc., so this was a huge…

Warnow-Blewett:

…commitment.

Vorobyov:

Yes, commitment for us; maybe one hundred people were occupied to prepare, not only these, but the Institute — maybe not unlikely a hundred people or more.

Warnow-Blewett:

So that would be engineers, electronics specialists.

Vorobyov:

And electronics specialists, workshops, physicists. So it really was a huge, but the priority was high at the Institute, it was international and the schedule… Why October 1, 1983; because by that date the Tevatron should come into operation.

Warnow-Blewett:

Was it the Tevatron or the superconducting…

Vorobyov:

Superconducting.

Warnow-Blewett:

It’s sometimes called the Doubler, too. It doubles the energy?

Vorobyov:

Ye-e-s, it doubles the energy, and we needed the energy also. And we were scheduled to be the first experiment at that accelerator, so. But the discussions even here at the institute were not very smooth, I should say.

Warnow-Blewett:

Smooth?

Vorobyov:

Yes.

Warnow-Blewett:

What were the discussions about?

Vorobyov:

It was not easy to make a (???) here at the Institute. Why? I think this psychologically for the Soviet Union still exists, but maybe not so strong as at that time. There are several arguments. One is, of course, this not an easy contribution, so there are all the efforts, especially the workshops that are supposed to be occupied, so that some other experiment would sacrifice, I guess for one year. So, that means, that this experiment should be at the expense of some other experiment. And, of course, the other people were not very happy with that, you understand.

Warnow-Blewett:

Sure.

Vorobyov:

Second argument was, as far as I remember, that the superconducting accelerator was the first attempt to construct a superconducting accelerator, and some people here were very skeptical about that. They did not believe that it could ever work. They’d say there were many, many Americans, say, if one American got out and then you should stop accelerator. They calculated the probability, they multiplied by the number of magnets and they resolved that it would never work. And these are very important physicists who made such a statement.

Warnow-Blewett:

Were they within the Institute?

Vorobyov:

Yes.

Warnow-Blewett:

In other words, you had your approval from the Academy, and you had your money.

Vorobyov:

No, this was before.

Warnow-Blewett:

Oh, this is before you got the approval.

Vorobyov:

Before we come to the Academy we should have support from the Institute. Because money is money, but…

Warnow-Blewett:

…the institute is the institute. Okay.

Vorobyov:

…oh, yes.

Warnow-Blewett:

So, were there any other argument against it?

Vorobyov:

Yes, there are some other arguments. There are some so-called patriotic arguments. They say that the priority shouldn’t be given to the outside experiment, because this is maybe important for Fermilab, but not so important for our Institute. So why should we put priority on such an experiment, we should give priority to our home experiments rather than outside experiments.

Warnow-Blewett:

Meaning Russian accelerators?

Vorobyov:

Russian accelerators. Here at the institute we have an accelerator, we have reactors, so we have a huge program, quite the best program in research.

Warnow-Blewett:

Yes.

Vorobyov:

So these people insisted that the priority should not be given to such experiments, but without priority it shouldn’t be done, it could not be done. So that’s another argument. Finally, there was a political argument, that relations are so unsolid…

Warnow-Blewett:

Unsolid?

Vorobyov:

…between the Soviet and the United States…

Warnow-Blewett:

Oh yes.

Vorobyov:

And at that times the United States was really crazy. They stopped Aeroflot flights, for example, so we couldn’t use them. They made many decisions to kill all the relations, so this was by the way the only one which survived. Our experiment. All the rest were killed. And this was by the State Department there. So it was not evident that if we spend all this money, all this effort, and then the experiment could be stopped. So they were very serious arguments against. And they are not very stupid, by the way, these arguments. They are quite serious, they are problems, okay?

Warnow-Blewett:

We are just getting towards the end of this tape, so just keep on talking.

Vorobyov:

Finally our Director (name maybe??) he supported it, that…

Warnow-Blewett:

Who supported that? Your Director.

Vorobyov:

Our Director of the Institute. And he convinced the other people.

Warnow-Blewett:

Okay. So we were just saying that your Director persuaded the Institute.

Vorobyov:

Yes, he supported us. Also the President of Academy of Sciences, Academician Alexandrov, also was a strong supporter. You remember that now it’s trivial, but in that time it was far from trivial. In the United States, Lederman was practically alone who managed to keep the collaboration. But now I should tell you something. Of course, we needed some official approval; and the line we used, the official line was the agreement between the United States and the Soviet Union. They called this the official standing agreement on the parliament of Social or something like that. It was signed by Brezhnev and Nixon. And under that agreement there was some special branch for the fundamental high-energy physics research. Since then there is a special committee, Soviet-American committee, which has regular meetings — once in the USA, second time here. And this committee also selects some topics suggested from the laboratories and puts them into protocol. It does not provide money. If you’re in the protocol, then it’s a good thing, because now you may refer to this protocol, you may fight all kinds of bureaucrats. Oh, look this is in protocol, etc. this is State agreement, so all kinds of visa, etc. It was very useful. But again, I repeat, that this doesn't mean anything about money. So it’s just bureaucratic…

Warnow-Blewett:

Smoothes the way.

Vorobyov:

Yes. This committee continued to work and this year its meeting will be in the United States at Fermilab. So fortunately we have all kinds of support — home support, Academy support, government support. And when it was created under Brezhnev and Nixon, this committee included, as far as I remember, thirty-five items in this protocol — several experiments and some meetings. By 1983, only three or four survived, and we were one of them. All the rest were killed. And always beginning with the State Department of the United States. Leon Lederman told me that it was very difficult to keep it, but he was very convinced that we should make our best, not only from a scientific point of view, but we believed in some future this would play some role in…

Warnow-Blewett:

In keeping the countries together.

Vorobyov:

Yes. Of course, people are joking always: “Oh, two big continents, two big countries, and you are so few. It’s negligible, your role, you’re not serious about it! But then I convinced all these people, saying (here in this institute), “Please tell me what do you know about China?” And this question is a dead question. Nobody knows anything about China. Because we’ve had, for many years absolutely zero information about China. Many, many years ago there were many Chinese here, and then everybody changed with this cultural revolution; we have absolutely no relations. I don’t understand, if they have television there, if they have telephones, if they have cars, what they eat, how do they look? We don’t have anything. Okay, so, what do you know about China? But now suppose one Chinese comes to our Institute — only one. He will tell us about China. Please tell me, how many hours, or how many days would be needed that all of Leningrad would know about China? I have friends who have friends. I will tell them, “Oh look China is here.” For example, there was a rumor that there was an accident of our reactor, and in only twenty hours all Leningrad was aware about it. No official announcement, the reactor was stopped and dismounted. This was a false rumor, and still it took only twenty hours for 4 million population to be aware about it. So I say, “Even one guy could tell a relative in Moscow, etc. So they will spread out this information.” I don’t say it’s so negligible when we have friends and we are home and visit families, etc., and it works really. So I was convinced and Leon Lederman was convinced that it’s really a good thing. So we were really very serious about that part, not only scientifically, but also internationally.

Warnow-Blewett:

So then, now if we go to the next stage of the collaboration, it would be when you went to Fermilab with your equipment. How did that work?

Vorobyov:

Ha, ha. This was the most difficult. Because you remember the traditional stuff: You can fail by many reasons, and at least one of them would be enough to kill the experiment. What happened? The first of the trouble at the starting point of our experiment. The 1st of September the Korean aircraft was…

Warnow-Blewett:

I remember.

Vorobyov:

You remember that. You remember the whole situation. Part of our team was already at Fermilab. Part of our team, me included, we were here. Part of our equipment was there. Parts somewhere on the way. All the flights were stopped. This time, not only by the United States government, but also by the Soviet Union, because everybody was afraid of complications. So we were harmed. As soon as I heard on the radio this announcement, I said, “Oh my God, so this is the finish!” We managed to penetrate many complications, but this, this is a dead (???). And I thought that this is it. I was in Georgia at that time. There was a conference here.

Warnow-Blewett:

In Georgia in the USSR.

Vorobyov:

Georgia, yes. And then I said, “That’s finished.” So all these pessimistic predictions. Okay, but still I came to the President of the Academy of Sciences — Alexandrov.

Warnow-Blewett:

Alexandrov.

Vorobyov:

Alexandrov, yes. I told him at this point it is not possible to stop this program. And of course Lederman and some of the other Americans they also realized it was extremely serious. So they were also mobilized. Alexandrov made such exclusion(?) so he phoned to the government, and I alone got the permission for flight. But there was no flight. So I used some Bulgarian or Yugoslavian plane to come to Montreal. And then I switched out from Montreal again. Anyhow I reached Fermilab. The problem with the equipment was more complicated, some of it was in Paris, some London, so there were many communications.

Warnow-Blewett:

Why was some of the equipment in Paris and London.

Vorobyov:

Aeroflot stopped, and where they stopped they just left everything. The problem was to find it, where it was. Fortunately most of them were already at Fermilab and it’s a miracle, I think, we managed to find everything. Now when people say, “Oh it’s a problem and it’s difficult,” I say “Okay, remember the Korean incident?” If you managed to survive at that time…

Warnow-Blewett:

This is nothing compared to it. So instead of starting October 1, when did you… ?

Vorobyov:

I started October 1.

Warnow-Blewett:

You did!

Vorobyov:

At noon.

Warnow-Blewett:

At noon, ah! So between September and October you got everything together. Fantastic.

Vorobyov:

Yes, I mentioned already most of the pieces were there, but if something is of value, we can’t do it! So we managed to have all the pieces and start the experiment. But the most surprising thing that happened on October, we also received beam on that accelerator… Of course, it was not very stable during one month period, but…

Warnow-Blewett:

The beam was not.

Vorobyov:

In a month it was already reasonably good, but from the New Year it was…

Warnow-Blewett:

…perfect. Ah ha! Now, so then, how long did it take when you had all the equipment there and the beam was coming in. Still did you have problems with setting up and testing?

Vorobyov:

Yes, but these are more or less normal problems. Normally we try to be prepared in advance, so this is our rule here. It’s different from some Western groups, because some people only start the testing when the beam occurs. We tried to make tests simulating the beam by some kinds of test signals. So we are well prepared. Normally we are well prepared. At CERN, for example, we made a world record — we were ready to run an experiment in three days. So this was noticed in some record book, and cited many times. Here it was much more complicated. We spent maybe one and half months run-in. This was coherent with the setting up the beam. In two months the accelerator was in good shape and we were in good shape.

Warnow-Blewett:

But now it wasn’t just Russian equipment, because you had the other equipment. Everything had to be organized.

Vorobyov:

Yes, but in this case, you know, we didn’t separate it. In so much we had collaboration, then we don’t see who is who. Our specialist was working on some other pieces which were provided by somebody, Yale University, or someone, so we were distributed. Of course, we dominated on that experiment. We have the most numerous, and we have many specialists.

Warnow-Blewett:

And you had the most important pieces of equipment, too, to build.

Vorobyov:

Yes, but we participated even with putting into operation the American equipment. Just because we had these experimental electronic engineers with us.

Warnow-Blewett:

So the rest of the groups came, but they didn’t have the specialists?

Vorobyov:

Some of them participated in the analysis. But then we needed some people just coming and going to shifts.

Warnow-Blewett:

Everyone went on shifts then, right?

Vorobyov:

Yes.

Warnow-Blewett:

It means that when you went on shifts, you Russians from Leningrad, you understood all the parts of the equipment, whereas, say, someone from Iowa may not have understood your equipment? Is that true?

Vorobyov:

Yes, that’s true. We were a more strong group.

Warnow-Blewett:

Yes. So, does it mean that you had someone from this Institute on every shift?

Vorobyov:

Yes. Of course, we had some main block of components, and in each block there is some guy who understands better than the others.

Warnow-Blewett:

People on the shifts, you mean?

Vorobyov:

No not on the shift, but in general — Expert on this block.

Warnow-Blewett:

On this block, you mean a part of the detector?

Vorobyov:

Yes, part of the detector. If something happens, he is consulted and he comes anytime to help. Then there are other people on the shifts, like physicists — physicists are not obliged to penetrate in integrated circuits, they should understand how everything behaves. Normally physicists run the shifts and the experts are just looking. The best combination is that some amount of experts are not in the shifts; they are permanently there.

Warnow-Blewett:

They can be called in.

Vorobyov:

They can be called anytime they are needed. Three, four such guys. We were not so rich. So, all of us went to shifts and some of them still might be experts.

Warnow-Blewett:

Did you have graduate students with you?

Vorobyov:

No, that’s again a very different system, the Soviet one. I understood that in America the graduate students, or postgraduate.

Warnow-Blewett:

Postdoc or graduate student both.

Vorobyov:

Those who are working for their thesis. So they are valuable on experiment and analysis. I understood that professors they are not so very active, so the professors normally should organize postgraduates. The advantage is that the postgraduates are very tough, very enthusiastic to make experiment. Disadvantage is that they are not so experienced, especially on the final stage when everybody disappears and there is always…, I noticed on the Western experiments — people are very active when the experiment is going on, but as soon as it stops everybody disappears and only one or two grads are left after that. Then what? Everything now from that point depends on the quality of these guys. If the graduate is good — for example, Joe Lach, when we competed with him, I couldn’t understand at first some of his articles were very bad, with many errors, even experimental errors, very trivial errors, and I pointed out to Joe, I said, “Okay, what happened?” Some of them, his articles, were (???). And I understood that this was just the quality of the student — good student made a good job, bad students spoiled the whole experiment. So there are advantages and disadvantages. Here we don't have graduates. As I mentioned, people who graduated, students who graduate from the Institute, they come to the permanent staff here. They start their research work and they defend their thesis, and they become doctors, etc. But they are not post-docs. We have really different system.

Warnow-Blewett:

But while they’re doing their research, and before they defend their thesis here, they are also the equivalent of a graduate student.

Vorobyov:

There is a big difference. The difference is that they are already permanent staff. While American graduates they are working alone.

Warnow-Blewett:

This is true.

Vorobyov:

Most of the graduates might disappear after that. Practically one hundred percent.

Warnow-Blewett:

As soon as they found a position, they had to leave.

Vorobyov:

They are looking for a position in industry rather than in the science. This is very bad, because that means that they are not so interested in the results. They may present any results. They need just an article; any kind of article to defend their thesis. Of course, some people are very honest, but some not. Objectively, it’s very bad because really all these guys who participated in our experiment they disappeared and they went to jobs. So it was not the main activity for them. I found this is a very bad drawback in the American system. In some sense, our system provides better, because for us when the running is finished, the experiment is not finished. We all are involved, we all are continuing to analyze. I don’t remember a case when we spoiled the experiment by bad analysis.

Warnow-Blewett:

I understand. We’ll come back to that too, in a minute. Did you have any — during the run, in taking the data — did you have any breakdown in the accelerator at all?

Vorobyov:

Oh, yes, that’s normal. Especially a new accelerator like that which was, you remember, people didn’t believe at all. So, breakdowns happened. But we considered that we had 80% efficiency.

Warnow-Blewett:

Eighty. That’s good.

Vorobyov:

Yes. That’s good. The accelerator came to such a figure in two months.

Warnow-Blewett:

And all the detector parts, sections, whatever, they all worked once you got it going. You didn’t have any breakdown there?

Vorobyov:

We had also some, especially in the initial phase. We had some problems with our equipment sometimes, but no major problems — some more or less trivial incidents; sometimes some stupid things. For example, we discovered — you know at Fermilab, everything is computerized, even at that time. All the magnets are under computer control. So, you just push buttons and you set cards. For example, you don’t need such a magnet, and you push zero.

Warnow-Blewett:

Off it goes.

Vorobyov:

And it’s off. So, we did that. But then one day, somebody with an iron piece was close to the magnet and puff! As you know, the iron piece is attracted. What happens: the computer was on, the program was on, but for us it was disaster, because we believed that that there was no magnetic (???) at this point, and in fact it already deflected our beam and introduced some asymmetry in our measurement which might spoil our…? To correct that, we should have a map of a magnet and it’s terrible, and we’re already running one week working under these conditions. When Leon came… Lederman… he was (???ized.) Forget about it! I’ll give you an extra week!

Warnow-Blewett:

No good! Right? At least he made good and gave you more time.

Vorobyov:

He did allow us enough time to finish the experiment.

Warnow-Blewett:

So, how long was the run? How many weeks did you collect data? You had one month to work out the problems.

Vorobyov:

Normally running periods at Fermilab are very long. It’s a really exhausting job. It’s six months running. You understand why.

Warnow-Blewett:

I don’t know why.

Vorobyov:

Now the strategy is that the accelerator runs half a year for colliding physics, half a year for fixed target, so they more or less subdivide it like that.

Warnow-Blewett:

That’s right, I’ve seen that.

Vorobyov:

This time we are running even more, some eight months. But we are doing four experiments in sequence.

Warnow-Blewett:

In that eight months period.

Vorobyov:

But this is tough. This is really… For example, here or at CERN, we are normally used to some other schedule. First we have some test running, one week, two weeks, then we analyze data. Understand what is bad, what is good, and then we do the main running. At Fermilab there is no such break. They say, this is in one piece. That’s difficult. You should analyze on line you should understand and you should be very attentive not to make any mistakes there. And here in that particular experiment, I remember there was a very critical point, when I was fighting with the whole collaboration. Because I understood that our trigger system was not ideal… was very dangerous, I should say. We might exclude already on this level, that we may exclude some good particles in a not-controllable way which might spoil our final results. And with our people –- Tkatch — and with other people we developed…

Warnow-Blewett:

With who?

Vorobyov:

Igor Tkatch, the electronician.

Warnow-Blewett:

I call him “Takatch.”

Vorobyov:

I understood also that politically it would be very difficult to defend. Because we already started data taking. We already had this problem with the magnet. One extra week. Politically we were already weak, because we made one mistake. Now, if I say let’s change the trigger, I should convince the other people that this new trigger is a really good trigger. But what if I am not right? So we need some time, etc., additional time to be sure that it is okay. That’s why we prepared everything, electronically. We had a cable… a new cable. I didn’t tell anything about that for some days… during some days. We prepared everything and then we had a cable. Then I said, “Guys, look, the only thing which is needed now: take off one cable and put on another cable. It’s very simple.” But they say, “No.” Four of them including Per Grafström who was my friend said, “No, it’s dangerous to change.”

Warnow-Blewett:

Including who?

Vorobyov:

Per Grafström, who is my beloved friend. Everybody said, “No, it’s too dangerous.”

Warnow-Blewett:

What do they mean by dangerous?

Vorobyov:

To change experiment during run.

Warnow-Blewett:

It’s a basic change.

Vorobyov:

It’s basic change. You should make some controls, self controlling, self… etc. before you made such a decision. We’re already running, we already have two weeks. They say, “We have two weeks, that’s good, we are not going to spoil this, we might use this.” “But the rest of it will be in even better conditions.” “How do we know that it’s better?” And then there was a “vote” and they say no. And I said: “You crazy guys, you, you have no strong arguments. You’re like my grandmother, you’re just afraid of changes.”

Warnow-Blewett:

Did you say that?

Vorobyov:

Yes. I was so irritated I just slammed the door and went to the village and said, “I don’t want to speak with you anymore.” So it was really fighting… but it was the only maybe critical moment. Normally we are very polite. We have friendly discussions, but that time I was surprised they were so strong they did not want to change their opinion. Okay, so they never saw me like that, so of course they started to think that maybe it’s serious. The next morning the delegation came to say, “Okay, we agree.”

Warnow-Blewett:

Fantastic! So you felt very strongly that this trigger should be changed in order to have the data improved.

Vorobyov:

The data should be safe. Because now… then I knew that in that trigger, I’m sure that I’m not killing good events. In the previous one I was not sure. But the argument these guys used was, how do we know that your electronic system is working perfectly as well.

Warnow-Blewett:

You mean the one you proposed.

Vorobyov:

Yes. It needs some controls and it needs some time, I say Okay! But just any kind of control can do this (???). But just because they were not experienced, this was new for them, it took one day to accept this idea, but then everybody agreed and it was a very good decision, really, because otherwise… it was not a catastrophe, but really…

Warnow-Blewett:

It was an improvement.

Vorobyov:

Yes it was important to improve… so it happens… things like that.

Warnow-Blewett:

Was it quick for them to see that you were right when you’d changed it?

Vorobyov:

They should think. Because there was no way to… you know, a trigger is always a terrible thing, because you kill some amount of events, and you don’t know what you kill. What is saved is on the data, so you may check that. But what is killed is already disappeared. So you have to think logically to probe all what is in (???) some test, (???)

Warnow-Blewett:

So you were able to test it?

Vorobyov:

Yea. But this is really the most serious decision on the level of trigger in all of this experiment. All the rest is on the tapes so you may play with the software.

Warnow-Blewett:

Now… So that happened two weeks into the run.

Vorobyov:

We used both data. But really when we analyzed later on, we realized that these two sets of data still have the defect… not too serious… but…

Warnow-Blewett:

But you could tell that it was really a change for the better, that you changed the trigger. So, then you ran for an additional four months?

Vorobyov:

Four months.

Warnow-Blewett:

Were you there the whole time?

Vorobyov:

Yes.

Warnow-Blewett:

And most of the group from here was there?

Vorobyov:

All of them. Most of them came much… some three or four months before experiment and stayed. They stayed more than one year.

Warnow-Blewett:

That’s very hard.

Vorobyov:

No, it was very nice! It was good time.

Warnow-Blewett:

But it’s still hard on families back home.

Vorobyov:

But the families were there too.

Warnow-Blewett:

Oh the families came too. Oh good. When did the data analysis start? Was it while you were still at Fermilab?

Vorobyov:

Of course part this… the signal was demonstrated immediately, so we were sure that the results would be good. The final results required several months of analysis. So we left some special group and Per Grafström was responsible for the first period of data analysis. I mentioned that he is very reliable. And then he was joined by some other people.

Warnow-Blewett:

!just want to make sure the tape is in. I just missed the last part on the tape. You were saying that Grafstrom stayed at Fermilab?

Vorobyov:

Most of our people… several people stayed permanently.

Warnow-Blewett:

To do data analysis.

Vorobyov:

Two physicists from our group. During the experiment we were six or seven. Then we sent two new physicists.

Warnow-Blewett:

Who were they?

Vorobyov:

One was Valerij Schegelsky. You met him. He was in the analysis. And then Smimov. I don’t remember his name.

Warnow-Blewett:

He’s not on that list.

Vorobyov:

He should be somewhere here.

Warnow-Blewett:

Maybe on the publications?

Vorobyov:

On the publications. Here.

Warnow-Blewett:

Smirnov, ah ha. So he went to Fermilab?

Vorobyov:

They are more experienced in physics and in data analysis. So they spent a lot of time there, half a year, maybe more. Also I joined them for a month or two.

Warnow-Blewett:

You stayed on for a month or two?

Vorobyov:

Came later. Came back when they were already in good.

Warnow-Blewett:

When they’d done a lot of work, you wanted to join them. When they worked, you had the raw data, then you had summary data?

Vorobyov:

I think by the end of 1983, we already had summary data. The main answer was obtained quite quickly; by the end of 1983 we already published it — the asymmetry. And we proved that the previous three experiments were wrong and the theory was right.

Warnow-Blewett:

The Cabibbo.

Vorobyov:

Cabibbo was happy. He sent us a telegram with only one word: “Bravo!” But maybe it was not so — it’s always more exciting to violate theory than to confirm it. But weak interaction theory really needs support rather than violation. That was an important step. Experiments were much more abundant — I mean not only that answer, we had much more information. In fact it was the full study of beta decay, polarized sigma decay. So we collected maybe 50,000 events. This was most statistically problem (???) experiment of beta decay sigma. So we continued to analyze and we had a lot of new information, we published that in this big article. Later on we also measured some magnetic moment of this (???)’s sigma minus. And then there is the fourth publication (???) minus magnetic moments also measured by that time. So these are two which were not foreseen measurements. We spent one week, not secretly, but not scheduled. We had enough. We decided that we had enough statistics for the main experiment. And we spent one week more to measure magnetic moments.

Warnow-Blewett:

But one of the things that surprises me, it sounds as though all the data analysis was done at Fermilab?

Vorobyov:

Oh. It’s not a surprise because Fermilab has a very good computer center. One of the most powerful computer centers among all the physical laboratories. It’s much better to use that center than any other. We’re not so strong here. Of course, if you have summary tape, then we might do some job.

Warnow-Blewett:

Didn't you have summary tape at Fermilab?

Vorobyov:

We could do that. Of course, we did. But still we decided that with Fermilab, in case with Fermilab, it’s easier to send people there.

Warnow-Blewett:

What about the other groups? What about Yale for example?

Vorobyov:

Yes. Peter Cooper was also participating.

Warnow-Blewett:

…in the analysis.

Vorobyov:

In the analysis. Teig participated. But he went to industry very soon, so…

Warnow-Blewett:

I see. Was he a student?

Vorobyov:

Post graduate. Then some other people, not mentioned here. Jeff Strenskij, he participated in that.

Warnow-Blewett:

Strenskij? From where?

Vorobyov:

From Fermilab. He also moved to industry.

Warnow-Blewett:

So he’s another one.

Vorobyov:

Yes, they defended their theses and…

Warnow-Blewett:

…and off they went. Okay. And then what about the others here. We have Iowa, I mean, Iowa State and the University of Iowa. What about Ronald Winston?

Vorobyov:

He was also very active.

Warnow-Blewett:

…In the data analysis, yes. Did he also stay at Fermilab to do the data analysis?

Vorobyov:

At Chicago, of course.

Warnow-Blewett:

Chicago, right. The thing that I’m used to in the past in most of the interviews that I’ve done, is that copies of the summary tapes, went out. But in this case, you didn’t have the strong computer center here?

Vorobyov:

No, the computer center is strong enough to work with summary tape, but still again, in this particular case, when we have very good relations with Fermilab, there was no question of money. I should mention to you that our stay is paid by Fermilab.

Warnow-Blewett:

I see. So, once they approved you, they paid for your whole stay. So your room and everything was taken care of.

Vorobyov:

For room and for salary and for cars. Everything was provided by Fermilab, which is quite essential support. Of course Fermilab is calculating also their profits and they calculated what is our contribution and we see that it’s much more than one million of dollars. And they compare it with what they are paying in salaries.

Warnow-Blewett:

Yes. It weighs out. Did you actually use the raw data tapes for your analysis, or did you use summary tapes there?

Vorobyov:

Raw tapes in the first initial stage and then we agreed on the criteria of selection very soon and prepared summary tapes. That’s a very essential decision.

Warnow-Blewett:

Was that a difficult discussion to decide what you were going to summarize?

Vorobyov:

Yes and no. In all experiments… as soon as… it was very clean, in fact. Only two particles detected. Analysis was not terribly difficult. But still we did two independent analyses. One made by Grafström and one by Schegelsky, so we were able to compare.

Warnow-Blewett:

Did you have any theorists in this group?

Vorobyov:

In this group, no. But we have a very strong theoretical department in the Institute. About 70 people. Not all of them are high-energy physicists, some, maybe 10 or 15 people are solid state physicists, about 50 people are nuclear and high-energy physics. And they are of course very useful, on the initial stage when we are discussing the proposal. They are very useful at the final stage.

Warnow-Blewett:

When you're doing the analysis.

Vorobyov:

When we present the article. In fact, in some sense this work was stimulated before theorists. They made some independent theoretical research. And published the results.

Warnow-Blewett:

In separate papers.

Vorobyov:

We don’t think they are needed during the experiment.

Warnow-Blewett:

Okay. When you were working at Fermilab, you and the others, and coming up with your analysis, did you report back your findings to the theorists here, as they were coming in?

Vorobyov:

Of course, they are interested.

Warnow-Blewett:

Yes, of course. So, was there discussion?

Vorobyov:

Oh, yes we are discussing. I mentioned already there was some workshop here and this workshop all our theorists participated in.

Warnow-Blewett:

When was that? Tell me when that workshop was?

Vorobyov:

I think it was 1984.

Warnow-Blewett:

So, this was after you had collected the data and published your first papers in 1984.

Vorobyov:

Yes.

Warnow-Blewett:

And so the theorists were involved then, right?

Vorobyov:

Yes.

Warnow-Blewett:

Now let’s see. You said you had two independent kinds of analyses, or two groups doing analysis, yes? And you tested then their results and everything worked out. Who were the people that you mentioned were heading those two groups?

Vorobyov:

The first was Grafström, the first analysis was Per Grafström.

Warnow-Blewett:

Yes, he was the head of the first group.

Vorobyov:

Not only that, but the main person. Then Schegelsky came.

Warnow-Blewett:

From here.

Vorobyov:

Grafström already went back to Europe by that time. But Schegelsky started from the beginning.

Warnow-Blewett:

So, then you had two different… I see. During the data analysis, the groups were just all there in Fermilab doing the work. Some communication back home by telephone?

Vorobyov:

By telephone, by letters.

Warnow-Blewett:

By letters! So you did have some letters.

Vorobyov:

Yes, of course. And also traveling people. But you know, the analysis phase is very delicate, so you couldn’t do much by telephone. That’s why I came to spent another two months.

Warnow-Blewett:

One of the things I’m interested in for this project, is the role of computers and software. Do you think… it’s interesting to ask this question. Could this experiment have been done ten years earlier? Try to take out the accelerator, because obviously that was a very important thing. But in terms of computers and software, what do you think?

Vorobyov:

I think yes. The requirement for computing power is not extreme in this case, as I mentioned, it relatively simple, the analysis. It’s difficult to get rid of background, but when you have clean sample of the event, the analysis is simple. It doesn’t really require the most powerful computers.

Warnow-Blewett:

That’s interesting. Then the next question is, how do you think this experiment could have been done today? It’s not ten years later yet. But would it have been different today. Would computers or any other thing… ?

Vorobyov:

That’s an interesting question. Because, you know, we started with thirty events… our previous background. Thirty events. Of course we were happy with fifty thousand events. But when we went through all the analysis and we came to such a delicate question like four factors of beta decay, etc., and we understood that it would be nice to have even better precision. Because we just approached a very fundamental thing which were not even discussed at that time when we started the experiment. You remember we discussed very trivial things by the Cabibbo prediction of the first form factor. But in fact, there are four form factors involved in the beta decay. We can feel… we determined (???) of the second one. But there are four, so we could control all four. But we need — especially the fourth is very fundamental — but it is very weak. We feel it, but we need more statistics. Of course, if I plan now, but I’m sure that this is maybe for history, it’s interesting, but my feeling is that nobody ever would repeat this experiment.

Warnow-Blewett:

The one that you did, 715? Why not?

Vorobyov:

We could repeat, but there is no enthusiasm. Because, you know, if this was a home accelerator and if the whole setup was there on this mount, then of course it would be natural to come back in a year and to repeat that experiment and collect more statistics, which you could do, as I mentioned using more powerful computers, for example now at Fermilab, it’s very remarkable. Really we are in a position now to collect more statistics in a second find(?) quality of the data. And there we will encounter this phenomenon, maybe problem. But that means that you should make an experiment on a precision — not one percent, not two or three percent as we did in this experiment — but on a level .1 or .2 percent. Only very few people, very few groups would dare to design such experiments as a rule.

Warnow-Blewett:

Why is that?

Vorobyov:

It’s difficult to make an experiment on the level to avoid all systematic errors, to control everything. You should understand everything. So it’s inevitable you should make first stage, and then second stage. To come directly to the second stage is not possible. You should understand your equipment very well, etc. But as soon as this collaboration already will never return back, and I know that nobody else, my prediction is that this is the limit, nobody will come back to this question. But I don’t know if I explained that in an understandable way. If it’s a CP violation or a fundamental problem, then of course people would come. It’s not as fundamental as CP. It’s fundamental, but not as fundamental. That’s what I don’t think people would dare to touch it.

Warnow-Blewett:

You’re saying that in order to do that, you have to go back to the beginning and re-tape. Everything would be just a little new. The computers would be just a little new.

Vorobyov:

Yes, and psychologically for me, for a lot of people to return back, is very difficult. We will always go forward. And to return back, no.

Warnow-Blewett:

And therefore you’ve just missed something. You’ve just missed this chance to do that.

Vorobyov:

Yes in some sense, in some sense, it’s a pity. It’s a pity that the experiment should be done in one piece, without repetition. Normally in my life I made many, many experiments, never did any in one; I always came back and repeated once or twice or three times.

Warnow-Blewett:

What is the experiment that you’re working on now at Fermilab? Is it related to this at all?

Vorobyov:

Yes. It’s related. It’s also hyperon beam. The experiment is… when we were in Fermilab and we were in the final stage, naturally we were thinking about continuations. And again the same problem. So we were sitting and having in mind different problems. And again trying to find some combination of this problem, solution, problem, solution. At that time there was a conference at Fermilab on hyperon physics. And Bjorken, “Bj”, he had organized this conference. He is very good in summing up the problems. He was very closely related to the experiment.

Warnow-Blewett:

So he was very interested too. So there were the Fermilab theorists.

Vorobyov:

Those Fermilab theorists were very useful for (???) Well, okay. There was a workshop. I happened to be at the workshop. Not on purpose, but happened to be at this workshop. I was impressed by Bjorken saying that among all the problems in hyperon physics there is one outstanding problem. He called it enigma… of Sigma plus (???) so there is some special rare decaying in… decaying (???) and normal decay, which decays into a very simple (???) gamma. But the background is terrible. (???) plus by (???) which decays into two gamma. So, you should separate two gamma from one gamma. The situation was fantastically similar to that. Theory says that there should be no parity violation to this reaction, but there were two and now three experiments which all see strong parity violation effect. Very, very difficult. But there are again, thirty events there, twenty events there. So you know I have strong suspicion that again history will be very similar.

Warnow-Blewett:

Repeat itself with 715?

Vorobyov:

But… history failed. The number of theoretical papers was more than the ongoing events detected. There were fifty theoretical papers I reviewed and no theoretical explanation of this phenomenon was found. So that’s why it was stressed by Bjorken that what happens is not understood. So this was set as a number one priority in hyperon physics. Of course as I mentioned, I was sleeping at that conference, but then I was awakened by this statement and stopped to think about that. Then… I suggested… I know why two gamma are difficult to separate from one gamma, of course, and you should find some other way. And then I suggested to make this again on the transition radiation detector as a gamma detector, but now not only… not to separate one particle from another particle, but to detect the (???). It’s a difficult experiment here, but there is some advantage, so it would be quite cheap but very precise measurement of recordings of the gamma(?). One two gamma they are distributed in such… when one gamma its in a predicted position. So if I detect my detector gives me the…

Warnow-Blewett:

…the coordinates?

Vorobyov:

The coordinates of that. Okay, then I solve the problem. Then I suggested that if I do such and such a thing, then I could detect better than (???) precision. And that solves the problem. So I went to Fermilab with the suggestion written. By that time we had terrible accident… so one of our guys decided to immigrate. Maybe you heard about that. His name is (Jan) Kulikov. Then everything was finished. This was the end of 1983.

Warnow-Blewett:

When everything was finished with 715.

Vorobyov:

715. Yes. Everybody was happy; it was just Christmas time, December 25th, January, and some other guys went back to Leningrad.

Warnow-Blewett:

Who did?

Vorobyov:

Kulikov and some other person. And then he disappeared… just disappeared from the… he is my friend, by the way, good friend, we spend many occasions together, etc… he just escaped.

Warnow-Blewett:

From Leningrad? He went back to Leningrad?

Vorobyov:

No.

Warnow-Blewett:

He was going to go back.

Vorobyov:

In the Chicago airport he disappeared. Later on, we know this story now… he came to the police and said that he wanted to have political asylum. Okay. Now, he’s safe and sound here working in Stanford. He is a very good engineer.

Warnow-Blewett:

Is he at SLAC?

Vorobyov:

SLAC, yes. He’s a very good engineer and a good expert in accelerators, combination of physicist and electronician, a very valuable guy. This was not his first trip, he participated in all our previous experiments. I mentioned he is my friend. And now he just disappeared. Okay. If I knew what happened, I don’t care. But we were sure that he was killed in the Chicago airport. Just disappeared. Went to a toilet, I don’t know, and disappeared. Why he is not there? Everything is there. And they call me back. I said him good-bye in the morning at 5:00 o’clock and then the people who help him to the airport, called me back and said, “Kulikov has disappeared.” And then it was a terrible story trying to find him, his traces. Leon Lederman later on was joking again. “Next time when somebody decides to give me a present, please not at Christmas!” [LAUGHTER] The Fermilab people were very panicked. I told Leon, “If you’re right, I don’t care. I’m not so stupid to force him back and change his mind, but I should be 100% sure that he is safe, etc. Understand if somebody is your friend and something happens in our country. What do you do?” So Leon and the office administration were sitting several days, and they phoned every day to the Secretary of the State Department, asking if he was imprisoned. Finally they convinced us that he was alive. I insisted that I should have at least a telephone call from him and then I would believe it. By the way, there were terrible stories about American police in our newspapers about provocations, etc. Who knows… I don’t know… or if they believe them or not.

Warnow-Blewett:

Sure.

Vorobyov:

So I say, “No, I should have from him a call,” and in five days we managed to have that. But these five days were terrible. Still this helps us to (???) problem(?). So this is why I said that I was sleeping… just after the New Year, I was not very well concentrated…

Warnow-Blewett:

So the workshop happened five days afterwards.

Vorobyov:

Yes. That’s the story repeated exactly. So we sit together and we understood that we can do this much better than the other people who did this before. Now it was easy, of course, we knew people. I would say, “Aha, Peter, are you going to participate?” “Yes.” Somebody say no, they are already engaged in some other project. Well anyhow, it would be a very easy collaboration.

Warnow-Blewett:

Are you running right now? Yes. Denisov is there.

Vorobyov:

Yes. And Joe runs the experiment. I was there during one month… this last spring. When I left we already were sure the experiment was okay. So we already demonstrated that it was.

Warnow-Blewett:

Very good. And what have you done? The results have confirmed the theory?

Vorobyov:

No. We decided. And it was forbidden. What was clearly demonstrated [was] the signal. We separated perfectly well the signal from the background. We demonstrated, I was reporting. Now, I’m spokesman so I was reporting on this meeting at Fermilab, and demonstrated the signal was convincing, very convincing. We would collect again 50,000 events. But the answer it was forbidden to any member of the collaboration to go further and to produce the answer.

Warnow-Blewett:

No one can do it.

Vorobyov:

No one can do it because the symmetry one could measure, of course, the symmetry. But is just forbidden. It’s very serious, because the rumor would spread.

Warnow-Blewett:

When will you make the announcement?

Vorobyov:

First we should finish. In a month we will finish. So, we did that experiment, then we did another one again on magnetic moment measurements. Now we turn to the third one and then the fourth one. The whole program finished, the 13th of August.

Warnow-Blewett:

That’s the end of your eight months.

Vorobyov:

And then we start to analyze more seriously. I don’t know, maybe by the end of this year.

Warnow-Blewett:

I’ll be watching for that. Let me ask you, besides the data tapes, you had raw data, and then some summary data. I’m thinking about records you produced. You also produced log books, did you?

Vorobyov:

Oh, yes, there are a lot of log books.

Warnow-Blewett:

Piles. And where are they?

Vorobyov:

At Fermilab.

Warnow-Blewett:

And will they stay at Fermilab?

Vorobyov:

I think so. Nobody ever considers them historical and they may be thrown away easily after the first publication.

Warnow-Blewett:

I’ll find out about that, I don’t know. How did you decide who should report the findings of 715 at meetings? Did you give the reports at conferences on your results?

Vorobyov:

Who?

Warnow-Blewett:

First off, what meetings did you decide? Was it important to give the results at meetings, or was it more important to focus on the publication?

Vorobyov:

Oh yes, of course we reported this at the conferences, but depends on the time of the conference. But normally, and this was very normal, all the members should be involved in such a state that they would be reported. If you don't have a workshop then you agree on another form.

Warnow-Blewett:

To determine that everyone’s agreed.

Vorobyov:

But it’s simple. We have always several obvious candidates.

Warnow-Blewett:

So, when you say you have several members who could give the report. Are they essentially senior people?

Vorobyov:

Yes, essentially.

Warnow-Blewett:

How did you write the papers, the same way, does one person draft the paper and then send it around. How did it work in this group?

Vorobyov:

Of course, somebody should take initiative. If it’s a small paper, for example the first paper, I think, I have written the first chapter. Next time we subdivided the thesis. One is responsible for one thing… for example describing the set-up (???) and the results.

Warnow-Blewett:

What was…, oh, the set-up! So, when you say you drafted the first paper, you mean the first Physical Review paper?

Vorobyov:

The first paper was Phys. Rev. Letters.

Warnow-Blewett:

And then that went all around the group.

Vorobyov:

Then we distributed that and some people made comments.

Warnow-Blewett:

You had no problem in this experiment in having agreement, did you, on the analysis?

Vorobyov:

I don’t remember any serious problem. I remember there was some when we were in Gatchina in a workshop and there was missing an alibi for that… so this sigma minus magnetic (???) that measured very precise. By the way, it was a very difficult experiment, not done before; this was the first time. But the reason why that the experiment was a byproduct (???) Sigma minus magnetic moment. Then the result was not so convincing and so we debated to publish or not to publish. And so it was really an open question discussion in Gatchina, that we find a way to improve the analysis. We did that and then we (???). Then everybody (???).

Warnow-Blewett:

That takes a long time sometimes doesn’t it?

Vorobyov:

Yea. But I don’t to be high in such cases (???) everybody would be persuaded.

Warnow-Blewett:

Now looking back on the whole experiment, what do you think was the most important or innovative physics to come out of it?

Vorobyov:

The most important in that experiment was the answer for the Cabibbo, the support for the Cabibbo theory. Before it was considered like a big mystery. And then everybody said, “Now we have everything okay with the weak interaction theory.” On the other hand, I mentioned some other byproducts. They are very interesting also, but not so fundamental and maybe not so appreciated by others in the community. To me it was also the full demonstration of the transition radiation. Now transition radiation is everywhere! But this one the first… large scale — nobody from there. We demonstrated practically with one meter by one by 0.6 meter(???) — an extremely good device. It was working very reliably. So, of course, this was a good impact for the development of that technique we demonstrated just in that energy region, maybe for some high energy work or future generation experiment transition radiation already would be equipped(?), but this is (???). So why not?

Warnow-Blewett:

Excellent. You may have answered this already. Did the original goals of the experiment change? In a sense they did, because you had other byproducts that you hadn’t expected.

Vorobyov:

The goal was not changed, of course. The goal was clear and it was straightforwardly solved — this problem. But the experiment was much more strong, we had a much better experiment than they needed for that. So, we have other things, yes.

Warnow-Blewett:

What about engineering goals, exposure of radiation detector?

Vorobyov:

I think this is the most important. I remember that after the experiment Leon Lederman sent to the President of the Academy of the Science some telex congratulating the Academy of Science with such an experiment (???) the transition radiation was really beautiful.

Warnow-Blewett:

How do you measure the success of the experiment against your original expectations?

Vorobyov:

Of course, I think it was a complete success, I would say. In spite of this one week when [the defection] took place which of course spoiled our spirit; especially since the time was not now, this was outstanding event. So it was not trivial. We were not sure again on the results back in the USSR. At that time such an event would mean a lot of things for me personally when I came back — of how I was responsible for the experiment, for human relations; they should investigate to which extend I was responsible for that, how to punish me — these were normal things.

Warnow-Blewett:

You came back to that. You came back here to face that.

Vorobyov:

Yes, I came, of course, and I faced it. But I was surprised that people were very dedicated. Nobody tried to punish me, so I found the situation already was changing. It was Andropov time. I stopped feeling — started breathing a little bit better. Not now, but then it was different… and also very important is Alexandrov. It’s not by accident that Leon Lederman addressed Alexandrov because of complication and then tried to help. But Alexandrov was (???) his really… personality. I was afraid not for me; I was afraid that our future collaborations might be destroyed. Alexandrov said, “Now tell me frankly, the experiment was a success?” I said, “Yes, 100 percent, sure.” “Then… be quiet.”

Warnow-Blewett:

So then he supported you.

Vorobyov:

Yes.

Warnow-Blewett:

Tell me, you’ve talked a lot about Fermilab, but would you say there was a characteristic style of Fermilab? You’ve been at CERN, you’ve been at Fermilab. How would you describe — we’ve been talking about the Lederman directorship, of course, but — other things at the lab?

Vorobyov:

No, we became friends also with John Peoples, who is new director of Fermilab. We made a workshop here recently and John Peoples came as a guest and spent one week here. We discussed future collaboration, large scale collaborations with Fermilab. We have already one more experiment called E781, where everybody separate(?) strongly(?), but already discussed in a long range collaboration, with home institutions collaborating on a wider scale. Okay, but you’re asking about Fermilab. After CERN, I should say this is a big difference of course. Fermilab is a home laboratory. CERN is a — I don’t really know what to compare it with — CERN looks like a railway station. Everybody is coming there for a while. There’s no host there. There’s a very big difference. I like more to be at Fermilab than to be at CERN. Of course, CERN is the center, more animated, more people come. More lively, more lectures, more in this sense. And, also Switzerland.

Warnow-Blewett:

And Geneva?

Vorobyov:

…skiing. The life of course, is maybe more interesting there. But I like more Fermilab, because I feel better there… I feel more comfortable in the experimental hall(?) discussing problems with people, no formalities… no things… understanding… you know where to go, whom to ask about all, etc. and really we are friends not only with our own (???) people but with (???), (???), like Rubinstein like other people. And we understand each [other]. Sometimes we are even fighting. For example I was quite recently not satisfied by the quality of the department, where Rubinstein gave(?) on people there…(???) not comfortable there… not quiet place. They said Oh. “You should change that, we are going to spend here…”

Warnow-Blewett:

Eight months.

Vorobyov:

More than eight months, one year. And people would be completely absorbed, they should think about anything else. They should be more (???). This is not for the people, this is for the experiment. I had a (???) to move these people to a little more expensive place, but where they are now satisfied and comfortable. It happens sometimes. But we are frankly discussing everything… and I don’t know, really… I like this laboratory.

Warnow-Blewett:

What about the interactions with the Fermilab staff physicists and technicians?

Vorobyov:

Technicians are very helpful and they always eager to help you.

Warnow-Blewett:

So that’s fine too?

Vorobyov:

That’s fine yes. I don’t know the other, by the way, national laboratories. This is the only laboratory I’m now aware of and I like.

Warnow-Blewett:

You didn’t have students here, so we don’t worry about that. Let’s talk for a minute again, about the style of the collaboration. What was the style like? Some collaborations are rigid. Some are informal. How would you… was it democratic?

Vorobyov:

The style is just the style I like. You know, I have a possibility to compare. We are in some other collaborations at CERN now at present and we are occupied. We did a lot of effort and (???) in L3 maybe you know this, L3. This is the lab experiment, electron positron collider, L3 one on the major(?) detectors there and we participate in that. This of course, absolutely different. More than 400 people in this collaboration. And of course absolutely no democracy. Sam Ting is the…

Warnow-Blewett:

He’s the spokesperson for it.

Vorobyov:

He’s the spokesperson and, of course, he’s kind of a dictator there, and I think this is the only way with such an experiment. You need such a dictator, when you have 400 or more than 400 people and more than 30 countries involved. He’s very good for that. So we collaborate on that. So we tried to understand how to work in such conditions, because this is where our physics finally has come…

Warnow-Blewett:

…the direction it’s going.

Vorobyov:

This is the direction, I never like this direction, but I know it is inevitable, so it’s not for me but for younger people. They should know how to meet with these new conditions. But my personal feeling is that for me I don’t know how to work with that. And also we had some responsibility for a piece of the detector, and we did this. But to be permanently responsible for the whole thing, or at least to have equal responsibility with the other labs, is not possible. And then I find it okay. (???) country what does mean dictatorship, as one dictator eliminate the first cycle… etc.

Warnow-Blewett:

Layers.

Vorobyov:

Layers. Some people are there, they never communicate with the top layer, or this layer or this layer. Oh, that’s terrible from that psychological point of view that’s… but you should accept it, that’s inevitable.

Warnow-Blewett:

But do you compare it with 715?

Vorobyov:

If compared with these experiments, 715 and 761, it’s very different. This is like… I spent all my life in such experiments.

Warnow-Blewett:

With a lot of discussion.

Vorobyov:

After that, I shouldn’t be involved completely, (???) that’s why we look (???)… as far as possible, but it might be exhausted some (???), I don’t know. The future of high energy physics is not very promising.

Warnow-Blewett:

The structure for making decisions, in 715 was that it was very open and you didn’t need to have… Is that true?

Vorobyov:

Yes, of course, it’s very open. Most people, there is a natural way… for which people understand very soon, very well very soon. So for example electronics specialist and electronicians they will never discuss the physical details, so they believe some other people, etc. In fact, for every (???), but on the other hand, when we discus people's experiment they are the most important, so other people rely on that. After some while people understand who is who, and if I could rely on that, okay, I say: If you say so I believe it.

Warnow-Blewett:

Meanwhile, did the young people feel that they could talk also?

Vorobyov:

Young people, yes. We like young people and they became very active. They may talk right on, but the problem is not that some… the problem is that they are afraid… of authority. So this is the main problem of the young people.

Warnow-Blewett:

Yes, but if you have a democratic group, then they’re less afraid?

Vorobyov:

Still they’re afraid… to seem to be stupid… to put stupid questions.

Warnow-Blewett:

So, they hesitate.

Vorobyov:

But then in half year probably… they became equal, on equal terms and they started talking.

Warnow-Blewett:

And you start to know which ones of them you can trust too? Because they’re good. Another thing that’s interesting is to figure out… I think you’ve already answered this… how individual contributions get accepted and did you ever feel that any of your contributions were not accepted? You told me the one dramatic story.

Vorobyov:

I think that in that collaboration it’s very dangerous to stress any individual contributions. Of course, there are individual contributions. But I would rather… I told you the story just showing the atmosphere. I don’t think we will try to remember who suggested first this experiment, or who did so, who did so. This is very bad feeling. Still people should be more or less even with those suggested something. Otherwise it spoils the atmosphere. This is a collective job. The word we instead of I should be. That is better.

Warnow-Blewett:

How about for the individual? The individual wants to think he’s making contributions too?

Vorobyov:

Yes, of course, and especially when somebody should defend some thesis, but then the collaboration then decides, they subdivide into pieces, you shall do this and you that.

Warnow-Blewett:

And do they… That’s interesting, so you say that when the group gets together they help the person who’s doing the thesis pick a problem?

Vorobyov:

Yes. But you know we never did even this problem before. Most of the people… Here’s some other problem, we don’t have people to defend. Most of them already defended.

Warnow-Blewett:

So you didn’t have that many young students. Looking on a broader questions now. There are different ways in which experiments can be less than successful. Oops! That’s the phone. We were just saying there’s different ways in which experiments can be less than successful. I wonder if you have had experiences with some. I mean sometimes the physics isn’t there. Sometimes the detector doesn’t work well. Sometimes the group doesn’t work well. Can you describe any experience you may have had in the collaboration that was less that successful?

Vorobyov:

Maybe you will find that I am boasting, but, really, in my life there was never a failure. So all our collaborative experiments were successful. It’s not a surprise, because the responsibility is high, so you should think beforehand a lot. And also you control everything a lot better and is much stronger than on a home experiment. Of course, that doesn’t mean that we didn’t have problems. For example, I remember in… we were preparing some experiment, I remember a group meeting in Paris and Rutherford physicists came to this group meeting and suddenly declared that they go out of our experiment. They explained there’s no money, the government, etc. But the explanation was of course different. I remember that we competed with Fermilab, and these people… they estimated our chances, and they estimated that our chances are low. So they decided to change their mind, to get out of the experiment. They entered the other one experiment which, by the way, was a complete failure.

Warnow-Blewett:

So Rutherford Lab changed and went over to a Fermilab?

Vorobyov:

No, to another CERN experiment. First they said they didn’t have money, but finally they entered the bad experiment. They found money, and they entered that experiment. For us it was really a huge problem because we were already in the final stage of preparations and it was nearly a disaster. But fortunately somebody recommended us to French groups from Lyon, and they joined us. And really they were very good groups and we became friends up to now… these people and we collaborate with them (???) collaborate. It was a very good replacement. There was moment when we were very close to failure. There was a possibility that we had to stop the experiment, because it was an essential part of the experiment.

Warnow-Blewett:

They were building part of the detector?

Vorobyov:

Yes.

Warnow-Blewett:

Is there two groups in Lyon?

Vorobyov:

One group, Rutherford, but it was replaced with two groups from Lyon. And so sometimes it happens, such complications, as you see…

Warnow-Blewett:

Still that worked out.

Vorobyov:

Also even in the running experiment, when I was… I mentioned that we have in mind four experiments.

Warnow-Blewett:

The four experiments you’re talking about now, are the ones at Fermilab?

Vorobyov:

Yes. We did already two, now we are running the fourth, I don’t know the quality of the data, because I left already. But we are preparing… it was not scheduled, but there will be like a byproduct, (???). Very interesting, challenging experiment. Very promising, everybody’s expecting the results. This was designed by our people, everything was fabricated here, but as soon as it was p(???) and I overestimated the quality maybe of these guys and they made many mistakes… Yes, trivial mistakes, like sending this very delicate thing by Aeroflot and when they opened the package, it was half destroyed. Such silly things. So we are losing, losing, losing, there and there and there… and so I am not to know… I’m not sure that it will be complete success. Already they demonstrated the charming(?) the experiment is beautiful. But I’m not sure that they will have the results now. I’ll be happy if they bring out the results now (???), but according to expectations the results should be already on the table after the first two months running that’s very (???). This was my only first failure.

Warnow-Blewett:

And for silly reasons too. One other thing.

Vorobyov:

….or half failure… I don’t know.

Warnow-Blewett:

What kind of personal characteristics do you think are important for being a success in high energy physics?

Vorobyov:

My experience is that you need a combination of people. Because if you require all the characteristics from the one… from the single person, these requirements would be never fulfilled. But when you combine several people, one is strong in one thing and the other in another way, then it helps. Then people shouldn’t be so universal. They should be strong in one particular… professional in one… They should understand other things, but they should be very professional in one thing. So this is our principle. If they are not professional in anything, then they are not valuable(reliable?). The strongest requirement is that they should be reliable and professional if in one area.

Warnow-Blewett:

What other kinds of characteristics?

Vorobyov:

And also they shouldn’t make quarrels. In one of our experiment I invited people whom I did not know well… just personal point… and then I discovered they’re so ambitious that they start quarrel some unimportant things and that’s also inevitable(?). Since then I never invite people I don’t know.

Warnow-Blewett:

I have a couple of questions now, about records. When we had the spokesperson for 715 who was Cooper, did he play a special role in terms of keeping everyone informed?

Vorobyov:

Yes.

Warnow-Blewett:

Did you all get mailings?

Vorobyov:

Yes. That was his responsibility.

Warnow-Blewett:

Do you believe that he has kept a full set of those records?

Vorobyov:

I’m not sure. There might be some he has. Since then Peter moved from Yale to Fermilab. He is on permanent staff now. He’s the head or vice head of the Fermilab computer center.

Warnow-Blewett:

Did you keep these sets of material that came to you?

Vorobyov:

Yes, of course we have a file. I’m sure that they should be somewhere. But of course the problem is space… so somebody may know; something may be destroyed but some is there.

Warnow-Blewett:

Indeed, do you know if there is someone at this institute who is responsible for archives? Is there an archivist at this Institute?

Vorobyov:

There is one a enthusiast about. I never was an enthusiast so I don’t know. I’ve never seen what is there. Do we have something or not.

Warnow-Blewett:

There may be a time when you could let me know who is in charge of records here. It would be interesting to find out.

Vorobyov:

Records on that experiment?

Warnow-Blewett:

Records in general. For example, who keeps the records for the archives of the director here. Are they kept? Maybe we’ll talk about that off the tape. Is there anything else you’d like to talk about, or have we covered everything?

Vorobyov:

Maybe one point important point besides this purely scientific activity. For example, I was involved in some political activity, or social activity, I don’t know what… I mentioned already we were very serious about it. And I should tell you that Joe Lach, Fermilab. He is very serious about it. He is a member of some societies for peace, for disarmament, etc. He is a (???) in lectures. He’s inviting me as a Russian so people can touch me and be convinced that I have two hands, etc.

Warnow-Blewett:

And no horns!

Vorobyov:

Yes. So he brings me to churches, to physicians’ societies.

Warnow-Blewett:

So he brings you to lecture before physicians.

Vorobyov:

Physicians and in churches even. So, I understood that the most active people in this field are church, physicians and physicists.

Warnow-Blewett:

The church and medical doctors and physicists.

Vorobyov:

And they collaborate, which I also discovered, in the United States. So they collaborate and they help each other in their activities. I was surprised how strong this activity is at Fermilab. For example, during this my visit, there was a special lecture at Fermilab with many, many people… 400 people in the auditorium, and one professor from Chicago University reported on crisis in the Soviet Union, and I was suggested…

Warnow-Blewett:

What year was this now?

Vorobyov:

This year.

Warnow-Blewett:

Oh, this year! When you were there for your new experiment.

Vorobyov:

And Joe asked me to officially open it. We made such a show. For example (???). The funny thing was that I proved to be much more revolutionary than he. So it was fun. This is just an example that people are interested not only in physics.

Warnow-Blewett:

Social concerns.

Vorobyov:

Yes, social concerns. And after lecture before lecture there were discussions, and I always accept these invitations to share information. (???) For example, I declared in there… by the way, this was on tape, video tape, this video tape is at Fermilab… our people have not seen(?) it not here. When I declared that I support the independence of the republics, I would insist on independence, and even if a republic does want to be dependent, I would try to convince them to be independent, because this is the only way for me how to save the situation in Russia. Everybody should be independent in Russia, including Russia.

Warnow-Blewett:

Including Russia.

Vorobyov:

Yes, including Russia. So some several months ago this sounded crazy, but now really a lot of parliaments declare independence. Russian parliament (???) in the lecture there had emigrated, and some of them came up to me to say hello and thank you (???) we are happy that in Soviet Union at least… (?). When you stand there, I am not so (???), as you think, but still there’s some … there’s already… for us it’s a big hope. I’m happy that we can do that even that part now.(???) What happens now, the situation has improved greatly. I’m sure that we contributed.

Warnow-Blewett:

The relations between the USA and the USSR. Yes.

Vorobyov:

It’s not because Gorbachev is such a guy. Gorbachev is being(?) forced to do that. The improvement is not because of Gorbachev, Gorbachev is such because of the country.

Warnow-Blewett:

…because the country… there are people in the country that say we must have it.

Vorobyov:

Because we are changing. He never did anything by his will. He has always been forced to do something. But at least he is involved in (???) very good (???) is that he is flexible.

Warnow-Blewett:

And he’s listening.

Vorobyov:

He is listening.

Warnow-Blewett:

Thank you very much…